ABSTRACT
In recent decades, the fabrication of composite membranes using nanoparticles has played a vital role in membrane distillation (MD) technique. It could make available membranes with superior characteristics as excellent candidates for MD technique. The most well-known obstacles regarding the MD method are the low productivity and high cost. Thus, fabricating membranes with superior properties is a significant challenge. In the current study, a composite membrane has been fabricated using 0.25, 0.5, and 0.75 weight percent (wt.%) of graphene nanoparticles (GNPs) with polystyrene (PS) as a base polymer and characterized using SEM, FTIR, and contact angle. The characterization results prove the successful fabrication using electrospinning and the validity of the fabricated membranes to be applied to direct contact membrane distillation (DCMD). In addition, a DCMD experimental setup has been designed to examine the performance of the fabricated membranes and compare the performance of blank PS with composite PS/GNPs membranes. The results show that all fabricated membranes produced an approximately similar average flux of about 10 kg/m2 h, while the highest GNPs wt.% showed the highest salt rejection. Accordingly, this composite membrane has been examined at different operating parameters and showed stable performance. Moreover, feed temperature and the rate of flow have a positive impact on the overall performance of the DCMD.
ABSTRACT
Membrane distillation is an active technique that provides pure water with very good rejection and could be applied to water of extremely high salinity. The low productivity of membrane distillation needs intensive efforts to be competitive with other desalination techniques. In this current study, a composite (PS/GNP) membrane, which is composed of polystyrene (PS) based and 0.25% weight percent graphene nanoplates (GNP) has been fabricated via electrospinning and compared with the blank PS membrane. SEM, FTIR, contact angle and porosity characterization have been performed, and the results show that the validity of the predefined conditions, and the contact angle of the composite membrane, which is found to be 91.68°, proved the hydrophobic nature of the composite membrane. A numerical simulation using Ansys 2020 software has been introduced to study the performance of the fabricated composite membrane when used in direct contact membrane distillation (DCMD). The numerical model has been validated with experimental work from the literature and showed an excellent match. The blank PS and composite PS/GNP membranes have been investigated and compared at different operating conditions, i.e., hot water supply temperature and system flow rate. The results show that the composite PS/GNP membrane outperforms the blank PS membrane at all studied operating conditions.
