Preparation And Properties Of Supported CuCl Adsorbents

The separation of CO from gas mixtures and the C₂H₄/C₂H₆ separation are two kinds of important separations in the chemical industry.Currently,the dominant technology for these separations is the cryogenic distillation,which is an extremely energy-consuming process.The?-complexation adsorption is the most promising substitute for these separations due to its high adsorption capacity,high adsorption selectivity,excellent reversibility,low energy cost and easy operation.For the?-complexation adsorption-based separation,the?-complexation adsorbents are the key to directly determine the separation performance.The development of Cu?I??-complexation adsorbents has practical significance,because that Cu⁺ions can interact with CO and C₂H₄ more strongly than other transition metal ions,and also for the economic reason.Currently,the Cu?I?-based adsorbents are mainly prepared by using CuCl as raw material in industry.However,in the preparation process of the adsorbents,all the steps and storage must be performed in a dry inert atmosphere to protect Cu⁺ions from oxidation.In this work,the Cu?I?-based adsorbents of zeolite Y supported CuCl?CuCl@Y?and activated carbon?AC?supported CuCl?CuCl@AC?have been prepared by using the cheap and stable CuCl₂ as precursor by a solid-state dispersion method.The preparation process is facile,and the preparation cost is more economic.Firstly,the effects of the supports,the activation conditions and the copper loadings on the adsorption capacity of the adsorbents were investigated.And then,the optimal CuCl@Y and CuCl@AC adsorbents were investigated for the CO and C₂H₄adsorption properties,including the adsorption capacity,the adsorption selectivity,the reversibility and the stability,and the regenerability of the deteriorated adsorbent oxidized by oxygen was investigated.In addition,the interactions of the prepared adsorbents with CO and C₂H₄ were discussed according to the corresponding isosteric heats of adsorption.Furthermore,a five-bed vacuum pressure swing adsorption?VPSA?process of CO separation from syngas utilizing the prepared CuCl@AC adsorbent was simulated with Aspen Adsorption software.The characterization results reveal that CuCl₂ supported on zeolite Y can be highly dispersed on the surfaces of zeolite Y support and completely converted to CuCl after activation at 663 K in CO atmosphere,and the monolayer dispersion capacity of CuCl on zeolite Y support is 5 mmol/g zeolite Y.For the preparation of the CuCl@AC adsorbent,after activation at a relatively lower temperature of 543 K in N₂atmosphere without any reducing gases,CuCl₂ supported on AC can be highly dispersed on the surfaces of AC support and completely converted to CuCl,and the monolayer dispersion capacity of CuCl on AC is 7 mmol/g AC.The adsorption results reveal that the resulting CuCl@Yand CuCl@AC adsorbents display high CO and C₂H₄ adsorption capacities,high adsorption selectivities,and excellent reversibility and the stability.For the CuCl@AC adsorbent,the desorptions of CO and C₂H₄ from the adsorbents can be achieved at ambient temperature under vacuum.And the deteriorated adsorbent oxidized by oxygen can be restored through the activation process.In addition,the isosteric heats of adsorption suggest that the interactions of CuCl@Y and CuCl@AC with CO and C₂H₄ are between physisorption and chemisorptions.The simulation result of Aspen Adsorption shows that,at ambient temperature and 0.79 MPa,the CO product with the purity of 98.1 vol.%can be separated from the syngas with the CO concentration of 32.3 vol.%utilizing the prepared CuCl@AC adsorbent,and the recovery of CO is 92.9%.