Adsorption And Catalytic Properties Of Congo Red On 4A-Fe@Cu/PES Blend Membrane

Heterogeneous Fenton technology is the most promising technology for dye degradation because of its high catalytic efficiency and recyclability.However,the catalytic efficiency of heterogeneous Fenton still needs to be further improved due to the influence of diffusion control.In recent years,the combination of Fenton and membrane technologies to enhance the rapid and efficient degradation of organic pollutants by catalysts has become a hot spot of effective treatment of wastewater.In this study,a core-shell Fe-Cu bimetallic Fenton catalyst（4A-Fe@Cu）was prepared using 4A zeolite as support,subsequently,a catalytic membrane reactor was prepared by blending with PES which has good chemical stability and excellent mechanical properties.The convection of membrane pores could reduce the mass transfer resistance of pollutant diffusion in the catalytic process,enhance adsorption and degradation of Congo red（CR）dyes over Fenton catalyst.The main research contents and results are as follows:1.The 4A-Fe@Cu bimetallic Fenton catalyst with three-dimensional core-shell structure was prepared by in-situ growth using 4A zeolite as support and used for adsorption and catalytic degradation of CR.The results showed that 4A-Fe@Cu catalyst exhibited a high adsorption capacity for CR with a maximum of 432.9 mg/g due to its open three-dimensional network structure and positive surface charge.The adsorption process was fitted by the kinetic equation,and the fitting results were more in line with the second-order kinetic model.The results of isothermal adsorption showed that the adsorption of CR on the catalyst was more consistent with Freundlich model.This suggested that the adsorption between the catalyst and CR was caused by chemical mode,and the distribution of CR dyes on the surface of the catalyst is not uniform.The excellent adsorption performance of 4A-Fe@Cu for CR not only could not deactivate the catalytic sites on 4A-Fe@Cu,but also promote the contact between CR and the active sites on the catalyst surface and accelerate the degradation process.The effects of p H,H₂O₂ and catalyst dosage on the catalytic performance of 4A-Fe@Cu were investigated.Under the optimum conditions of 7.2 m M H₂O₂,2.0 g/L 4A-Fe@Cu,1.0 g/L CR solution,the CR degradation rate of 4A-Fe@Cu was 99.2%at p H 8.0,which was higher than single-metal 4A-Fe and 4A@Cu catalysts.This was mainly due to the synergistic effect between Fe and Cu in bimetallic catalyst make the overall work function of the catalyst lower and the electron transfer ability stronger,therefore,4A-Fe@Cu bimetallic catalyst has higher catalytic activity than single metal catalyst.This study provided a new method for the design of high performance Fenton-like catalysts with adsorption and catalytic properties for the treatment of dye wastewater.2.The 4A-Fe@Cu/PES blending catalytic membrane reactor（APMMMs）with high porosity and macroporous structure was prepared by non-solvent induced phase separation method,and was applied to the adsorption and dynamic catalytic experiments of CR.The large pore structure of the membrane ensured the exposure of the active sites of the catalyst.The dynamic continuous flow accelerated the contact between the reactants and the catalyst,reduced the mass transfer resistance and enhanced the oxidative degradation of CR by Fenton reaction.In addition,CR adsorbed by 4A-Fe@Cu will form catalytic micro-zone on the membrane,which was beneficial to further enhance the catalytic efficiency.Compared with 4A-Fe@Cu particles,the apparent activation energy of dynamic catalysis（21.1 k J/mol）was significantly lower than that of static catalysis（93.7 k J/mol）,indicating that the dynamic catalysis process had better adsorption and catalytic effect.In cross-flow circulation mode,the maximum CR adsorption capacity of APMMM-18（doping amount of 4A-Fe@Cu is 18wt%）was 199.53 mg/g_4A-Fe@Cu with a catalyst/CR mass ratio of 1/1.5 and initial CR concentration of 50 mg/L.For catalysis,the APMMM-18 could remove 99.8%CR after 5 h with a catalyst/CR mass ratio of 1/1.5 and 1.94 m M of H₂O₂ at p H 8.The combination of Fenton catalyst and membrane technology has realized the efficient degradation of CR,which provided a potential and feasible method for the effective removal of dye pollutants.