(昆明理工大學(xué) 環(huán)境科學(xué)與工程學(xué)院，昆明 650093)
摘 要: 采用“石灰中和−曝氣微電解−絮凝沉淀法”技術(shù)處理含重金屬鉛鋅冶煉廢水，考察微電解進(jìn)水pH值、水力停留時(shí)間、鐵炭質(zhì)量比、絮凝pH值和助凝劑用量等反應(yīng)條件對廢水中鉛、鋅、鎘、銅和砷離子去除率的影響。采用掃描電鏡(SEM)和能譜(EDS)等測試手段，研究微電解反應(yīng)前后鐵屑和活性炭的表面形貌及物質(zhì)組成的變化，分析鐵炭微電解原理及鐵炭床失效原因。結(jié)果表明：在微電解鐵炭質(zhì)量比為1:1.5、進(jìn)水初始pH值為2.5、水力停留時(shí)間為40 min、絮凝pH值為11、助凝劑PAM用量為4×10−6(質(zhì)量分?jǐn)?shù))的條件下，微電解−絮凝耦合技術(shù)對廢水中各離子的去除效果最佳，Cd2+出水濃度達(dá)到了《污水綜合排放標(biāo)準(zhǔn)》(GB8978-1996)中的一級標(biāo)準(zhǔn)，Pb2+、Cu2+、Zn2+和總砷的出水濃度滿足《地表水環(huán)境質(zhì)量標(biāo)準(zhǔn)》(GB 3838-2002)中Ⅲ類水標(biāo)準(zhǔn)。
關(guān)鍵字: 重金屬；鉛；鋅；砷；微電解；絮凝；冶煉廢水
（Faculty of Environmental Science and Engineering, Kunming University of Science and Technology,
Kunming 650093, China）
Abstract:The combined process of “l(fā)ime neutralization-micro-electrolysis-flocculation” was used to treat lead and zinc smelting wastewater containing heavy metal ions. The influence of the experimental conditions on the removal rate of Pb2+, Zn2+, Cd2+, Cu2+ and As ions in the wastewater was also investigated. The experimental conditions included the mass ratio of Fe to C, initial pH of the infall wastewater, and hydraulic retention time for the micro-electrolysis reactions, and pH and dosage of PAM flocculant for following flocculation reactions. The morphology and compositions of the carbon and iron surface were also characterized by SEM and EDS before and after the treatment of the micro-electrolysis reaction, the reaction mechanism of Fe/C micro-electrolysis and the invalidation cause of Fe/C wadding were analyzed. The results show that the optimal conditions of the micro-electrolysis-flocculation are the mass ratio of Fe to C of 1:1.5, initial pH 2.5 and reaction time 40 min for the micro-electrolysis reactions, and pH 11 and dosage of PAM of 4×10−6 (mass fraction) for flocculation reaction, under which the combined technique has the highest removal efficiency for the heavy metal ions in this wastewater. Cd2+concentration in the outlet wastewater satisfies the primary standard in 《Integrated Wastewater Discharge Standard》(GB8978-1996) in China, and the concentrations of Pb2+, Zn2+, Cu2+ and As ions satisfy the Ⅲ surface water standard of《Environmental Quality Standard for Surface Water》(GB 3838-2002) in China.
Key words: heavy metal; lead; zinc; arsenic; micro-electrolysis; flocculation; smelting wastewater
