Preparation Of Heterogeneous Fenton Catalyst And Its Application In The Treatment Of Humic Acid Wastewater

Heterogeneous Fenton catalysis is a technology that can effectively remove organic pollutants from water.The process has the advantages of mild reaction conditions,simple equipment and low cost,but the disadvantages of low catalyst activity and low H₂O₂ utilization rate limit the application of this technology in industry.Therefore,it is of great significance to develop a novel heterogeneous Fenton catalyst with high catalytic activity and H₂O₂ utilization under neutral conditions.Three kinds of copper based catalysts with different carriers were prepared using powdered activated carbon,granular activated carbon,and activated alumina balls.They were applied to the treatment of humic acid wastewater.Taking COD as the removal index,the adsorption and catalytic properties of the catalysts were tested,and the activated alumina balls were selected as the best carrier for the catalysts.Determination of Cu O through single factor and orthogonal experimental optimization.The optimal preparation conditions of Cu O/γ-Al₂O₃ catalyst and the stability experiment show that the COD removal rate of HA from the catalyst prepared under the optimal conditions is 87%.For the Cu O/γ-Al₂O₃catalyst,doping Fe ions into the new support to prepare Fe₂O₃/Cu O/γ-Al₂O₃ composite catalyst and its application to the preparation of the optimal preparation conditions of Fe₂O₃/Cu O/γ-Al₂O₃ catalyst were analyzed and optimized.The optimal preparation conditions were determined as follows:Fe:Cu ratio 1:1,immersion time 9 h,calcination temperature 400℃,and calcination time 4 h.The catalysts prepared under the optimal conditions were used to investigate the catalytic oxidation reaction of Cu O/γ-Al₂O₃ and Fe₂O₃/Cu O/γ-Al₂O₃ with H₂O₂.The best conditions for the catalytic oxidation reaction between Fe₂O₃/Cu O/γ-Al₂O₃catalyst and H₂O₂ are as follows:The best COD removal effect of Fe₂O₃/Cu O/γ-Al₂O₃ catalyst for HA can reach 93%.The stability and reaction mechanism of the two catalysts were investigated.After five repeated reactions,the COD removal rates of Cu O/γ-Al₂O₃ and Fe₂O₃/Cu O/γ-Al₂O₃ catalysts were maintained at 74%and 80%,respectively,indicating that the two catalysts have high stability and reusability.The reaction mechanism of the reaction system is discussed.In the polyphase Fenton experiment,Cu²⁺and Fe³⁺can react with H₂O₂ to form Cu⁺and Fe²⁺.At the same time,H₂O₂,Cu⁺and Fe²⁺react to form·OH to remove organic pollutants in wastewater.The synergistic effect between Cu and Fe can improve the utilization rate of H₂O₂ by promoting the formation rate of·OH,thus shortening the reaction time.