Mixed matrix membranes based on sodium alginate modified by fullerene derivatives with L-amino acids for pervaporation isopropanol dehydration

Abstract

Biopolymer sodium alginate (SA) is actively used as a green membrane material. To improve the pervaporation properties of the SA membrane in the isopropanol dehydration, different water-soluble fullerene derivatives with L-amino acids (threonine, hydroxyproline, and arginine) were used. In this study, fullerene–arginine derivative (C60-Arg) was shown to be an optimal filler acting both as a modifier and a cross-linking agent for SA. Different cross-linking agents (phosphoric and citric acids, calcium chloride) were tested for dense membrane cross-linking to reinforce the membranes for the separation of diluted solutions. Two types of membranes based on SA and SA/C60-Arg (5%) were developed: dense and supported on polyacrylonitrile substrate. The structural features of obtained membranes were investigated by the following methods: FTIR spectroscopy, scanning electron (SEM), and atomic force (AFM) microscopies. The optimal transport properties in dehydration of isopropanol (12–100 wt.% water) were found for the cross-linked SA/C60-Arg (5%) membrane supported on PAN substrate. The following parameters were obtained: 0.5–4.7 kg/(m2h) permeation flux and constant 99.99 wt.% water content in the permeate.