We present poly(2,5-benzimidazole) (ABPBI) based membranes, doped with orthophosphoric acid (OPA), for the sorption and pervaporative dehydration of key industrial solvents: tetrahydrofuran (THF), acetonitrile (AN), and 1,4-dioxane (DX). The ABPBI-OPA complexes were formed via protonation and hydrogen bonding, as supported by spectroscopic and structural analyses. These complexes exhibited improved separation efficacy, further enhanced by thermal treatment. The separation factors for aprotic solvent:water mixtures (85/15 w/w%) were 115 +/- 7 for THF, 350 +/- 27 for AN, and 242 +/- 92 for DX. Long-term stability tests were conducted for 360 h to evaluate the membrane stability during the dehydration of azeotropic mixtures. The present work also introduces a drying approach for hollow fiber membrane modules to restore membrane performance. The results highlight the potential of the developed membranes for the dehydration of harsh solvents and for azeotrope-breaking applications, with no observable membrane degradation over the investigated period.

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