Wang Gang, Du Feng-ling, Chang Qing, Xu Min
Huan Jing Ke Xue. 2015 May;36(5):1707-12.
A novel macromolecule flocculant, polyethyleneimine-sodium xanthogenate (PEX), was applied in the treatment of wastewater containing Cr(VI) ions. The trapping performance of PEX for Cr(VI) ions was studied, and effects of selective important factors, such as initial Cr(VI) concentration, pH value, coexisting inorganic substance and turbidity etc., on the removal of chromium by PEX were investigated. The experimental results indicated that PEX could efficiently remove different concentrations of chromium in strong acidic media. The maximum removal rate of Cr(VI) and total Cr reached 99.1% and 96.6% at pH 2.0, respectively. The existence of influencing substance (e. g. NaCl, NaF, Na2SO4, CaCl2 and turbidity) would inhibit the removal of Cr(VI) ions, and promote the removal of total Cr to some extent. Fourier transform infrared spectroscopy (FTIR) analysis showed that the behaviors in the removal of Cr(VI) ions included reduction and chelation. Cr(VI) ions were reduced to Cr(III) ions by dithiocarboxylic acid groups on the PEX molecule, and then chelating reactions existed between Cr(III) ions and dithiocarboxylic acid groups and amino groups of PEX.
一种新型高分子絮凝剂，聚乙烯亚胺-黄原酸钠（PEX），被应用于含Cr(VI)离子废水的处理。研究了PEX对Cr(VI)离子的捕集性能，并考察了初始Cr(VI)浓度、pH值、共存无机物和浊度等选择性重要因素对PEX去除铬的影响。实验结果表明，PEX能在强酸性介质中有效去除不同浓度的铬。在pH 2.0时，Cr(VI)和总Cr的最大去除率分别达到99.1%和96.6%。影响物质（如NaCl、NaF、Na2SO4、CaCl2和浊度）的存在会抑制Cr(VI)离子的去除，并在一定程度上促进总Cr的去除。傅里叶变换红外光谱（FTIR）分析表明，去除Cr(VI)离子的行为包括还原和螯合。PEX分子上的二硫代羧酸基团将Cr(VI)离子还原为Cr(III)离子，然后Cr(III)离子与PEX的二硫代羧酸基团和氨基之间存在螯合反应。
