Hydrocarbon degradation and separation of bilge water via a novel TiO₂-HNTs/PVDF-based photocatalytic membrane reactor (PMR)

Abstract

This paper focuses on the potential of a novel flat sheet nanocomposite titanium dioxide (TiO 2 )-halloysite nanotubes (HNTs)/polyvinylidene fluoride (PVDF) membrane as a photocatalytic separator in the photocatalytic membrane reactor (PMR). The photocatalytic nanocomposite membrane acted the roles of both degradation and separation for bilge water. Both TiO 2 -HNTs photocatalyst and photocatalytic nanocomposite membranes were characterized by thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and field emission scanning electron microscopy (FESEM) combined energy dispersive X-ray spectroscopy (EDX). The hydrocarbon degradation and removal efficiency of the PMR was evaluated by gas chromatography mass spectroscopy (GC-MS). It was found that 99.9% of hydrocarbons were removed by the PMR within 8 h, which is likely due to uniform distribution and high effectiveness of the TiO 2 -HNTs photocatalyst in the PVDF polymer matrix. The TiO 2 leaching from the nanocomposite membrane during the membrane permeation was analyzed using flame atomic adsorption spectrophotometer (AAS), which recorded 1.0 ppb of TiO 2 leaching in the permeate tank.

Nanocomposite materials for photocatalytic degradation of pollutants

“…The MPR showed reasonable permeation flux and anti-fouling properties and the TiO 2 leaching from the nanocomposite during membrane permeation was found about 1.0 ppb [120,121,145]. PVDF/TiO 2 dual layer membrane achieved a 85% removal of nonylphenol after 4 h of UVA irradiation in submerged membrane photoreactor with a kinetic rate of 0.0092 min −1 [123].…”

“…Commercial TiO 2 P25 NPs-halloysite nanotubes (HNTs) were embedded in polyvinylidene fluoride (PVDF) for the construction of a novel flat sheet membrane that were installed as a photocatalytic separator, in a photocatalytic membrane reactor (PMR) for the degradation and removal of hydrocarbons from bilge water [121]. HNTs were used as support of the TiO 2 P25 NPs that were chemically immobilized to the surface OH groups of HNTs via N-␤-(aminoethyl)aminopropyltrimethoxysilane.…”

Novel hybrid photocatalytic reactor-UF nanocomposite membrane system for bilge water degradation and separation

“…In particular, photooxidation by photocatalytic reactor is known as one of the novel techniques of advanced oxidation processes (AOPs) 12,13 . It has been used to decompose the organic and inorganic compounds 10,11 .…”

Photocatalytic Membrane Reactors (PMRs) in Water Treatment: Configurations and Influencing Factors

“…For PMRs with photocatalyst blended with the membrane, the photocatalyst is blended into the membrane matrix, reducing the possibility of photocatalyst leaching compared to photocatalytic-coated membranes [35]. Most researchers selected polyvinylidene fluoride (PVDF) polymeric membranes for the photocatalyst entrapment [36][37][38][39][40][41][42][43], while polyethersulfone (PES) [44][45][46], polyacrylonitrile (PAN) [47], cellulose acetate (CA) [48,49], polystyrene (PS) [50] and polysulfone (PSF) [51,52] were also used. For PMRs with free-standing photocatalytic membrane, its production is often performed via the electrochemical anodization of a titanium metallic substrate, followed by the separation of the TiO 2 nanotube film and different annealing treatments [17].…”