钝化膜水解菌筛选及其协同零价铁去除Cr(Ⅵ)的研究

Use of Zero Valent Iron Combined with a Passive Film Hydrolyzing Strain for Effective Removal of Cr(Ⅵ) from Wastewater

作为一种环保价廉的还原剂,零价铁广泛应用于被铬(Cr)污染土壤和地下水的修复.但零价铁在反应过程中会生成铁氧化物覆盖其表面,从而导致活性降低,零价铁的规模化应用因此受到了影响.通过实验筛选出一株具有水解零价铁表面铁氧化物(钝化膜)能力的微生物Lysinibacillus sp.JLT12,对其水解条件进行了优化.结果表明,当溶液中葡萄糖浓度为8 g/L、酵母粉浓度为10 g/L以及pH=7时,Lysinibacillus sp.JLT12协同零价铁去除Cr(Ⅵ)的效果最好.协同作用体系可以显著提高Cr(Ⅵ)的去除速率和最大去除量.Lysinibacillus sp.JLT12是一株产酸菌,因此具有水解钝化膜的能力. SEM-EDS分析结果表明,Lysinibacillus sp.JLT12能够促进零价铁表面腐蚀,吸附固定Cr,并阻止钝化膜的形成,进而提高Cr(Ⅵ)的去除效率.

Zero valent iron (ZVI) is widely used in the treatment of Cr(VI) contaminated soil and groundwater as a green and cheap chemical reducer. However, low reduction efficiency resulted from accumulation of iron oxide on the surface prevents it from wide application. Lysinibacillus sp. JLT12, which could hydrolyze the surface iron oxide (passive films) was selected and its hydrolysis condition was optimized. The results demonstrate that the optimal condition for Lysinibacillus sp. JLT12 is 8 g/L of glucose, 10 g/L of yeast and pH=7. The maximal removal rate and removed quality are obtained under the condition. Lysinibacillu s sp. JLT12 could produce acid, which accounts for its hydrolysis ability. SEM-EDS demonstrates that Lysinibacillus sp. JLT12 could adsorb Cr(VI) and accelerate the corrosion of ZVI to promote the reduction reaction.