黄原胶对多硫化钙还原地下水中Cr(Ⅵ)的影响

EFFECT OF XANTHAN GUM ON CHROMIUM( Ⅵ) REDUCTION IN GROUNDWATER BY CALCIUM POLYSULFIDE

通过加入黄原胶对流体进行黏度改性,增强修复剂在地下非均质环境中的迁移性能和污染物的接触效率,从而提高修复效率。实验重点研究了在黄原胶存在条件下,各因素(黄原胶浓度、多硫化钙剂量、地下水离子)对多硫化钙处理Cr(Ⅵ)的影响。结果表明,黄原胶对Cr(Ⅵ)去除具有一定抑制作用且在反应45 min内符合二级动力学方程;多硫化钙剂量对Cr(Ⅵ)去除影响显著:随着多硫化钙剂量的增加,Cr(Ⅵ)的去除率显著增加,但增加到1.25×后,Cr(Ⅵ)去除率增速减缓;HCO_3^-具有抑制作用,Mg^(2+)具有促进作用,NO_3^-、SO_4^(2-)、Cl^-、Ca^(2+)和K^+影响很小。

The fluid was modified by adding xanthan gum（ XG） in viscosity. The modified fluid could enhance the migration performance of remedial amendment in subsurface heterogeneous environment and the contact efficiency with pollutant,so as to improve the effect of remediation. The paper focused on the factors for treating chromium（ Ⅵ） by calcium polysulfide（ CPS）in the presence of XG,including XG concentration,CPS dosage,ions in groundwater. Results indicated that XG had some inhibitory effect on the removal of chromium（ Ⅵ） and the reaction fitted well with the second dynamics equation in 45minutes; CPS dosage had a prominent effect on the removal of chromium（ Ⅵ） ： The chromium（ Ⅵ） removal rate increased with the increase of CPS dosage,but increased slowly after the dosage increased to 1. 25 ×; HCO_3^- had an inhibitory effect,Mg^（2＋） had a promoting effect,while NO_3^-、SO_4^（2-）、Cl^-、Ca^（2＋） and K~＋ had a little effect.