Sarah Farrukh

Fabrication and characterization of microfiltration blended membranes

AbstractWoven Kevlar fabric supported polypropylene (PP)–thermoplastic polyurethane (TPU) blended microfiltration membranes were synthesized using thermally induced phase separation (TIPS) technique. Microporosity in the fabricated membranes was analyzed using scanning electron microscopy. The PP–TPU blending was confirmed through the Fourier transform infrared spectra of pure resins and blended polymer membranes. Surface roughness, pore geometry, and adhesion between the blended polymer and fabric were influenced with increasing TPU blending concentration in the PP solution. The proposed polymers were found compatible with each other and properly blended to form membranes; most importantly, the TPU helped to transform hydrophobic PP membrane into hydrophilic PP–TPU membrane. Water and methanol flux through the fabricated membranes were measured, and it was found that the permeation through the membranes depended upon the type of membrane.

Comparative CO2 Adsorption Analysis in Pure and Amine-Modified Composite Membranes

ABSTRACT In this study, the CO2 adsorption analysis in cellulose acetate–TiO2- and cellulose acetate–3-aminopropyl-trimethoxysilane TiO2-blended membranes was performed. The membranes were also characterized using scanning electron microscopy and Fourier transform infrared analysis techniques. The adsorption results indicated that 120 and 90°C were considered as optimized temperatures for regeneration of cellulose acetate–TiO2 and cellulose acetate–3-aminopropyl-trimethoxysilane-modified TiO2 membranes. The testing results revealed that adsorption capacity reached maximum at 3.0 bars. Validation of experimental results was performed by pseudo-first-order, second-order and intraparticle diffusion models. The correlation factor R2 represented that the second-order model was fitted well with the experimental data. The intraparticle diffusion model represented that adsorption is not a single-step process. GRAPHICAL ABSTRACT

Synthesis, Characterization and NH3/N2 Gas Permeation Study of Nanocomposite Membranes

Carbon nanotubes have exceptional mechanical properties which make them very attractive for the development of composite membranes. In this research, NH3/N2 gas permeation behavior of flat sheet composite membranes was examined. The cellulose acetate-multiwalled carbon nanotubes composite membranes were synthesized using solution casting method. The morphology and dispersion of carbon nanotubes were observed through SEM. However, the composite membranes were also characterized using several analytical techniques such as X-ray diffraction analysis, tensile testing analysis, and thermal gravimetric analysis. Characterization of these membranes depicted that carboxylic group functionalized MWCNTs are extremely compatible with CA. The permeation experiments were performed with NH3 and N2 to explore the host–guest interaction of MWCNTs with chosen gases. The permeability of NH3 was found pronounced compared to N2. The NH3/N2 selectivity up to 90 was documented.

Carbon capture from natural gas using multi-walled CNTs based mixed matrix membranes

ABSTRACT Most of the polymers and their blends, utilized in carbon capture membranes, are costly, but cellulose acetate (CA) being inexpensive is a lucrative choice. In this research, pure and mixed matrix membranes (MMMs) have been fabricated to capture carbon from natural gas. Polyethylene glycol (PEG) has been utilized in the fabrication of membranes to modify the chain flexibility of polymers. Multi-walled carbon nanotubes (MWCNTs) provide mechanical strength, thermal stability, an extra free path for CO2 molecules and augment CO2/CH4 selectivity. Membranes of pure CA, CA/PEG blend of different PEG concentrations (5%, 10%, 15%) and CA/PEG/MWCNTs blend of 10% PEG with different MWCNTs concentrations (5%, 10%, 15%) were prepared in acetone using solution casting techniques. Fabricated membranes were characterized using SEM, TGA and tensile testing. Permeation results revealed remarkable improvement in CO2/CH4 selectivity. In single gas experiments, CO2/CH4 selectivity is enhanced 8 times for pure membranes containing 10% PEG and 14 times for MMMs containing 10% MWCNTs. In mix gas experiments, the CO2/CH4 selectivity is increased 13 times for 10% PEG and 18 times for MMMs with 10% MWCNTs. Fabricated MMMs have a tensile strength of 13 MPa and are more thermally stable than CA membranes. GRAPHICAL ABSTRACT

Highly integrated nanocomposites of RGO/TiO2 nanotubes for enhanced removal of microbes from water

ABSTRACT Highly integrated nanocomposite of Graphene oxide (GO) and its derivatives with metal oxides is essential for enhanced performance for various applications. Tuning the morphology is an important aspect during nanomaterials synthesis; this has an amplifying influence upon physicochemical properties of advanced functional materials. In this research work, GO/TiO2 nanotube composites have been successfully synthesized via alkaline hydrothermal treatment method by augmenting GO layers with two different phases of TiO2 (anatase and rutile) nanoparticles, followed by the hydrothermal treatment that also have caused reduction of GO to reduced GO (RGO). The morphology of the as-prepared samples appeared to be nanotubes with a large aspect ratio (length to diameter). The synthesized materials have been characterized using various techniques to determine their morphological and functional properties. Large surface area (158 m2/g) nanotube composites found accountable as effective disinfectant for water containing microorganisms. The antimicrobial activity of the synthesized composites was examined by disk diffusion method and optical density for bacterial growth using two different bacterial species; Escherichia Coli (E.coli, Gram-negative) and Staphylococcus Aureus (Methicillin-resistant Staphylococcus aureus, Gram-positive). The antibacterial study revealed that, the anatase phase RGO/TiO2 nanotube composites manifested appreciable effect on both bacteria as compared to rutile phase RGO/TiO2 nanotubecomposite. GRAPHICAL ABSTRACT