Enhancing membrane distillation stability: Isoamyl alcohol coagulation as a novel strategy to mitigate membrane swelling at elevated temperatures

Abstract

Membrane distillation (MD) shows significant potential for desalination but is hindered by technical challenges, such as membrane swelling at high operating temperatures, compromising long-term stability. Conventional coagulation baths, like water, produce dense membrane sur­ faces that limit performance, while ethanol promotes larger pores but induces swelling due to its low boiling point. This study presents isoamyl alcohol as a novel coagulation bath to enhance MD membrane stability. With its high boiling point (131 ◦C) and extended alkyl group, isoamyl alcohol improves membrane hydrophobicity (152 ± 2.3◦), and porosity (84 ± 2.5 %), effectively mitigating swelling under thermal stress. The optimized MD membrane achieved over 99.8 % salt rejection, and a stable flux of 19.2 litre per square meter per hour (LMH) over 10 days of natural seawater operation. These results highlight isoamyl alcohol coagulation as a promising innova­ tion in MD membrane fabrication, advancing the potential for commercial seawater desalination applications.