Fe-ZSM-5协同真空紫外和过硫酸盐催化氧化甲苯的强化工艺与机制
A study on enhanced process and mechanism for toluene remocal by combining Fe-ZSM-5 with vacuum ultraviolet and persulfate
李江鸿 1许伟城 2梁发文 1李富华 2吴小莲 2江学顶 2林志峰 2陈忻2
作者信息
- 1. 佛山科学技术学院交通与土木建筑学院,佛山,528000
- 2. 佛山科学技术学院环境与化学工程学院,佛山,528000
- 折叠
摘要
近年来,真空紫外(VUV)协同过硫酸盐的高级氧化工艺已被逐渐开发用于处理低浓度挥发性有机污染物(VOCs).然而,如何根据VUV及PMS的特性选择合适的催化剂从而提高工业低浓度苯系VOCs的降解和矿化效率成为当前的挑战.因此,本研究从改性ZSM-5的酸性入手,通过浸渍湿法成功制备了 Fe-ZSM-5催化剂.利用Fe-ZSM-5耦合真空紫外和过硫酸盐的高级氧化体系在湿法条件下降解低浓度甲苯污染物,并对其催化性能和降解机制进行了探讨.结果表明,VUV+PMS+Fe-ZSM-5体系在240min内仍能保持接近100.0％的甲苯去除率,矿化率高达67.0％.采用氨程序升温脱附(NH3-TPD)和吡啶红外(Py-FTIR)等表征对样品酸类型和酸量进行定性和定量分析,结果表明Fe改性减少了 ZSM-5催化剂Brønsted酸的量,而显著增加了 Lewis酸的量,有利于提高反应的活性和稳定性.电子顺磁共振谱(EPR)结果表明,在VUV+PMS+Fe-ZSM-5体系下,硫酸根自由基(SO4-)和羟基自由基(·OH)作为主要活性物种参与了甲苯的降解.液相色谱-质谱(LC-MS)检测到苯甲醇、苯甲醛、苯甲酸、醋酸、丙酸、2-戊酮等多种中间产物,而气相色谱仪(GC)没有检测到出口气体中的气态中间产物,表明该工艺能有效避免空气的二次污染并将中间产物转移到液相进行下一步处理.研究结果为VUV/PMS湿法处理工业低浓度苯系VOCs工艺的开发提供新思路.
Abstract
In recent years,the advanced oxidation process of vacuum ultraviolet(VUV)synergistic peroxymonosulfate has been gradually developed for the treatment of low concentration of volatile organic pollutants(VOCs).However,it is urgent to select an appropriate catalyst for coupling with VUV/PMS system to further enhance the degradation efficiency and mineralization efficiency of industrial low-concentration benzene series of VOCs.Therefore,based on the acidity characteristics of ZSM-5,this study aims to fabricate Fe-ZSM-5 catalyst through wet impregnation method,and evaluates the catalytic activity and degradation mechanism of VUV+PMS+Fe-ZSM-5 system on toluene removal under wet condition.The results showed that nearly 100.0％of toluene was degraded within 240 min in VUV+PMS+Fe-ZSM-5 system,and the mineralization rate was as high as 67.0％.Ammonia temperature programmed desorption(NH3-TPD)and pyridine infrared(FTIR)were utilized to analyze the type and amount of acid species of the catalysts.It can be achieved that Fe modification reduces the amount of Brønsted acid in ZSM-5 catalyst,but increases the amount of Lewis acid,which may be beneficial to improve the activity and stability of the reaction.Electron paramagnetic resonance(EPR)spectrum demonstrated that sulfate radicals(SO4-)and hydroxyl radicals(OH)are the main active species in the VUV+PMS+Fe-ZSM-5 for toluene removal.Several intermediate products including benzyl alcohol,benzaldehyde,benzoic acid,acetic acid,propionic acid,2-pentanone were detected during the degradation process by liquid chromatography-mass spectrometry(LC-MS),while no gaseous intermediates were found in the outlet by gas chromatographic(GC),indicating that this process can effectively avoid secondary air pollution and transfer intermediates to the liquid phase for further treatment.The study provides a new idea for low-concentration benzene series of VOCs control by catalyst+VUV/PMS wet process.
关键词
真空紫外/过硫酸盐/湿法/Fe-ZSM-5/甲苯Key words
vacuum ultraviolet/peroxymonosulfate/photocatalysis/Fe-ZSM-5/toluene引用本文复制引用
基金项目
国家自然科学基金(52000031)
广东省普通高校科研项目(2020KTSCX129)
出版年
2024
NETL
NSTL
万方数据