Rare earth oxide doping and synthesis of spinel ZnMn2O4/KIT-1 with double gyroidal mesopores for desulfurization nature of hot coal gas

Abstract

In this work, spinel ZnMn2O4/KIT-1 using KIT-1 with 3-dimensional wormhole-like channels as support was fabricated for hot coal gas desulfurization at high temperature via a sol-gel method. Effects of ZnMn2O4 contents, desulfurization temperature, rare earth oxide doping and steam volume on the desulfurization performances of ZnMn2O4/KIT-1 were investigated systematically. A superior sorbent of ZnMn(Ce)2O4/KIT-1 was obtained with the addition of 45%ZnMn2O4 and doping of CeO2, which was suitable for 550 °C desulfurization and endured a small impact of steam. Moreover, the crystal lattice replace between Ce3+ and Mn3+ facilitated the dispersion of active species and avoided Zn2+ converting to elemental Zn. The high sulfur capacity of ZnMn(Ce)2O4/KIT-1 was maintained after five consecutive desulfurization-regeneration cycles. The textural properties of sorbents were evaluated successively by means of XRD, BET, HRTEM, XPS, H2-TPR and TG/DSC techniques. Results revealed that the main active components in sorbent were robustly existed in form of ZnMn2O4 spinel which effectually prevented the vaporization of Zn in high temperature. Therefore, a low-cost sorbent of ZnMn(Ce)2O4/KIT-1 with the high BSC (171.7 mg S/g sorbent) has an excellent performance for H2S removal from hot coal gas.