Abstract:

Biochar can be used as an excellent platform for supporting various photocatalytic particles due to its unique surface properties,easily tunable functional groups, chemical stability, and electrical conductivity. Compounding photocatalysts with biochar can produce biochar-based photocatalysts and combine the advantages of biochar with catalysts.The resulting composites can significantly improve in functional groups, pore properties, surface active sites, catalytic degradation ability and so on.The electron-conductive nature of biochar can reduce the quick recombination of the e^-/h⁺ pair during photocatalysis and suitable surface functional groups enable immobilization of different pollutants, which is favorable for photocatalysis. The paper aims to review and summarize the various synthetic techniques and physicochemical properties of biochar-based photocatalysts and their effects on the decontamination of wastewater. Various preparation methods including sol-gel, ultrasound, hydrothermal/solvothermal, hydrolysis, calcination, precipitation and thermal polycondensation are summarized and discussed in detail. Furthermore, the synergistic effects of adsorption and photodegradation of pollutants by biochar-based photocatalysts are discussed with in-depth mechanistic evidence. Finally, the application of biochar-based photocatalysts for different contaminants removal is summarized, and some future trends and potentials are outlined.

Key words: biochar, photocatalyst, wastewater, degradation

摘要：

生物炭因具有独特的表面性质、易修饰的官能团、良好的导电性和化学稳定性常被用作光催化剂的载体。将光催化剂与生物炭复合制备得到生物炭基光催化剂，不仅将二者的优势有效结合起来，同时得到的复合材料在官能团、孔性能、表面活性位点、催化降解能力等方面均有显著改善。生物炭良好的导电性提高了光催化过程中电子-空穴对分离的效率，丰富的表面官能团能够吸附固定不同的污染物，便于其光催化去除。本文综述了生物炭基光催化剂的各种制备工艺、催化性能及其对废水处理的影响，详细地介绍了溶胶-凝胶、超声、水热/溶剂热、水解、焙烧、沉淀和热缩聚等生物炭基光催化剂的制备方法。此外，还通过深入的机理分析，探讨了生物炭基光催化剂对污染物的吸附和光催化降解的协同效应。最后，归纳了生物炭基光催化剂在不同污染物去除方面的应用并展望了未来的发展前景和潜力。

关键词: 生物炭, 光催化剂, 废水, 降解