Benzoic Acid Degradation by Highly Active Heterogeneous Fenton-like Process using Fe<sup>3+</sup>-Al<sub>2</sub>O<sub>3 </sub>Catalyst

Abstract

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.