Study on the trapping Ni2+ ions and the removing turbidity behavior of macromolecule heavy metal flocculant
高分子重金属絮凝剂PEX捕集Ni2+及除浊性能研究

A novel water-soluble amphoteric macromolecule heavy metal flocculant polyethyleneimine-sodium xanthogente (PEX) has been synthesized by reacting polyethyleneimine with CS2 in alkaline medium. In jar tests, the flocculation performance of PEX was evaluated by using wastewater which contains Ni2 or/and turbidity. Some factors which affect the removal of Ni2 and turbidity were also studied. The experimental results showed that: (1) PEX had strong binding capabilities with Ni2 . The highest removal rate of Ni2 reached above 99%. (2) The pH value had some effect on the dosage of PEX, but little effect on the highest removal rate of Ni2 . (3) The existence of alkali metal or alkaline-earth metal ions in wastewater could promote the removal of Ni2 to some extent. (4) When there were Fe3 ions in wastewater, the removal rate of Ni2 would decrease evidently at lower pH value, and the existence of Fe3 ions would promote the removal of Ni2 with pH value increasing. (5) The existence of Cl- or NO-3 ions in wastewater could promote the removal of Ni2 , but SO2-4 ions would depress the removal of Ni2 . (6) Ni2 and turbidity-causing substance effected the removal of each other in the co-existing system of heavy metal ions and turbidity.