钡盐法处理六价铬Cr(Ⅵ)废水的研究

Research of hexavalent chromium wastewater treated by barium salt

用钡盐法处理含铬废水,考察了废水初始pH、重铬酸钾的浓度、反应温度及计量比(氯化钡与六价铬物质的量比)对六价铬回收效果的影响。采用原子吸收分光光度法测量溶液中六价铬浓度。结果表明,废水初始pH为8～9时,六价铬的回收率达95%以上;重铬酸钾的浓度对六价铬的回收率几乎没有影响,但处理后废水中六价铬的浓度随其浓度的增加而上升;10℃以上时,反应温度对六价铬的回收率没有很大影响,当温度降至10℃时,六价铬的回收率随反应温度的下降而急剧下降;计量比为1.1∶1时,六价铬的回收率为99.22%,处理后废水中六价铬的浓度为0.276 7 mg/L,达到了国家关于含铬污水排放时的标准。

Wastewater containing chromium was treated by barium salt.The effect of the pH,concentration of potassium dichromate,reaction temperature and the stoichiometry（molar ratio of barium chloride to hexavalent chromium）was mainly studied.The concentration of hexavalent chromium was measured by atomic absorption spectrophotometry.The results indicated that when the pH was 8～9,recovery rate of hexavalent chromium exceeded 95%;the concentration of potassium dichromate had no effect on the recovery rate of hexavalent chromium,but the concentration of hexavalent chromium in treated wastewater increased as it went up;when the reaction temperature reduced,the recovery rate of hexavalent chromium was hardly steady,while the temperature dropped at 10 ℃,it began to decline;if the stoichiometry was 1.1 ∶1,the recovery rate of hexavalent chromium arrived at 99.22%.The concentration of hexavalent chromium in treated wastewater was 0.276 7 mg/L,which belowed the maximum concentration of discharging hexavalent chromium of the national standards.