Nanofiltration Composite Membranes Based on KIT-6 and Functionalized KIT-6 Nanoparticles in a Polymeric Matrix with Enhanced Performances.

Gabriela Paun,Andrei Munteanu,Larisa Ionita,Elena Neagu,Monica Elisabeta Maxim,Viorica Parvulescu,Madalina Ciobanu,Camelia Albu,Gabriel Lucian Radu

doi:10.3390/membranes11050300

Abstract

The nanofiltration composite membranes were obtained by incorporation of KIT-6 ordered mesoporous silica, before and after its functionalization with amine groups, into polyphenylene-ether-ether-sulfone (PPEES) matrix. The incorporation of silica nanoparticles into PPEES polymer matrix was evidenced by FTIR and UV–VIS spectroscopy. SEM images of the membranes cross-section and their surface topology, evidenced by AFM, showed a low effect of KIT-6 silica nanoparticles loading and functionalization. The performances of the obtained membranes were appraised in permeation of Chaenomeles japonica fruit extracts and the selective separation of phenolic acids and flavonoids. The obtained results proved that the PPEES with functionalized KIT-6 nanofiltration membrane, we have prepared, is suitable for the polyphenolic compound’s concentration from the natural extracts.

Highlights

Particular interest has been given in recent years to finding solutions to improve the characteristics of membranes, such as a high permeate flux, rejection, and better antifouling capacity
The previous studies demonstrated that inorganic nanoparticles such as silica (SiO2) [11,12,13,14], zeolites [15,16], metal oxide (Al2O3, TiO2, ZnO) [15,17,18,19,20,21,22,23], and carbon nanotubes [23,24] could improve the hydrophilicity of the modified polymer hydrophobic membranes
Silica nanoparticles have chemical compatible and the mechanical stability needed for preparation of polymeric membrane, and their structure can be changed by chemical functionalization [25]

Summary

Introduction

Particular interest has been given in recent years to finding solutions to improve the characteristics of membranes, such as a high permeate flux, rejection, and better antifouling capacity. The obtained membranes show superior performances, such as mechanical toughness, thermal properties, permeability, and selectivity, compared to polymeric membranes All of these depend on the quality of interface between nanoparticles and the polymer. A higher compatibility and adhesion between inorganic nanoparticles and polymer matrix were obtained by functionalization with amine groups of silica surface in the presence of (3-aminopropyl) triethoxysilane (APTES) as coupling agent. Another method to improve hydrophilicity of the polymer membranes is the addition of polyvinyl pyrrolidone (PVP) or polyethylene glycol (PEG) in different concentrations [27,28]. The properties of membranes and the influence of incorporation and composition of KIT-6 and KIT-6-NH2 nanoparticles on permeation and selectivity of phenolic acids and flavonoids of Chaenomeles japonica fruit extracts were studied

Materials and Methods

Preparation of Nanofiltration Membranes

Characterization of the Obtained Materials

Permeability and Selectivity of Membranes

Characterizations of the Inorganic Nanoparticles