TY - JOUR
T1 - Effect of liquid-phase O3 oxidation of activated carbon on the adsorption of thiophene
AU - Wu, Luoming
AU - Sitamraju, Siddarth
AU - Xiao, Jing
AU - Liu, Bing
AU - Li, Zhong
AU - Janik, Michael J.
AU - Song, Chunshan
N1 - Funding Information:
We are grateful to acknowledge the research Grants provided by the National Natural Science Foundation of China ( 21306054 ), Guangdong Natural Science Foundation ( S2013040014747 ), Specialized Research Fund for the Doctoral Program of Higher Education ( 20130172120018 ), and Fundamental Research Funds for the Central Universities ( 2013ZM0047 ).
PY - 2014/4/15
Y1 - 2014/4/15
N2 - In this work, a combined experimental and computational study is carried out to investigate the effect of O3 oxidation of activated carbon (AC) in various types of aqueous media (alkaline, acidic and neutral aqueous solutions) on the adsorption of thiophene. A high surface area AC (BET surface area of 2880m2/g) is modified by ozone-oxidation in different aqueous media under ambient conditions. Experimental results show liquid phase ozone oxidation of AC introduces oxygen functional groups to the AC surface, resulting in enhanced adsorption capacity of thiophene. The impact of oxidation media on the adsorption capacity follows the order of NaOH>H2SO4>H2O, consistent with the order of the concentrations of oxygen functionalities introduced on the carbon surface. Computational results suggest that phenol and carboxyl groups on the surface lead to stronger thiophene adsorption than the bare (unfunctionalized) graphite surface, corroborating our experimental results. Additionally, the presence of bridging-oxygen functionalities on the carbon surface leads to extremely exothermic adsorption energies of thiophene, which can be attributed to sulfoxide formation and H-bonding interactions. DFT calculations suggest the adsorption strength of thiophene follows the order of bridging-O-functionalized (Ads E=-1.51eV)≫OH-functionalized (Ads E=-0.36eV)>COOH-functionalized (Ads E=-0.27eV)>bare graphite (Ads E=-0.26eV). The combined experimental and computational study provides direction for carbon surface functionalization for adsorptive desulfurization.
AB - In this work, a combined experimental and computational study is carried out to investigate the effect of O3 oxidation of activated carbon (AC) in various types of aqueous media (alkaline, acidic and neutral aqueous solutions) on the adsorption of thiophene. A high surface area AC (BET surface area of 2880m2/g) is modified by ozone-oxidation in different aqueous media under ambient conditions. Experimental results show liquid phase ozone oxidation of AC introduces oxygen functional groups to the AC surface, resulting in enhanced adsorption capacity of thiophene. The impact of oxidation media on the adsorption capacity follows the order of NaOH>H2SO4>H2O, consistent with the order of the concentrations of oxygen functionalities introduced on the carbon surface. Computational results suggest that phenol and carboxyl groups on the surface lead to stronger thiophene adsorption than the bare (unfunctionalized) graphite surface, corroborating our experimental results. Additionally, the presence of bridging-oxygen functionalities on the carbon surface leads to extremely exothermic adsorption energies of thiophene, which can be attributed to sulfoxide formation and H-bonding interactions. DFT calculations suggest the adsorption strength of thiophene follows the order of bridging-O-functionalized (Ads E=-1.51eV)≫OH-functionalized (Ads E=-0.36eV)>COOH-functionalized (Ads E=-0.27eV)>bare graphite (Ads E=-0.26eV). The combined experimental and computational study provides direction for carbon surface functionalization for adsorptive desulfurization.
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U2 - 10.1016/j.cej.2013.12.077
DO - 10.1016/j.cej.2013.12.077
M3 - Article
AN - SCOPUS:84892665670
SN - 1385-8947
VL - 242
SP - 211
EP - 219
JO - Chemical Engineering Journal
JF - Chemical Engineering Journal
ER -