A dual-scale analysis of mass transfer enhancement in liquid desiccant system for indoor VOCs removal by adding surfactant

Abstract

Indoor volatile organic compounds (VOCs) pollution control is a major challenge facing the healthy development of people. Liquid dehumidification is expected to be a potential way for VOCs removal. However, the poor mass transfer ability for some hydrophobic VOCs in liquid desiccant (LD) system results in a lower removal performance. Therefore, a dual-scale perspective is proposed to enhance VOCs transfer in this study. It includes micro material property for VOCs transfer at solution interface, and macro system model for heat-moisture-VOCs transfer in LD system. The micro and macro sub-perspectives are combined via key information exchange. Moreover, surfactant is firstly introduced into LD system to enhance VOCs transfer from dual-scale perspective. The surfactant can effectively improve the solubility of hydrophobic VOCs in LD and enhance their mass transfer at solution interface. Through experiment and simulation, the influences of micro material properties and macro working parameters on VOCs transfer characteristic are investigated considering air dehumidification requirements. Using the proposed dual-scale perspective, a new LD is designed. Thus, the VOCs transfer ability at micro interface and macro system are improved by 19.24% and 16.67%, respectively. It is found that the enhanced VOCs transfer ability is co-determined by micro material properties and macro working parameters. In a way, the proposed approach can realize the dual-scale co-design from “micro interface - macro system”. Entirety analysis of the VOCs transfer characteristics in LD system is feasible with this methodology.