生物磁分离新技术处理含铬废水最佳条件的研究

为了探索新工艺"趋磁细菌-磁分离法"处理含铬废水的最佳条件,首先进行了趋磁细菌对铬离子的去除影响因素试验,研究了pH、温度、时间和微生物量对吸附的影响;其次进行了趋磁细菌的分离试验,考查了磁分离器中悬丝摆放位置和磁场强度对溶液中菌体的去除效果的影响.试验结果表明,体系的pH值对铬离子的去除效率影响最大,pH值的最佳范围为5～11;在室温范围内,温度对吸附的影响不大;随着菌量的增加,菌对Cr(Ⅲ)的去除率略有提高,而单位质量菌的吸附量却有明显下降.在分离趋磁细菌时,磁场强度为100高斯时分离效果很高,而超过100高斯以后,效果不明显;另外,分离器中的金属丝和磁场方向垂直放置要比平行放置效果好,并用扫描电镜放大5 000倍观察了金属丝上被捕集的趋磁细菌的形态和结构.

A novel technology for treatment of wastewater containing Cr(III) ions

Magnetotactic bacteria(MTB)-magnetic separation method was put forward for treatment of wastewater containing Cr(III). The effects of performance parameters such as pH, temperature, sorption duration and biomass concentration in the process of removing Cr(III) by MTB were investigated, and intensity of magnetic field and the place of wire casing were also analyzed. The experimental results indicated that pH value and concentration of biomass exerted important influence on the sorption process, and their optimum scopes were 5~11 and 4.0~10.0 g/L, respectively. No significant effect of temperature had been observed in the discussed range, and the process could be finished within 5 min. The separation efficiency was very good when magnetic field intensity was 100 Gauss, and no distinct improvement with higher magnetic field intensity. Moreover, the separation efficiency was better when metal wires were vertical than parallel with magnetic force line. At the same time, the wires loading MTB were magnified 5 000 times by scanning electron microscope (SEM).