Preparation of Fouling-Resistant Nanofibrous Composite Membranes for Separation of Oily Wastewater

Abstract

A facile and low-cost method has been developed for separation of oily wastewater. Polyvinylidene fluoride/polyacrylonitrile (PVDF/PAN) nanofibers laminated on a supporting layer were tested. In order to create highly permeable and fouling-resistant membranes, surface modifications of both fibers were conducted. The results of oily wastewater separation showed that, after low vacuum microwave plasma treatment with Argon (Ar) and chemical modification with sodium hydroxide (NaOH), the membranes had excellent hydrophilicity, due to the formation of active carboxylic groups. However, the membrane performance failed during the cleaning procedures. Titanium dioxide (TiO 2 ) was grafted onto the surface of membranes to give them highly permeable and fouling-resistance properties. The results of the self-cleaning experiment indicated that grafting of TiO 2 on the surface of the membranes after their pre-treatment with Ar plasma and NaOH increased the permeability and the anti-fouling properties. A new surface modification method using a combination of plasma and chemical treatment was introduced.

Electrospun Polyacrylonitrile Nanofibrous Membranes for Point‐of‐Use Water and Air Cleaning

“…PAN is easy to electrospun into nanofiber and has thermal stability, tolerance to most solvents, and commercial availability. [34,35] The mechanical strength of the prepared electrospun web was improved by lamination with a supporting layer and adhesive web. The lamination conditions, such as temperature, duration of heat-press and force of the press have been investigated.…”

“…In this work, polyacrylonitrile (PAN) nanofiber web was prepared using needle‐free wire electrospinning industrial production method. PAN is easy to electrospun into nanofiber and has thermal stability, tolerance to most solvents, and commercial availability ,. The mechanical strength of the prepared electrospun web was improved by lamination with a supporting layer and adhesive web.…”

Effect of argon plasma treatment on hydrophilic stability of nanofiber webs

“…Another reason to select these polymers is their opposite selectivity for an oil–water mixture. Based on our previous experience, PVDF nanofiber layers showed oleophilic characteristics, while PA6 nanofibers showed oleophobic/hydrophilic characteristics in an oil–water mixture …”

“…Moreover, plasma treatment influenced the selectivity of the membranes at the beginning due to an increase in hydrophilicity. A third surface modification is necessary to have stable hydrophilic/oleophobic membranes …”

“…Based on our previous experience, PVDF nanofiber layers showed oleophilic characteristics, while PA6 nanofibers showed oleophobic/hydrophilic characteristics in an oil-water mixture. 20,[70][71][72] The filtration test was run after one day of plasma modification. Figure F5 5 shows the permeability results of both plasma-treated and neat nanofiber webs.…”