天然FeS矿处理含Cr(Ⅵ)废水研究

Natural FeS Mineral Treatment of Wastewater with Cr(Ⅵ)

采用天然硫化亚铁矿处理含Cr(VI)模拟废水,系统探讨了初始pH、投加量、矿粉粒径、Cr(VI)含量、DO含量等因素对Cr(VI)去除率的影响,并采用X射线光电子能谱仪对反应前后矿物表面的铁与铬元素形态进行分析,初步探讨了Cr(VI)的去除机制。结果表明,FeS矿粉对Cr(VI)的去除主要依靠吸附与表面还原作用;Cr(VI)去除率随pH的升高而降低,当pH≥4时,其去除率明显减小;随矿粉投加量增加和矿粉粒径减小,Cr(VI)去除率升高但逐渐趋于平衡;溶解氧对反应影响很小。在pH=3、投加量为2 g/L、矿粉粒径<筛孔0.25 mm的优化条件下,对于初始质量浓度为25 mg/L的Cr(VI),其在1 h之内的去除率可达到近100%。研究发现一次回收矿粉的去除率仍可达80%,具有很高的再利用价值。

Natural FeS mineral powder was explored to treat simulated wastewater containing Cr(Ⅵ). The effects of influencing factors of initial pH, FeS dosage, FeS diameter, Cr(Ⅵ) content and DO content on Cr(Ⅵ) removal rate were discussed. The morphology of Fe and Cr in the mineral surface before and after reaction was analyzed by XPS, and the removal mechanism of Cr(Ⅵ) was preliminarily discussed. The results indicated that the removal of Cr (Ⅵ) by FeS powder mainly depends on adsorption and surface reduction. And the removal rate of Cr(Ⅵ) decreased with the increase of pH, and obvious decrease appeared when pH more than 4. The removal of Cr(Ⅵ) increased and then after gradually reached into balance with the increase of mineral dosage and the decrease of mineral particle size. Dissolved oxygen hardly affected the reaction. Under the optimized conditions of pH was 3.0, FeS dosage was 2 g/L as well as the mineral particle size less than 0.25 mm, initial mass concentration of Cr(Ⅵ) was 25 mg/L, the removal rate could reach close to 100% within 1 h reaction. The removal of Cr(Ⅵ) by the reused powder was more than 80%, which indicated that Natural FeS mineral has high recycle value.