Heterogeneous Fenton-like catalytic degradation of phenazine dye over CeO2 (CP-2) nanoscale powder

Abstract

A heterogeneous Fenton-like process was explored for oxidation of phenazine dye using ceria polishing material (CP-2). XRD, SEM, FTIR, UV-vis DRS, and pH PZC techniques were applied to characterize the catalyst features. The performance of the heterogeneous Fenton-like process was investigated under various parameters (reaction time, pH, H 2 O 2 concentration, catalyst dosage, initial dye concentration, temperature of the medium, and inorganic salt content). Results indicated that the main content of CP-2 catalyst was CeO 2 (60-70%) with lower contents of La 2 O 3 (30-40%), Pr 6 O 11 (≤6%), Nd 2 O 3 , and CaF 2 (≤5%). CP-2 possessed a typical CeO 2 cubic fluorite structure with high content of rare earth oxides (REO) and α-Fe 2 O 3 . The average crystallite size and band gap energy of CP-2 were found to be 37.2 nm and 3.0 eV, respectively. Over 81.3% of neutral red (NR) oxidation efficiency was achieved in 60 min. Pseudo-first-order kinetic model gave the best fit with an acceptable coefficient of determination R 2 . The activation energy (E a ) was 16.4 kJ/mol suggesting that the degradation reaction proceeded with a low energy barrier and the removal process was feasible, spontaneous, and endothermic. The synergistic effect of Fe-and/or REO-CP-2 and H 2 O 2 greatly enhanced the reactive oxygen species (ROS) such as • OH, O 2•-, 1 O 2 , and HO 2 • for effective oxidation of NR via a heterogeneous Fenton-like process.

Sustainable and Green Synthesis of Iron Nanoparticles Supported on Natural Clays via Palm Waste Extract for Catalytic Oxidation of Crocein Orange G Mono Azoic Dye

“…From the slope of the line, E a was computed. The E a of ordinary thermal reactions is usually between 60 and 250 kJ·mol –1 in general, , so the E a value of 33.1 kJ mol –1 indicated that the oxidation of COG by the heterogeneous Fenton-like reaction proceeded with a low energy barrier and can easily be activated. Moreover, an activation energy of 33.11 kJ/mol was reported for the rapid decolorization of azo dye methyl orange in aqueous solution by nanoscale zero-valent iron particles.…”