纳米铁去除饮用水中As(Ⅲ)和As(Ⅴ)

Removal of As(Ⅲ) and As(Ⅴ) from Drinking Water by Nanoscale Zero-Valent Iron

在好氧水体中,As（Ⅲ）比As（Ⅴ）更易迁移,而且在水处理过程中去除效率更低。在实验室合成制得BET比表面积为49.16 m2/g,直径范围为20~40 nm的纳米铁。通过批试验考察纳米铁对As（Ⅲ）和As（Ⅴ）去除能力及其反应动力学情况。结果表明,在pH为7,温度20℃时纳米铁能够快速地去除As（Ⅲ）和As（Ⅴ）,在60 m in内,0.25 g纳米铁对起始浓度为968.6μg/L As（Ⅲ）和828.9μg/L As（Ⅴ）的去除率大于99.5%。反应遵循准一级反应动力学方程,标准化后的As（Ⅲ）和As（Ⅴ）比表面积速率常数kSA分别为1.30 mL/（m2.m in）和1.64 mL/（m2.m in）。由实验结果可知,具有高反应活性的纳米铁是用于含砷饮用水处理非常有效的吸附材料。

Under oxic condition, water treatment process than As（ As（ Ⅴ）.Ⅲ） is more mobile in natural waters and with less removal efficiency in In order to remove As（Ⅲ） and As（ Ⅴ ） from drinking water, nanoscale zero-valent iron （NZVI） was synthesized in laboratory. Average BET surface area of the synthesized particles was 49.16 m2/g with diameter range of 20 -40 nm. Batch experiments were carried out to study the removal efficiency of inorganic arsenic and reaction kinetics of NZVI. The results showed that both arsenate and arsenite compounds could be removed efficiently by NZVI at pH =7 and under 20 ℃. The removal rate for As（Ⅲ） and As （ Ⅴ ） was over 99.5 % within 60 rain by 0.25 g NZVI for the sample solution with 968.6/L of As （ Ⅲ ） and 828.9 μg/L of As （ V ）. The reaction followed the first-order kinetic equation and the normalized reaction rate coefficients were 1.3 mL/（ m^2· min） and 1.64 mL/（ m^2 ·min） for As （ Ⅲ ） and As （ Ⅴ ） respectively. Based on the experiment results, NZVI has been proved to be a suitable sorbent for removal of arsenic from drinking water due to its high reactivity.