【摘要】 分析了发生突发性镉污染时镉在水体中的存在形式,考察了常规混凝、化学沉淀以及两者联用对镉污染源水的处理效果。结果表明:发生突发性镉污染时,镉在水体中主要以溶解态形式存在,所占比例>60%;常规混凝沉淀可有效去除吸附态镉,但对溶解态镉的去除效果有限;化学沉淀法对镉有良好的去除效果,但会增加滤后水的浊度;化学沉淀与混凝联用技术可大大提高对镉的去除效果,在预调pH值至10、PAC的投加量为20 mg/L时,对镉的去除率>97.7%,最大可处理浓度提高至0.220~0.264 mg/L。更多还原

【Abstract】 The existing forms of cadmium(Cd) in water polluted accidentally by Cd were analyzed,and the removal effects of Cd by conventional coagulation-sedimentation,chemical precipitation and the combined process were investigated.The results show that the dissolved Cd accounts for above 60% of the total Cd under accidental Cd pollution.The adsorbed Cd can be removed efficiently by the conventional coagulation-sedimentation,while the removal efficiency of the dissolved Cd is poor.The chemical precipitation process has good removal effect of Cd,which would bring the increase of the turbidity.The combined process of conventional coagulation-sedimentation and the chemical precipitation can further improve the removal effects.When presetting the pH value to 10 and adding 20 mg/L PAC,the Cd removal rate is above 97.7%,and the maximum concentration that can be treated is 0.220 mg/L to 0.264 mg/L.更多还原