Development of photoactive ZnS-SiO2 composites on biogenic silica matrix for organic pollutant degradation

• Published in: Environmental science and pollution research international 2024-11, Vol.31 (52), p.61612-61628
• Main Authors: Arefieva, Olga, Vasilyeva, Marina, Lukiyanchuk, Irina, Korochentsev, Vladimir, Opra, Denis, Tkachev, Vladimir, Shlyk, Daria
• Format: Article
• Language: English
• Subjects: Aquatic Pollution; Aqueous solutions; Atmospheric Protection/Air Quality Control/Air Pollution; Comparative studies; comparative study; Composite materials; Current carriers; Degradation; Dyes; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Irradiation; methyl orange; Photocatalysis; Photocatalysts; Photodegradation; pollutants; Porous materials; Research Article; Silica; Silica gel; Silicon dioxide; Sol-gel processes; sol-gel processing; species; sulfides; Sunlight; Ultraviolet radiation; Waste Water Technology; Water Management; Water Pollution Control; X ray photoelectron spectroscopy; Xenon; Xerogels; Zinc; Zinc sulfide
• ISSN: 1614-7499; 0944-1344; 1614-7499
• DOI: 10.1007/s11356-024-35357-5

Sulfide ZnS-SiO 2 composite photocatalysts with biogenic silica matrix were prepared by sol–gel method based on wet gel and xerogel. FT-IR, SEM, XRD, EDXRF, UV–Vis, and XPS methods were systematically used to characterize the obtained materials. The use of support allowed to obtain stable porous (S BET  = 79–105 m 2  g −1 ; V pore  = 0.25–0.17 cm 3 ·g −1 ) ZnS-SiO 2 photocatalysts in aqueous solutions. Zn 2+ content in methyl orange solution after its degradation was 0.4 MPC. ZnS-SiO 2 composites had 3.68–3.70 eV band gap. The obtained materials were photoactive under different irradiation conditions (sunlight, UV-light, Xenon light, visible light) due to effective separation of charge carriers (e − and h + ). Methyl orange degradation degree under UV light excitation was 35–88%, under sunlight – 11–30%. ZnS-SiO 2 composite synthesized using silica xerogel showed a greater photoactivity due to a presence of cone-shaped or cylindrical pores with one open end in its structure and a higher content of ZnS photoactive component. A comparative study of photocatalytic performance of methyl orange degradation by ZnS-SiO 2 under UV irradiation was investigated using radical scavengers. • O 2 − was main active species during MO degradation under UV irradiation, and electrons played additional role during the photocatalytic process.