Institute of Environmental Pollution Control and Treatment, Zhejiang University, Hangzhou 310058, China.
Hangzhou No. 14 High School, Hanzhou 310006, China.
Water Res. 2021 Jan 1;188:116569. doi: 10.1016/j.watres.2020.116569. Epub 2020 Oct 25.
Intimately coupled photocatalysis and biodegradation (ICPB) combining photocatalysis with microbial degradation is an attractive wastewater treatment technology. However, when prepared in conventional ways, the supported-photocatalysts aggregate frequently, detach easily from carriers, and prohibit the colonization of microorganisms inside the carriers. To overcome these challenges, silane coupling agent (SCA)-enhanced TiO coating method is developed in this study. The coupling agent γ-glycidoxypropyltrimethoxysilane (KH560) greatly enhanced the adhesion between photocatalysts and the carrier through ether and Ti-O-Si linkages. The dense TiO layer was firmly adhered to the carrier outer surface, and the loading amount reached 351.8±8.2 mg/g, over ten times higher than using the powder sintering method (31.5±2.4 mg/g). In the ICPB system constructed with the KH560-enhanced TiO-supported polyurethane sponge (KH560-TiO-PU) carriers, removal efficiencies of two model odor substances, 2-methylisoborneol (2-MIB) and geosmin (GSM), reached 88.9±0.3% and 85.0±1.0% in 12 h at an initial concentration of 500 ng/L respectively, which were 17.7±0.6% and 19.4±0.4% greater than those of the ICPB system prepared with the powder sintering method. After 5 operating cycles, the novel ICPB system remained stable with high 2-MIB and GSM removal efficiencies, reaching 89.9±0.8% and 86.1±0.2% respectively after 12h, while TiO peeling ratio was as low as 5.0±2.8%. Biofilms attached onto the carrier inner surface were resilient over the operating cycles with the increase of both richness and diversity of microbial communities. Analysis of biofilm microbial community and pollutant degradation pathways revealed the enhanced removal of 2-MIB and GSM in the novel ICPB system might be attributed to multiple factors. First, the alleviated aggregation and increased adhesion of photocatalysts onto carriers improved the overall photocatalysis efficiency. Second, biofilm inside of the carrier was protected and the microbial activity was well remained. Third, photocatalytic intermediate products were efficiently biodegraded by the enriched functional microbial populations, such as Thauera and Flavobacterium, with little concern of excessive oxidation. Collectively, this research provides a new technological solution that synergizes photocatalysis and biodegradation for effective removal of odorous substances in polluted natural water.
将光催化与微生物降解相结合的紧密偶联光催化和生物降解（ICPB）技术是一种很有吸引力的废水处理技术。然而，以传统方式制备时，负载型光催化剂容易团聚，容易从载体上脱落，并且阻止了微生物在载体内部的定殖。为了克服这些挑战，本研究中采用硅烷偶联剂（SCA）增强 TiO 涂层法。偶联剂γ-缩水甘油醚丙基三甲氧基硅烷（KH560）通过醚键和 Ti-O-Si 键极大地增强了光催化剂与载体之间的粘附力。致密的 TiO 层牢固地附着在载体外表面上，负载量达到 351.8±8.2mg/g，是使用粉末烧结法（31.5±2.4mg/g）的十倍以上。在使用 KH560 增强的 TiO 负载型聚氨酯海绵（KH560-TiO-PU）载体构建的 ICPB 系统中，在初始浓度为 500ng/L 时，两种模型气味物质 2-甲基异莰醇（2-MIB）和土臭素（GSM）的去除效率分别达到 88.9±0.3%和 85.0±1.0%，分别比使用粉末烧结法制备的 ICPB 系统高 17.7±0.6%和 19.4±0.4%。经过 5 个运行周期后，新型 ICPB 系统仍保持稳定，具有较高的 2-MIB 和 GSM 去除效率，在 12h 后分别达到 89.9±0.8%和 86.1±0.2%，而 TiO 剥落率仅为 5.0±2.8%。附着在载体内表面的生物膜在运行周期中具有较强的弹性，微生物群落的丰富度和多样性都有所增加。对生物膜微生物群落和污染物降解途径的分析表明，新型 ICPB 系统中 2-MIB 和 GSM 的去除增强可能归因于多个因素。首先，光催化剂在载体上的聚集和附着得到缓解，提高了整体光催化效率。其次，保护了载体内部的生物膜，保持了微生物的活性。第三，光催化中间产物被富含有功能微生物种群（如陶厄氏菌和黄杆菌）有效地生物降解，几乎没有过度氧化的担忧。总的来说，本研究为有效去除受污染天然水中的恶臭物质提供了一种将光催化与生物降解相结合的新技术解决方案。
