Naturally Derived Allylated Gallic Acid for Interfacially Polymerized Membranes

Abstract

A naturally derived monomer, allylated gallic acid (AG), was herein proposed as a monomer for interfacially polymerized thin-film composite nanofiltration membranes. We investigated the synthesis of the thin-film composite polyester membranes by varying the concentration of the AG monomer and the reaction time with trimesoyl chloride. In addition, we demonstrated the synthesis of a polyesteramide film using a mixture of AG and m-phenylene diamine, although there are a few orders of magnitude differences in their reactivity. While membranes prepared using the classical polyamide process had a water permeance of 0.54 L m −2 h −1 bar −1 , the prepared polyesteramide and polyester films had water permeances of 12.3 and 47.6 L m −2 h −1 bar −1 , respectively The rejection of dyes was larger than 700 g mol −1 and could be tuned to 327 g mol −1 by changing the chemical composition and reaction time. The retention of inorganic salts followed the order Na 2 SO 4 > MgSO 4 ≈ NaCl. Therefore, the membrane performance demonstrates the potential of the phenolic monomer to be integrated into the synthesis of thin-film composite membranes. Besides, the availability of the free allyl group holds potential for further modification and covalent binding onto the surface.

Alternative materials for interfacial polymerization: recent approaches for greener membranes

“…67 The resultant membrane had very good performance and stability. Alhazmi et al 68 used allylated gallic acid as IP monomer to react with TMC. The MWCO was tuned between 700 and 327 g mol −1 by changing the chemical composition and reaction time.…”

“…50 Furthermore, the same group chose an alternative greener monomer allylated gallic acid and instead of n -hexane, isopar-G was used as a solvent and the crosslinking was performed at room temperature conditions. 68 This resulted in the Eco-Scale score of 90. Avoiding toxic substances like MPD monomer and n -hexane organic solvent saved 10 penalty points each.…”