Reaction Dynamics Research Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency, SPring-8, Hyogo 679-5148, Japan.
Environ Sci Pollut Res Int. 2013 Jan;20(1):421-30. doi: 10.1007/s11356-012-0936-7. Epub 2012 May 5.
Arsenic contamination of groundwater has been called the largest mass poisoning calamity in human history and creates severe health problems. The effective adsorbents are imperative in response to the widespread removal of toxic arsenic exposure through drinking water. Evaluation of arsenic(V) removal from water by weak-base anion exchange adsorbents was studied in this paper, aiming at the determination of the effects of pH, competing anions, and feed flow rates to improvement on remediation. Two types of weak-base adsorbents were used to evaluate arsenic(V) removal efficiency both in batch and column approaches. Anion selectivity was determined by both adsorbents in batch method as equilibrium As(V) adsorption capacities. Column studies were performed in fixed-bed experiments using both adsorbent packed columns, and kinetic performance was dependent on the feed flow rate and competing anions. The weak-base adsorbents clarified that these are selective to arsenic(V) over competition of chloride, nitrate, and sulfate anions. The solution pH played an important role in arsenic(V) removal, and a higher pH can cause lower adsorption capacities. A low concentration level of arsenic(V) was also removed by these adsorbents even at a high flow rate of 250-350 h(-1). Adsorbed arsenic(V) was quantitatively eluted with 1 M HCl acid and regenerated into hydrochloride form simultaneously for the next adsorption operation after rinsing with water. The weak-base anion exchange adsorbents are to be an effective means to remove arsenic(V) from drinking water. The fast adsorption rate and the excellent adsorption capacity in the neutral pH range will render this removal technique attractive in practical use in chemical industry.
地下水砷污染被称为人类历史上最大的群体性中毒灾难，会造成严重的健康问题。对于通过饮用水广泛去除有毒砷暴露，有效的吸附剂是必不可少的。本文研究了弱碱性阴离子交换吸附剂从水中去除砷（V）的效果，旨在确定 pH 值、竞争阴离子和进料流速对修复的影响。使用两种弱碱性吸附剂在批处理和柱处理方法中评估砷（V）去除效率。通过两种吸附剂在批处理方法中的阴离子选择性来确定吸附容量。使用两种吸附剂填充的柱进行固定床实验的柱研究，动力学性能取决于进料流速和竞争阴离子。弱碱性吸附剂表明，这些对砷（V）具有选择性，而对氯离子、硝酸盐和硫酸盐阴离子具有竞争性。溶液 pH 值在砷（V）去除中起着重要作用，较高的 pH 值会导致较低的吸附容量。即使在 250-350 h(-1) 的高流速下，这些吸附剂也能去除低浓度水平的砷（V）。用 1 M HCl 酸定量洗脱吸附的砷（V），同时用清水冲洗后再生为盐酸盐形式，以备下一次吸附操作。弱碱性阴离子交换吸附剂是从饮用水中去除砷（V）的有效手段。在中性 pH 范围内的快速吸附速率和优异的吸附容量将使这种去除技术在化学工业中的实际应用中具有吸引力。
