Analysis of antifouling behavior of high dispersible hydrophilic poly (ethylene glycol)/vinyl functionalized SiO_2 nanoparticles embedded polyethylene membrane

摘要

In this work, nanocompsite membranes containing high density polyethylene (HDPE) and functionalized SiO2 nanoparticles were fabricated via thermally induced phase separation method. Silica nanoparticles were functionalized by grafting of poly(ethylene glycol) (PEG) and vinyl functional groups to improve both interfacial adhesion and hydrophilic characteristics of the nanoparticles. HDPE nanocomposite membranes were fabricated by incorporation of the functionalized particles into polymer matrix in the presence of dicumyl peroxide as a free radical initiator. EDAX and BSE analyses showed that a high dispersion of nanoparticles could be achieved in the presence of vinyl moieties due to significant improvement in interaction between particles and HDPE chains. FE-SEM images showed that the vinyl grafted particles embedded membranes has an interconnected structure with interwoven polyethylene fibers. It was seen that pure water flux increases from 11 L.m(-2) h(-1) to higher than 90 L.m(-2) h(-1) in the presence of 2 wt.% PEG/vinyl grafted nanoparticles, compared to pure HDPE membrane. The obtained results confirmed that incorporation of PEG/vinyl grafted nanoparticles, caused to achieve a fouling resistance membrane during filtration of humic acid solution, even at higher loading of nanoparticles. Also, pre-treatment with polyaluminium chloride could significantly mitigate fouling and improve humic acid removal. It means that by using the polyethylene microfiltration membrane combined with coagulation process, the results were obtained similar to UF membranes, which usually require higher operation pressure and severe fouling drawbacks.