Enhanced photocatalytic degradation of cimetidine by using SnS2/TiO2 nanocomposite under simulated solar light
Journal
Journal of Water Process Engineering
Journal Volume
90
Start Page
110410
ISSN
22147144
Date Issued
2026-08
Author(s)
Abstract
Water pollution by emerging contaminants that evade conventional treatment is a pressing concern, but visible-light-driven photocatalytic oxidation is a promising process for eliminating them. This study successfully synthesized a visible-light-responsive SnS2/TiO2 heterojunction and investigated its performance for cimetidine degradation under simulated solar irradiation. To our knowledge, this is the first study reporting generation and involvement of 1O2 in the SnS2/TiO2 system. Material characterization verified that the heterostructure had well-dispersed constituents. The SnS2/TiO2 composite exhibited faster pseudo-first-order kinetics ( k obs = 0.060 min−1) than did pristine TiO2 and SnS2 (0.032 and 0.010 min−1, respectively). Cimetidine degradation was optimal for a 25 mg L−1 catalyst concentration and pH 5, and cimetidine adsorption was negligible. Electron paramagnetic resonance and scavenger tests identified •OH and 1O2 as the dominant oxidants, and probe experiments revealed that [1O2]ss exceeded [•OH]ss by approximately 102–103. Low Cl−, NO3−, and SO42− concentrations minimally affected performance, whereas higher concentrations suppressed degradation; HCO3− and dissolved organic matter (DOM) markedly inhibited degradation, even at low concentrations. The degradation rates in real tap, drinking water treatment plant influent, and wastewater treatment plant effluent waters were lower than that in deionized water, likely because of HCO3− and DOM. The SnS2/TiO2 composite preferentially degraded 1O2-reactive pharmaceuticals (sulfamethoxazole and sulfisoxazole; k obs = 0.021 and 0.014 min−1, respectively) but barely removed cyclophosphamide and ketamine (0.005 and 0.002 min−1, respectively). Reusability was stable for two cycles and declined thereafter. These findings provide insight into SnS2/TiO2 photocatalysis, highlighting a preferential, visible-light-driven 1O2 pathway for removing emerging contaminants.
Subjects
Cimetidine
Emerging contaminants
Photocatalytic degradation
Singlet oxygen (1O2)
SnS2/TiO2 composite
Solar irradiation
Publisher
Elsevier Ltd
Type
journal article