A Highly Reversible Sorption for Sulfur-Containing Toxic VOCs Emissions Under Ambient Temperature and Pressure

Abstract

Sulfur-containing toxic volatile organic compounds (VOCs) can cause odor problems and serious health hazards, thus need to be removed. Metal–organic frameworks (MOFs) with advantages of large surface area, high porosity, tunable pore size and so on, show a great potential in the adsorption field. In this study, we selected Zn-MOF-74 as an adsorbent to investigate the removal performance for two target sulfur-containing VOCs (dimethyl sulfide and ethyl mercaptan), and the samples before and after adsorption were characterized by XRD, XPS, FTIR and TGA. Dynamic breakthrough test in a fixed bed reactor show that, with the increase of adsorption temperature, the sulfur capacity of dimethyl sulfide decreased, while that of ethyl mercaptan increased. According to the regeneration performance results, it can be inferred that a weak physical force existed between the zinc metal center and dimethyl sulfide, while the interaction between MOFs and ethyl mercaptan was strong. It was found that the difference in adsorption behavior was due to the steric hindrance produced by sulfides during the experimental process. In addition, it was considered that hydrogen bonding forces between the sulfhydryl groups (–SH) and hydroxyl groups (–OH) may occur and contribute to the strong force between ethyl mercaptan and MOFs. Moreover, the excellent recyclability of dimethyl sulfide indicated that Zn-MOF-74 has a potential to be an effective adsorbent.