Adsorptive Desulfurization Of Liquid Fuels By Using Carbon Based Mof Materials

Sulfur in liquid fuels can cause serious environmental pollution after combustion.It is therefore necessary to develop efficient and economic processes for desulfurization of liquid fuels.Recently some non-hydrodesulfurization,or alternative desulfurization,processes have been studied,e.g.bio-desulfurization,complex desulfurization,extractive desulfurization,oxidative desulfurization,and adsorptive desulfurization(ADS).Among them,the adsorptive desulfurization is gaining more popularity due to its promising sulfur removal performance and mild operating conditions at ambient pressure and temperature.Besides,ADS is holding future promise of ultra-clean sulfur-free fuel oils.And,the key to success for ADS is the development of highly efficient and specific adsorbents.This work is aimed to develop some new composite adsorbents of MOFs and carbons for ADS by using hydrothermal carbons(HTC),graphene oxide(GO),activated carbon oxide(ACO),activated carbon(AC)as starting materials,and study their ADS performance.For this,the hydrothermal carbon materials(HTC)were synthesized with different raw materials and activated by varying amounts of KOH.The adsorption capacity the HTC carbons is found to be increased with the KOH amount used,specifically from 24.8 mgS/g to 29.3 mgS/g as the KOH/HTC ratio was increased from 0.5 to 4.By using GO as crosslinking agent,four HTC composites HTC@GO were synthesized and activated with KOH,and their adsorption capacity is a little higher than neat HTC,being increased from 26.8 mgS/g to 32.4 mgS/g as the KOH/carbon ratio increased from 0.5 to 4.Second,by using GO as poly acid some interlinked MOF sorbents of MOF@GO were prepared and their ADS performance for model oil was studied.Their adsorption capacity is found to be decreased with the increased GO amount,namely from 48.2 to 43.9 mgS/g as the GO percentage increased from 0%to 15%.This indicates that GO is not helpful for enhancing the adsorption capacity of MOF@GO adsorbents.Herein,the pure MOF shows the highest adsorption capacity due to its smaller pore size,higher specific volume and surface area,and the layered GO sheets as a poly-acid functioned only as substrate and cross-liker to form a highly interlinked MOF composite of MOF@GO.Third,by using oxidized activated carbon(ACO)as substrate,a carbon based MOF,MOF@ACO with different amount of ACO,was synthesized,and its ADS performance for DBT model oil was investigated.In MOF@ACO,ACO was functioned as a poly acid substrate to make the MOF crystals interlinked each other,forming highly porous sorbents with large surface area,and smaller pore size.Their adsorption capacity is decreased slightly from 48.2 mgS/g to 42.3 mgS/g as the ACO increased from 0 to 1.1 g,which suggests that the ADS performance of the composite sorbent is mainly originated from MOF.Finally,by using AC as substrate,a carbon supported MOF sorbent(MOF@AC)was prepared,and its adsorption behaviors was investigated for DBT model oil.The adsorption capacity of MOF@AC for DBT model oil of 1000 ppm was 17.1 mgS/gm,which is much lower than that of MOF.This is ascribed to the lower ratio of MOF components and the filling of the inner pores of the carbon substrate by the in situ formed MOF particles..