Application of Catalytic Ozonation Process Using a Novel Fe3O4/Mg(OH)2/4A-Zeolite Catalyst for Swift Treatment of Dairy Effluent

The present study investigated the feasibility of employing a catalytic ozonation process by a novel Fe3O4/Mg(OH)2/4A zeolite catalyst to facilitate the treatment of real dairy effluent. The Fe3O4/Mg(OH)2 magnetic nanoparticles supported onto 4A zeolite (Fe3O4/Mg(OH)2/4AZ) were synthesized and characterized by extensive techniques (XRD, FE-SEM, TEM, EDS, VSM, and BET). Reaction rate, operating conditions, mechanism, and thermodynamics of the dairy effluent treatment by the Fe3O4/Mg(OH)2/4AZ-catalyzed ozonation process were investigated. Catalytic ozonation experiments indicated that synchronous use of Fe3O4/Mg(OH)2/4AZ and O3 considerably accelerated the rate of COD reduction, compared to sole ozonation. Results of the designed experiments by response surface methodology (RSM) revealed that approximately 80% of COD was reduced within 30 min at natural pH of solution (≈ 7) when the catalyst and ozone dosages were 5 g L−1 and 9 mg min−1, respectively. Exploration of the mechanism disclosed that the process mainly followed a hydroxyl radical reaction pathway. Thermodynamics studies demonstrated that the process was endothermic and temperature sensitive, so that it was spontaneous at the temperature of 313 K. Overall, this study supplies a bold and quick manner as well as environmental friendliness (no secondary pollution) to eradicate refractory substances and wastewater treatment.