M. Obaid

Amorphous SiO2 NP-Incorporated Poly(vinylidene fluoride) Electrospun Nanofiber Membrane for High Flux Forward Osmosis Desalination

Novel amorphous silica nanoparticle-incorporated poly(vinylidine fluoride) electrospun nanofiber mats are introduced as effective membranes for forward osmosis desalination technology. The influence of the inorganic nanoparticle content on water flux and salt rejection was investigated by preparing electrospun membranes with 0, 0.5, 1, 2, and 5 wt % SiO2 nanoparticles. A laboratory-scale forward osmosis cell was utilized to validate the performance of the introduced membranes using fresh water as a feed and different brines as draw solution (0.5, 1, 1.5, and 2 M NaCl). The results indicated that the membrane embedding 0.5 wt % displays constant salt rejection of 99.7% and water flux of 83 L m(-2) h(-1) with 2 M NaCl draw solution. Moreover, this formulation displayed the lowest structural parameter (S = 29.7 μm), which represents approximately 69% reduction compared to the pristine membrane. Moreover, this study emphasizes the capability of the electrospinning process in synthesizing effective membranes as the observed water flux and average salt rejection of the pristine poly(vinylidine fluoride) membrane was 32 L m(-2) h(-1) (at 2 M NaCl draw solution) and 99%, respectively. On the other hand, increasing the inorganic nanoparticles to 5 wt % showed negative influence on the salt rejection as the observed salt flux was 1651 mol m(-2) h(-1). Besides the aforementioned distinct performance, studies of the mechanical properties, porosity, and wettability concluded that the introduced membranes are effective for forward osmosis desalination technology.

ZrO2 nanofibers/activated carbon composite as a novel and effective electrode material for the enhancement of capacitive deionization performance

Among the various forms of carbon materials, activated carbon still possesses the maximum attention as an optimum commercially available, cheap, and effective electrode material for the capacitive deionization desalination process. However, the well-known hydrophobicity and low specific capacitance limit its wide application. In this study, incorporation of zirconia nanofibers with activated carbon is reported as an effective and simple strategy to overcome the abovementioned problems. Typically, zirconia nanofibers, which were synthesized by the calcination of electrospun nanofiber mats, were added to the activated carbon to fabricate novel electrodes for the capacitive deionization units. In a single-mode cell, it was observed that the addition of the proposed metal oxide nanofibers distinctly enhanced the desalination process as the electrosorption capacity and the salt removal efficiency improved from 5.42 to 16.35 mg g−1 and from 16.37% to 53.26% for the pristine and composite electrodes, respectively. However, the inorganic nanofiber content should be optimized; a composite having 10 wt% zirconia nanofibers with respect to the activated carbon showed the best performance. This distinct enhancement in the performance is attributed to the improvement in the wettability and specific capacitance of the electrode. Numerically, the water contact angle and the specific capacitance of the pristine and composite electrodes were found to be 145° and 26.5°, and 875 and 225 F g−1, respectively. Overall, the present study strongly draws attention towards zirconia nanostructures as effective, cheap, environmentally friendly, and biologically safe candidates to enhance the performance of capacitive deionization electrodes.

A novel strategy for enhancing the electrospun PVDF support layer of thin-film composite forward osmosis membranes

A simple and novel treatment methodology is introduced to produce PVDF-based thin-film composite forward osmosis (TFC-FO) electrospun membranes for enhanced desalination performance. The proposed treatment strategy is based on improving the surface properties of the PVDF electrospun nanofiber support layer using triethylamine (TEA). The results indicated that this strategy enhanced the interfacial polymerization step by overcoming the hydrophobicity feature dilemma of the PVDF support layer. As an FO membrane, the characterization of the modified membrane shows a distinct decrease in the structure parameter of the support layer by 67%, which mitigates the adverse effect of the internal concentration polarization (ICP) by 45%. Moreover, the performance of the modified TFC-FO membrane exhibited a high water flux, approximately 68 LMH and low reverse salt flux, about 2 g m−2 h−1 at 2 M NaCl draw solution, with >99.5% salt rejection. Overall, the introduced modification technique has the advantages of being inexpensive, easy to implement, and appropriate for commercial membranes.

Electrodepositing technique for improving the performance of crystalline and amorphous carbonaceous anodes for MFCs

The properties and cost of anode materials are essential factors affecting the microbial fuel cell (MFC) performance. Therefore, in this study, an electrodeposition technique is presented as a cheap, easy, efficient, and straightforward strategy to increase the exoelectroactive bacterial adhesion and improve the surface properties of the crystalline and amorphous carbonaceous materials for use as anodes in the microbial fuel cells enriched with unconditioned industrial wastewater. Individually, the surfaces of commercial activated carbon AC (amorphous), carbon paper CP (crystalline), and carbon cloth (CC) were modified by an iron electrodeposition technique. In air-cathode microbial fuel cells, the suggested modification strategy strongly enhanced the power generation as the observed increase was 18.5%, 47.5% and 65.8% for the activated carbon, carbon cloth and carbon paper, respectively. Moreover, the coulombic efficiency (CE) is increased after iron electrodeposition modification process to reach up to 80% in case of treated activated carbon anode. Overall, the results confirmed the successful electrodeposition of iron, as an effective, simple and cheap surface treatment technique, is more efficient in the crystalline materials as compared to the amorphous materials.