Open AccessComparison of the photocatalytic efficacy and environmental impact of CdS, ZnFe2O4, and NiFe2O4 under visible light irradiation
Author(s) -
Xiaoyu Wang,
Susan J. Masten,
Elaheh Esfahanian
Publication year - 2021
Publication title -
water science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.406
H-Index - 137
eISSN - 1996-9732
pISSN - 0273-1223
DOI - 10.2166/wst.2021.036
Subject(s) - photocatalysis , visible spectrum , spinel , adsorption , materials science , hydrothermal circulation , methylene blue , absorption (acoustics) , nanoparticle , chemical engineering , aqueous solution , irradiation , photochemistry , catalysis , nuclear chemistry , nanotechnology , chemistry , optoelectronics , organic chemistry , metallurgy , composite material , physics , nuclear physics , engineering
Three photocatalysts (CdS, ZnFe2O4, and NiFe2O4) were synthesized and their ability to photodegrade methylene blue (MB) was evaluated. MB was degraded by both spinel photocatalysts under visible light at room temperature, although their efficacy was less than that for CdS. The photocatalytic efficacies of NiFe2O4 were observed to be much greater than that for ZnFe2O4. All the synthesized nanoparticles absorbed visible light, while CdS had a larger absorption range within the visible light spectra and the most porous surface. Photo-deactivation was observed during the study, which could be due to the chemical adsorption of the degraded products on the catalyst surface. The factors that affected MB removal efficacy include the absorption range of photocatalysts, initial MB concentrations, amount of photocatalysts added, and photoreactor conditions. Life cycle analysis was used to compare the preparation methods of the photocatalysts in terms of energy consumption and environmental impact. The results showed that the hydrothermal method for NiFe2O4 preparation was less energy-intensive than the sol-gel method for CdS and ZnFe2O4 as the hydrothermal method is effective over a wider range of temperatures in aqueous media. Also, as ZnFe2O4, and NiFe2O4 have lower environmental impacts than CdS both show promise as photocatalysts.