Evaluation of the performance of catalytic advanced oxidation processes (AOPs) in homogeneous and/or heterogeneous phases: application to the removal of refractory organic pollutants
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Date
2025-01-20
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University of 20th August 1955 - Skikda
Abstract
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
Description
Keywords
oxidation processes, catalytic