Study On The Sewage Sludge-based Activated Carbon Supported TiO₂-Fe₃O₄ Magnetized Photocatalyst

The current methods of wastewater treatment are physical,chemical,biological,and catalytic oxidation.The biological treatment method commonly used in urban sewage treatment plants will generate large amounts of sludge and must be properly disposed of.Sludge recycling technology is one of the research hotspots of the current sludge non-hazardous treatment.The pyrolysis of sludge into activated carbon can achieve the goal of“reduction,resource,and harmlessness”.In practical applications,there is a problem in separation and recovery of activated carbon.To address this issue,the magnetization modification of activated carbon is an important research direction.The photocatalyst TiO₂,which is commonly used in photocatalytic processes,has problems with difficulty in loading and recovery.In this experiment,a magnetic photocatalyst was prepared by using magnetic carbon as a carrier and supporting TiO₂ on the surface of magnetic carbon.On the one hand,the sludge treatment is realized;on the other hand,effective recovery of the photocatalyst is achieved and the synergistic effect of the magnetic carbon and the TiO₂ in removing organic pollutants can improve the photocatalytic reaction efficiency.First,the smut activated carbon SAC was prepared from sewage treatment plant sludge.Secondly,the chemical co-precipitation method was adopted,and the calcination process was performed through temperature control.Magnetic Fe₃O₄/SAC,which can realize magnetic separation,was prepared.Finally,on the basis of magnetic carbon,TiO₂ was loaded onto Fe₃O₄/SAC by liquid phase deposition method with butyl titanate as a titanium source to prepare a TiO₂-Fe₃O₄/SAC magnetic photocatalyst with good performance.Through orthogonal experiments,the optimum process conditions for the preparation of magnetic carbon were determined as follows:the iodine value was used as a control index.The best conditions were a magnetization temperature of 65°C,a ratio of ferrous sulfate to ferric chloride of 1:2.5,and a magnetization agent.The ratio of argillaceous activated carbon is 1:3;the methylene blue adsorption value is used as the control index.The best conditions are that the magnetization temperature is 65°C,the ratio of ferrous sulfate to ferric chloride is 1:2,and the ratio of magnetizing agent and argillaceous activated carbon is 1:3.5.The optimum technological conditions for preparing TiO₂-Fe₃O₄/SAC magnetic photocatalysts were as follows:1 gram of butyl titanate dosing volume in 1.0 g of magnetic carbon,calcination temperature was 450°C and titanium source was loaded twice.The results showed that the maximum removal rate of aniline wastewater was 37.87%when the magnetic photocatalyst was prepared under the optimal preparation conditions.The maximum removal rate of aniline wastewater was 29.61 after magnetic carbon photocatalyst was prepared with commercial carbon as raw material.