生物炭添加对缓解膜生物污染的影响

The efficiency and mechanism of biochar addition to mitigate membrane biofouling

为了研究生物炭对膜生物污染的缓解效能,选用大肠杆菌为目标微生物,通过静态吸附,动态过滤以及生物炭对微生物及其释放的胞外聚合物(EPS)的影响分析,结合生物炭投加对膜面性质的影响.结果表明,与对照组相比,添加生物炭主要通过增大微生物与膜表面的静电斥力,增大膜的亲水性和膜表面的粗糙度来有效缓解微生物在膜表面的粘附,生物炭组膜表面细菌数降低了近30%.此外,在过滤实验中,添加生物炭可以延缓通量衰减的时间(6.5h),过滤终点时通量是对照组的3.7倍,且通过吸附微生物及其释放的EPS来缓解污染物负荷进一步缓解膜污染.生物炭对大肠杆菌、蛋白类、多糖类EPS的吸附量分别为2.4×10^(5)CFU/mL/g、3.729mg/g、1.135mg/g,其中对蛋白类EPS的影响效果明显.

In order to study the mitigation effect of biochar on membrane biofouling,Escherichia coli was selected as the model microorganism,and the effects of static adsorption,antibiofouling experiments and biochar on microorganisms and the extracellular polymers substances(EPS)released by microorganisms was analyzed,combined with the effect of biochar addition on membrane properties.The results showed that compared with the control group,the addition of biochar mainly alleviates the adhesion of microorganisms on the membrane surface by increasing the electrostatic repulsion between foulant and the membrane surface,increasing the hydrophilicity and roughness of the membrane surface,the number of bacteria on the membrane surface decreased by nearly 30%after adding biochar.In addition,in the antibiofouling experiment,the time to effectively delay the flux decay(6.5h)after adding biochar,the flux of dosing biochar at the end of filtration was 3.7times that of the control group,and to further alleviate the membrane pollution by absorbing microorganisms and extracellular polymeric substances.The adsorption capacity of biochar for Escherichia coli,protein-like and polysaccharide-like was 2.4×10^(5)CFU/mL/g、3.729mg/g、1.135mg/g respectively,among which the effect on protein was more remarkable.