采用钡盐沉淀法处理六价铬电镀废水，研究了废水预调pH、破氰方式和Cr(VI)沉淀剂加入量对六价铬、总铬、铜和镍去除率的影响，并研究了硫酸加入量对铬酸钡沉淀中六价铬回收率的影响。钡盐法处理六价铬电镀废水的最优工艺参数为：预调pH 8，钡盐加入量为理论值的2.4倍，双氧水破氰，液碱终调pH至10。采用最优工艺参数处理后，出水总铬含量为0.4 mg/L，镍含量为0.3 mg/L，铜未检出，均低于GB 21900-2008中表2的排放限值。用浓硫酸对处理废水所得铬酸钡沉淀进行转化反应后，六价铬的回收率可达65%。钡盐沉淀法的药剂成本和危险固废处理成本均较传统化学还原法高，因此钡盐沉淀法较适用于专业镀铬厂和铬水严格分质排放的电镀园区。%Hexavalent chromium-containing electroplating wastewater was treated by barium salt precipitation. The effects of pH pre-adjustment of wastewater, cyanide decomposition method, and addition of Cr(VI) precipitator on the removal of hexavalent chromium, total chromium, copper, and nickel were studied. The influence of the dosage of sulfuric acid on the recovery of hexavalent chromium was examined. The optimal process parameters for treatment of hexavalent chromium-containing electroplating wastewater by barium salt precipitation are as follows:pre-adjusted pH 8, barium salt dosage 2.5 times of the theoretical value, cyanide decomposition with hydrogen peroxide, and final pH 10 adjusted with liquid caustic soda. After treating under the optimal process conditions, the total chromium content and nickel content in effluent is 0.4 mg/L and 0.3 mg/L, and no copper is detected, all of which are below the emission limits of Table 2 in the GB 21900–2008 standard. The recovery of hexavalent chromium in barium chromate sediment reaches 65% by solid–solid transformation using sulfuric acid. The costs for reagent and treatment of hazardous solid waste by barium salt precipitation are higher than those of traditional chemical reduction. Barium salt precipitation is suitable for professional chrome plating factories and plating industrial parks where chromium wastewater is strictly discharged and collected individually.
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