光辅助下灰菜生物炭活化过一硫酸盐降解碘帕醇的研究
- Light-assisted activation of of peroxymonosulfate by Chenopodium album L biocarbon for the degradation of iopmidol
- 基金项目：国家自然科学基金资助项目(No.51979223)，榆林市科技局项目(CXY-2022-142)
- 摘要：本文利用灰菜(Chenopodium album L)生物质在紫外到可见光(200 nm-700 nm)范围的光吸收特性.通过慢速直接热解法制备灰菜生物炭(CABC-x),考察其在300W氙灯(320 nm-800 nm, 长波紫外光UVA-可见光Vis范围)光照(Xenon-lamp irradiation, XLS)下活化过一硫酸盐(Peroxymonosulfate, PMS)降解碘帕醇(Iopmidol, IPM)的效果, 并探讨主要影响因素与机理.通过对不同温度(500℃、600℃、700℃) CABC-x活化PMS的性能及理化特性进行比较研究,发现CABC-600具有较丰富的含氧官能团和显著的石墨化结构,从而更有利于对PMS的活化. CABC-600投加量0.3 g/L,PMS浓度0.4 mmol/L时,XLS/CABC-600/PMS体系15 min内对IPM的降解率可达100%(kobs=0.4307 min-1).XLS/CABC-600/PMS体系在pH=3.0-11.0范围均可高效去除IPM, pH=11.0时去除效果最佳.CABC-600具有较好的稳定性,5次循环后20 min对IPM的去除率仍保持92.5%.通过自由基抑制实验、荧光光谱分析和电子顺磁共振(EPR)表明,XLS/CABC-600/PMS降解IPM的活性物种包括SO4??,.OH,O2??,1O2, h+及e-.此外,XLS/CABC-600/PMS体系对IPM的降解主要包括酰胺裂解,脱氢,脱碘和羟基加成,共生成8种中间产物.研究表明,灰菜生物炭可以作为光辅助PMS催化剂实现碘帕醇的高效去除.
- Abstract：This study investigates the light absorption properties of Chenopodium album L biomass in the ultraviolet to visible light range (200–700 nm). Using a slow direct pyrolysis method, biochar (CABC-x) was produced from Chenopodium album L and applied to activate peroxymonosulfate (PMS) for the catalytic degradation of Iopmidol (IPM) under the illumination of 300 W xenon-lamp (320-800 nm, long-wave ultraviolet (UVA)-visible range (Vis)). The study also explored the factors affecting this process and the underlying mechanisms. By comparing the PMS activation performance and physicochemical properties of CABC-x prepared at different temperatures (500°C, 600°C, and 700°C), it was found that CABC-600 had more oxygen-containing functional groups, a better-developed graphitized structure and excellent catalytic activation. IPM (8 mg/L) can be completely degraded in 15 min (kobs=0.4307 min-1) under the optimum condition (CABC-600 dosage of 0.3 g/L, PMS concentration of 0.4 mmol/L). XLS/CABC-600/PMS system worked efficiently across a pH range of 3.0 to 11.0, with the best results observed at pH11.0. CABC-600 also showed excellent stability, maintaining a 92.5% removal rate for IPM even after 5 cycles. Free radical quenching experiment, semiquantitative fluorescence analysis and electron paramagnetic resonance (EPR) showed that the active species for IPM degradation by XLS/CABC-600/PMS included SO4??, .OH, O2??, 1O2, h+ and e-. In addition, IPM degradation pathway involved side chain amide hydrolysis, hydrogen abstraction, deiodination and hydroxyl addition, resulting in the formation of 8 intermediate products. The results suggest that biochar made from Chenopodium album L shows great potential as a photocatalyst for activating PMS and efficiently removing Iopamidol from the environment.
