高分子重金属絮凝剂PEX捕集Cr^(3+)性能研究

Study on the Performance of Macromolecule Heavy Metal Flocculant PEX Trapping Cr(Ⅲ) Ions

为提高含铬废水的处理效率及简化处理流程,以聚乙烯亚胺、NaOH、CS2为原料,在一定条件下用化学方法合成了一种新型高分子重金属絮凝剂PEX.通过絮凝实验研究了PEX捕集Cr3+的性能,并对几个影响因素作了考察.实验结果表明:1)该絮凝剂对Cr3+有一定的捕集功能,但需要与硫酸铝复配才能表现出较高的去除效率,且Cr3+的去除率随着硫酸铝浓度的增加而增大.2)pH值对PEX/硫酸铝复配去除Cr3+有一定的影响,pH值较低时Cr3+的去除率较小,当pH值升高后,Cr3+的去除率明显增大.3)Cr3+和致浊物质共存时,会相互促进彼此的去除,pH=5.0时,Cr3+和浊度的最高去除率均在99%以上.

The paper intends to introduce the authors＇ development of a novel water-soluble macromolecule heavy metal flocculant PEX with its purpose to increase the efficiency of treatment of sewage containing Cr^3＋ as well as to simplify its process.The novel water-soluble macromolecule heavy metal flocculant PEX was synthesized by means of making polyethyleneimine reacted with CS2 in alkaline medium.Using the jar tests,the flocculation performance was evaluated by using wastewater which contains Cr^3＋.Some factors which affected the removal of Cr^3＋ were also studied.The experimental results show that firstly,PEX has some chelating capability with Cr^3＋,but aluminium sulfate solution must be added in the system to perform the better removal efficiency of Cr^3＋,and the removal rate of Cr^3＋ will be improved evidently with an increase in the concentration of aluminum sulfate.Secondly,The pH value has some effect on the removal efficiency of Cr^3＋ with the complex of PEX and aluminium sulfate.It is poor at lower pH value,and it will increase evidently with pH value increasing.Thirdly,Cr^3＋ and turbidity-causing substance promote the removal of each other in the co-existing system for heavy metal ions and turbidity,and when pH is 5.0,the maximum removal rates of both Cr^3＋ and turbidity are above 99%.