Novel Nanocomposite HNT-TiO2/PVDF Adsorptive Nanofiber Membranes for Arsenic (III) Removal

Abstract

In this work, the removal of arsenic (III) from contaminated water by means of electrospun nanofiber adsorptive membranes (ENAMs) has been reported. Polyvinylidene fluoride (PVDF) was used for preparation of the ENAMs incorporating titanium dioxide (TiO2)-halloysite nanotubes (HNTs) nanoparticles as adsorbents. Removal of arsenic (III) by the prepared ENAMs was studied at adsorbent to polymer ratios of 0, 0.25, and 0.5 w/w. The addition of TiO2-HNTs to the polymer left visible changes on the structural morphology and fibers properties of the membrane. The membrane samples were characterized by pure water permeability, contact angle measurement, TEM, SEM, XPS, and XRD. Results indicated that by increasing the TiO2-HNT content, the adsorption capacity of the membrane improved. A maximum of 31.2 mg/g of arsenic adsorption was achieved using TiO2-HNT<br />to PVDF ratio of 0.5 w/w. The ENAMs were able to reduce the arsenic (III) concentration to less than 10 ppb, the level recommended by the World Health Organization (WHO). Moreover, the adsorptive properties of the nanocomposite fibers were restored to 94% of the original capacity by cleaning the membranes using sodium hydroxide solution followed by DI water flushing.