Synergistic effect of bimetal in isoreticular Zn–Cu–1,3,5-benzenetricarboxylate on room temperature gaseous sulfides removal

Abstract

Isoreticular bimetal M−Cu−BTC has considerable potential in improving the sulfides removal performance of Cu–BTC. Herein, three transition metals, namely, Zn2+, Ni2+ and Co2+, were assessed to fabricate M−Cu−BTC, a desirable isoreticular bimetal. Results demonstrated the feasibility of using Zn2+ to fabricate an isoreticular bimetallic Zn–Cu–BTC. The Zn2+ doping content of Zn–Cu–BTC was varied to investigate its influence on the hydrogen sulfide (H2S) and methyl sulfide (CH3SCH3) removal performance of Cu–BTC. The experimental results indicated that the sulfides removal performance of Zn–Cu–BTC increased and then decreased with increasing Zn doping content. The highest H2S and CH3SCH3 removal capacities of 84.3 and 93.9 mg S/g, respectively, were obtained when the Zn2+ doping content was 17%. The hybridisation of Zn and Cu in Zn–Cu–BTC induced a strong interaction between them. This interaction increased the binding energies of H2S and CH3SCH3 towards the Cu and Zn adsorption sites while weakening the bond order between Zn and Cu. The weakened bond order made the Zn–Cu bonds easier to form metal sulfides during desulfurization process, thereby synergistically enhancing sulphide removal.