摘要
针对黑炭/零价铁复合材料(BF)、金属还原菌(GY-1)单独使用修复Cr(Ⅵ)污染环境存在的问题,构建了黑炭零价铁与金属还原菌的耦合体系,考察了耦合体系中溶液pH值、Cr(Ⅵ)浓度、反应时间、温度对微生物生长和溶液中Cr(Ⅵ)去除的影响,并且研究了耦合体系中铁的动态变化。实验结果表明:黑炭/零价铁复合材料可作为金属还原菌的固定化载体,为金属还原菌提供繁殖场所的同时,提高其对Cr(Ⅵ)的抗性。耦合体系中Cr(Ⅵ)的去除效果明显优于单独使用零价铁/黑炭和单独铬还原菌的效果。在耦合体系中,3 mL细胞培养液(OD600为1.2-1.6)和0.1 g黑炭负载零价铁材料,Cr(Ⅵ)初始质量浓度为100mg·L^-1条件下,反应24h后可将溶液中Cr(Ⅵ)完全去除。XPS结果显示,反应阶段Cr(Ⅵ)和Cr(Ⅲ)共同存在于耦合体系中,但大部分的Cr(VI)会被零价铁和铬还原菌还原为Cr(Ⅲ),此外,存在黑炭和菌体对Cr(Ⅵ)的吸附作用。耦合体系中Fe(Ⅱ)含量高于单独黑炭负载零价铁材料,说明微生物能还原零价铁钝化层的Fe(Ⅲ)为Fe(Ⅱ),使Fe(II)继续参与还原反应,产生循环效果,增强耦合体系对Cr(Ⅵ)的去除效果。同时,铁离子作为一种电子传递介质增强微生物对Cr(Ⅵ)还原过程中的电子传递,加速反应进行的同时,解决零价铁表面易钝化问题。
To solve the problem of chromium(Ⅵ) pollution, a coupling system composed of biomass carbon/zero-valent-iron composite and reduced metal bacteria, biomass was constructed. In the system, the influencing parameters of solution pH, chromium(Ⅵ) concentration, reaction time and temperature on microbial growth and the removal efficiency of chromium(Ⅵ) have been studied. Besides, the dynamic change of iron in the coupled system is also discussed. The results showed that black carbon/zero-valent iron composite can be used as fixed carrier for metal reduced bacteria, providing breeding home for metal reduced bacteria and improving their resistance ability to Cr(Ⅵ). The removal efficiency of Cr(Ⅵ) in the coupled system is obviously better than that of single system of zero valent iron/black carbon and single chromium reducing bacteria. The coupled system was composed of 3 mL cell culture medium(OD600 is 1.2–1.6) and 0.1 g black carbon loading with zero-valent iron under the initial concentration of Cr(Ⅵ) of 100 mg·L^-1 can completely remove Cr(Ⅵ) from the solution within 24 hours. With the increased concentration of Cr(Ⅵ), the concentration of protein and the removal rate of Cr(Ⅵ) were decreased. PH=7 is the best condition for the growth of the strain and it has a high removal efficiency of hexavalent chromium. XPS results show that Cr(Ⅵ) and Cr(Ⅲ) may co-exist in the coupled system, but most of the Cr(Ⅵ) can be reduced to Cr(Ⅲ) by zero-valent iron and chromium reducing bacteria. The content of Fe(Ⅱ) is higher than that of the zero-valent iron material loaded on black carbon alone. It indicates that Fe(Ⅲ) in the passivation layer of zero-valent iron can be reduced to Fe(Ⅱ), which was beneficial for the continue reaction of Fe(Ⅱ), causing the cyclic effect and enhancing the removal effect of Cr(Ⅵ) in the coupled system. Besides, It also can be used as an electron transfer medium to enhancing the electron transfer between zero-valent iron and Cr(Ⅵ), accelerating the reaction, finally solve the problem of passivation layer of zero-valent iron, and enhance the effect of removing Cr(Ⅵ).
作者
王维大
李硕
林薇
李玉梅
张连科
韩剑宏
WANG Weida;LI Shuo;LIN Wei;LI Yumei;ZHANG Lianke;HAN Jianhong(School of Energy and Environment,Inner Mongolia University of Science and Technology,Baotou 014010,China)
出处
《生态环境学报》
CSCD
北大核心
2019年第10期2062-2069,共8页
Ecology and Environmental Sciences
基金
内蒙古科技大学创新基金项目（2016QDL-B08）
内蒙古自然科学基金博士基金项目（2016BS0511）
内蒙古自然科学基金项目(2018MS02015)
关键词
铬还原菌
零价铁
黑炭
Cr(Ⅵ)
耦合体系
chromium reducing bacteria
zero-valent iron
biochar
Cr(Ⅵ)
coupled system
作者简介
王维大(1984年生),男,讲师,博士,研究方向为污染物防治。E-mail:wangweida888@163.com;通信作者:韩剑宏(1966年生),女,教授,博士,研究方向为水资源管理与水污染控制技术。E-mail:hjhlpm@163.com。
