Preparation And Adsorptive Desulfurization Properties Of Activated Carbon From Deactivated Resin Catalyst For MTBE Synthesis

In this paper,activated carbons(ACs)derived from deactivated resin catalyst(DRC)for MTBE synthesis were successfully prepared through carbonization and subsequent steam activation or KOH activation.During activation procedure,single factor experiment was applied to optimize the activation process.The influences of activation temperature,activation time and/or impregnation ratio of KOH/char on the texture proprieties and yield of ACs were studied.Differences in physical and chemical properties of ACs prepared in the optimal activation process and their performance on dibenzothiophene(DBT)adsorption from model fuel were investigated systematically.AC prepared by KOH activation(KAC)has abundant micropores,whereas mesopores are the major part of AC prepared by steam activation(HAC).Both KAC and HAC possess poor chemical properties,so DBT adsorption performance is dependent largely on physical properties.The maximum adsorption capacity(16.1 mgS/g at 100 ppmS)and the longest breakthrough time(16 h,10h-1 WHSV)were observed for KAC.Then,KAC was functionalized by HNO3,(NH4)2S2O8 and air oxidation respectively.HNO3 and(NH4)2S2O8 oxidation result in a significant decrease in pore structure,while air oxidation only causes slight pore reduction due to the re-activation by O2.The oxygen-containing functional groups(OFGs)increase markedly after oxidative modification,in which(NH4)2S2O8 oxidation is considered as the most efficient method with respect to the introduction of OFGs.HNO3 and(NH4)2S2O8 oxidation are more selective to generate carboxyls and lactones,whereas air oxidation creates more phenols,carbonyls and ethers.The DBT adsorption capacity follows the order:NAC(HNO3 oxidized KAC)>OAC(air oxidized KAC)>KAC(starting material)>SAC((NH4)2S2O8 oxidized KAC),implying the introduction of OFGs is beneficial for the DBT adsorption process,especially for selectivity,but excessive OFGs have a negative effect on the removal of DBT.Thus,to achieve high DBT adsorption performance,there should be a trade-off between the micropore volume and the OFGs amount.