Fouling Control Strategies for High Concentrated Liquid Desiccants Concentrating Using Membrane Distillation

Seonguk Ha; Jieun Lee; Seongeom Jeong; Sanghyun Jeong

doi:10.3390/membranes13020222

Fouling Control Strategies for High Concentrated Liquid Desiccants Concentrating Using Membrane Distillation

Membranes (Basel). 2023 Feb 10;13(2):222. doi: 10.3390/membranes13020222.

Authors

Seonguk Ha¹, Jieun Lee², Seongeom Jeong¹, Sanghyun Jeong¹

Affiliations

¹ Department of Environmental Engineering, Pusan National University, Busan 46241, Republic of Korea.
² Institute for Environmental and Energy, Pusan National University, Busan 46241, Republic of Korea.

Abstract

Air conditioning using a liquid desiccant (LD) is an energy-efficient air purification and cooling system. However, high energy is required to concentrate or regenerate the LD. This study aimed to investigate the characteristics of membrane fouling in more detail and determine control strategies for LD concentrating using membrane distillation (MD). Two different LDs-lithium chloride (LiCl) and potassium formate (HCOOK)-were used. Because LDs require high concentrations by nature (i.e., 40 wt% for LiCl and 70 wt% for HCOOK), the concentration was started from half of those concentrations. This resulted in a flux decline with severe membrane fouling during the concentration using MD. Different membrane fouling mechanisms were also observed, depending on the LD type. Three different physical membrane fouling control methods, including water flushing (WF), air backwashing (AB), and membrane spacer (SP), were introduced. Results showed that WF was the most effective. Both AB and SP showed a marginal change to no cleaning; however, an initial flux with SP was about 1.5 times higher than no cleaning. Therefore, WF combined with the SP could maintain a high flux and a low fouling propensity in the treatment of a high-concentration solution using MD.

Keywords: fouling control; liquid desiccant; lithium chloride; membrane distillation; potassium formate.

Grants and funding

This research was supported by a grant (code 21CTAP-C157250-02) from the Technology Advancement Research Program of the Ministry of Land, Infrastructure and Transport of the Korean Government and the Korean Environmental Industry & Technology Institute (KEITI) through the “Aquatic Ecosystem Conservation Research Program” funded by the Korean Ministry of the Environment (MOE) (2021003040001). This research was also supported by Basic Science Research Programs through the National Research Foundation of Korea (NRF), funded by the Ministry of Education (NRF-2021R1A6A1A03039572).