Browsing by Author "Ahmedchekkat, Fatiha"

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    Evaluation of the performance of catalytic advanced oxidation processes (AOPs) in homogeneous and/or heterogeneous phases: application to the removal of refractory organic pollutants
    (University of 20th August 1955 - Skikda, 2025-01-20) Kahoul, Khadidja; Ahmedchekkat, Fatiha
    The persistence of refractory organic pollutants (ROPs) in aquatic environments poses a significant challenge due to their chemical stability, resistance to conventional treatment methods, and adverse ecological and health impacts. Among these pollutants, Rhodamine B (RhB) is widely used as a model compound to assess advanced oxidation processes (AOPs). This work focuses on the performance evaluation of catalytic AOPs in both homogeneous and heterogeneous phases, with particular emphasis on semiconductor-based photocatalysis. Titanium dioxide (TiO₂) nanoparticles were synthesized via a non-conventional sol-gel route and calcined at different temperatures (400, 600, and 800 °C). The materials were extensively characterised using TG/DSC, FTIR/ATR, XRD, BET, SEM/EDX, UV/Vis, and pHpzc analysis. Their photocatalytic performance was investigated through the degradation of RhB under various operational conditions, including pollutant concentration, catalyst loading, pH solution, irradiation wavelength, and calcination temperature. The TiO₂-400 sample exhibited the highest degradation efficiency (96.11%) and stability, demonstrating its suitability as an efficient photocatalyst. To further enhance its photocatalytic activity, TiO₂ was incorporated into bentonite clay supports with varying contents (10% TiO₂-BN, 30% TiO₂-BN, and 50% TiO₂- BN) using the same non-conventional sol-gel method. The TiO₂-bentonite composites (TiO₂- BN) were characterised using FTIR/ATR, XRD, BET, SEM/EDX, and pHpzc, and tested for RhB removal under various conditions: pollutant concentration, catalyst loading, solution pH, and irradiation wavelength. The incorporation of bentonite enhanced surface area, adsorption capacity, and charge separation, leading to improved degradation performance. The 50% TiO₂- BN sample displayed the best balance between adsorption and photocatalytic activity, with a degradation rate of 99.64%. Kinetic studies confirmed that RhB degradation followed a pseudofirst-order model based on the Langmuir-Hinshelwood (L-H) mechanism. A direct comparison between TiO₂-400 and 50% TiO₂-BN composites highlighted the synergistic role of bentonite in enhancing photocatalytic efficiency. Overall, this research demonstrates that tailoring the synthesis route, calcination temperature, and support material significantly influences photocatalytic performance. The findings contribute to the development of sustainable catalytic AOPs for the removal of refractory organic pollutants from water, offering promising perspectives for environmental remediation