Abstract：
Biofouling limits applications of membrane technology in wastewater treatment, but dosing additives to membrane tanks is an effective method to alleviate biofouling. In this study, biochar derived from corncob and pyrolyzed at 300, 500, and 700°C was dosed to determine the underlying anti-biofouling mechanism. The effects of the biochar on the membrane properties and foulant behavior were systematically investigated. The results showed that biochar delayed the occurrence of the fouling transition (0.5-3.0 h), and decreased the flux decline rate, thus achieving a higher water flux (3.1-3.7 times of the control group). Biochar altered membrane surface properties, and increased the membrane surface charge, roughness, and hydrophilicity, which all contributed to higher membrane permeability. Moreover, adding biochar reduced the number of foulants in the fouling layer, particularly protein substances. The flux model fit and the XDLVO theory further revealed the mitigating effect of biochar on membrane biofouling. At the initial intermediate-blocking stage, the effect of biochar on membrane fouling was determined by its properties, and adsorption capacity to the foulants, BC500 presented the best mitigation performance. At the later cake-filtration stage, the role of biochar in membrane fouling was strongly associated with protein content in the fouling layer, and the minimum rate of flux decline occurred in BC300. This study promotes the understanding and development of biochar to alleviate membrane biofouling.
摘要：
生物污染限制了膜技术在废水处理中的应用，但是向膜罐中添加添加剂是减轻生物污染的有效方法。在这项研究中,从玉米芯中提取并在300、500和700°C下热解的生物炭以确定潜在的抗生物污染机理。系统研究了生物炭对膜性能和污垢行为的影响。结果表明，生物炭延缓了污垢转变的发生（0.5-3.0h），并降低了通量下降率，从而实现更高的水通量（对照组的3.1-3.7倍）。生物炭改变了膜表面特性，增加了膜表面电荷，粗糙度,和亲水性，这些都有助于提高膜的通透性。此外，添加生物炭减少了污垢层中污垢的数量，特别是蛋白质物质。通量模型拟合和XDLVO理论进一步揭示了生物炭对膜生物污染的缓解作用。在最初的中间阻塞阶段，生物炭对膜污染的影响取决于其性质，和对污垢的吸附能力，BC500表现出最佳的缓解性能。在后期的滤饼过滤阶段，生物炭在膜污染中的作用与污染层中的蛋白质含量密切相关，BC300的通量下降率最小。这项研究促进了生物炭的理解和发展，以减轻膜生物污染。
