Modification of polyamide TFC nanofiltration membrane for improving separation and antifouling properties

Abstract

In this work, a dendrimer trimesoyl amide amine (TMAAM) monomer was proposed to be used as a key functional monomer to modify the conventional aromatic polyamide thin-film composite (TFC) nanofiltration (NF) membrane, and a new kind of TMAAM-based semi-aromatic polyamide composite NF membrane was thus prepared by interfacial polymerization. The effects of the PIP/TMAAM ratio (PIP ¼ piperazine) on the membrane chemical structure, surface properties and separation performances were investigated systematically. With the increase in TMAAM content loaded in the membrane, the water flux strongly increased but the salt rejection decreased only slightly. When the PIP/TMAAM ratio was 1, the membrane NF-2 exhibited a smoother and more hydrophilic surface, as a result of which it displayed an optimum separation performance for different valent salts. In addition, the TMAAM modified TFC membrane presented an extremely high rejection to negatively charged dye molecules and high permeation for monovalent salts, leading to good prospects for dye/salt separation application. Moreover, both the water flux and salt rejection of the TMAAM-based membrane were stable in a longterm running process, and the membrane showed a favourable anti-fouling property and efficient cleaning recovery. Therefore, this work provides a new type of semi-aromatic polyamide composite NF membrane fabricated by a facile and straightforward method via interfacial polymerization with high hydrophilicity, good stability and strong anti-fouling property.

Molecularly soldered covalent organic frameworks for ultrafast precision sieving

“…Therefore, the pDA/TpPa(W/E)-COF membrane had a superior mono/bivalent salt selectivity, surpassing that of most of the established desalination membranes (Fig. 4F) (44,(48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58). Such superior performance mainly resulted from the water transport channels formed in 2D COF membrane.…”

Preparation and characterization of polyzwitterionic hydrogel coated polyamide‐based mixed matrix membrane for heavy metal ions removal

“…As shown in this figure, the characteristic peaks around 1,450 cm −1 corresponding to the carbon-carbon double bond of the benzene ring were observed for all of the membranes. [42] Peaks at 1,722 cm −1 are assigned to the ester carbonyl group, while the 1,036 cm −1 peak is assigned to sulfonic acid group of the zwitterionic hydrogel. [26,43] These peaks are obviously seen in hydrogel modified samples (HTFC and HMMM).…”

Nutrients Enrichment and Process Repercussions in Hybrid Microfiltration Osmotic Membrane Bioreactor: A Guideline for Forward Osmosis Development Based on Lab-Scale Experience

“…This phenomenon might be due to the possible reverse salt transport flow from the DS reservoir into the bioreactor that enabled the diffusion of charged PO 4 -P via the same route [28]. Nevertheless, relatively high and stable rejection of PO 4 -P by the FO membrane was observed and explained by the larger hydrated radius of phosphate molecules and their negative charged ions (H 2 PO 4 − and HPO 4 2− ), and the negatively charged FO membrane surface [29].…”

“…Water 2020, 10, x 9 of 18 larger hydrated radius of phosphate molecules and their negative charged ions (H2PO4 − and HPO4 2− ), and the negatively charged FO membrane surface [29].…”