Department of Chemical Engineering, Environmental Engineering Program, Yale University, 9 Hillhouse Ave., New Haven, CT 06520, United States.
Water Res. 2010 Nov;44(19):5722-9. doi: 10.1016/j.watres.2010.05.045. Epub 2010 Jun 11.
A novel sorbent for arsenic, TiO(2)-impregnated chitosan bead (TICB), has been synthesized and successfully tested. Kinetic plots, pH dependence, isotherm data, and bead morphology are reported. Equilibrium is achieved after 185 h in batch experiments with exposure to UV light. The TICB system performs similarly to the mass equivalent of neat TiO(2) nanopowder. The point of zero charge (pzc) for TICB was determined to be 7.25, and as with other TiO(2)-based arsenic removal technologies, the optimal pH range for sorption is below this pH(pzc). Without exposure to UV light, TICB removes 2198 μg As(III)/g TICB and 2050 μg As(V)/g TICB. With exposure to UV light, TICB achieves photo-oxidation of As(III) to As(V), the less toxic and more easily sequestered arsenic form. UV irradiation also results in enhanced arsenic removal, reaching sorption capacities of 6400 μg As/g TICB and 4925 μg As/g TICB, where arsenic is initially added as As(III) and As(V), respectively. Because the TICB system obviates filtration post-treatment, TICB is superior to TiO(2) nanopowder from the perspective of implementation for decentralized water treatment.
一种新型的砷吸附剂——负载 TiO2 的壳聚糖珠（TICB）已被合成并成功测试。本文报道了动力学图、pH 值依赖性、等温线数据和珠体形态。在有紫外光照射的间歇实验中，经过 185 小时的接触，达到了平衡。TICB 系统的性能与纯 TiO2 纳米粉末相当。TICB 的零电荷点（pzc）被确定为 7.25，与其他基于 TiO2 的除砷技术一样，吸附的最佳 pH 值范围低于这个 pH 值（pzc）。在没有暴露于紫外光的情况下，TICB 可以去除 2198 μg As(III)/g TICB 和 2050 μg As(V)/g TICB。在暴露于紫外光的情况下，TICB 实现了 As(III)的光氧化为毒性较低、更容易螯合的 As(V)形式。紫外光照射还导致了砷的去除增强，达到了 6400 μg As/g TICB 和 4925 μg As/g TICB 的吸附容量，其中砷最初分别以 As(III)和 As(V)的形式添加。由于 TICB 系统避免了过滤后处理，因此从分散式水处理的实施角度来看，TICB 优于 TiO2 纳米粉末。
