The University of Manchester, UK
Title: Preparation and characterization of PVDF/reduced graphene oxide nanocomposite membranes for air gap membrane distillation
Biography: Ahmed Abdel-Karim
Water represents the main driving force of sustainable development and is critical for socio-economic development as well. In this context, membrane distillation (MD) is a promising technology to produce clean water via desalting highly saline waters. Different module configurations are well-established such as direct contact (DCMD), air gap (AGMD) and sweeping gas (SGMD). In this work, AGMD module was selected to skip the disadvantages associated with other configurations such as wetting problems or high energy consumption; only about 1 kWh/m3 energy consumption has been reported by Gazagnes, et al. 2006 which is much lower than typical values reported for DCMD and other MD processes. Hydrophobic polyvinylidene fluoride (PVDF) membranes are generally used in AGMD; however, its performance in terms of permeation flux and salt rejection has room for improvement. In this study, different loads of reduced graphene oxide (rGO) (0–0.7 wt%) were blended with PVDF to investigate its effect on the MD performance. GO was prepared from graphite using a modified hummer’s method and rGO was further prepared using an eco-friendly reductant (i.e. Vit. C). Surface chemistry of the fabricated membranes (bare PVDF membrane as well as hybrids containing rGO) was studied via Fourier transform infrared spectroscopy (FTIR). Membranes microstructures have been visualized using SEM and AFM. Besides, the membrane properties, including contact angle, pore size, porosity and pore size distribution, were systematically examined. The results revealed that PVDF/ 0.5% rGO membranes exhibit better membrane morphology, pore size, pore structure and hydrophobicity, and hence, delivered better distillation performance in comparison with their PVDF membrane counterpart (2.4 LMH for PVDF up to 6.8 LMH for modified PVDF/0.5rGO with SR more than 99.9% for all membranes). The graphical abstract in Fig. 1 summarizes the work.