Investigation on the sulfur state and phase transformation of spent and regenerated S zorb sorbents using XPS and XRD

Abstract A series of industrial S zorb sorbents extracted from production line were characterized by XPS and XRD. The formation of ZnAl 2 O 4 and Zn 2 SiO 4 is the major reason for the deactivation of spent sorbent. The stability of the Zn-containing spinel species leads to the decrease of the desulfurization efficiency of regenerated sorbent. The chemical states of sulfur atom were examined by XPS. The depth distribution of sulfur species and the reductive behavior of sulfate in H 2 atmosphere were explored using Ar + etching XPS and in situ XPS. The formation of sulfate species in the regeneration process decreases the content of ZnO in the surface significantly and should be avoided. XPS and XRD are excellent tools to follow the sulfur chemical states and phase evolution of S zorb sorbent, respectively, which provide important information for the investigation of deactivation pathways and regenerated mechanisms for S zorb sorbent.