Pervaporation chitosan membranes modified with carbon nanoparticles for enhanced isopropanol dehydration

Carbon particles (CP) with functional groups are one of the promising modifiers for polymer matrices to create pervaporation mixed matrix membranes (MMM) with tailored properties. In this context, a detailed study of the effect of polymer modification with various CP is required. Thus, in this study, highly efficient MMM based on chitosan (CS) for enhanced pervaporation dehydration of isopropanol were developed by modification with graphene oxide, fullerenol, carboxyfullerene, single- and multi-walled (MWCNT) nanotubes. The effect of CP introducing into the CS matrix was investigated, where the CS/MWCNT composite demonstrated optimal transport properties as a dense membrane material. To increase efficiency, an optimal cross-linking agent for improvement of the membrane stability in an aqueous media was selected, and supported membranes from CS/MWCNT composite were developed. The structural changes during modifications were investigated by spectroscopic (FTIR and NMR) and microscopic (SEM and AFM) methods. Physicochemical properties of MMM were studied by thermogravimetric analysis, measurements of contact angles and swelling degree. The optimal cross-linked supported membrane with a thin dense layer from CS/MWCNT (5%) composite had in 2–4 times increased permeation flux and higher water content in the permeate (99.9–98.5 wt.%) compared to the pristine dense CS membrane in pervaporation dehydration of isopropanol (12–50 wt.% water). This membrane also demonstrated high stability in separation till 90 wt.% water in the feed with the following transport parameters of 1 kg/(m²h) and 97.5 wt.% water in the permeate.

Graphical abstract