Cooperative adsorption based kinetics for dichlorobenzene dechlorination over Pd/Fe bimetal

• Introduced dichlorobenzene treatment with Pd/Fe bimetal.
• Introduced cooperative adsorption in surface reaction.
• The treatment process was modeled kinetically.
• Experimental data was used to verify the model.

Pd/Fe bimetal has been used in dichlorobenzene treatment with high efficiency. In order for an industrial application of this process, the dechlorination kinetics was studied. As a catalytic reaction, the overall dechlorination process can be characterized by the step of adsorption and surface reaction. A cooperative adsorption theory was applied to describe the adsorption behaviors in this system. Four chemicals: dichlorobenzene, chlorobenzene, benzene and hydrogen, are adsorbed on the catalyst surface, where active centers provide the space for adhesion. Two groups of active centers, “σσ” and “σ*σ*”, are divided by size in order to distinguish the capability of capturing aromatic compounds. Apparent multilayer adsorption was used to model the cooperative adsorption behaviors in this system. The adsorption sites were characterized by two energy levels. Based on the cooperative adsorption theory, a kinetic model was built for the dechlorination process under adsorption limitation. There are five parameters in the final model including the concentration of active sites, CσCσ, one reaction rate constant: kDCBkDCB and three equilibrium constants: K1,K2 and KeKe. The resultant model was found to describe the experimental data well.

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