Photocatalytic degradation is an effective strategy for the removal of environmental pollutants. However, the development of low-cost and high-efficiency photocatalysts continues to present a significant challenge. This work reported the fabrication of a composite photocatalyst directly from waste biomass (rice hulls) in a single step, which efficiently degraded oxytetracycline (OTCs) under sunlight. The morphology, microstructures and photoelectric features of the fabricated materials were subjected to comprehensive investigation using characterization techniques. The results found that the improved photocatalytic activity in sunlight was attributed to the complexation of rice hull-derived biochar and nano-ZnO generated in the preparation, which exhibited favourable adsorption, conductivity characteristics and small bandgap. The photocatalytic efficiency was observed to reach 72.6 % in 120 min under the irradiation of a 100 W xenon lamp. The effect of natural waters, degradation kinetics and degradation TOC analysis were also examined. The dominant agent responsible for the degradation of OTCs was the •O radical. Furthermore, the principal photocatalytic degradation pathway of OTCs was identified with the assistance of UHPLC/MS.

中文翻译：

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具有光催化活性的稻壳生物炭可在阳光下有效降解水中的土霉素


光催化降解是去除环境污染物的有效策略。然而，低成本和高效光催化剂的开发仍然面临着重大挑战。这项工作报告了直接从废弃生物质（稻壳）一步制备复合光催化剂，该催化剂在阳光下有效降解土霉素（OTC）。使用表征技术对所制造材料的形貌、微观结构和光电特性进行了全面研究。结果发现，在阳光下光催化活性的提高归因于稻壳生物炭与制备过程中生成的纳米ZnO的络合，其表现出良好的吸附、导电特性和小带隙。在100W氙灯照射下，120min内光催化效率达到72.6%。还检查了天然水体的影响、降解动力学和降解 TOC 分析。导致OTC 降解的主要因素是•O 自由基。此外，在 UHPLC/MS 的帮助下确定了 OTC 的主要光催化降解途径。