Preparation of TiO2-deposited silica-based catalysts for photocatalytic decomposition of chloro-pesticide to environmentally less toxic species

Abstract

Herein, titanium (IV) oxide (TiO2) loaded into montmorillonite (MK10) and sand is presented as an efficient heterogeneous catalyst for the degradation of 1,4-dichlorobenzene (DCB) as a model organic pollutant in the aqueous phase. The catalyst was synthesized by incorporating titanium isopropoxide as a precursor into MK10 through a simple solvent impregnation method, followed by direct calcination. The same protocol was applied to a clean quartz matrix. The resulting catalysts were characterized in detail using a variety of techniques. The TiO2 deposited MK10 and sand exhibited photochemical removal of DCB (>99% of 100 mg L−1) from the aqueous phase; this process followed a pseudo second-order kinetic model values in the range of Qe:111–113 mg g−1 and K2: 4–5 × 10−4 g mg−1 min−1. The kinetic plots indicate that after 30 min, the intermediates start to decrease and complete degradation occurs in 180 min. The modified materials showed fast DCB degradation kinetics under photochemical reaction conditions and adsorption under dark reaction conditions. The unmodified matrix adsorbed 99.12–99.88% of the DCB under both dark and light reaction conditions. These photocatalysts are stable, reusable, and least amount of titanium leaching. The simple two step synthesis, and high photocatalytic performance (with 10 mg of the catalyst without any oxidants) of our catalysts can be promising in environmental applications to treat similar organic pollutants in wastewater. These catalysts have enhanced activity and durability for environmental catalytic pollutant degradation reactions and can provide insights beyond single metal oxide catalysts for heterogeneous catalysis at diverse operating conditions.