Low-Temperature Desulfurization on Iron Oxide Hydroxides: Influence of Precipitation pH on Structure and Performance

Abstract

A series of iron oxide hydroxides were prepared by precipitation at different pH values using sodium carbonate as the precipitant and their performances for low-temperature H2S adsorption were investigated. The synthesized materials were characterized by N2 adsorption–desorption measurements, powder X-ray diffraction, Raman spectroscopy, scanning electron microscope and electron spin resonance. We revealed that the iron oxide hydroxides precipitated in neutral and alkaline media exhibited high breakthrough sulfur capacity, attributed to the formation of a pure α-FeOOH phase with more crystal defects and hydroxyl groups as activity sites. In addition, with the increasing precipitation pH, a gradual increase in the surface area of the materials was detected with Brunauer–Emmett–Teller analysis and was believed to be partially responsible for the improved desulfurization capability.