改性聚乙烯亚胺捕集和回收水中的Cu2+

为提高含铜废水的处理效果及简化处理流程，采用CS₂、NaOH对聚乙烯亚胺进行改性，制备出一种新型高分子絮凝剂--PEX（聚乙烯亚胺基黄原酸钠）.以含Cu2+水样为处理对象，探讨了初始ρ（Cu2+）、pH、共存无机物质、有机物质以及浊度对PEX捕集Cu2+性能的影响，并考察了螯合絮体中Cu2+的回收情况.结果表明:PEX对含Cu2+水样具有很好的捕集性能，Cu2+去除率最高可达到100%；PEX对Cu2+的去除效果随着水样初始pH的升高而增强，但pH位于PEX等电点处时，Cu2+去除率有所降低.在较低的PEX投加量下，水样中共存的NaCl、CaCl₂、NaNO₃、Na₂SO₄、柠檬酸、焦磷酸钠对PEX去除Cu2+均可起到促进作用，而共存的EDTA、氨基乙酸、浊度对PEX去除Cu2+具有一定的抑制作用；增加PEX投加量后，可减弱或消除上述影响.螯合絮体采用HNO₃溶液进行静态浸泡30 d后，Cu的回收率可达100%.研究显示，PEX能有效去除和回收水样中的Cu2+. 

Removal and Recovery of Copper Ions from Aqueous Solutions by Modified Polyethyleneimine

Abstract: The increasing production of copper ion-containing wastewater is becoming one of the most serious environmental problems. Recently, the removal of copper ions from industrial effluents has attracted a lot of attention. In order to improve the treatment efficiency of sewage containing copper ions as well as to simplify the process, a novel macromolecule flocculant polyethyleneimine-sodium xanthogenate (PEX) was prepared by modifying polyethyleneimine with carbon disulfide and sodium hydroxide. The effects of initial Cu²⁺ concentration, pH, coexisting inorganic substances, organic substances and turbidity on the performance of trapping Cu²⁺ from aqueous solutions by PEX were studied. The recovery of copper was also investigated from the flocs. The results showed that PEX had a strong copper ion trapping capability, and the removal of Cu²⁺ could reach 100% under optimal conditions. The removal efficiency of Cu²⁺ by PEX increased with the increase of the initial pH value of the water sample, but the removal rate of Cu²⁺ decreased at the isoelectric point of PEX. When the dosage of PEX was lower, the coexistence of NaCl, CaCl₂, NaNO₃, Na₂SO₄, citric acid and sodium pyrophosphate in the water sample could promote the removal of Cu²⁺, but the existence of EDTA, aminoacetic acid and turbidity depressed the removal of Cu²⁺. However, these influences could be reduced or eliminated through increasing the dosage of PEX. The recovery rate of copper in the flocs was 100% when the flocs were immersed in nitric acid solutions for 30 days. The research showed that PEX could effectively remove and recover copper ions from aqueous solutions.