Arsenic Removal and Recovery from Copper Smelting Wastewater Using TiO2
Arsenic Removal and Recovery from Copper Smelting Wastewater Using TiO2
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DOI：
10.1021/es1024355
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发表时间：
2010-12-01
影响因子：
11.4
通讯作者：
Jing, Chuanyong
中科院分区：
文献类型：
--
作者：
Luo, Ting;Cui, Jinli;Jing, Chuanyong
铜冶炼废水中砷的去除和回收是一个巨大的环境挑战。首次研究了用TiO2吸附去除废水中的砷，并用NaOH对废吸附剂进行再生和回收的新方法。EXAFS结果表明，As（III）作为原水中唯一存在的As种类，不与其他金属离子形成水络合物。在连续21个处理循环中，再生TiO2可将pH为1.4时废水中平均3890 +/- 142 mg/L的As（III）降至最终pH为7时的59 +/- 79 mu g/L。同时存在的重金属Cd、Cu和Pb浓度分别为369 mg/L、24 mg/L和5 mg/L，被降至0.02 mg/L以下。As（III）吸附遵循准二级速率动力学，吸附行为用电荷分布多位点表面络合模型描述。EDX和XPS分析表明，TiO2再生过程后废液中约60%的As（III）通过热汽化和随后的亚砷酸钠沉淀回收。这种“零”污泥法为冶金工业酸性废水的成功修复技术提供了新的思路。
Removal and recovery of high levels of arsenic (As) in copper smelting wastewater present a great environmental challenge. A novel approach was investigated for the first time using TiO2 for As adsorptive removal from wastewater and subsequent spent adsorbent regeneration and As recovery using NaOH. EXAFS results demonstrate that As(III), as the only As species present in the raw water, does not form an aqueous complex with other metal ions. An average of 3890 +/- 142 mg/L As(III) at pH 1.4 in the wastewater was reduced to 59 +/- 79 mu g/L in the effluent with final pH at 7 in the 21 successive treatment cycles using regenerated TiO2. Coexisting heavy metals including Cd, Cu, and Pb with concentrations at 369 mg/L, 24 mg/L, and 5 mg/L, respectively, were reduced to less than 0.02 mg/L. As(III) adsorption followed pseudosecond-order rate kinetics, and the adsorption behavior was described with the charge distribution multisite surface complexation model. Approximately 60% As(III) in the waste solution after the TiO2 regeneration process was recovered by therm.) vaporization and subsequent precipitation of sodium arsenite, as suggested by the EDX and XPS analysis. This "zero" sludge process sheds new light on successful As remediation technology for acidic metallurgical industry wastewater.