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RISS 인기검색어
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- 저자 : ttge, Andreas (검색결과 2 건)
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Niazi, Nabeel Khan,Bibi, Irshad,Shahid, Muhammad,Ok, Yong Sik,Shaheen, Sabry M.,Rinklebe, Jö,rg,Wang, Hailong,Murtaza, Behzad,Islam, Ejazul,Farrakh Nawaz, M.,Lü,ttge, Andreas Elsevier 2018 Science of the Total Environment Vol.621 No.-
<P><B>Abstract</B></P> <P>In this study, we examined the sorption of arsenite (As(III)) and arsenate (As(V)) to Japanese oak wood-derived biochar (OW-BC) in aqueous solutions, and determined its efficiency to remove As from As-contaminated well water. Results revealed that, among the four sorption isotherm models, Langmuir model showed the best fit to describe As(III) and As(V) sorption on OW-BC, with slightly greater sorption affinity for As(V) compared to As(III) (<I>Q<SUB>L</SUB> </I> =3.89 and 3.16mgg<SUP>−1</SUP>; R<SUP>2</SUP> =0.91 and 0.85, respectively). Sorption edge experiments indicated that the maximum As removal was 81% and 84% for As(III)- and As(V)-OW-BC systems at pH7 and 6, respectively, which decreased above these pH values (76–69% and 80–58%). Surface functional groups, notably OH, COOH, CO, CH<SUB>3</SUB>, were involved in As sequestration by OW-BC, suggesting the surface complexation/precipitation and/or electrostatic interaction of As on OW-BC surface. Arsenic K-edge X-ray absorption near edge structure (XANES) spectroscopy indicated that 36% of the added As(III) was partially oxidized to As(V) in the As(III) sorption experiment, and in As(V) sorption experiment, 48% of As(V) was, albeit incompletely, reduced to As(III) on OW-BC surface. Application of OW-BC to As-contaminated well water (As: 27–144μgL<SUP>−1</SUP>; <I>n</I> =10) displayed that 92 to 100% of As was depleted despite in the presence of co-occurring competing anions (e.g., SO<SUB>4</SUB> <SUP>2−</SUP>, CO<SUB>3</SUB> <SUP>2−</SUP>, PO<SUB>4</SUB> <SUP>3−</SUP>). This study shows that OW-BC has a great potential to remove As from solution and drinking (well) water. Overall, the combination of macroscopic sorption data and integrated spectroscopic and microscopic techniques highlight that the fate of As on biochar involves complex redox transformation and association with surface functional moieties in aquatic systems, thereby providing crucial information required for implication of biochar in environmental remediation programs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Arsenic removal efficiency of Japanese oak wood biochar (OW-BC) was explored. </LI> <LI> Langmuir model provided the best fit, with a greater <I>Q<SUB>L</SUB> </I> for arsenate than arsenite. </LI> <LI> XANES spectroscopy indicated redox transformation of arsenite⇔arsenate on OW-BC. </LI> <LI> FTIR spectra revealed arsenite/arsenate association with functional groups on OW-BC. </LI> <LI> OW-BC efficiently removed As (92 to 100%) from drinking well water. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
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Niazi, Nabeel Khan,Bibi, Irshad,Shahid, Muhammad,Ok, Yong Sik,Burton, Edward D.,Wang, Hailong,Shaheen, Sabry M.,Rinklebe, Jö,rg,Lü,ttge, Andreas Elsevier 2018 Environmental pollution Vol.232 No.-
<P><B>Abstract</B></P> <P>In this study, we examined the removal of arsenite (As(III)) and arsenate (As(V)) by perilla leaf-derived biochars produced at 300 and 700 °C (referred as BC300 and BC700) in aqueous environments. Results revealed that the Langmuir isotherm model provided the best fit for As(III) and As(V) sorption, with the sorption affinity following the order: BC700-As(III) > BC700-As(V) > BC300-As(III) > BC300-As(V) (<I>Q</I> <SUB> <I>L</I> </SUB> = 3.85–11.01 mg g<SUP>−1</SUP>). In general, As removal decreased (76–60%) with increasing pH from 7 to 10 except for the BC700-As(III) system, where notably higher As removal (88–90%) occurred at pH from 7 to 9. Surface functional moieties contributed to As sequestration by the biochars examined here. However, significantly higher surface area and aromaticity of BC700 favored a greater As removal compared to BC300, suggesting that surface complexation/precipitation dominated As removal by BC700. Arsenic K-edge X-ray absorption near edge structure (XANES) spectroscopy demonstrated that up to 64% of the added As(V) was reduced to As(III) in BC700- and BC300-As(V) sorption experiments, and in As(III) sorption experiments, partial oxidation of As(III) to As(V) occurred (37–39%). However, XANES spectroscopy was limited to precisely quantify As binding with sulfur species as As<SUB>2</SUB>S<SUB>3</SUB>-like phase. Both biochars efficiently removed As from natural As-contaminated groundwater (As: 23–190 μg L<SUP>−1</SUP>; <I>n</I> = 12) despite in the presence of co-occurring anions (e.g., CO<SUB>3</SUB> <SUP>2−</SUP>, PO<SUB>4</SUB> <SUP>3−</SUP>, SO<SUB>4</SUB> <SUP>2−</SUP>) with the highest levels of As removal observed for BC700 (97–100%). Overall, this study highlights that perilla leaf biochars, notably BC700, possessed the greatest ability to remove As from solution and groundwater (drinking water). Significantly, the integrated spectroscopic techniques advanced our understanding to examine complex redox transformation of As(III)/As(V) with biochar, which are crucial to determine fate of As on biochar in aquatic environments.</P> <P><B>Highlights</B></P> <P> <UL> <LI> BC700 (high temperature) perilla leaf biochar removed more arsenite at pH 7–9 than BC300 (low temperature). </LI> <LI> Langmuir model efficiently delineated sorption affinity for arsenite and arsenate, notably by BC700. </LI> <LI> FTIR spectroscopy and elemental maps indicated arsenic association with surface functional groups. </LI> <LI> XANES spectroscopy revealed redox transformation/fate of arsenite and arsenate on biochars. </LI> <LI> Both biochars depleted arsenic in groundwater, with slightly higher removal by BC700. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
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