TY - JOUR
T1 - Arsenic re-mobilization in water treatment adsorbents under reducing conditions
T2 - Part II. XAS and modeling study
AU - Liu, Suqin
AU - Jing, Chuanyong
AU - Meng, Xiaoguang
PY - 2008/3/15
Y1 - 2008/3/15
N2 - The mechanism of arsenic re-mobilization in spent adsorbents under reducing conditions was studied using X-ray absorption spectroscopy and surface complexation model calculations. X-ray absorption near edge structure (XANES) spectroscopy demonstrated that As(V) was partially reduced to As(III) in spent granular ferric hydroxide (GFH), titanium dioxide (TiO2), activated alumina (AA) and modified activated alumina (MAA) adsorbents after 2 years of anaerobic incubation. As(V) was completely reduced to As(III) in spent granular ferric oxide (GFO) under 2-year incubation. The extended X-ray absorption fine structure (EXAFS) spectroscopy analysis showed that As(III) formed bidentate binuclear surface complexes on GFO as evidenced by an average As(III)-O bond distance of 1.78 Å and As(III)-Fe distance of 3.34 Å. The release of As from the spent GFO and TiO2 was simulated using the charge distribution multi-site complexation (CD-MUSIC) model. The observed redox ranges for As release and sulfate mobility were described by model calculations.
AB - The mechanism of arsenic re-mobilization in spent adsorbents under reducing conditions was studied using X-ray absorption spectroscopy and surface complexation model calculations. X-ray absorption near edge structure (XANES) spectroscopy demonstrated that As(V) was partially reduced to As(III) in spent granular ferric hydroxide (GFH), titanium dioxide (TiO2), activated alumina (AA) and modified activated alumina (MAA) adsorbents after 2 years of anaerobic incubation. As(V) was completely reduced to As(III) in spent granular ferric oxide (GFO) under 2-year incubation. The extended X-ray absorption fine structure (EXAFS) spectroscopy analysis showed that As(III) formed bidentate binuclear surface complexes on GFO as evidenced by an average As(III)-O bond distance of 1.78 Å and As(III)-Fe distance of 3.34 Å. The release of As from the spent GFO and TiO2 was simulated using the charge distribution multi-site complexation (CD-MUSIC) model. The observed redox ranges for As release and sulfate mobility were described by model calculations.
KW - Arsenic
KW - CD-MUSIC model
KW - EXAFS
KW - Re-mobilization
KW - XANES
UR - http://www.scopus.com/inward/record.url?scp=38549109082&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=38549109082&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2007.10.033
DO - 10.1016/j.scitotenv.2007.10.033
M3 - Article
C2 - 18076973
AN - SCOPUS:38549109082
SN - 0048-9697
VL - 392
SP - 137
EP - 144
JO - Science of the Total Environment
JF - Science of the Total Environment
IS - 1
ER -