Application of PVDF/HDTMA-modified clinoptilolite nanocomposite membranes in removal of reactive dye from aqueous solution

Abstract

Nowadays, dye-containing effluents are one of the important environmental issues which attracted researcher attentions extensively. Among different methods, used for dye containing effluents treatment, membrane technology has been considered recently. In this study, neat polyvinylidene fluoride (PVDF) nanofiltration membrane and nanocomposite membranes containing clinoptilolite nanoparticles, modified with hexadecyltrimethylammonium bromide surfactants (PVDF/HDTMA-modified clinoptilolite), were fabricated by wet phase inversion method and their performance in reactive red 120 (RR120) separation from aqueous solution, was investigated. Morphology, surface roughness, functional groups, hydrophilicity and pore size of the fabricated membranes were characterized respectively by field emission scanning electron microscopy (FESEM), Atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), contact angle measurement (CA), and gravimetric tests. The separation properties of the membranes were also determined by permeation and rejection experiments. Gravimetric test results showed that the average pore size decreased from 5.72 nm in neat PVDF membrane to 4.41 nm in the membrane containing 2.5 wt% HDTMA-modified clinoptilolite nanoparticles. Considering contact angle results of the neat PVDF membrane (CA = 77.5°) and nanocomposite membrane containing 2.5% nanoparticles (CA = 63.7°) it was found that hydrophilicity of the nanocomposite membranes increase as HDTMA-modified clinoptilolite nanoparticles content increases in the polymer matrix. Permeation test results showed that 98.5% of RR120 can be separated by using a nanocomposite membranes containing 2.5 wt% HDTMA-modified clinoptilolite nanoparticles while its flux can be recovered to 96%.