Saad A. Aljlil

From hydrophobic to hydrophilic polyvinylidenefluoride (PVDF) membranes by gaining new insight into material's properties

This work provides an easy and versatile strategy to manufacture novel polyvinylidenefluoride (PVDF) membranes by solution casting and phase separation techniques displaying tailored physicochemical and microstructural features depending on the opportune combination of functionalization by blending chemical additives (multiwalled carbon nanotubes, MWCNTs) and manufacturing procedure. The systematic study of the effect of (i) polymer concentration, (ii) use of pore forming additives (LiCl), and (iii) type and concentration of MWCNTs, on the PVDF crystalline composition and membrane microstructure, highlights the strong relationships of these parameters with the wettability, fouling and transport attributes of the formed membranes. The results provide the key to discriminate membrane preparation conditions favoring hydrophilic, low fouling, and highly selective PVDF–MWCNTs membranes, for water-treatment applications in pressure-driven membrane operations, from conditions favoring the formation of hydrophobic and waterproof membranes, to be used in the membrane contactors field. Also, they open exciting perspectives for a more effective development of PVDF-based nanostructured membranes for advanced separations based on a comprehensive investigation and understanding of materials properties.

Polyvinylidenefluoride/carbon nanotubes mixed matrix membranes with tailored properties

Membrane operations are promising tools for efficient and environmentally friendly separations. However, the development of advanced membranes with tailored properties is a key issue to be addressed in order to better exploit the potentialities of membrane-based separations. An important approach toward this aim is the development of mixed matrix membranes in which an organic and an inorganic phase coexist in order to have synergic effects on membrane properties. The peculiar properties of carbon nanotubes (CNTs) such as high electrical and thermal conductivity, high strength and unique transport properties, has motivated a considerable effort to produce CNT-polymer composites in order to engineer membrane properties. In this work the roughness, wettability, morphology, crystalline phase and pore size of polyvinylidenefluoride (PVDF) membranes were tailored working on the membrane preparation conditions, as well as, by blending the polymer with multiwalled carbon nanotubes (MWCNTs). A study on the effect ...

Carbon-Based Polymer Nanocomposites as Electrodes for Microbial Fuel Cells

Abstract Being a green and sustainable technology, microbial fuel cells (MFCs) offer an integrated pathway to simultaneously produce bioelectricity and treat wastewater. However; their applications are limited due to their relatively low-output power density. The MFC’s low-output power density is related to low electron-transfer rate at the anode and/or the cathode. The transfer of electrons is greatly influenced by the electrode materials’ properties. Carbon-based materials are seen as promising candidates for electrodes in MFCs because of their favorable characteristics in terms of weight, microbial adhesion, stability, and cost. However, the use of plain carbon material led to weak biofilm formation and all the required properties for the oxygen reduction reaction in cathode could not be met. The MFC performance could be improved by modifying the carbon-based electrodes through nano- and/or polymeric materials. This chapter presents a review of the modified carbon-based polymer nanocomposites as they serve as electrodes for MFCs.

Mass Transfer Characteristics of Binary Heavy Metal Ions Mixture in Gas Sparged Dialysis Cells

The effect of air sparging on mass transfer of a mixture of two heavy metals ions (Cu and Ni) was studied in dialysis cells by measuring the conductivity of dialysate solution. The variables studied were the air velocity and heavy metal ion concentrations ranging between 300 mg L−1 and 1000 mg L−1. A mass transfer equation was derived to represent an overall mass transfer coefficient for ion mixture. The presence of gas enhanced the rate of mass transfer by increasing the overall mass transfer coefficient. Also, an equation was developed for the transfer of ionic mixture that agreed with the previous studies on mass and heat transfer in the bubble stirred systems. The increase in mass transfer coefficient ranged from 83.4-196% for the mixture of two heavy metal ions above the natural convection value depending on the experimental conditions. Overall, a new model was developed for mass transfer in Binary solution for industrial purposes. The novelty of this process is that it was applied for the removal of heavy metal ions from wastewaters as compared to other different types of salt solutions.