Optimal Performance of Thin-Film Composite Nanofiltration-Like Forward Osmosis Membranes Set Off by Changing the Chemical Structure of Diamine Reacted with Trimesoyl Chloride through Interfacial Polymerization.

Manuel Reyes De Guzman,Micah Belle Marie Yap Ang,Kueir-Rarn Lee,Qing-Yi Huang,Shu-Hsien Huang,Yu-Hsuan Chiao

doi:10.3390/polym13040544

Abstract

Thin-film composite (TFC) polyamide membranes formed through interfacial polymerization can function more efficiently by tuning the chemical structure of participating monomers. Accordingly, three kinds of diamine monomers were considered to take part in interfacial polymerization. Each diamine was reacted with trimesoyl chloride (TMC) to manufacture TFC polyamide nanofiltration (NF)-like forward osmosis (FO) membranes. The diamines differed in chemical structure; the functional group present between the terminal amines was classified as follows: aliphatic group of 1,3-diaminopropane (DAPE); cyclohexane in 1,3-cyclohexanediamine (CHDA); and aromatic or benzene ring in m-phenylenediamine (MPD). For FO tests, deionized water and 1 M aqueous sodium sulfate solution were used as feed and draw solution, respectively. Interfacial polymerization conditions were also varied: concentrations of water and oil phases, time of contact between the water-phase solution and the membrane substrate, and polymerization reaction time. The resultant membranes were characterized using attenuated total reflectance-Fourier transform infrared spectroscopy, field emission scanning electron microscopy, atomic force microscopy, and surface contact angle measurement to identify the chemical structure, morphology, roughness, and hydrophilicity of the polyamide layer, respectively. The results of FO experiments revealed that among the three diamine monomers, CHDA turned out to be the most effective, as it led to the production of TFC NF-like FO membrane with optimal performance. Then, the following optimum conditions were established for the CHDA-based membrane: contact between 2.5 wt.% aqueous CHDA solution and polysulfone (PSf) substrate for 2 min, and polymerization reaction between 1 wt.% TMC solution and 2.5 wt.% CHDA solution for 30 s. The composite CHDA-TMC/PSf membrane delivered a water flux (Jw) of 18.24 ± 1.33 LMH and a reverse salt flux (Js) of 5.75 ± 1.12 gMH; therefore, Js/Jw was evaluated to be 0.32 ± 0.07 (g/L).

Highlights

Technologies continually develop for the sake of industrialization and the growing population
forward osmosis (FO) membranes—1,3-diaminopropane (DAPE), 1,3-cyclohexanediamine (CHDA), and mphenylenediamine (MPDA). These monomers were all diamines, their structures differed in terms of the moiety in between the terminal amines. We considered such types of diamine monomers to investigate if they could be potential candidates to replace MPD, a commonly used monomer for fabricating reverse osmosis (RO) or FO membranes, with the goal of fabricating FO membranes with higher efficiency
Each of them was reacted with trimesoyl chloride (TMC), an acyl chloride monomer, through interfacial polymerization

Summary

Introduction

Technologies continually develop for the sake of industrialization and the growing population. New technologies entail processing and fabrication of materials, which require intensive use of water and other solvents. The extent of pollution worsens or the level of environmental contaminants, produced as by-products of such processes, rises. For this reason, governments enjoin industries to build their own wastewater treatment facilities or to discharge their effluents into wastewater treatment plants. Membrane separation processes have more compact systems, incur lower costs, and are more efficient [1]

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Results

Conclusion