Emerging Contaminants (Jun 2024)
UV-induced simultaneous oxidation/reduction of cefixime and chromium
Abstract
This study explores a novel approach utilizing a UV-based photo-removal process to simultaneously eliminate organic (Cefixime-CFX) and inorganic (chromium) pollutants from wastewater. The photoreactor's configuration, segregating wastewater inlets and outlets, facilitates efficient removal. The study investigates the effect of various parameters such as pH, CFX:Cr molar ratio, and kinetic models on the removal efficiency.Analytical methods involve high-performance liquid chromatography for CFX concentration determination and atomic absorption for chromium measurement. Results showed that higher pH levels favored enhanced photo-removal of both compounds, with pH 9 displaying optimal removal efficiencies of 100 % for CFX and 46.7 % for chromium. The CFX/Cr molar ratio of 20:1 exhibited superior removal rates, achieving approximately 100 % CFX and 82.3 % chromium removal within 25 min. Additionally, kinetic analyses indicated the importance of pH in accelerating organic breakdown and subsequent production of reducing and oxidizing species, facilitating chromium precipitation. Effluent toxicology tests using the Kirby & Bauer method indicate a significant reduction in toxicity over time, suggesting the suitability of the effluent for discharge into the environment. Additionally, sludge analysis through FTIR identifies various chromate species produced during the photo-removal process, contributing to a comprehensive understanding of sludge composition. The investigation demonstrates that the UV-based photo-removal process efficiently removes both organic and inorganic pollutants while minimizing energy consumption and avoiding the formation of hazardous secondary intermediates. This study provides insights into a sustainable and effective method for wastewater treatment, with potential applications in environmental protection and pollution control.
