Nanofiltration Membrane with a Mussel-Inspired Interlayer for Improved Permeation Performance

Abstract

A mussel-inspired interlayer of polydopamine (PDA)/polyethylenimine (PEI) is codeposited on the ultrafiltration substrate to tune the interfacial polymerization of piperazine and trimesoyl chloride for the preparation of thin-film composite (TFC) nanofiltration membranes (NFMs). This hydrophilic interlayer results in an efficient adsorption of piperazine solution in the substrate pores. The solution height increases with the PDA/PEI codeposition time from 45 to 135 min due to the capillary effect of the substrate pores. The prepared TFC NFMs are characterized with thin and smooth polyamide selective layers by ATR/IR, XPS, FESEM, AFM, zeta potential, and water contact angle measurements. Their water permeation flux measured in a cross-flow process increases to two times as compared with those TFC NFMs without the mussel-inspired interlayer. These TFC NFMs also show a high rejection of 97% to NaSO and an salt rejection order of NaSO ≈ MgSO > MgCl > NaCl.

Design of ultrathin hybrid membranes with improved retention efficiency of molecular dyes

“…As a matter of fact, dyes are discharged into water and into the environment by various industries working, for example, in the paper, cosmetics, leather, and textiles sectors to name just a few, because dyes are part of the chemicals used to impart special properties to their products. 1,2 Dyes are usually classied into anionic, cationic and non-ionic (neutral) molecules, are stable to light and resistant to biological degradation and aerobic digestion. Although chemical, physical, and biological methods are frequently used to remove dyes form industrial effluents, adsorption is considered the cheapest and most effective method compared to the all the available dye removal strategies.…”

Monitoring the Interfacial Polymerization of Piperazine and Trimesoyl Chloride with Hydrophilic Interlayer or Macromolecular Additive by in-situ FT-IR Spectroscopy

“…The PDA/PEI interlayer was constructed on the porous substrate, according to the reported literature. DA and PEI were dissolved in Tris-buffer (50 mM, pH = 8.5) at a mass ratio of 1:1, with a concentration of 2.0 mg/mL [30]. The porous substrate was immersed in the freshly prepared DA/PEI solution for 1 h. After that, the PDA/PEI modified substrate was washed thoroughly by DI water and dried at room temperature for 1 h.…”

“…Additionally, Ren et al used FT-IR microscopy for IP reaction of microporous polymer film formed in the aqueous/organic interface, for polyesterification by choosing the adequate phenol monomer [29]. Yang et al reduced the IP reaction rate of piperazine (PIP) and trimesoyl chloride (TMC) reaction system to a certain extent, by introducing interlayers between the porous substrate and the polyamide layer [30][31][32]. Tan et al added the macromolecular additives in the aqueous solution of PIP and obtained the Turing structure [33].…”

Monitoring the Interfacial Polymerization of Piperazine and Trimesoyl Chloride with Hydrophilic Interlayer or Macromolecular Additive by In Situ FT-IR Spectroscopy

“…Additionally, Ren et al used FT-IR microscopy for IP reaction of microporous polymer film formed in the aqueous/organic interface for polyesterification by choosing the adequate phenol monomer [29]. Yang et al reduced the IP reaction rate of piperazine (PIP) and trimesoyl chloride (TMC) reaction system to a certain extent by introducing interlayers between the porous substrate and the polyamide layer [30][31][32]. Tan et al added the macromolecular additive of polyvinyl alcohol (PVA) in the aqueous solution of PIP and obtained the Turing structure [33].…”