超声辅助制备的LaFeO3/PS催化可见光芬顿降解盐酸四环素

粉末状LaFeO₃材料具有易团聚、分离困难等缺点，规模化应用中受到限制。聚苯乙烯树脂(PS)上沉积粉末状催化剂，弥补了以上粉末材料的不足。为此，本文采用超声辅助溶胶-凝胶和水热法，在PS上沉积了自组装形成的LaFeO₃凝胶微球，制得了LaFeO₃/PS催化剂，并对其结构和性能进行了系统的研究。LaFeO₃凝胶微球在PS上的分散分布使LaFeO₃的禁带宽度变宽，从而增加了氧化还原能力，并解决了催化剂团聚等问题，提高了LaFeO₃的光芬顿催化活性。在La∶Fe∶柠檬酸(CA)摩尔比=1∶1∶2、超声40 min、水热时间18 h、水热温度90℃、LaFeO₃起始剂/PS质量比=32∶1的制备条件制得的复合材料，在可见光下催化芬顿降解盐酸四环素(TC),TC的去除率可达96.51%(降解速率k=0.0160 min^-1)。自由基捕获实验表明，·O₂^-是主要活性物种。结合捕获实...

Study of the degradation of tetracycline by visible photo-Fenton catalyzed by ultrasound-assisted LaFeO3/PS

The powdered LaFeO₃ material had shortcomings such as easy agglomeration and difficult separation, so it was limited in large-scale applications. The deposition of powdered catalysts in polystyrene resin (PS) made up for the above shortcomings of powdered materials. Therefore, in this study, the self-assembled LaFeO₃ gel was deposited on the PS through ultrasound-assisted sol-gel and hydrothermal methods. The dispersion and distribution of LaFeO₃ on PS broadens the forbidden band width of LaFeO₃, improves its redox ability, solves the problem of agglomeration, and consequently improves its photo-Fenton catalytic activity. The LaFeO₃/PS composite prepared under the following experimental conditions shows the highest photocatalytic activity: La∶Fe∶Citric acid(CA) molar ratio=1∶1∶2, ultrasonic time 40 min, hydrothermal temperature 90℃, hydrothermal time 18 h, LaFeO₃ initiator/polystyrene mass ratio=32∶1. The removal rate of tetracycline hydrochloride (TC) is up to 96.51%(rate of degradation k=0.0160 min?1) under visible light irradiation in the Fenton process catalyzed by LaFeO₃/PS. Free radical capture experiments show that ?O₂? is the main active species. According to the capture experiment, the degradation mechanism of TC was proposed. Through LC/MS analysis, the degradation path of TC was obtained. The photo-Fenton process catalyzed by LaFeO₃/PS is a promising technology for the degradation of organic pollutants due to the high stability of the catalyst and the efficient use of solar energy.