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

本财年重点开展了以下研究工作：(1)开发用于水净化的z -方案g-C3N4-Ag/Ag2O/BiPO4/Bi2WO6 (CN-Ag/P/BWO)；(2)调查对肠球菌的消毒活性；(3)明确肠球菌的消毒机制；(4)评价环境水消毒的实用性；(5)揭示了CN-Ag/P/BWO固定化体系的循环能力；(6)探讨CN-Ag/P/BWO对有机物（苯酚/四环素）的降解活性。结果表明，成功构建的CN-Ag/P/BWO方案对肠球菌具有良好的消毒效果。其消毒机理表明，光生空穴、超氧自由基和羟基自由基起主要作用。抗氧化系统的恶化导致细胞膜和能量系统的破坏，进一步导致细胞内成分的泄漏，最终导致细菌的崩溃。CN-Ag/P/BWO在环境水消毒中具有较高的实用性。此外，固定化CN-Ag/P/BWO系统在5个循环中对肠球菌具有较高的消毒活性。CN-Ag/P/BWO由于其π共轭结构稳定，对苯酚的降解性能较差，但经过60 min的处理，四环素的去除率达到97%，表明其具有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.