Arsenic leachability in water treatment adsorbents
Arsenic leachability in water treatment adsorbents
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DOI：
10.1021/es050290p
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发表时间：
2005-07-15
影响因子：
11.4
通讯作者：
Meng, XG
中科院分区：
文献类型：
--
作者：
Jing, CY;Liu, SQ;Meng, XG
采用间歇浸出试验、表面络合模型和扩展X射线吸收精细结构（EXAFS）谱研究了水处理吸附剂中砷的可吸附性。废吸附剂收集从五个中试规模的过滤器进行了测试，从新泽西南部的地下水中去除砷。废介质包括颗粒氢氧化铁（GFH）、颗粒氧化铁、二氧化钛、活性氧化铝和改性活性氧化铝。用毒性特征浸出程序（TCLP，0.1 M醋酸盐溶液）测定的所有废培养基的砷可吸收性均低于180 μ g L-1。加州废物提取测试（0.2 M柠檬酸盐溶液）中的浸出液As浓度比TCLP中的浓度高出10倍以上，并且在废GFH样品中高达6650 μ g L-1。EXAFS的结果表明，作为形成内层双齿双核表面配合物在所有五个吸附剂表面。用电荷分布多位络合模型描述了As在各介质中的吸附/解吸行为。该研究提高了对吸附介质表面砷键合结构和不同吸附剂砷浸出行为的认识。
Arsenic leachability in water treatment adsorbents was studied using batch leaching tests, surface complexation modeling and extended X-ray absorption fine structure (EXAFS) spectroscopy. Spent adsorbents were collected from five pilot-scale filters that were tested for removal of arsenic from groundwater in Southern New Jersey. The spent media included granular ferric hydroxide (GFH), granular ferric oxide,titanium dioxide, activated alumina, and modified activated alumina. The As leachability determined with the Toxicity Characteristic Leaching Procedure (TCLP, 0.1 M acetate solution) was below 180 mu g L-1 for all spent media. The leachate As concentration in the California Waste Extraction Test (0.2 M citrate solution) was more than 10 times higher than that in the TCLP and reached as high as 6650 mu g L-I in the spent GFH sample. The EXAFS results indicate that As forms inner-sphere bidentate binuclear surface complexes on all five adsorbent surfaces. The As adsorption/desorption behaviors in each media were described with the charge distribution multisite complexation model. This study improved the understanding of As bonding structures on adsorptive media surfaces and As leaching behavior for different adsorbents.