硫化物还原Cr(VI)的反应动力学研究  

Study on kinetics of chromium (Cr(VI)) reduction by sulfide

作　　者：杨俊香[1] 兰叶青[1] 

机构地区：[1]南京农业大学理学院化学系,南京210095

出　　处：《环境科学学报》2005年第3期356-360,共5页Acta Scientiae Circumstantiae

摘　　要：在恒温和除氧封闭条件下 ,通过批式试验研究了水溶液中Cr(VI)与S2 - 的反应动力学及其影响因素 .研究结果表明 ,在恒定溶液pH值 (7～ 9范围内 )和硫化物浓度过量时 ,反应分 2个阶段 .初始反应阶段 (Cr(VI)反应物消耗约 5 0 %～ 70 %区间 ) ,反应动力学服从假 1级反应规律 ,lnC t作图呈线性关系 ;反应后期 (Cr(VI)反应物剩余大约 3 0 %～ 5 0 %区间 ) ,lnC t曲线出现转折 ,反应速率明显加速 .对过程进行分析 ,认为硫化物的最初氧化产物为单质S ,然后逐渐形成胶体态S ,继而胶体态S对硫化物产生强烈吸附作用 ,提高了硫化物的反应活性 ,促进了反应的加速进行 .胶体态S对硫化物参与的氧化还原反应有明显的催化作用 .此外 ,溶液酸度对总反应速率有显著影响 ,H+ 的反应级数为 1.In the constant temperature and the anaerobic conditions, the kinetics of chromium (Cr(VI)) reduction by sulfide and its affecting factors were conducted in batch experimental systems. The results showed that the reaction displayed in two stages when solution pH (between 7～9) kept stable and the initial concentration of sulfide was excessive. At the initial stage Cr(VI) was consumed ranging from 50%～70%, the reaction followed the pseudo first-order and the plots of ln C(Cr(VI)) versus reaction time (t) was linear. At the later stage,when Cr(VI) remained about 30%～50%, the plots of ln C(Cr(VI)) versus t was deviated from the initial line and reaction rate was accelerated dramatically. The further study indicated that elemental sulfur was the main product of sulfide oxidation, then the substance gradually formed colloid. Sulfide was adsorbed on the surfaces of colloid S, which accelerated the reaction rate remarkably. Colloid sulfur acted as a catalyst in the reaction of sulfide as a reacting substance. In addition, the reaction was first order with respect to c(H^+).

关 键 词：反应动力学 硫化物 铬 污染物 污染治理技术 废水处理工艺 

分 类 号：X703[环境科学与工程—环境工程] X131.2