Organo-Functionalization: An Effective Method in Enhancing the Separation and Antifouling Performance of Thin-Film Nanocomposite Membranes by Improving the Uniform Dispersion of Palygorskite Nanoparticles.

Liu Yang,Kefeng Zhang,Qikun Wang,Wande Ding,Qianwen Zhang

doi:10.3390/membranes11110889

Abstract

Recently, palygorskite (Pal) has become a promising new membrane additive in flux enhancement and fouling reduction, which is an environmentally friendly nanoclay material under the 2:1 layer composition with 1D tubular structure. However, the aggregation of Pal due to the intermolecular forces is still an obstacle to be solved in improving membrane performance. Herein, Pal nanoparticles were chemically modified by KH550 to weaken the aggregation and improve the dispersibility, and then incorporated into the organic phase to prepare thin-film nanocomposite (TFN) membranes. The results showed that the organo-functionalization could effectively improve the membrane hydrophilicity and dispersion of Pal nanoparticles in the polyamide layer, which contributed to the enhanced water flux (from 25 to 38 L/m2·h), unchanged salt rejection (98.0%) and better antifouling capacity (91% flux recovery rate), which suggested that the organo-functionalization of nanoparticles was an efficient method in further enhancing membrane performance

Highlights

IntroductionClay nanoparticles have been popular since they are naturally abundant and cost effective; in particular, the two-dimensional sheet structures and inherent hydrophilicity make them potential ideal nanofillers for thin-film nanocomposite (TFN)
After grinding or modification by KH550, it was found that the characteristic peaks of all the samples correspond basically, which suggested that the crystal structure of Pal was not destroyed [14]
The results showed that when the mass ratio of KH550 and g-Pal was 3:4, the K-Pal possessed the lowest particle size (312 nm) and settling rate (1.22 × 10−5 cm/s)

Summary

Introduction

Clay nanoparticles have been popular since they are naturally abundant and cost effective; in particular, the two-dimensional sheet structures and inherent hydrophilicity make them potential ideal nanofillers for thin-film nanocomposite (TFN). Membranes [1,2] Clay materials, such as halloysite nanotubes (HNTs), layered double hydroxides (LDHs) and montmorillonites (MMTs), have been added into mixed matrix membranes and presented the positive effect on the TFN membrane performance, the enhanced water flux, and improved antifouling capacity and chlorine resistance [3,4,5]. The nanoscale porous structure with the cross-sectional area of 0.37 nm × 0.63 nm could provide extra parallel nanochannels in the polyamide (PA) layer and make it conducive to the transport of the water molecules, which has drawn more attention as capable membrane nanofillers [7,8]

Methods

Results

Conclusion