电气石/H_2O_2体系对Cu(Ⅱ)–乙二胺四乙酸废水的降解及反应机理

DEGRADATION OF CHELATING Cu(Ⅱ)-ETHYLENEDIAMINETETRAACETIC ACID WASTEWATER AND ITS REACTION MECHANISM BY TOURMALINE/H_2O_2 SYSTEM

利用电气石/H2O2体系处理含Cu(Ⅱ)-乙二胺四乙酸(ethylenediamine tetraacetic acid,EDTA)废水,对其降解过程及机理进行了探讨。结果表明:黑色电气石较锂电气石对Cu(Ⅱ)-EDTA废水的处理效果好;化学需氧量的下降率和Cu2+去除率随电气石投加量和颗粒粒度的减小而逐渐增大,溶液pH=3时,两者最大。紫外-可见吸收光谱显示,处理后的Cu(Ⅱ)-EDTA被降解为小分子有机物。电气石与EDTA降解中间产物发生络合,反应过程中废水颜色发生明显变化。电气石/H2O2的反应过程与Fenton反应类似,溶解氧及电气石对溶液pH的调控也是影响有机物降解的重要因素。

The treatment of wastewater containing Cu（ Ⅱ ）-ethylene diamine tetraacetic acid （EDTA） was investigated. The degradation process and mechanism were discussed as well. The results show that tourmaline has higher treatment efficiency compared with elbaite. The decreasing rates of the chemical oxygen demand and the removal rate of Cu^2＋ ions increase with the increase of tourmaline addition and the decrease of the particle size. The largest removal rate is found at pH=3. Ultraviolet-visible spectra show that the structure of chelating Cu（ Ⅱ ）-EDTA decomposes to low-molecular organic material. The tourmaline and degradation products of EDTA chelate in the degradation manifest as a color change of the wastewater. The reaction of tourmaline/H2O2 is similar to the Fenton reaction. Additionally, the generation of dissolved oxygen and control of the pH are both key factors of degradation.