Preparation And Photoelectrocatalysis Performance Of Ag/Ag₃PO₄/Carbonized Resin Composites

Domestic and foreign researchers have done a lot of research on water pollution control technology.Compared with other wastewater treatment methods,advanced oxidation methods such as electrocatalysis and photocatalysis have attracted extensive attention because they can generate hydroxyl radicals that can deeply oxidize pollutants in water.However,the application and development of photocatalytic technology have encountered bottlenecks due to low quantum efficiency,while the cost of electrocatalytic technology is relatively high.Therefore,multi-technology collaborative processing can be used to solve the above problems to meet the actual needs.In recent years,photoelectrocatalytic technology has been widely used in the field of environmental protection due to its advantages of good catalytic efficiency and effect,green and no secondary pollution.In this paper,Ag/Ag₃PO₄/carbonized resin composites were prepared by ion exchange method and template method.The effects of catalysts calcined at different carbonization temperatures and time on their photocatalytic and electrocatalytic properties were investigated.The photocatalytic effect of the catalyst on methylene blue solution and chemical wastewater was studied under different conditions.XRD results showed that the resin composite surface prepared at carbonization temperature below 250℃under nitrogen protection was composed of Ag,Ag₃PO₄ particles and residual AgCl.When the carbonization temperature rises to 250℃,Ag₃PO₄ and AgCl on the surface of Ag/Ag₃PO₄/carbonized resin composites are completely reduced to Ag.It is proved that Ag/carbonized resin composites can be prepared by carbonization at 250℃-700℃.SEM results showed that the Ag/Ag₃PO₄/carbonized resin composite was spherical,and the diameter was between 250-500μm.With the increase of carbonization time and carbonization temperature,the spherical diameter decreased,and the surface particles of the microspheres increased.BET results showed that with the increase of carbonization temperature,the average pore size of Ag/Ag₃PO₄/carbonized resin composite gradually decreased.When carbonized at 300℃,it was basically large pores.At 500℃,they contain macropores and mesopores.After carbonized at 700℃,large pores,mesopores and micropores were formed.The specific surface area of the catalyst prepared at 300℃and 500℃had little difference,while the specific surface area of the catalyst increased to 31.25 m²/g at700℃,which increased the adsorption capacity of the catalyst.The photocatalytic properties of Ag/Ag₃PO₄/carbonized resin composites prepared at different carbonization temperature and carbonization time under nitrogen protection were studied.The results of photocatalytic degradation of methylene blue showed that the photocatalytic performance of Ag/Ag₃PO₄/carbonized resin composites was the best when the preparation temperature was200℃and the preparation time was 7h.The electrocatalytic experiment results show that the optimal conditions for the electrocatalytic degradation of methylene blue simulated wastewater and chemical wastewater are as follows:graphite was used as anode and cathode,initial MB concentration was 5mg/L,electrode spacing was 1.25cm,current density was 4 m A/cm²,electrolyte（NaCl）concentration was 1.5 g/L,the removal rate of methylene blue was 97.03%in 60 min,COD in chemical wastewater decreased from 99.4 mg/L to 13.9 mg/L in 10 h,and the removal rate of COD was86.02%.2000m L methylene blue solution with an initial concentration of 5mg/L and chemical wastewater with COD concentration of 165 mg/L were respectively taken to carry out catalytic degradation experiments in a photocatalytic converter.Two graphite anodes and three graphite cathodes were used,the current density was 4 m A/cm²,the electrode spacing was 1.25cm,the NaCl concentration was 1.5 g/L,and the Ag/Ag₃PO₄/carbonized resin composite prepared at 200℃ for 5h under the protection of 1g nitrogen gas is added,the methylene blue removal rate can reach 100%under visible light for 50min.After 10h of photocatalysis,the COD in chemical wastewater decreases from 165mg/L to 0.3mg/L,and the COD removal rate reaches 99.82%.Experimental results show that photoelectrocatalytic technology has good application prospect in wastewater treatment.