Study On The Preparation And Adsorption Of Dichloromethane By Phenolic Resin-Based Activated Carbon

With the rapid development of industries such as semiconductors and medicine,the issue of dichloromethane（DCM）pollution has attracted people’s high attention.The most simple,mature,and economical method for removing DCM is adsorption technology,and the core of adsorption technology is the adsorbent.In this paper,phenolic resin is used as precursor to prepare phenolic resin-based adsorption material（activated carbon）,and evaluate the performance of DCM;BET,FT-IR,XPS,Raman,NH3-TPD,SEM is used,to analyze the adsorption dynamics of activated carbon.1.The optimal preparation conditions for PFAC were investigated,and the results show that when phenolic resin is pre-oxidized at 130℃for 2 h,carbonized at 600℃for 1 h,and activated at 650℃for 1 h,the prepared PFAC has the best adsorption performance for DCM,with a maximum saturation adsorption capacity of 251.56 mg/g.This activated carbon also exhibits good regeneration and adsorption performance.2.Metal ion(Mg²⁺,Cu²⁺,Fe³⁺,and Ce³⁺)impregnation was used to modify PFAC.The results show that when the metal ion loading is 1%,the modified activated carbon has higher saturation adsorption capacity for DCM than unmodified activated carbon,with Fe³⁺-1-PFAC>Cu²⁺-1-PFAC>Ce³⁺-1-PFAC>Mg²⁺-1-PFAC>PFAC.3.PFAC was treated with various kinds of acid solutions.It was found that weak acids such as boric acid et slightly increase the adsorption performance of activated carbon for DCM,while strong oxidizing acids such as nitric acid are not conducive to its adsorption.4.Ammonia was used to modify PFAC,and the effects of ammonia concentration,immersion time,and immersion temperature on the adsorption performance of activated carbon for DCM were investigated.The results show that activated carbon modified with 20%ammonia at55℃for 15 h has the best adsorption performance for DCM,and its saturation adsorption capacity is 32.5%higher than that of unmodified PFAC.5.Phenolic resin-based activated carbon was prepared by modifiy PFAC with diammonium hydrogen phosphate.The effects of the ammonium dihydrogen phosphate impregnation ratio and impregnation temperature on the adsorption performance of the modified activated carbon for DCM were studied.The results show that when the impregnation ratio of ammonium dihydrogen phosphate and phenolic resin is 1:1 and the impregnation temperature is 40℃,the modified activated carbon prepared under these conditions has the highest adsorption performance for DCM,with a maximum saturation adsorption capacity that is 33%higher than that of unmodified activated carbon.6.The adsorption equilibrium data of PFAC adsorption DCM were fitted by Langmuir and Freundlich equations,and the heat of adsorption was calculated.The results show that the Langmuir model has a higher fit,indicating that the adsorption of activated carbon to DCM belongs to monolayer physical adsorption.7.The quasi-first-order model,quasi-second-order model,Elovich model and Bangham model were used to study the kinetic process of DCM of activated carbon adsorption.The results showed that the process of activated carbon adsorption complied with the Bangham model,indicating that the adsorption of activated carbon was mainly controlled by pore diffusion.