除镉最佳混凝剂的筛选及应用条件研究

摘要

This studies conducted precipitation experiment on the influence of polymeric aluminum ferric chloride,iron chlorides and poly ferric sulphate on cadmium-containing wastewater.The data showed that all three coagulants achieve good results with removing rates of 98.22%,92.19% and 93.63%,respectively.Precipitation effect of polymeric aluminium ferric chloride on cadmium was studied.The results indicated that alkaline condition is beneficial to precipitation of cadmium ions.The removing rate is up to 98% when the pH is 9-11.For wastewater with initial concentration of 4.000 0 mg·L-1,the concentration of water bodies reduced to 0.184 0 mg·L-1 after precipitation.For initial concentration of 0.400 0 mg·L-1,the concentration of water bodies dropped to 0.007 2 mg·L-1 after precipitation.Certain amount of lime milk played a large role in the treatment,when the dosage is 30.00 mg·L-1,the removing rate is 99.91%.By means of kinetic fitting that polymeric aluminum ferric chloride influence on cadmium,corresponding pseudo first order equation.%通过采用聚合氯化铝铁（PAFC）、氯化铁（FeCl3）及聚合硫酸铁（PFS）对含镉废水的处理研究表明,三种混凝剂对含镉水体均有良好的处理效果,同等条件下,三种混凝剂对含镉水体去除率分别为98.22%、92.19%和93.63%。研究了PAFC对含镉水体的混凝沉淀效果,实验结果表明：碱性条件有利于镉离子的沉淀,当pH为9～11时,去除率可达98.00%左右;对于初始浓度为4.000 0 mg.L-1的含镉废水,经处理后,水体浓度可降至0.184 0 mg.L-1,对于初始浓度为0.400 0 mg.L-1的含镉废水,经处理后水体浓度降至0.007 2 mg.L-1;废水中投加一定量的石灰乳对PAFC除镉起一定的作用,投加量达30.00 mg.L-1时,其去除率达99.91%;通过对PAFC除镉动力学拟合,符合一级线性动力学方程。