Complete elimination with a combined system of aerobic granular sludge and photocatalytic technology for the treatment of petroleum refinery wastewater

本财年的研究重点包括：（1）开发Z型g-C3 N4-Ag/Ag 2 O/BiPO 4/Bi 2 WO 6（CN-Ag/P/BWO）净水剂;（2）考察对肠球菌的消毒活性; (3)阐明肠球菌的消毒机理; (4)（5）揭示CN-Ag/P/BWO固定化体系的循环能力;（6）探索CN-Ag/P/BWO对有机物（苯酚/四环素）的降解活性。结果表明，成功构建了Z型CN-Ag/P/BWO体系，对肠球菌具有良好的杀菌效果。其杀菌机理主要是光生空穴、超氧自由基和羟基自由基的作用。抗氧化系统的恶化是导致细胞膜和能量系统受损的原因，进一步导致细胞内成分的泄漏和细菌的最终崩溃。CN-Ag/P/BWO在环境水消毒中具有很高的实用性。固定化CN-Ag/P/BWO体系在5个循环中均表现出较高的杀菌活性。虽然CN-Ag/P/BWO具有稳定的π共轭结构，对苯酚的降解效果不佳，但60 min后四环素的去除率可达97%，显示出较高的光催化活性和降解抗生素的前景。因此，这项工作提供了一种高效的水净化技术，有助于改善公众健康和环境。

In this fiscal year, the study was carried out through the following key points: (1) Develop Z-scheme g-C3N4-Ag/Ag2O/BiPO4/Bi2WO6 (CN-Ag/P/BWO) for water purification; (2) Investigate the disinfection activity for Enterococcus sp.; (3) Clarify the disinfection mechanism for Enterococcus sp.; (4) Evaluate the practicability to environmental water disinfection; (5) Reveal the cyclic ability of CN-Ag/P/BWO immobilized system; (6) Explore the degradation activity of CN-Ag/P/BWO for organics (phenol/tetracycline). The results showed that Z-scheme CN-Ag/P/BWO was successfully constructed with remarkable disinfection performance for Enterococcus sp.. The disinfection mechanism demonstrated the major roles of photogenerated holes, superoxide radicals and hydroxyl radicals. The deteriorated antioxidant system was responsible for the damaged cell membrane and energy system, further leading to the leakage of intracellular components and final collapse of bacteria. CN-Ag/P/BWO exhibited high practicability to environmental water disinfection. Besides, the immobilized CN-Ag/P/BWO system showed high activity for Enterococcus sp. disinfection during five cycles. Although, CN-Ag/P/BWO exhibited poor performance for phenol degradation due to its stable π-conjugated structure, 97% of tetracycline was removed after 60-min treatment, indicating its high photocatalytic activity and prospect for antibiotics degradation. Therefore, this work provides a high-efficiency technology for water purification, contributing to the improvement of public health and environment.