黄铜矿催化电Fenton降解吡虫啉效果及浸出性能

Degradation efficiency of imidacloprid by chalcopyrite-catalyzed electro-Fenton process and catalyst leaching behavior

以模拟吡虫啉废水为处理对象,采用天然黄铜矿作为电Fenton反应的催化剂,考察了该体系降解吡虫啉的效果和黄铜矿浸出18种元素的性能。结果表明,在阴极和阳极分别为石墨板和钌铱镀层钛电极、黄铜矿用量为60 g/L、溶液初始pH为3、电流密度为40 mA/cm^(2)、极板间距为2.5 cm、反应时间为4 h的条件下,该体系对溶液COD和270 nm处特征峰的吸光度(UV270)的去除率分别达64.37%,84.69%。原子吸收和ICP-MS检测结果表明,反应后溶液中的Cu离子含量超过了《污水综合排放标准》(GB 8978—1996)三级标准值,但经过加碱沉淀(pH 10)和过滤处理,可以将Cu离子含量降到三级标准值以下。黄铜矿在酸性条件下可能会浸出较高含量的Mn、Cu、Zn、Cd、Pb等有毒重金属,在作为电Fenton催化剂处理废水的运用中应引起注意。

Natural chalcopyrite was used as catalyst for electro-Fenton process to treat the simulated imidacloprid wastewater,and the degradation efficiency of imidacloprid as well as leaching behavior of chalcopyrite with regard to 18 elements were investigated.The results showed that the removal rate of COD and UV absorbance at 270 nm(UV 270)after 4 h of reaction reached 64.37% and 84.69% respectively,when the cathode was graphite plate,the anode was titanium plate coated with RuO 2 and IrO 2,the chalcopyrite dosage was 60 g/L,the initial pH of electrolyte solution was 3,the current density was 40 mA/cm^(2) and the plate spacing was 2.5 cm.The results of atomic absorption and ICP-MS showed that the content of Cu ions in electrolyte solution after reaction exceeded the third-level standard value of Integrated Wastewater Discharge Standard(GB 8978-1996).However,the content of Cu ions could decrease to below the third-level standard value through chemical precipitation by adding alkali(pH to 10)and filtration treatment.Chalcopyrite may leach high levels of toxic heavy metals such as Mn,Cu,Zn,Cd,and Pb under acidic condition,which should be paid attention during the application of natural chalcopyrite as electro-Fenton catalyst for wastewater treatment.