An innovative and sustainable approach for water purification: Thermal decomposition of tetracycline contaminant adsorbed on thermally stable montmorillonite

Abstract

Access to clean water is crucial for human survival, yet global water pollution persists due to organic contaminants. Adsorption, using materials like montmorillonite clay, is a well-established method to purify water. However, the adsorption capacity diminishes over time as pollutants saturate the material. This study focuses on employing montmorillonite (MONT) to eliminate tetracycline (TC) from contaminated water, introducing a novel approach to address contaminant buildup on the adsorbent. Thermal combustion effectively decomposes adsorbed contaminants, regenerating and activating MONT for further adsorption without the adsorbed TC. Results show high efficiency, achieving complete TC adsorption in 40 minutes with only 0.1g of MONT in a 100 mL solution of 100 ppm TC. Characterization confirms MONT stability during use, activation, and reuse. This study highlights thermally stable adsorbents, like MONT, as environmentally safe, economically sensible, and sustainable for eliminating organic pollutants from water sources. The proposed technique supplements current water treatment methods, offering hope amid the global water contamination crisis by thermally decomposing and removing adsorbed TC. Kinetic isotherms experiments align with Langmuir adsorption, supporting a monolayer adsorption of TC on MONT surface. The pseudo-second-order model elucidates the adsorption mechanism, and Gibbs free energy and entropy values suggest a chemisorption predominance mechanism.

Keywords

• Montmorillonite
• Tetracycline
• Water purification
• Adsorption
• Thermal decomposition