Wang Jiawei, Wang Guoqiao, Yu Tian, Ding Nengjie, Wang Meicheng, Chen Yao
College of Architecture and Environment, Sichuan University Chengdu 610065 China
China Construction Third Engineering Bureau Group Co., Ltd Wuhan 430000 China.
RSC Adv. 2023 Aug 14;13(35):24237-24249. doi: 10.1039/d3ra03789d. eCollection 2023 Aug 11.
Biochar-modified TiO (C/TiO) was prepared by a sol-gel method in this study to improve the photocatalytic capacity for ammonia-nitrogen (NH-N) removal from aqueous solutions. The results showed that biochar was successfully modified on TiO and helped improve its photocatalytic performance for pollutant degradation. The removal capacity of ammonia-nitrogen on the synthesized photocatalyst performed well at pH 10 with 1 g L C/TiO under both 60 (12.25 mg g) and 120 min (16.31 mg g) irradiation (xenon lamp, AM1.5, 25 A). Characterization of C/TiO through scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectrometry (FT-IR) analyses showed the successful introduction of biochar on TiO. SEM-EDS and BET analyses displayed that C/TiO had a larger surface area and more pores than the raw materials. XRD spectroscopy illustrated that C/TiO had typical characteristic peaks of anatase-TiO and presented a good photocatalytic degradation performance. It was confirmed from XPS and FT-IR analyses that -COOH groups were present in C/TiO and originated from biochar modification, and these enhanced the photocatalytic performance. Through radical quenching experiments, it was found that superoxide radicals (˙O) played a dominant role in NH-N photocatalytic reactions with hydroxyl radicals (˙OH) and valence band holes (h) playing a synergistic role. N was the main degradation product after 6 h NH-N photocatalytic degradation, which was much larger than NO/NO (both almost undetected) and NH ( 2 times lower than N). The new composite C/TiO has potential for ammonia-nitrogen degradation in wastewater treatment and favorable for treating sewage sludge.
本研究采用溶胶 - 凝胶法制备了生物炭改性的TiO（C/TiO），以提高从水溶液中去除氨氮（NH - N）的光催化能力。结果表明，生物炭成功改性到TiO上，并有助于提高其对污染物降解的光催化性能。在pH值为10、1 g L C/TiO的条件下，在60分钟（12.25 mg g）和120分钟（16.31 mg g）光照（氙灯，AM1.5，25 A）下，合成的光催化剂对氨氮的去除能力表现良好。通过扫描电子显微镜 - 能谱仪（SEM - EDS）、布鲁诺尔 - 埃米特 - 泰勒（BET）、X射线衍射（XRD）、X射线光电子能谱（XPS）和傅里叶变换红外光谱（FT - IR）分析对C/TiO进行表征，结果表明生物炭成功引入到TiO上。SEM - EDS和BET分析表明，C/TiO比原材料具有更大的表面积和更多的孔隙。XRD光谱表明，C/TiO具有锐钛矿型TiO的典型特征峰，并呈现出良好的光催化降解性能。从XPS和FT - IR分析证实，C/TiO中存在 - COOH基团，其源于生物炭改性，这些基团增强了光催化性能。通过自由基猝灭实验发现，超氧自由基（˙O）在NH - N光催化反应中起主导作用，羟基自由基（˙OH）和价带空穴（h）起协同作用。在NH - N光催化降解6小时后，N是主要降解产物，其含量远高于NO/NO（两者几乎未检测到）和NH（比N低2倍）。新型复合材料C/TiO在废水处理中具有氨氮降解潜力，有利于处理污水污泥。
