Effects of wavelength on the treatment of contaminants of emerging concern by UV-assisted homogeneous advanced oxidation/reduction processes

Liang Tang; Aozhou Li; Minghao Kong; Dionysios D Dionysiou; Xiaodi Duan

doi:10.1016/j.scitotenv.2023.165625

Effects of wavelength on the treatment of contaminants of emerging concern by UV-assisted homogeneous advanced oxidation/reduction processes

Sci Total Environ. 2023 Nov 15:899:165625. doi: 10.1016/j.scitotenv.2023.165625. Epub 2023 Jul 20.

Authors

Liang Tang¹, Aozhou Li¹, Minghao Kong², Dionysios D Dionysiou³, Xiaodi Duan⁴

Affiliations

¹ Key Laboratory of Organic Compound Pollution Control Engineering (MOE), School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China.
² Environmental Engineering and Science Program, Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221, USA.
³ Environmental Engineering and Science Program, Department of Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221, USA. Electronic address: dionysdd@ucmail.uc.edu.
⁴ Key Laboratory of Organic Compound Pollution Control Engineering (MOE), School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China. Electronic address: duanxiaodi@shu.edu.cn.

PMID: 37481088
DOI: 10.1016/j.scitotenv.2023.165625

Abstract

Pollutants of emerging concern in aqueous environments present a significant threat to both the aquatic ecosystem and human health due to their rapid transfer. Among the various treatment approaches to remove those pollutants, UV-assisted advanced oxidation/reduction processes are considered competent and cost-effective. The treatment effectiveness is highly dependent on the wavelength of the UV irradiation used. This article systematically discusses the wavelength dependency of direct photolysis, UV/peroxides, UV/chlor(am)ine, UV/ClO₂, UV/natural organic matter, UV/nitrate, and UV/sulfite on the transformation of contaminants. Altering wavelengths affects the photolysis of target pollutants, photo-decay of the oxidant/reductant, and quantum yields of reactive species generated in the processes, which significantly impact the degradation rates and formation of disinfection byproducts. In general, the degradation of contaminants is most efficient when using wavelengths that closely match the highest molar absorption coefficients of the target pollutants or the oxidizing/reducing agents, and the contribution of pollutant absorption is generally more significant. By matching the wavelength with the peak absorbance of target compounds and oxidants/reductants, researchers and engineers have the potential to optimize the UV wavelengths used in UV-AO/RPs to effectively remove pollutants and control the formation of disinfection byproducts.

Keywords: Advanced oxidation processes (AOPs); Advanced reduction processes (ARP); Reactive species; UV; Water treatment; Wavelength.