针对低浓度生物冶金浸出液难以处理的现状,利用硫酸盐还原菌(Sulfate Reducing Bacteria,SRB)沉淀分离有价金属离子的微生物法是很有应用前景的处理方法.本工作以提高SRB的还原活性为出发点,通过间歇式实验首先确定适宜的初始COD/SO4^2-比值和pH值,进而探讨固定化载体对SRB还原性能的影响.研究结果表明,初始COD/SO4^2-比值为3、初始pH值为7时SRB具有较高的生物活性.影响生物膜形成及SRB活性的首要因素是固定化载体的表面粗糙度,其次是孔容.表面光滑的惰性玻璃珠作为载体时没有生物膜形成,SRB的活性低,SO4^2-的去除率仅为50%;其他载体均观测到生物膜,且载体的孔容越大,SRB的SO4^2-去除率也越高.从SO4^2-的去除效果和工艺的稳定性考虑,多孔聚氨酯泡沫是较优的固定化载体,SRB的还原活性高,SKO4^2-的去除率高达95%,工艺操作简便.
In view of the difficulty in treating the bioleaching solutions, the selective precipitation of metals using H2S produced biologically by sulfate reducing bacteria (SRB) was as an alternative process. At first, the initial COD/SO4^2- ratio and pH value were determined, and then the capability of different immobilized carders was investigated by batch experiments. The results showed that high removal rate of SO4^2- was achieved when the initial COD/SO4^2- ratio was 3 and the initial pH value was 7. In the experiments, it was found that two factors were important for influencing the formation of biofilm and the reducing capability of SRB, the roughness of the immobilized carriers and the pore volume. There was no biofilm found when glass beads were immobilized carder, and the reducing capability of SRB was low, the removal rate of SO4^2- was only 50%. Furthermore, the removal rate of SO4^2- increased with the pore volume of immobilized carders. So, in view of the stability of process and the removal rate of SO4^2-, polyurethane foam was top priority as the immobilized carder in the experiments, the removal rate of SO4^2- with it reached 95%, and the process was easily operated.