Solar photodecomposition for removing BTEX compounds from groundwater contaminated by gasoline station activities

Abstract

The study investigates the application of solar photodecomposition to remove BTEX compounds (benzene, toluene, ethylbenzene, and xylenes) from groundwater contaminated by gasoline station activities. BTEX compounds, known for their toxicity and carcinogenicity, pose significant environmental and public health risks. The primary goal of this research was to develop effective and sustainable technology for treating and removing BTEX from groundwater using solar photodecomposition. To achieve this objective, microstructured titanium dioxide (TiO2) was combined with diatomite to leverage heterogeneous photocatalysis for BTEX degradation. The TiO2-Diatomite (TiO2-Dt) composite was characterized using scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). SEM provided detailed insights into the material’s structure and morphology, while TGA assessed the thermal stability of the photocatalyst in BTEX degradation processes. Experimental results demonstrated that solar photodecomposition is an effective method for water remediation. Tests conducted with 9.0 g of TiO2-Dt and 40% BTEX solutions evaluated the removal efficiency across varying catalyst masses (0.8 g to 2.5 g). The highest BTEX removal efficiency, 79.0%, was achieved with 1.0 g of TiO2-Dt. Catalyst amounts between 1.0 g and 1.2 g showed good performance, with removal efficiencies ranging from 71.4% to 79.0%. However, increasing the catalyst mass to 2.0 g and 2.5 g resulted in reduced efficiencies (57.4% to 64.4%), suggesting saturation or dispersion limitations. Breakthrough curves and Boltzmann calculations confirmed TiO2-Dt’s effectiveness in solar photodecomposition. Moderate catalyst amounts (1.0 - 1.2 g) optimized BTEX removal, while higher quantities reduced efficiency, underscoring solar radiation’s role in accelerating pollutant degradation.