Advanced PEBA-based membranes for enhanced removal of volatile organic compounds from wastewater

Abstract

The removal of volatile organic compounds (VOCs) from aqueous streams is of considerable environmental and public-health importance. In the present work, nanocomposite membranes were fabricated by incorporating CaF₂ nanocrystals into a poly(ether-b-amide) (PEBA) matrix and evaluated for the hydrophobic pervaporation (PV) of (1-methylethyl)benzene (1-MEB) from dilute aqueous solutions. Relative to Pure PEBA membrane, the introduction of CaF₂ nanocrystals produced pronounced changes in the physicochemical properties of the membranes. The water contact angle (CA) increased to a maximum of 108.77° at 0.5 wt% loading, the degree of swelling (DS) declined from 25.99% to 12.5%, fractional free volume (FFV) were reduced, and mechanical properties were enhanced at optimal nanocrystal contents. These modifications resulted in substantially improved separation performance: at 1 wt% CaF₂ the separation factor rose from 82.51 to 63330.16, water flux decreased from 721.5 to 7.5 g m⁻² h⁻¹, and 1-MEB flux increased to 23.75 g m⁻² h⁻¹. To gain deeper insight into the interaction between the feed components and the prepared membranes, Hansen solubility parameters (HSP) were applied, and modified Bagley relationship incorporating the agglomeration index \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\:{(\text{A}}_{\text{i}})\:$$\end{document}was introduced to calculate the HSP of nanocomposites. The modified HSP provided a reliable explanation for the variations observed in the membrane properties at different nanofiller loadings.