化学
六价铬
铬
激进的
核化学
电子顺磁共振
人体净化
可见光谱
反应速率常数
降级(电信)
量子产额
羟基自由基
光降解
光化学
光催化
动力学
荧光
有机化学
材料科学
催化作用
光电子学
核物理学
量子力学
核磁共振
物理
电信
计算机科学
作者
Cui Huang,Tao Yang,Mingwei Li,Jiamin Mai,Sisi Wu,Juan Li,Guobiao Ma,Changyu Liu,Jianbo Jia,Jun Ma
标识
DOI:10.1016/j.jhazmat.2022.129913
摘要
Hexavalent chromium (Cr(VI)) was activated by ultraviolet-A light-emitting diode (UVA-LED), resulting in efficient removal of various pollutants, including dye, pharmaceuticals, and pesticides, with pseudo-first-order rate constants of 0.0610-0.159 min-1. Comparatively, UVA-LED or Cr(VI) alone barely degraded selected pollutants. Both HO• and Cr(V) were produced in the UVA-LED/Cr(VI) system based on scavenging and probing experiments, UV-visible and electron spin resonance spectra analysis. HO• was demonstrated to be the dominant reactive species via stepwise regeneration of Cr(V) to Cr(VI). The quantum yield of HO• was determined to be 7.79 × 10-4 mol Es-1 at a Cr(VI) dosage of 0.5 mM and pH of 6.0. Additionally, the degradation efficiency of sulfamethoxazole (SMX) as a model compound decreased linearly as UVA-LED wavelengths increased from 365 to 405 nm, while SMX was barely degraded at visible light irradiation wavelength ranges (449-505 nm). SMX degradation efficiency increased from 71.0 % to 97.5 % as Cr(VI) dosage increased from 0.05 to 0.7 mM. pH displayed a negative impact on SMX degradation with its removal efficiency decreasing from 99.4 % to 13.3 % as pH increased from 3.0 to 9.0. This study first reported that HO• was generated via activation of Cr(VI) by UVA-LED, which is instructive for the removal of pollutants co-existed in chromium-containing wastewater.
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