lnu.sePublications
Change search
Refine search result
12 51 - 95 of 95
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 51.
    Bhatnagar, Amit
    et al.
    University of Porto, Portugal.
    Sillanpää, Mika
    Lappeenranta University of Technology, Finland.
    A review of emerging adsorbents for nitrate removal from water2011In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 168, no 2, p. 493-504Article in journal (Refereed)
    Abstract [en]

    Nitrate, due to its high water solubility, is possibly the most widespread groundwater contaminant in the world, imposing a serious threat to human health and contributing to eutrophication. Among several treatment technologies applied for nitrate removal, adsorption has been explored widely and offers satisfactory results especially with mineral-based and/or surface modified adsorbents. In this review, an extensive list of various sorbents from the literature has been compiled and their adsorption capacities for nitrate removal as available in the literature are presented along with highlighting and discussing the key advancement on the preparation of novel adsorbents tested for nitrate removal.

  • 52.
    Bhatnagar, Amit
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Sillanpää, Mika
    Lappeenranta University of Technology, Finland.
    Application of Nanoadsorbents in Water Treatment2014In: Nanomaterials for Environmental Protection / [ed] Boris I. Kharisov, Oxana V. Kharissova, & H. V. Rasika Dias, John Wiley & Sons, 2014, 1, p. 237-247Chapter in book (Other academic)
    Abstract [en]

    Water treatment using the adsorption process has been found to be one of the most widely used methods, and several wastewater treatment plants around the world are operating on the principle of adsorption. Numerous adsorbents, for example, activated carbon, silica gel, zeolites, low-cost adsorbents from agro-industrial wastes, biosorbents, mineral-based adsorbents, and layered-double hydroxides, have been examined for their potential in the removal (adsorption) of diverse types of aquatic pollutants. In recent years, nanotechnology has emerged as one of the attractive technologies for water treatment, and various nanoadsorbents have been explored for water treatment applications. This chapter briefly summarizes the progress, advances, and applications of nanoadsorbents for water remediation. A compilation of various nanoadsorbents as reported in the literature has been presented, and their main findings related to water treatment applications are discussed. The chapter concludes with a discussion on the future perspectives in this field.

  • 53.
    Bhatnagar, Amit
    et al.
    aboratory of Applied Environmental Chemistry, Department of Environmental Sciences, University of Kuopio, FI-50100 Mikkeli, Finland.
    Sillanpää, Mika
    aboratory of Applied Environmental Chemistry, Department of Environmental Sciences, University of Kuopio, FI-50100 Mikkeli, Finland.
    Applications of chitin- and chitosan-derivatives for the detoxification of water and wastewater - A short Review2009In: Advances in Colloid and Interface Science, ISSN 0001-8686, E-ISSN 1873-3727, Vol. 152, p. 26-38Article in journal (Refereed)
    Abstract [en]

    Chitin and chitosan-derivatives have gained wide attention as effective biosorbents due to low cost and high contents of amino and hydroxyl functional groups which show significant adsorption potential for the removal of various aquatic pollutants. In this review, an extensive list of chitin- and chitosan-derivatives from vast literature has been compiled and their adsorption capacities for various aquatic pollutants as available in the literature are presented. This paper will give an overview of the principal results obtained during the treatment of water and wastewater utilizing chitin and chitosan-derivatives for the removal of: (a) metal cations and metal anions; (b) radionuclides; (c) different classes of dyes; (d) phenol and substituted phenols; (e) different anions and other miscellaneous pollutants. The review provides a summary of recent information obtained using batch studies and deals with the various adsorption mechanisms involved. It is evident from the literature survey that chitin- and chitosan-derivatives have shown good potential for the removal of various aquatic pollutants. However, still there is a need to find out the practical utility of such developed adsorbents on commercial scale.

  • 54.
    Bhatnagar, Amit
    et al.
    Tech Univ Hamburg, Inst Environm Technol & Energy Econ, D-21073 Hamburg, Germany & Univ Kuopio, LAEC, Dept Environm Sci, FI-50100 Mikkeli, Finland .
    Sillanpää, Mika
    Utilization of agro-industrial and municipal waste materials as potential adsorbents for water treatment- A Review2010In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 157, no 2-3, p. 277-296Article in journal (Refereed)
    Abstract [en]

    Adsorption process has been proven one of the best water treatment technologies around the world and activated carbon is undoubtedly considered as universal adsorbent for the removal of diverse types of pollutants from water. However, widespread use of commercial activated carbon is sometimes restricted due to its higher costs. Attempts have been made to develop inexpensive adsorbents utilizing numerous agro-industrial and municipal waste materials. Use of waste materials as low-cost adsorbents is attractive due to their contribution in the reduction of costs for waste disposal, therefore contributing to environmental protection. In this review, an extensive list of low-cost adsorbents (prepared by utilizing different types of waste materials) from vast literature has been compiled and their adsorption capacities for various aquatic pollutants as available in the literature are presented. It is evident from the literature survey that various low-cost adsorbents have shown good potential for the removal of various aquatic pollutants. However, there are few issues and drawbacks on the use of low-cost adsorbents in water treatment that have been discussed in this paper. Additionally, more research is needed to find the practical utility of low-cost adsorbents on commercial scale.

  • 55.
    Bhatnagar, Amit
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Vilar, V.J.P.
    Botelho, C.M.
    Boaventura, R.A.
    Optimization of nickel biosorption on surface modified algae, COBEQ2012Conference paper (Refereed)
  • 56.
    Bhatnagar, Amit
    et al.
    LSRE — Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Química, Faculdade de Engenharia da Universidade do Porto (FEUP), Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
    Vilar, V.J.P.
    LSRE — Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Química, Faculdade de Engenharia da Universidade do Porto (FEUP), Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
    Botelho, C.M.S.
    LSRE — Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Química, Faculdade de Engenharia da Universidade do Porto (FEUP), Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
    Boaventura, R.A.R.
    LSRE — Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Química, Faculdade de Engenharia da Universidade do Porto (FEUP), Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
    Coconut based biosorbents for water treatment: A review of the recent literature2010In: Advances in Colloid and Interface Science, ISSN 0001-8686, E-ISSN 1873-3727, Vol. 160, no 1-2, p. 1-15Article in journal (Refereed)
    Abstract [en]

    Biosorption is an emerging technique for water treatment utilizing abundantly available biomaterials (especially agricultural wastes). Among several agricultural wastes studied as biosorbents for water treatment, coconut has been of great importance as various parts of this tree (e.g. coir, shell, etc.) have been extensively studied as biosorbents for the removal of diverse type of pollutants from water. Coconut-based agricultural wastes have gained wide attention as effective biosorbents due to low-cost and significant adsorption potential for the removal of various aquatic pollutants. In this review, an extensive list of coconut-based biosorbents from vast literature has been compiled and their adsorption capacities for various aquatic pollutants as available in the literature are presented. Available abundantly, high biosorption capacity, cost-effectiveness and renewability are the important factors making these materials as economical alternatives for water treatment and waste remediation. This paper presents a state of the art review of coconut-based biosorbents used for water pollution control, highlighting and discussing key advancement on the preparation of novel adsorbents utilizing coconut wastes, its major challenges together with the future prospective. It is evident from the literature survey that coconut-based biosorbents have shown good potential for the removal of various aquatic pollutants. However, still there is a need to find out the practical utility of such developed adsorbents on commercial scale, leading to the superior improvement of pollution control and environmental preservation.

  • 57. Bhatnagar, Amit
    et al.
    Vilar, V.J.P.
    Botelho, C.M.S.
    Boaventura, R.A.R.
    Review on the use of red mud as adsorbent for the removal of toxicpollutants from water and wastewater2011In: Environmental technology, ISSN 0959-3330, E-ISSN 1479-487X, Vol. 32, no 3, p. 231-249Article in journal (Refereed)
    Abstract [en]

    Red mud (an aluminium industry waste) has received wide attention as an effective adsorbent for water pollution control, showing significant adsorption potential for the removal of various aquatic pollutants. In this review, an extensive list of red‐mud‐based adsorbents has been compiled and their adsorption capacities (maximum uptake value of the adsorbent for the pollutant or adsorbate being removed) for various aquatic pollutants (metal ions, dyes, phenolic compounds, inorganic anions) are presented. The review provides a summary of recent information obtained using batch studies and deals with the adsorption mechanisms involved. It is evident from the literature survey that red mud has been found to be efficient for the removal of various aquatic pollutants, especially arsenic and phosphate. However, there is still a need to investigate the practical utility of these adsorbents on a commercial scale.

  • 58.
    Bhatnagar, Amit
    et al.
    Univ Porto, Fac Engn, LSRE, Lab Separat & React Engn,Associate Lab LSRE LCM, P-4200465 Oporto, Portugal .
    Vilar, V.J.P.
    Ferreira, C
    Botelho, C.M.S.
    Boaventura, R.A.R.
    Optimization of nickel biosorption by chemically modified brown macroalgae (Pelvetia canaliculata)2012In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 193, p. 256-266Article in journal (Refereed)
    Abstract [en]

    In the present work, various forms of algae Pelvetia canaliculata were prepared by different chemical modifications, in order to get the best form of algae for the maximum uptake of nickel. Potentiometric titration revealed that the carboxyl groups were more abundant (3.9 mmol/g) as compared to hydroxyl groups (2.0 mmol/g) on the biosorbent surface. Fourier transform infrared (FUR) analysis of algae was done to identify the role of different functional groups present on algae surface during nickel biosorption. The protonated algae showed least sorption of nickel suggesting that after acid treatment, some of the binding sites were destroyed. Among the various forms of prepared algae. Na-algae prepared directly from raw algae (without protonation) showed highest uptake of nickel. The release of sodium ions during the uptake of nickel ions has shown that the current biosorption mechanism involves ion-exchange being a stoichiometrical ratio of 2:1 between sodium and nickel ions.

  • 59.
    Bhatnagar, Amit
    et al.
    Univ Porto, LSRE, Associate Lab LSRE LCM, Fac Engn, P-4200465 Oporto, Portugal.
    Vilar, V.J.P
    Santos, JC
    Botelho, C.M.S
    Boaventura, R.A.R
    Valorisation of marine Pelvetia canaliculata Ochrophyta for separation and recovery of nickel from water: equilibrium and kinetics modeling on Na-loaded algae2012In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 200, p. 365-372Article in journal (Refereed)
    Abstract [en]

    In the present study, biosorption of Ni2+ by Na-loaded (raw algae treated with NaCl), algae Pelvetia canaliculata Ochrophyta, was studied in a batch system. Kinetics and equilibrium experiments were conducted at different pH values (2.0, 3.0 and 4.0). The metal uptake capacity decreased by decreasing the solution pH, suggesting that competition exists between hydrogen ions, present in high concentrations at low pH values, and metal ions. An ion-exchange model, considering two different binding sites, sulfonic and carboxylic groups, was developed to describe equilibrium data. A mass transfer model, considering intraparticle resistance was also developed to describe kinetics in a batch system. The release of sodium ions during the uptake of nickel ions revealed that the biosorption mechanism involved ion-exchange between sodium and nickel ions with a stoichiometrical ratio of 2:1. Nickel showed higher affinity to the sulfonic groups than for carboxylic ones of algae biomass. Kinetic results show that hydrogen ions diffuse faster as compared to nickel and sodium ions. The maximum uptake capacity of Na-loaded algae, P. canaliculata, for Ni2+ was found to be ca. 100 mg/g at pH 4.0.

  • 60. Daneshvar, E.
    et al.
    Kousha, M.
    Koutahzadeh, N.
    Sohrabi, M.S.
    Bhatnagar, Amit
    LSRE—Laboratory of Separation and Reaction Engineering, Departamento de Engenharia Química, Faculdade de Engenharia da Universidade do Porto (FEUP), Porto, Portugal.
    Biosorption and Bioaccumulation Studies of Acid Orange 7 Dye by Ceratophylum demersum2013In: Environmental Progress & Sustainable Energy, ISSN 1944-7442, E-ISSN 1944-7450, Vol. 32, no 2, p. 285-293Article in journal (Refereed)
    Abstract [en]

    Biosorption and bioaccumulation studies of acid orange 7 (AO7) dye by an aquatic plant, C. demersum, were investigated in the present work. The effects of different parameters such as, initial solution pH (2–11), initial dye concentration (30–90 mg/L), contact time (5–150 min), biomass dosage (1.8–23.4 g/L for living and 0.2–2.6 g/L for nonliving or dried plant) and salt concentration (0.5–20 g/L) on the decolorization of AO7 dye were investigated by batch method. The efficiency of both leaf and stem of the living plant was also assessed for the dye removal. Living plant of C. demersum exhibited higher decolorization potential as compared with the dried plant which might be attributed to the active metabolism of the former. The sorption kinetic data were successfully described with pseudo-second order model for living and dried plant. Thermodynamic studies revealed that the sorption process is endothermic in nature at studied temperature range of 283–313 K. These findings revealed that aquatic plant, C. demersum, can be a suitable alternative for decolorization of AO7 dye from aqueous solution.

  • 61.
    Daneshvar, Ehsan
    et al.
    Isfahan Univ Technol, Dept Fisheries, Fac Nat Resources, Esfahan, Iran.
    Kousha, Masoud
    Isfahan Univ Technol, Dept Fisheries, Fac Nat Resources, Esfahan, Iran.
    Sohrabi, Mohammad Salar
    Isfahan Univ Technol, Dept Fisheries, Fac Nat Resources, Esfahan, Iran.
    Panahbehagh, Bardia
    Kharazmi Univ, Fac Math & Comp Sci, Tehran, Iran.
    Bhatnagar, Amit
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Younesi, Habibollah
    Tarbiat Modares Univ, Fac Nat Resources, Dept Environm Sci, Noor, Iran.
    Sternberg, Steven P. K.
    Univ Minnesota, Dept Chem Engn, Duluth, MN 55812 USA.
    Application of response surface methodology for the biosorption of Acid Blue 25 dye using raw and HCl-treated macroalgae2015In: Desalination and Water Treatment, ISSN 1944-3994, E-ISSN 1944-3986, Vol. 53, no 6, p. 1710-1723Article in journal (Refereed)
    Abstract [en]

    The present study was conducted to optimize the various experimental conditions, such as biomass loading, initial C.I. Acid Blue 25 (AB25) dye concentration, and initial solution pH for biosorption of dye on raw and HCl-treated brown alga, Padina australis and red alga, Jania adhaerens. Biosorption process was optimized in a batch system under Box-Behnken design. Second-order polynomial equation was successfully used to describe the effects of studied variables on response. The quadratic models exhibited higher R-2 values, significant p-values, and insignificant lack-of-fit p-values showed high adequacy for predicting the response. Chemically modified red alga exhibited better AB25 dye biosorption capacity as compared to modified brown alga. Maximum dye removal efficiencies of 77.34, 71.28, 50.56, and 85.19% for P. australis, HCl-treated P. australis, J. adhaerens, and HCl-treated J. adhaerens, respectively, were obtained at optimal conditions. The surface modification on tested algal biomass was found to be strongly dependent on their cell wall constituents.

  • 62.
    Fathollahzadeh, Homayoun
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Kaczala, Fabio
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Bhatnagar, Amit
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Hogland, William
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Significance of environmental dredging on metal mobility from contaminated sediments in the Oskarshamn Harbor, Sweden2015In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 119, p. 445-451Article in journal (Refereed)
    Abstract [en]

    Metals are often seen as immobile in bottom sediments as long as these environmental sinks remain undisturbed. The aim of this paper was to evaluate the potential metal mobility due to resuspension under pseudo-dredging conditions of contaminated sediments in the Oskarshamn Harbor that are likely to be dredged as part of a remediation program established in Sweden. To address this concern, mixtures of water slurries were sampled from pore, leaching, and surface water over a period of nearly 36 d, and the major ions and trace metal concentrations determined. The results of this study pointed out the potential mobility and toxicity of metals posed by temporary changes during dredging operations, and highlighted the potential release of Cu, Pb, Zn, Mn, and Ni to the environment. Among the toxic metals, regarding pre and post dredging, Cu and Pb significantly demonstrated to be in ionic form, apparently because of dissolution of Fe-Mn oxy/hydroxides and decomposition of organic matter. (C) 2014 Elsevier Ltd. All rights reserved.

  • 63.
    Fathollahzadeh, Homayoun
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Sveriges Lantbruksuniversitet, Uppsala.
    Kaczala, Fabio
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Bhatnagar, Amit
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Hogland, William
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Speciation of metals in contaminated sediments from Oskarshamn Harbor, Oskarshamn, Sweden2014In: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 21, no 4, p. 2455-2464Article in journal (Refereed)
    Abstract [en]

    Bottom sediments in coastal regions have been considered the ultimate sink for a number of contaminants, e. g., toxic metals. In this current study, speciation of metals in contaminated sediments of Oskarshamn harbor in the southeast of Sweden was performed in order to evaluate metal contents and their potential mobility and bioavailability. Sediment speciation was carried out by the sequential extraction BCR procedure for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn and the exchangeable (F1), reducible (F2), oxidizable (F3), and residual (R) fractions were determined. The results have shown that Zn and Cd were highly associated with the exchangeable fraction (F1) with 42-58 % and 43-46 %, respectively, of their total concentrations in the mobile phase. The assessment of sediment contamination on the basis of quality guidelines established by the Swedish Environmental Protection Agency (SEPA) and the Italian Ministry of Environment (Venice protocol for dredged sediments) has shown that sediments from Oskarshamn harbor are highly contaminated with toxic metals, especially Cu, Cd, Pb, Hg, As, and Zn posing potential ecological risks. Therefore, it is of crucial importance the implementation of adequate strategies to tackle contaminated sediments in coastal regions all over the world.

  • 64.
    Hokkanen, Sanna
    et al.
    Lappeenranta Univ Technol.
    Repo, Eveliina
    Lappeenranta Univ Technol.
    Bhatnagar, Amit
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Tang, Walter Zhonghong
    Florida Int Univ.
    Sillanpaa, Mika
    Lappeenranta Univ Technol.
    Adsorption of hydrogen sulphide from aqueous solutions using modified nano/micro fibrillated cellulose2014In: Environmental technology, ISSN 0959-3330, E-ISSN 1479-487X, Vol. 35, no 18, p. 2334-2346Article in journal (Refereed)
    Abstract [en]

    In the present study, microfibrillated cellulose (MFC) was modified by aminopropyltriethoxysilane (APS), hydroxy-carbonated apatite (HAP), or epoxy in order to produce novel nanostructured adsorbents for the removal of hydrogen sulphide (H2S) from the aqueous solutions. Structural properties of the modified MFC materials were examined using a scanning electron microscope, Fourier transform infrared spectroscopy and acid/base titration. These methods were used to verify the presence of nanostructures on the adsorbents surfaces as well as functionalities suitable for H2S adsorption. Adsorption of H2S by prepared adsorbents was investigated in batch mode under different experimental conditions, i.e. varying pH and H2S concentrations. H2S uptake was found to be 103.95, 13.38 and 12.73mg/g by APS/MFC, HAP/MFC and epoxy/MFC, respectively from 80mg/L H2S solution. The equilibrium data were best described by the Langmuir isotherm for HAP/MFC and APS/MFC and the Sips isotherm for epoxy/MFC.

  • 65.
    Hwang, JH
    et al.
    Department of Environmental Engineering, Yonsei University, Wonju, Gangwon-do, 220-710, South Korea.
    Choi, JA
    Department of Environmental Engineering, Yonsei University, Wonju, Gangwon-do, 220-710, South Korea.
    Abou-Shanab, R.A.I.
    Department of Environmental Engineering, Yonsei University, Wonju, Gangwon-do, 220-710, South Korea / Department of Environmental Biotechnology, Mubarak City for Scientific Research, Alexandria, Egypt.
    Bhatnagar, Amit
    Department of Environmental Engineering, Yonsei University, Wonju, Gangwon-do, 220-710, South Korea.
    Min, B.
    Song, H.
    Kumar, E.
    Department of Environmental Engineering, Yonsei University, Wonju, Gangwon-do, 220-710, South Korea.
    Choi, J.
    Lee, E.S.
    Kim, Y. J.
    Um, S.
    Lee, D.S.
    Jeon, B.H.
    Department of Environmental Engineering, Yonsei University, Wonju, Gangwon-do, 220-710, South Korea.
    Effect of pH and sulfate concentration on hydrogen production using anaerobic mixed microflora2009In: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 34, no 24, p. 9702-9710Article in journal (Refereed)
    Abstract [en]

    The effects of varying sulfate concentrations with pH on continuous fermentative hydrogen production were studied using anaerobic mixed cultures growing on a glucose substrate in a chemostat reactor. The maximum hydrogen production rate was 2.8 L/day at pH 5.5 and sulfate concentration of 3000 mg/L. Hydrogen production and residual sulfate level decreased with increasing the pH from 5.5 to 6.2. The volatile fatty acids (VFAs) and ethanol fractions in the effluent were in the order of butyric acid (HBu) > acetic acid (HAc) > ethanol > propionic acid (HPr). Fluorescence In Situ Hybridization (FISH) analysis revealed the presence of hydrogen producing bacteria (HPB) under all pH ranges while sulfate reducing bacteria (SRB) were present at pH 5.8 and 6.2. The inhibition in hydrogen production by SRB at pH 6.2 diminished entirely by lowering to pH 5.5, at which activity of SRB is substantially suppressed.

  • 66. Hwang, J.W.
    et al.
    Cha, G.C.
    Jeong, T.Y.
    Kim, D.J.
    Bhatnagar, Amit
    Department of Environmental Engineering, Yonsei University, Wonju, Gangwon-do 220-710, South Korea.
    Jung, D.W.
    Chung, H.K.
    Park, Y.T.
    Choi, J.
    Abou-Shanab, R.A.I.
    Jeon, B.H.
    Effect of COD/SO42- ratio and Fe(II) under the variable hydraulic retention time (HRT) on fermentative hydrogen production2009In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 43, p. 3525-3533Article in journal (Refereed)
    Abstract [en]

    The effect of chemical oxygen demand/sulfate (COD/SO42−) ratio on fermentative hydrogen production using enriched mixed microflora has been studied. The chemostat system maintained with a substrate (glucose) concentration of 15 g COD L−1 exhibited stable H2 production at inlet sulfate concentrations of 0–20 g L−1 during 282 days. The tested COD/SO42− ratios ranged from 150 to 0.75 (with control) at pH 5.5 with hydraulic retention time (HRT) of 24, 12 and 6 h. The hydrogen production at HRT 6 h and pH 5.5 was not influenced by decreasing the COD/SO42− ratio from 150 to 15 (with control) followed by noticeable increase at COD/SO42− ratios of 5 and 3, but it was slightly decreased when the COD/SO42− ratio further decreased to 1.5 and 0.75. These results indicate that high sulfate concentrations (up to 20,000 mg L−1) would not interfere with hydrogen production under the investigated experimental conditions. Maximum hydrogen production was 2.95, 4.60 and 9.40 L day−1 with hydrogen yields of 2.0, 1.8 and 1.6 mol H2 mol−1 glucose at HRTs of 24, 12 and 6 h, respectively. The volatile fatty acid (VFA) fraction produced during the reaction was in the order of butyrate > acetate > ethanol > propionate in all experiments. Fluorescence In Situ Hybridization (FISH) analysis indicated the presence of Clostridium spp.Clostridium butyricumClostridium perfringens andRuminococcus flavefaciens as hydrogen producing bacteria (HPB) and absence of sulfate reducing bacteria (SRB) in our study.

  • 67. Hwang, K.W.
    et al.
    Lee, J.H.
    Jeong, DY
    Lee, C.H.
    Bhatnagar, Amit
    Department of Environmental Engineering, YIEST, Yonsei University, Republic of Korea.
    Park, JM
    Kim, SH
    Observation of difference in the size distribution of carbon and major inorganic compounds of atmospheric aerosols after the long-range transport between the selected days of winter and summer2008In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 42, no 5, p. 1057-1063Article in journal (Refereed)
    Abstract [en]

    This paper presents the results from a study conducted in two urban areas in Korea to compare the size distributions of atmospheric aerosols, focusing on carbonaceous and certain major inorganic compounds, after long-range transport between selected days in winter and summer. Size segregated aerosols were sampled for 3 consecutive days each in February and July, 2004, and were analyzed to obtain the 24-h averaged concentrations of total mass, elemental carbon, organic carbon, nitrate, and sulfate. Backward trajectories from the receptor site on the sampling days were calculated to estimate the elapsed time for the air parcel to travel between Wonju and the Seoul metropolitan area. The averaged elapsed time on the sampling days was 3–12 h in the winter and 10–19 h in the summer. The enrichment of fine particles as expressed in particulate matter (PM)2/(PM10–PM2) was higher in the summer as compared to that in the winter. Size-fractionized concentration ratios of the organic to the elemental carbon at Wonju were two times as high as those at Seoul except for the particles with size <0.5 μm. This increasing trend was in proportional to the length of the elapsed time during the summer. Ultrafine particles in the summer were further enriched in carbon compounds, particularly in organic carbons and those in winter more enriched in the sulfates and nitrates. The mass fractions of organic carbon, elemental carbon, sulfate and nitrate became more significant with the decrease in the particle size.

  • 68. Jain, A.K.
    et al.
    Gupta, V.K.
    Bhatnagar, Amit
    Department of Chemistry , Indian Institute of Technology Roorkee , Roorkee, India.
    Suhas, S.
    A comparative study of adsorbents prepared from industrial wastes for removal of dyes2003In: Separation science and technology (Print), ISSN 0149-6395, E-ISSN 1520-5754, Vol. 38, no 2, p. 463-481Article in journal (Refereed)
  • 69. Jain, A.K
    et al.
    Gupta, V.K.
    Bhatnagar, Amit
    Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, India.
    Suhas, S.
    Utilization of industrial waste products as adsorbents for the removal of dyes2003In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 101, no 1, p. 31-42Article in journal (Refereed)
  • 70. Jain, A.K.
    et al.
    Suhas, S.
    Bhatnagar, Amit
    Methylphenols removal from water by low-cost adsorbents2002In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 251, no 1, p. 39-45Article in journal (Refereed)
  • 71. Jain, A.K.
    et al.
    Suhas, S.
    Jain, S.
    Bhatnagar, Amit
    Department of Chemistry , Indian Institute of Technology Roorkee , Roorkee, 247667, India.
    Removal of 2-fluoro and 2-iodophenol from aqueous solutions using industrial wastes2004In: Environmental technology, ISSN 0959-3330, E-ISSN 1479-487X, Vol. 25, p. 15-22Article in journal (Refereed)
  • 72. Jain, A.K.
    et al.
    Suhas, S.
    Jain, S.
    Bhatnagar, Amit
    Department of Chemistry Indian Institute of Technology Roorkee Roorkee - 247 667 India.
    Utilization of industrial wastes for the removal of anionic dyes2003In: Toxicological and Environmental Chemistry, ISSN 0277-2248, Vol. 84, no 1-4, p. 41-52Article in journal (Refereed)
  • 73. Kousha, M.
    et al.
    Daneshvar, E.
    Dopeikar, H
    Taghavi, D.
    Bhatnagar, Amit
    Univ Porto FEUP, Dept Engn Quim, LSRE, Fac Engn, P-4200465 Oporto, Portugal.
    Box-Behnken Design Optimization of Acid Black 1 Dye Biosorption by different Brown Macroalgae2012In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 179, p. 158-168Article in journal (Refereed)
    Abstract [en]

    Response surface methodology (RSM) based on three-variable-three-level Box-Behnken design was employed to interpret the adsorption characteristics of Acid Black 1 (AB1) dye onto three brown macroalgae viz., Nizamuddin zanardini, Sargassum glaucescens and Stoechospermum marginatum. The effects of three independent variables, viz. biomass dosage, dye concentration, and initial solution pH were studied for the removal of AB1 dye by the three macroalgae. A second-order polynomial model successfully described the effects of independent variables on the AB1 dye removal. The maximum experimental dye removal efficiency of 99.27, 98.12 and 97.62% for N. zanardini, S. glaucescens and S. marginatum, respectively, was obtained, which was in agreement with the calculated values. The results of the present study suggest that these macroalgae can be used as an efficient biosorbents for dye removal from aqueous solution.

  • 74. Kousha, M.
    et al.
    Daneshvar, E.
    Sohrabi, M.S.
    Jokar, M.
    Bhatnagar, Amit
    FEUP, LSRE, Dept Engn Quim, P-4200465 Oporto, Portugal .
    Adsorption of acid orange II dye by raw and chemically modified brown macroalga Stoechospermum marginatum2012In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 192, p. 67-76Article in journal (Refereed)
    Abstract [en]

    The adsorption of acid orange II (AO7) dye from aqueous solution was examined onto untreated and chemically modified forms (treated with (i) propylamine, (ii) acidic methanol, (iii) formaldehyde and (iv) formic acid with formaldehyde) of brown alga, Stoechospermum marginatum. The adsorption was studied as a function of initial solution pH (2.0-10.0), initial dye concentration (30-90 mg/L), contact time (5-60 min) and biomass dosage (0.2-2.2 g/L) at constant temperature and agitation speed. The kinetic data were well described with the pseudo-second-order model. The results revealed that amine functional groups were mainly responsible for the adsorption of acid orange II dye. The modification of biomass with propylamination enhanced the dye adsorption capacity about two times of the untreated algal biomass. These findings were confirmed by Fourier transform infrared (FT-IR) spectroscopy.

  • 75. Kousha, Masoud
    et al.
    Farhadian, Omidvar
    Dorafshan, Salar
    Soofiani, Nasrollah Mahboobi
    Bhatnagar, Amit
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Optimization of malachite green biosorption by green microalgae-Scenedesmus quadricauda and Chlorella vulgaris: Application of response surface methodology2013In: Journal of the Taiwan Institute of Chemical Engineers / Elsevier, ISSN 1876-1070, E-ISSN 1876-1089, Vol. 44, no 2, p. 291-294Article in journal (Refereed)
    Abstract [en]

    The present study was carried out to optimize the various experimental conditions for biosorption of malachite green (MG) dye onto Scenedesmus quadricauda and Chlorella vulgaris biomass by applying response surface method (RSM). The effects of process parameters, viz. initial MG dye concentration (mg/L), initial solution pH, algae amount (mg/L) and contact time (mm) on the dye biosorption were analyzed using Box-Behnken design. The maximum experimental dye removal efficiency of 73.49 and 91.61% for S. quadricauda and C vulgaris, respectively, was obtained, which was in agreement with calculated values. The FT-IR analysis confirmed the presence of different functional groups on the surface of biosorbents which were responsible for sorption of MG dye. Kinetic studies revealed that experimental data fitted well with the pseudo-second order model. In addition, thermodynamic parameters for dye biosorption were calculated, and negative Delta G degrees values indicated spontaneous nature of biosorption. (C) 2012 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

  • 76. Koutahzadeh, N.
    et al.
    Daneshvar, E.
    Kousha, M.
    Sohrabi, M. S.
    Bhatnagar, Amit
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Biosorption of hexavalent chromium from aqueous solution by six brown macroalgae2013In: Desalination and Water Treatment, ISSN 1944-3994, E-ISSN 1944-3986, Vol. 51, no 31-33, p. 6021-6030Article in journal (Refereed)
    Abstract [en]

    The biosorption potential of six brown macroalgae viz. Nizamuddina zanardinii, Stoechospermum marginatum, Cystoseira indica, Dictyota cervicornis, Padina australis, and Sargassum glaucescens, for the removal of hexavalent chromium (Cr(VI)) was investigated in the present study. Optimum conditions were determined by studying the effect of initial solution pH, biomass dosage, initial Cr(VI) concentration, and contact time on Cr(VI) removal by the macroalgae. Cr(VI) sorption was found to be highly pH dependent and maximum sorption was obtained at pH 1.0. Freundlich isotherm model showed the best fit with the equilibrium data. The removal rate of Cr(VI) was relatively rapid during the first 30min, although the rate decreased gradually and the sorption reached equilibrium in about 70min for S. marginatum, 90min for N. zanardinii, and 150min for D. cervicornis, P. australis, S. glaucescens, and C. indica. Different kinetic models such as pseudo-first-order, pseudo-second-order, and intra-particle diffusion model were tested, and the experimental data was in agreement with the pseudo-second-order model. The results of the present study suggest that brown macroalgae could be used as effective biosorbents for Cr(VI) removal from aqueous solution.

  • 77.
    Kumar, Eva
    et al.
    Yonsei Univ, Dept Environm Engn, Wonju 220710, Gangwon Do, South Korea.
    Bhatnagar, Amit
    Yonsei Univ, Dept Environm Engn, Wonju 220710, Gangwon Do, South Korea.
    Choi, Jeong-A
    Kumar, Umesh
    Min, Booki
    Kim, Yongje
    Song, Hocheol
    Paeng, Ki Jung
    Jung, Yong Mee
    Abou-Shanab, R.A.I.
    Jeon, Byong-Hun
    Perchlorate removal from aqueous solutions by granular ferric hydroxide (GFH)2010In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 159, no 1-3, p. 84-90Article in journal (Refereed)
    Abstract [en]

    The present research evaluates the efficacy of granular ferric hydroxide (GFH) for perchlorate removal from aqueous solutions. Laboratory scale experiments were conducted to investigate the influence of various experimental parameters such as contact time, initial perchlorate concentration, temperature, pH and competing anions on perchlorate removal by GFH. Results demonstrated that perchlorate uptake rate was rapid and maximum adsorption was completed within first 30 min and equilibrium was achieved within 60 min. Pseudo-second-order model favorably explains the sorption mechanism of perchlorate on to GFH. The maximum sorption capacity of GFH for perchlorate was ca. 20.0 mg g(-1) at pH 6.0-6.5 at room temperature (25 degrees C). The optimum perchlorate removal was observed between pH range of 3-7. The Raman spectroscopy results revealed that perchlorate was adsorbed on GFH through electrostatic attraction between perchlorate and positively charged surface sites. Results from this study demonstrated potential utility of GFH that could be developed into a viable technology for perchlorate removal from water.

  • 78.
    Kumar, Eva
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Bhatnagar, Amit
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Hogland, William
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Marques, Marcia
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Sillanpaa, Mika
    Lappeenranta Univ Technol, Finland.
    Interaction of inorganic anions with iron-mineral adsorbents in aqueous media - A review2014In: Advances in Colloid and Interface Science, ISSN 0001-8686, E-ISSN 1873-3727, Vol. 203, p. 11-21Article, review/survey (Refereed)
    Abstract [en]

    A number of inorganic anions (e.g., nitrate, fluoride, bromate, phosphate, and perchlorate) have been reported in alarming concentrations in numerous drinking water sources around the world. Their presence even in very low concentrations may cause serious environmental and health related problems. Due to the presence and significance of iron minerals in the natural aquatic environment and increasing application of iron in water treatment, the knowledge of the structure of iron and iron minerals and their interactions with aquatic pollutants, especially inorganic anions in water are of great importance. Iron minerals have been known since long as potential adsorbents for the removal of inorganic anions from aqueous phase. The chemistry of iron and iron minerals reactions in water is complex. The adsorption ability of iron and iron minerals towards inorganic anions is influenced by several factors such as, surface characteristics of the adsorbent (surface area, density, pore volume, porosity, pore size distribution, pH(pzo) purity), pH of the solution, and ionic strength. Furthermore, the physico-chemical properties of inorganic anions (pore size, ionic radius, bulk diffusion coefficient) also significantly influence the adsorption process. The aim of this paper is to provide an overview of the properties of iron and iron minerals and their reactivity with some important inorganic anionic contaminants present in water. It also summarizes the usage of iron and iron minerals in water treatment technology. (C) 2013 Elsevier B.V. All rights reserved.

  • 79.
    Kumar, Eva
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Bhatnagar, Amit
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Hogland, William
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Marques, Marcia
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Department of Sanitary and Environmental Engineering, Rio de Janeiro State University, UERJ, Rio de Janeiro, Brazil.
    Sillanpää, Mika
    Laboratory of Green Chemistry, Faculty of Technology, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli, Finland.
    Interaction of anionic pollutants with Al-based adsorbents in aqueous media – A review2014In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 241, p. 443-456Article in journal (Refereed)
    Abstract [en]

    Many anionic pollutants (e.g., fluoride, nitrate and nitrite, bromate, phosphate, arsenate and arsenite, selenate and selenite, perchlorate) have been detected in surface and groundwater in different parts of the world and strict measures are being taken to minimize their concentrations and to control their mobility in aqueous media. Mineral surfaces, in general, have shown enhanced uptake of many anionic pollutants. Various phases of aluminum (Al) oxides, hydroxides and oxyhydroxide are increasingly being employed as adsorbents for the detoxification of water and wastewater contaminated with anionic pollutants. Understanding the structural properties and morphology of adsorbents is important in order to gain knowledge about the governing mechanism behind the adsorption of anions by these adsorbents. The adsorption ability of aluminum oxides, hydroxides and oxyhydroxide depends on several key factors including properties of the adsorbent (surface area, pore size, pHpzc, porosity) and that of the adsorbates. This paper provides an overview of the physical and chemical properties of various aluminum oxides, hydroxides and oxyhydroxides and their application in water and wastewater treatment with the focus on the removal of anionic pollutants. Furthermore, the performance of these minerals and that of the synthetically prepared hybrid adsorbents (containing Al-minerals) for the adsorption of various anions has been reviewed with an emphasis on the behavior of adsorbent-water interface in presence of the anionic pollutants.

  • 80.
    Kumar, Eva
    et al.
    Yonsei Univ, Dept Environm Engn, Wonju 220710, Gangwon Do, South Korea.
    Bhatnagar, Amit
    Yonsei Univ, Dept Environm Engn, Wonju 220710, Gangwon Do, South Korea.
    Ji, Minkyu
    Jung, Woosik
    Lee, Sang-Hun
    Kim, Sun-Joon
    Lee, Giehyeon
    Song, Hocheol
    Choi, Jae-Young
    Yang, Jung-Seok
    Jeon, Byong-Hun
    Defluoridation from aqueous solutions by granular ferric hydroxide (GFH)2009In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 43, no 2, p. 490-498Article in journal (Refereed)
    Abstract [en]

    This research was undertaken to evaluate the feasibility of granular ferric hydroxide (GFH) for fluoride removal from aqueous solutions, Batch experiments were performed to study the influence of various experimental parameters such as contact time (1 min-24 h), initial fluoride concentration (1-100 mg L(-1)), temperature (10 and 2S degrees C), pH (3-12) and the presence of competing anions on the adsorption of fluoride on GFH. Kinetic data revealed that the uptake rate of fluoride was rapid in the beginning and 95% adsorption was completed within 10 min and equilibrium was achieved within 60 min. The sorption process was well explained with pseudo-first-order and pore diffusion models. The maximum adsorption capacity of GFH for fluoride removal was 7.0 mg g(-1). The adsorption was found to be an endothermic process and data conform to Langmuir model. The optimum fluoride removal was observed between pH ranges of 4-8. The fluoride adsorption was decreased in the presence of phosphate followed by carbonate and sulphate. Results from this study demonstrated potential utility of GFH that could be developed into a viable technology for fluoride removal from drinking water.

  • 81.
    Kumar, Eva
    et al.
    Univ Porto, Fac Engn, Dept Engn Quim, LSRE, P-4200465 Oporto, Portugal.
    Bhatnagar, Amit
    Univ Porto, Fac Engn, Dept Engn Quim, LSRE, P-4200465 Oporto, Portugal / Tech Univ Hamburg, Inst Environm Technol & Energy Econ, D-21073 Hamburg, Germany.
    Kumar, Umesh
    Natl Cheng Kung Univ, Dept Chem, Tainan 701, Taiwan.
    Sillanpää, Mika
    Lappeenranta Univ Technol, Fac Technol, FI-50100 Mikkeli, Finland.
    Defluoridation from aqueous solutions by nano-alumina: Characterization and sorption studies2011In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 186, no 2-3, p. 1042-1049Article in journal (Refereed)
    Abstract [en]

    The present study was conducted to evaluate the feasibility of nano-alumina (Al(2)O(3)) for fluoride adsorption from aqueous solutions. The nature and morphology of pure and fluoride-sorbed nano-alumina were characterized by SEM with EDX, XRD, and FTIR analysis. Batch adsorption studies were performed as a function of contact time, initial fluoride concentration, temperature, pH and influence of competing anions. Fluoride sorption kinetics was well fitted by pseudo-second-order model. The maximum sorption capacity of nano-alumina for fluoride removal was found to be 14.0 mg g(-1) at 25 degrees C. Maximum fluoride removal occurred at pH 6.15. The fluoride sorption has been well explained using Langmuir isotherm model. Fluoride sorption was mainly influenced by the presence of PO(4)(3-), SO(4)(2-) and CO(3)(2-) ions.

  • 82. Lee, S.H.
    et al.
    Kim, S.
    Jeon, B.H.
    Bhatnagar, Amit
    Yonsei University, South Korea.
    Ji, S.
    Youngwook, C.
    Lee, G.
    Activity of Sulfate Reducing Bacteria in Successive Alkalinity Producing System: Part I- Effect of Temperature2010In: Research Journal of Chemistry and Environment, ISSN 0972-0626, Vol. 14, no 4, p. 67-73Article in journal (Refereed)
    Abstract [en]

    Successive alkalinity producing system (SAPS) is one of the most preferred passive treatment system for acid mine drainage. Sulfate reducing bacteria (SRB) in SAPS make anaerobic environment needed to successive alkalinity production of limestone. It was observed that the SRB activity was most apparent at 36 oC and sulfate removal rate of up to 86% was achieved at this temperature when SAPS had 8 cm thickness of mushroom compost layer and hydraulic retention time (HRT) of 8 days. The sulfate removal rate was directly proportional to the temperature and it significantly decreased at 1 oC. The unexpected observation on the increased effluent sulfate concentration at 1 oC was due to the effect of sulfate elution from the mushroom compost. Iron removal rate was governed by both temperature and thickness of the mushroom compost layer. Finally, cultivation experiments revealed that SRB growth was significantly influenced by the temperature. The results of the present study suggest that the temperature directly influences on the SRB growth and subsequently controls the treatment efficiency of SAPS.

  • 83.
    Levchuk, Irina
    et al.
    Lappeenranta Univ Technol.
    Bhatnagar, Amit
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Sillanpaa, Mika
    Lappeenranta Univ Technol.
    Overview of technologies for removal of methyl tert-butyl ether (MTBE) from water2014In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 476, p. 415-433Article, review/survey (Refereed)
    Abstract [en]

    Wide use of methyl tert-butyl ether (MTBE) as fuel oxygenates leads to worldwide environment contamination with this compound basically due to fuel leaks from storage or pipelines. Presence of MTBE in drinking water is of high environmental and social concern. Existing methods for MTBE removal from water have a number of limitations which can be possibly overcome in the future with use of emerging technologies. This work aims to provide an updated overview of recent developments in technologies for MTBE removal from water. (C) 2014 Elsevier B.V. All rights reserved.

  • 84.
    Matilainen, Annu
    et al.
    University of Eastern Finland, Finland.
    Gjessing, Egil T.
    University of Oslo, Norway.
    Lahtinen, Tanja
    University of Jyväskylä, Finland.
    Hed, Leif
    Technology Centre Ketek LTD, Finland.
    Bhatnagar, Amit
    LSRE – Laboratory of Separation and Reaction Engineering, Portugal.
    Sillanpää, Mika
    University of Eastern Finland, Finland ; Lappeenranta University of Technology, Finland.
    An overview of the methods used in the characterization of natural organic matter (NOM) in relation to drinking water treatment2011In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 83, no 11, p. 1431-1442Article in journal (Refereed)
    Abstract [en]

    Natural organic matter (NOM) is found in all surface, ground and soil waters. During recent decades, reports worldwide show a continuing increase in the color and NOM of the surface water, which has an adverse affect on drinking water purification. For several practical and hygienic reasons, the presence of NOM is undesirable in drinking water. Various technologies have been proposed for NOM removal with varying degrees of success. The properties and amount of NOM, however, can significantly affect the process efficiency. In order to improve and optimise these processes, the characterisation and quantification of NOM at different purification and treatment processes stages is important. It is also important to be able to understand and predict the reactivity of NOM or its fractions in different steps of the treatment. Methods used in the characterisation of NOM include resin adsorption, size exclusion chromatography (SEC), nuclear magnetic resonance (NMR) spectroscopy, and fluorescence spectroscopy. The amount of NOM in water has been predicted with parameters including UV-Vis, total organic carbon (TOC), and specific UV-absorbance (SUVA). Recently, methods by which NOM structures can be more precisely determined have been developed; pyrolysis gas chromatography-mass spectrometry (Py-GC-MS), multidimensional NMR techniques, and Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS). The present review focuses on the methods used for characterisation and quantification of NOM in relation to drinking water treatment.

  • 85. Metsämuuronen, Sari
    et al.
    Sillanpää, Mika
    Bhatnagar, Amit
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Mänttäri, Mika
    Natural organic matter removal from drinking water by membrane technology2014In: Separation and Purification Reviews, ISSN 1542-2119, Vol. 43, no 1, p. 1-61Article in journal (Refereed)
    Abstract [en]

    Aquatic natural organic matter (NOM) is a heterogeneous mixture of biopolymers and their degradation products that cause harmful by-products during drinking water production. The great variability in NOM composition makes it difficult to completely remove from drinking water by any single technique. The current paper reviews the NOM removal by micro-, ultra- and nanofiltration and by hybrid processes combining membrane techniques with other unit processes: coagulation, adsorption, and oxidation, and by membrane bioreactors.

  • 86.
    Park, JM
    et al.
    Department of Nuclear Engineering, Texas A&M University, College Station, TX 77843-3133, USA / Department of Environmental Engineering, Yonsei University Wonju, Gangwon-Do 220-710, South Korea.
    Rock, J.C.
    Department of Nuclear Engineering, Texas A&M University, College Station, TX 77843-3133, USA.
    Wang, L.
    Department of Biological & Agricultural Engineering, North Carolina State University, Raleigh, NC 27695-7625, USA.
    Seo, Y.C.
    Department of Environmental Engineering, Yonsei University Wonju, Gangwon-Do 220-710, South Korea.
    Bhatnagar, Amit
    Department of Environmental Engineering, Yonsei University Wonju, Gangwon-Do 220-710, South Korea.
    Kim, S.
    Department of Environmental Engineering, Yonsei University Wonju, Gangwon-Do 220-710, South Korea.
    Performance evaluation of six different aerosol samplers in a particulate matter generation chamber2009In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 43, no 2, p. 280-289Article in journal (Refereed)
    Abstract [en]

    The present study was carried out with the aim of evaluating the performance of six different aerosol samplers in terms of mass concentration, particle size distribution, and mass fraction for the international size-sampling conventions. The international size-sampling criteria were defined as inhalable, thoracic, and respirable mass fractions with 50% cutoff at an aerodynamic equivalent diameter of 100 μm, 10 μm, and 4 μm, respectively. Two Andersen, four total suspended particulate (TSP), two RespiCon, four PM10, two DustTrak, and two SidePak samplers were selected and tested to quantitatively estimate human exposure in a carefully controlled particulate matter (PM) test chamber. The overall results indicate that (1) Andersen samplers underestimate total suspended PM and overestimate thoracic and respirable PM due to particle bounce and carryover between stages, (2) TSP samplers provide total suspended PM as reference samplers, (3) TSP samplers quantified by a coulter counter multisizer provide no information below an equivalent spherical diameter of 2 μm and therefore underestimate respirable PM, (4) RespiCon samplers are free from particle bounce as inhalable samplers but underestimate total suspended PM, (5) PM10 samplers overestimate thoracic PM, and (6) DustTrak and SidePak samplers provide relative PM concentrations instead of absolute PM concentrations.

  • 87. Pudasainee, D.
    et al.
    Sapkota, B.
    Bhatnagar, Amit
    Yonsei Univ, YIEST, Dept Environm Engn, Seoul 120749, South Korea.
    Kim, SH
    Seo, YC
    Influence of weekdays, weekends and bandhas on surface ozone in Kathmandu valley2010In: Atmospheric research, ISSN 0169-8095, E-ISSN 1873-2895, Vol. 95, no 2-3, p. 150-156Article in journal (Refereed)
    Abstract [en]

    In this paper, variations of nitric oxide (NO), nitrogen dioxide (NO2), oxides of nitrogen (NOx), ozone (O-3) and total oxidant (O-X) concentration in ambient air of Kathmandu valley are presented. O-3 behavior during weekdays, weekends and bandhas (general strike) is analyzed and the mechanism related to it is discussed. The increased NO2/Ox ratio with increasing NOx concentration and the inverse relation between NOx and O-3 imply that the residual O-3 remaining after the NO-NO2-O-3 reaction chain controlled O-3 concentration in the valley atmosphere and the radical channel was likely to have a minor contribution. The higher positive correlation coefficient for O-3 variation during weekdays and bandhas, weekdays and weekends suggests common sources for the weekends and bandhas O-3 variation. The higher O-3 concentration during weekends and bandhas compared to weekdays was due to less destruction of O-3. Enhanced reduction in traffic emission levels, enforcement of stringent emission standards within the valley and the surroundings may help to address the O-3 problem in the valley atmosphere.

  • 88.
    Pulkka, Susanna
    et al.
    Lappeenranta Univ Technol, Finland.
    Martikainen, Mika
    Outotec, Ind Water Treatment, Espoo 02230, Finland.
    Bhatnagar, Amit
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Sillanpaa, Mika
    Lappeenranta Univ Technol, Finland.
    Electrochemical methods for the removal of anionic contaminants from water - A review2014In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 132, p. 252-271Article, review/survey (Refereed)
    Abstract [en]

    Different electrochemical methods such as electrocoagulation, electro-oxidation, and electroreduction have been found effective for the removal of various anionic pollutants from water and wastewater. Electrochemical processes can transform contaminants directly or manipulate the redox condition of the environmental matrix to achieve adaptive condition. This review focuses on the removal of different anions, including cyanide, fluoride, nitrate, nitrite, phosphate, and sulfate, from water by electrocoagulation, electro-oxidation, and electroreduction methods. Optimum treatment conditions for studied anions in each electrochemical method are discussed. An overview of electrochemical methods used for anions removal together with specific applications and experimental results are presented and discussed. It is evident from the literature reviewed that these methods have shown considerable potential for the removal of anionic pollutants from water. However, the most challenging issue in this research area is to find out the practical application of these methods on commercial scale, leading to the improvement of pollution control. (C) 2014 Elsevier B.V. All rights reserved.

  • 89. Repo, E.
    et al.
    Mäkinen, M.
    Rengaraj, S.
    Natarajan, G.
    Bhatnagar, Amit
    Univ Porto, Fac Engn, Dept Engn Quim, LSRE, P-4200465 Oporto, Portugal .
    Sillanpää, M.
    Lepidocrocite and its heat-treated forms as effective arsenic adsorbents in aqueous medium2012In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 180, p. 159-169Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to investigate the adsorption potential of heat treated lepidocrocites (gamma-FeOOH) towards As(III) and As(V) ions in aqueous solutions. Initially, mesoporous lepidocrocite was synthesized, treated at different temperatures, and characterized using various analytical techniques. During the heating, transformation of lepidocrocite into hematite was observed. The adsorption of As(III) and As(V) was studied by batch experiments and the effects of different operational parameters e.g., adsorbent dose, solution pH, contact time, and the initial concentration of As(III)/(V) (isotherms) were studied. Lepidocrocite treated at 250 degrees C exhibited >99% and 94% adsorption from 50 mg/L As(V) and As(III) solutions, respectively with an adsorbent dose of 2.5 g/L. The highest uptake capacity was obtained for As(III) (55 mg/g) on lepidocrocite without the heat treatment and for As(V) (38 mg/g) on lepidocrocite treated at 250 degrees C, which was assigned to be a mixture of maghemite and hematite. The adsorption kinetic data fitted well with the pseudo-second-order model and the BiLangmuir isotherm had the best applicability to describe the adsorption equilibrium.

  • 90. Repo, Eveliina
    et al.
    Warchol, Jolanta K.
    Bhatnagar, Amit
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Mudhoo, Ackmez
    Sillanpaa, Mika
    Aminopolycarboxylic acid functionalized adsorbents for heavy metals removal from water2013In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 47, no 14, p. 4812-4832Article, review/survey (Refereed)
    Abstract [en]

    Due to the excellent chelating properties of aminopolycarboxylic acid (APCAs), they can be used for the removal of metals from contaminated waters. This paper reviews the research results obtained for both commercial and self-prepared adsorbents functionalized with four most common APCAs: iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), and diethylenetriaminepentaacetic acid (DTPA). The structural characteristics and unique metal binding properties of these chelating adsorbents are presented. The theory of the adsorption phenomena is discussed based on the kinetics of adsorption, equilibrium adsorption isotherm models, and thermodynamic models. The most important applications of APCA-functionalized adsorbents are also described. APCA-functionalized adsorbents are found to be highly promising materials for metal removal from contaminated waters. (C) 2013 Elsevier Ltd. All rights reserved.

  • 91. Santo, C.E.
    et al.
    Vilar, V.J.P.
    Bhatnagar, Amit
    Univ Porto, Fac Engn, LSRE LCM, LSRE Associate Lab, P-4200465 Oporto, Portugal.
    Kumar, E.
    Botelho, C.M.S.
    Boaventura, R.A.R.
    Sulphide removal from petroleum refinery wastewaters by catalytic oxidation2012In: Desalination and Water Treatment, ISSN 1944-3994, E-ISSN 1944-3986, Vol. 46, no 1-3, p. 256-263Article in journal (Refereed)
    Abstract [en]

    The catalytic oxidation of sulphides present in oil refinery wastewaters was investigated in the present study. The wastewaters were obtained from the wastewater treatment plant of the oil refinery in Matosinhos (Portugal), Galp Energia. Air, NaOCl and H2O2 were chosen as oxidants and Fe3+ and Mn2+ as the two catalysts to assess the effective combination of catalyst-oxidant for sulphide removal after oil separation in parallel plate interceptors. Primarily, air (oxygen) was used as the oxidant and the efficiency of two catalysts (Fe3+ and Mn2+) for sulphide removal was evaluated. Experimental data suggested that Fe3+ catalysed sulphide removal in the presence of oxygen was more effective than Mn2+ catalysed reaction. In a subsequent study, oxygen was replaced by NaOCl and H2O2, and the potential of various catalyst-oxidant combinations, NaOCl + [Fe3+], NaOCl + [Mn2+], H2O2 + [Fe3+], H2O2 + [Mn2+], was assessed. The NaOCl + [Fe3+] combination achieved the maximum sulphide oxidation. Pseudo-first-order and pseudo-second-order reaction models were fitted to the kinetic experimental data. The influence of temperature on the kinetic rate was also investigated.

  • 92. Santo, C.E.
    et al.
    Vilar, V.J.P.
    Botelho, C.M.S.
    Bhatnagar, Amit
    Univ Porto, Fac Engn, LSRE Lab Separat & React Engn Associate Lab LSRE, P-4200465 Oporto, Portugal .
    Kumar, E.
    Boaventura, R.A.R.
    Optimization of coagulation-flocculation and flotation parameters for the treatment of a petroleum refinery effluent from a Portuguese Plant2012In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 183, p. 117-123Article in journal (Refereed)
    Abstract [en]

    Petroleum refineries generate significant amounts of wastewater which have to be treated and processed before their discharge into water streams. The refinery wastewater treatment plants (WWTPPs) employ physico-chemical processes to achieve effluents of satisfactory oil content to be further treated by biological processes. In the present study, coagulation-flocculation and flotation processes are optimised to reduce the concentrations of organic matter, oil and grease and other contaminants in order to obtain an effluent with suitable characteristics ready to be treated by an aerobic biological process. PAX-18 (17% Al2O3), aluminium sulphate (Al-2(SO4)(3)) and ferric sulphate (Fe-2(SO4)(3)) are chosen for affecting coagulation-flocculation as a primary treatment. NALCO 71408 is employed as flocculant. Treatment efficiency is evaluated in terms of chemical oxygen demand (COD), total organic carbon (TOC) and turbidity measurements. The experiments are conducted both in discontinuous and continuous mode to assess the feasibility of the process. Flotation is investigated as a post-treatment process for the removal of emulsified hydrocarbons and satisfactory results are obtained.

  • 93.
    Svensson, Henric
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Marques, Marcia
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science. Rio de Janeiro State University, Brazil.
    Svensson, Britt-Marie
    Kristianstad University, Sweden.
    Mårtensson, Lennart
    Kristianstad University, Sweden.
    Bhatnagar, Amit
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Hogland, William
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Treatment of wood leachate with high polyphenols content by peat and carbon-containing fly ash filters2015In: Desalination and Water Treatment, ISSN 1944-3994, E-ISSN 1944-3986, Vol. 53, no 8, p. 2041-2048Article in journal (Refereed)
    Abstract [en]

    In the present study, two combinations of filter materials in filter/columns were examined for removal of total organic carbon (TOC) and polyphenols (PP) found in storm water runoff from wood storage areas in a wooden floor industry. One filter/column was packed with peat mixed with carbon-containing fly ash, while another filter/column contained only peat (without ash). The mixture of peat and ash has shown faster and higher removal capacity for TOC and faster removal with the same final removal capacity for PP (in grams of pollutant per kg of sorbent) at the saturation point. The superiority observed for the peat and ash filter is presumably due to the unique characteristics of peat and ash, which enhanced the treatment efficiency when used together in a mixture. Based on the observed results, filters formed by peat and carbon-containing ashes proved to be a potentially low-cost option for the treatment of storm water generated at storage areas of wood materials such as logs, sawdust and wood chips.

  • 94. Vepsäläinen, M.
    et al.
    Selin, J.
    Rantala, P.
    Pulliainen, M.
    Särkkä, H.
    Kuhmonen, K.
    Bhatnagar, Amit
    Sillanpää, M.
    Precipitation of dissolved sulphide in pulp and paper mill wastewater by electrocoagulation2011In: Environmental technology, ISSN 0959-3330, E-ISSN 1479-487X, Vol. 32, no 12, p. 1393-1400Article in journal (Refereed)
    Abstract [en]

    The precipitation of dissolved sulphide ions by electrocoagulation was studied at laboratory scale using pulp and paper mill wastewaters. Concentrations of dissolved organic carbon and phosphorus were analysed before and after the electrocoagulation process to examine the suitability of the process for treatment of sulphide odour from pulp and paper mill wastewater. The electrochemical cell used in this study was constructed from monopolar dissolving iron electrodes. The dissolved iron concentration was directly proportional to the applied electric charge (C/L) at the tested current densities. Electrochemically produced ferrous iron (Fe2+) precipitated dissolved sulphide ions efficiently. Electricity consumption of the treatment was 4-8 C/mg S2- while iron consumption was 1.1-2.2 mg/mg S2- during the initial phase of the sulphide precipitation when the applied electric charge was 10-60 C/L. When 60 C/L was applied, 88% of dissolved sulphides and 40% of phosphorus was precipitated. The reduction in DOC was low during the sulphide precipitation. According to these results, electrocoagulation can precipitate dissolved sulphides effectively and thereby reduce sulphide odours of pulp and paper mill wastewaters.

  • 95. Vilar, V.J.P.
    et al.
    Valle, J.A.B
    Bhatnagar, Amit
    LSRE – Laboratory of Separation and Reaction Engineering, Associate Laboratory LSRE/LCM, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
    Santos, J.C.
    De Souza, S.M.A.G.U.
    De Souza, A.A.U.
    Botelho, C.M.S.
    Boaventura, R.A.R.
    Insights into trivalent chromium biosorption onto protonated brownalgae Pelvetiacanaliculata: distribution of chromium ionic species on thebinding sites2012In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 200-202, p. 140-148Article in journal (Refereed)
    Abstract [en]

    In the present study, biosorption of trivalent chromium by protonated brown algae, Pelvetia canaliculata, was studied in batch system. FTIR analyses provided information about the possible binding groups present in the algae, as carboxylic, hydroxyl and sulfonate groups. Potentiometric acid–base titrations showed a heterogeneous distribution of two major binding groups, carboxyl and hydroxyl ones, following the Quasi-Gaussian affinity constant distribution suggested by Sips, which allowed to estimate the maximum amount of acidic functional groups (2.26 ± 0.02 mmol g−1) and proton binding parameters () for an ionic strength of 0.2 M. The trivalent chromium removal was found to increase with pH and the maximum chromium uptake was observed at pH 4.0 (∼0.6 mmol/g), corresponding to 1.34 meq/g, since at that pH, 25.8% of total chromium is in the Cr3+ form and 72.7% as CrOH2+. An equilibrium model incorporating the hydrolysis reactions that chromium undergoes in the aqueous phase was able to predict the chromium biosorption at different pH values and chromium concentrations, enabling the prediction of the distribution of chromium ionic species on the binding sites. A mass transfer model provided a good representation of the chromium biosorption kinetics, resulting in intraparticle homogeneous diffusion coefficients of 4.6 × 10−7 cm2/s for Cr3+ and 1.8 × 10−8 cm2/s for CrOH2+. The distribution of chromium ionic species in the solution and on the binding sites was also predicted by the kinetic model.

12 51 - 95 of 95
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf