Zheng Bin, Ye Yizi, Hu Baowei, Luo Chunhui, Zhu Yuling
College of Economics and Management, Nanjing Forestry University 159 Longpan Road Nanjing Jiangsu province 210037 P. R. China.
School of Life Sciences, Shaoxing University Huancheng West Road 508 Shaoxing 312000 P. R. China
RSC Adv. 2019 Nov 6;9(62):36144-36153. doi: 10.1039/c9ra06516d. eCollection 2019 Nov 4.
In order to effectively destroy the structure of the passive oxidation film that covers zero-valent iron (ZVI), an Fe(iii)-reducing strain, namely sp., was isolated from anaerobic activated sludge and coated on ZVI, which was distributed in porous ceramsite made of iron dust, kaolin and straw, with a ratio of 7 : 3 : 1. Batch experiments showed that under the optimized conditions, the maximum removal amount of Cr(vi) by ZVI increased from 7.33 mg g to 26.87 mg g in the presence of the Fe(iii)-reducing bacterium. The column experiment was performed with the addition of the agar globules to supply nutrients to the strain. Compared with ZVI, the column penetration time and maximum capture amount of RB-ZVI increased to 17 h and 112.5 mg g, respectively, on the 15 day. Furthermore, the service life of RB-ZVI was prolonged in the existence of the strain. Based on X-ray diffraction, Raman spectroscopy and X-ray photoelectron spectroscopy analyses, the key mechanisms for the removal of Cr(vi) by ZVI coated with Fe(iii)-reducing bacterium were determined to be adsorption, reduction, coprecipitation and biomineralization.
为了有效破坏覆盖在零价铁（ZVI）表面的被动氧化膜结构，从厌氧活性污泥中分离出一株铁（III）还原菌，即 菌，并将其包覆在ZVI上，ZVI分布在由铁粉、高岭土和秸秆按7:3:1比例制成的多孔陶粒中。批次实验表明，在优化条件下，在铁（III）还原菌存在的情况下，ZVI对Cr（VI）的最大去除量从7.33 mg/g提高到了26.87 mg/g。柱实验通过添加琼脂球向菌株提供养分进行。与ZVI相比，RB-ZVI在第15天的柱穿透时间和最大捕获量分别增加到了17 h和112.5 mg/g。此外，在菌株存在的情况下，RB-ZVI的使用寿命得以延长。基于X射线衍射、拉曼光谱和X射线光电子能谱分析，确定铁（III）还原菌包覆的ZVI去除Cr（VI）的关键机制为吸附、还原、共沉淀和生物矿化。
