Polyvinylidene Fluoride-Graphene Oxide Membranes for Dye Removal under Visible Light Irradiation.

Sabri Alyarnezhad,Claudia Ursino,Alberto Figoli,Hermenegildo Garcìa,Jalal Basiri Parsa,Francesco Galiano,Marta Puche,Tiziana Marino

doi:10.3390/polym12071509

Abstract

In this study, polyvinylidene fluoride (PVDF)-graphene oxide (GO) membranes were obtained by employing triethyl phosphate (TEP) as a solvent. GO nanosheets were prepared and characterized in terms of scanning and transmission electron microscopy (SEM and TEM, respectively), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), chemical analysis and inductively coupled plasma mass spectroscopy (ICP). Two different phase inversion techniques, Non-Solvent Induced Phase Separation (NIPS) and Vapour-Induced Phase Separation (VIPS)/NIPS, were applied to study the effect of fabrication procedure on the membrane structure and properties. Membranes were characterized by SEM, AFM, pore size, porosity, contact angle and mechanical tests, and finally tested for photocatalytic methylene blue (MB+) degradation under visible light irradiation. The effect of different pH values of dye aqueous solutions on the photocatalytic efficiency was investigated. Finally, the influence of NaCl salt on the MB+ photodegradation process was also evaluated.

Highlights

The shortage of fresh water and increasing industrial discharge from human activities are the most critical concerns in industrialized cities
graphene oxide (GO) was obtained by the deep chemical oxidation of graphite and exfoliation by sonication, as previously reported [55]
Sheets of lateral size from 0.8 to 3.0 microns, was used in the present study. This was confirmed by atomic force microscopy (AFM) measurements (Figure 2a,b) of the GO suspended in aqueous medium

Summary

Introduction

The shortage of fresh water and increasing industrial discharge from human activities are the most critical concerns in industrialized cities In this framework, several processes oriented to the treatment and reuse of wastewaters and seawater such as membrane bioreactors (MBRs) [1], membrane distillation [2], solar to steam generation systems [3,4,5] are undergoing rapid expansion. One of the most important sources of water contamination is the textile wastewater that includes a variety of organic dyes, which should not be underestimated because of their poisonousness, carcinogenic potential and non-biodegradability From this perspective, effective wastewater treatment technologies with minimum consumption of energy and reagents for chemical conversion of organic dyes into safe (non-toxic) or harmless compounds are required [6]. Only 4–7% of the solar spectrum is UV

Methods

Results

Conclusion