Controllable construction of Cu(Ⅰ)in Y zeolite for adsorptive separation of ethylene/ethane
The similarity in the physical properties of ethylene(C2H4)and ethane(C2H6)makes their selective separation one of the most challenging chemical separation processes.Utilizing the π-complexation between Cu(Ⅰ)active species and C2H4,Cu(Ⅰ)-based adsorbents can achieve their selective separation,significantly reducing the cost and environmental impact resulting from the high energy consumption of traditional distillation processes.Cu(Ⅰ)-based adsorbents are prepared by reducing Cu(Ⅱ)-containing samples,but the uncontrollable Cu(Ⅱ)reduction,low Cu(Ⅰ)yields,and high energy consumption have been the obstacles to the application of Cu(Ⅰ)-based materials.Here,a selective reduction strategy has been successfully employed to selectively construct Cu(Ⅰ)active sites in Y zeolite,enabling the selective separation of C2H4/C2H6 under mild conditions.Using formaldehyde(HCHO)vapor diffusion transfer to react with Cu(Ⅱ)in zeolite,the selective construction of Cu(Ⅰ)at low temperature(140℃)was achieved.Compared to the original Cu(Ⅱ)Y,Cu(Ⅰ)Y exhibits excellent C2H4/C2H6 selective separation performance.Cu(Ⅰ)Y achieves a selectivity of 16.3,far higher than the selectivity of Cu(Ⅱ)of 3.2.Finally,the formation mechanism of Cu(Ⅱ)is revealed,in which Cu(Ⅱ)in the zeolite is selectively converted to Cu(Ⅰ)along with the production of CO2 and H2O.
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