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Impact of Bioreduction on Remobilization of Adsorbed Cadmium on Iron Minerals in Anoxic Condition
Ghorbanzadeh, Nasrin,Lakzian, Amir,Halajnia, Akram,Choi, Ui-Kyu,Kim, Ki-Hyun,Kim, Jong-Oh,Kurade, Mayur,Jeon, Byong-Hun Wiley (John WileySons) 2017 Water environment research Vol.89 No.6
<P>The impact of bioreduction on the remobilization of adsorbed cadmium Cd(II) on minerals, including hematite, goethite, and two iron(III)-rich clay minerals nontronites (NAU-1 and NAU-2) under anoxic conditions was investigated. Langmuir isotherm equation better described the sorption of Cd(II) onto the all minerals. The maximum adsorption capacity was 6.2, 18.1, 3.6, and 4 mg g(-1) for hematite, goethite, NAU-1 and NAU-2, respectively. The desorption of Cd(II) was due to the production of Fe(II) as a result of bioreduction of structural Fe(III) in the minerals by Shewanella putrefaciens. The bioreduction of Cd(II)-loaded Fe(III) minerals was negligible during the initial 5 days followed by a rapid increase up to 20 days. The amount of Cd(II) in solution phase at the end of 30 days increased up to 0.07 mmol L-1 for hematite, NAU-1, and NAU-2 and 0.02 mmol L(-)1 for goethite. The X-ray diffraction study showed negligible changes in bioreduced minerals phases.</P>
Removal of arsenate and arsenite from aqueous solution by adsorption on clay minerals
Nasrin Ghorbanzadeh,정우식,Akram Halajnia,Amir Lakzian,Akhil N. Kabra,전병훈 한국자원공학회 2015 Geosystem engineering Vol.18 No.6
Sorption of arsenic species [As(V) and As(III)] on different clay minerals including kaolinite (KGa-1), montmorillonite (SWy-1), and nontronites (NAU-1 and NAU-2) with respect to sorption kinetics, isotherms and pH was investigated. As(V) and As(III) sorption on clay minerals was significantly influenced by pH. Higher sorption of As(V) was observed at low pH that decreased above pH 5.0, while As(III) sorption was maximum around pH 7.0. The sorption kinetics was well described by the pseudo-second-order equation for both As(V) and As(III). Among the tested clay minerals, NAU-2 was most effective for the removal of arsenic with rate constants of 0.084 and 0.056 g mg− 1 min− 1 for As(V) and As(III), respectively. A good correlation was observed between adsorbing capacity (qe) and equilibrium mass concentration (Ce) using the isothermal Freundlich adsorption model for SWy-1, NAU-1, and NAU-2 minerals as indicated by the high values of R2 coefficient. Our results indicate that clay minerals can serve as effective sorbents for the removal of As from contaminated water streams.
Nasrin Ghorbanzadeh,전병훈,Amir Lakzian,Akram Halajnia,Muthukannan Satheesh Kumar 한국자원공학회 2014 Geosystem engineering Vol.17 No.2
Abiotic reduction of Cr(VI) by ferrous iron was investigated in the presence of bioreduced goethite, hematite and two types of nontronites (NAU-1 and NAU-2). Bioreduction experiments were performed with structural Fe(III) in the minerals as sole electron acceptor, lactate as sole electron donor, Shewanella putrefaciens CN32 cells as a mediator and anthraquinone-2,6-disulfate (AQDS) was added as an electron shuttle. The results showed that bioreduction of Fe(III) occurred in all the studied minerals and the reduction increased with the application of AQDS. The maximum (21%) and minimum (3%) bioreduction of Fe(III) occurred in the nontronite (NAU-2) and hematite, respectively. The removal of Cr(VI) for all studied minerals was increased with decreasing pH. Most of the abiotic reduction of Cr(VI) by biogenic Fe(II) at pH 7 was observed in the bioreduced NAU-2 treatment with a maximum efficiency about 75%.