Advanced Oxidation Processes: A Powerful Treatment Option for the Removal of Recalcitrant Organic Compounds

Advanced oxidation processes (AOPs) are the technologies that generally use the hydroxyl radicals, the ultimate oxidant for the remediation of organic contaminants in wastewater. These are highly effective novel methods speeding up the oxidation process. AOP can combine with ozone (O3), catalyst, or ultraviolet (UV) irradiation to offer a powerful treatment of wastewater. Future research should be focused on enhancing the properties of heterogeneous catalysts in AOPs. This chapter reports general review of different AOPs utilized for the removal of various phenolic compounds and textile dyes in wastewater. The chapter also aimed at an investigation of efficiency for different photochemical AOPs. The authors have carried out the experimental runs at a laboratory scale for the removal of malachite green oxalate (MGO) dye with photochemical AOPs. The influence of ferrous ions and oxidant dosage on percentage decolorization of MGO in wastewater has been reported. The discussion extends to the utilization of different modified photocatalysts for the photocatalysis process. The future challenges, such as the adoption of strategies for the integration of processes and the decrement in operational cost of AOPs, are discussed. The discussion covers the utilization of different heterogeneous catalysts, the reduction of input demands of chemicals and energy for the processes

Benzoic Acid Degradation by Highly Active Heterogeneous Fenton-like Process using Fe3+-Al2O3 Catalyst

This work examines oxidative degradation of benzoic acid in an aqueous solution using an eco-friendly advanced oxidation (heterogeneous Fenton) process. The degradation of benzoic acid (1,000 mgL−1) with H2O2 was performed using Fe3+ immobilized within an Al2O3 matrix as a heterogeneous Fenton catalyst and the efficiency of the system was compared to that of the homogeneous Fe3+/H2O2 system. The influence of various operational conditions like catalyst dosage, H2O2 concentration, Fe3+ concentration, pH of the solution and initial substrate concentration on % degradation for both the processes has been studied to find out the best operating conditions for these processes. The experimental results show that the optimum conditions for homogeneous Fe3+/H2O2 process are [Fe3+] = 1,250  mgL−1, [H2O2] = 2,000 mgL−1, initial pH = 3 and 87.5 % degradation was obtained within 35 min. In the case of heterogeneous catalyst, degradation improved to 91.7% using 12.5 gL−1 catalyst for the same duration keeping other operating conditions the same. The use of iron immobilized in alumina matrix as heterogeneous Fenton catalyst is an alternative approach for degrading organic contaminants

Benzoic Acid Degradation by Highly Active Heterogeneous Fenton-like Process using Fe³⁺-Al₂O₃ Catalyst

262-268This work examines oxidative degradation of benzoic acid in an aqueous solution using an eco-friendly advanced oxidation (heterogeneous Fenton) process. The degradation of benzoic acid (1,000 mgL−1) with H2O2 was performed using Fe3+ immobilized within an Al2O3 matrix as a heterogeneous Fenton catalyst and the efficiency of the system was compared to that of the homogeneous Fe3+/H2O2 system. The influence of various operational conditions like catalyst dosage, H2O2 concentration, Fe3+ concentration, pH of the solution and initial substrate concentration on % degradation for both the processes has been studied to find out the best operating conditions for these processes. The experimental results show that the optimum conditions for homogeneous Fe3+/H2O2 process are [Fe3+] = 1,250 mgL−1, [H2O2] = 2,000 mgL−1, initial pH = 3 and 87.5 % degradation was obtained within 35 min. In the case of heterogeneous catalyst, degradation improved to 91.7% using 12.5 gL−1 catalyst for the same duration keeping other operating conditions the same. The use of iron immobilized in alumina matrix as heterogeneous Fenton catalyst is an alternative approach for degrading organic contaminants