TY - JOUR
T1 - Arsenic remobilization in water treatment adsorbents under reducing conditions
T2 - Part I. Incubation study
AU - Jing, Chuanyong
AU - Liu, Suqin
AU - Meng, Xiaoguang
PY - 2008/1/15
Y1 - 2008/1/15
N2 - The redox transformation and mobility of arsenic in spent adsorbents under reducing conditions were studied using an incubation test with mixed reducing bacteria, high-performance liquid chromatography-atomic fluorescence spectrometry for speciation of soluble arsenic (As), and thermodynamic calculations. The spent adsorptive media, including granular ferric hydroxide, granular ferric oxide, titanium dioxide, activated alumina and modified activated alumina, were collected from pilot-scale filters that were tested for removal of arsenate [As(V)] from groundwater in New Jersey, USA. During 65 days of incubation of the spent adsorbents with nutrient media in closed containers, the electron activity, pe, was reduced from about 1.7 to - 7. Meanwhile, reduction of Fe(III) to Fe(II), As(V) to arsenite [As(III)], and sulfate to sulfide occurred. Less than 4% total As was released from iron-based media in the pe range between - 3 and - 7 due to reduction of As(V) to As(III) and reductive dissolution of ferric (hydr)oxides. Up to 38% As was released from the TiO2 adsorbent, which occurred at extremely low redox potential (i.e., pe < - 6). The findings of this study will improve our ability to predict arsenic mobility when As-containing spent media are disposed of in landfills and the environment.
AB - The redox transformation and mobility of arsenic in spent adsorbents under reducing conditions were studied using an incubation test with mixed reducing bacteria, high-performance liquid chromatography-atomic fluorescence spectrometry for speciation of soluble arsenic (As), and thermodynamic calculations. The spent adsorptive media, including granular ferric hydroxide, granular ferric oxide, titanium dioxide, activated alumina and modified activated alumina, were collected from pilot-scale filters that were tested for removal of arsenate [As(V)] from groundwater in New Jersey, USA. During 65 days of incubation of the spent adsorbents with nutrient media in closed containers, the electron activity, pe, was reduced from about 1.7 to - 7. Meanwhile, reduction of Fe(III) to Fe(II), As(V) to arsenite [As(III)], and sulfate to sulfide occurred. Less than 4% total As was released from iron-based media in the pe range between - 3 and - 7 due to reduction of As(V) to As(III) and reductive dissolution of ferric (hydr)oxides. Up to 38% As was released from the TiO2 adsorbent, which occurred at extremely low redox potential (i.e., pe < - 6). The findings of this study will improve our ability to predict arsenic mobility when As-containing spent media are disposed of in landfills and the environment.
KW - Arsenic
KW - Incubation
KW - Redox potential
KW - Reducing bacteria
KW - Spent adsorbent
UR - http://www.scopus.com/inward/record.url?scp=36148957867&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=36148957867&partnerID=8YFLogxK
U2 - 10.1016/j.scitotenv.2007.08.030
DO - 10.1016/j.scitotenv.2007.08.030
M3 - Article
C2 - 17897702
AN - SCOPUS:36148957867
SN - 0048-9697
VL - 389
SP - 188
EP - 194
JO - Science of the Total Environment
JF - Science of the Total Environment
IS - 1
ER -