高分子重金属絮凝剂的制备及含铜废水处理

PREPARATION OF FLOCCULANT PEX AND TREATMENT OF WASTEWATER CONTAINING COPPER

以聚乙烯亚胺和二硫化碳制备聚乙烯亚胺基黄原酸钠(PEX),研究了PEX对废水中浊度及铜的去除效果．实验证明,在含铜废水中投加PEX,铜和浊度均可被去除,显示了其除浊与除重金属的双重功能．PEX与投加氧化钙的化学沉淀法相比:适用的废水pH值在5．0-6．0之间,低于化学沉淀法所必需的 pH值;出水中残余铜远低于化学沉淀法;生成的矾花较大,易于沉降分离,化学沉淀法生成的沉淀细小, 难于分离．研究还表明,PEX为两性聚合电解质,在较低的pH值下,分子上的氨基带正电荷,发挥电中和作用达到絮凝除浊效果;在较高的pH值下,分子上的黄原酸基和氨基均可与重金属离子发生配位及螯合反应,从而达到去除重金属离子的效果．

A flocculant polyethyleneimine-sodium xanthogenate （PEX） was prepared, The effects of PEX on removing copper ions and turbidity of wastewater was studied. So it was proved that PEX has the function of removing both turbidity and copper. Compared with the traditional chemical precipitation by CaO, PEX showed obvious advantages： ①For PEX, the optimum waste water pH ranges from 5.0 to 6. 0 which is lower than that for traditional chemical precipitation method. ②PEX achieves lower residual aqueous phase metal concentration and turbidity than CaO only. ③Further more , the former floc is large and settle well, the latter floc was tiny and difficult to separate from water. The investigation showed that PEX is an amphoteric polyelectrolyte. At the lower pH value, the amino groups of the molecular are positive, so the turbidity is removed because of electro-neutralization flocculation ; at the higher pH value, both amino groups and xanthogenate groups contribute to the removal of heavy metal because of coordination and chelation.