Arshad Hussain

A Single Stage Membrane Process for CO2 Capture from Flue Gas by a Facilitated Transport Membrane

Carbon dioxide is the most important anthropogenic greenhouse gas and it accounts for about 80% of all greenhouse gases (GHG). The global atmospheric CO2 concentrations have been increased significantly and have become the major source responsible for global warming; the greatest environmental challenge the world is facing now. The efforts to control the GHG emissions include the recovery of CO2 from flue gas. In this work, feasibility analysis, based on a single stage membrane process, has been carried out with an in-house membrane program interfaced within process simulation program (AspenHysys) to investigate the influence of process parameters on the energy demand and flue gas processing cost. A novel CO2-selective membrane with the facilitated transport mechanism has been employed to capture CO2 from the flue gas mixtures. The results show that a membrane process using the facilitated transport membrane can also be considered as an alternative CO2 capture process and it is possible to achieve more than 90% CO2 recovery and 90% CO2 purity in the permeate with reasonable energy consumption compared to amine absorption and other capture techniques.

Preparation and characterization of PVA/nanocellulose/Ag nanocomposite films for antimicrobial food packaging

Antimicrobial packaging is an area of emerging interest and is rapidly expanding with application of nanotechnology. The present work investigates the effect of nanocellulose (NC) and Ag NPs on the physical, mechanical and thermal properties of PVA nanocomposite films. The tensile strength of PVA was improved from 5.52 ± 0.27 MPa to 12.32 ± 0.61 MPa when filled with 8 wt% of NC. Nanocomposite films exhibited strong antibacterial activity against both Staphylococcus aureus (MRSA) and Escherichia coli (DH5-alpha). The maximum inhibition zone at 0.5 g Ag NPs with 12 wt% NC against DH5-alpha was 14 ± 0.70 mm. While, the maximum inhibition zone at 0.3 g Ag NPs for 16 wt% NC was 13.6 ± 0.68 mm against MRSA. Moreover, nanocomposites films have no cytotoxicity effect on HepG2 and cell viability was more than 90%. Based on mechanical properties and antibacterial potential of the developed nanocomposite films, it can be envisaged to use these films for packaging applications.

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.

CO2 adsorption using TiO2 composite polymeric membranes: A kinetic study

CO2 is the main greenhouse gas which causes global climatic changes on larger scale. Many techniques have been utilised to capture CO2. Membrane gas separation is a fast growing CO2 capture technique, particularly gas separation by composite membranes. The separation of CO2 by a membrane is not just a process to physically sieve out of CO2 through the controlled membrane pore size. It mainly depends upon diffusion and solubility of gases, particularly for composite dense membranes. The blended components in composite membranes have a high capability to adsorb CO2. The adsorption kinetics of the gases may directly affect diffusion and solubility. In this study, we have investigated the adsorption behaviour of CO2 in pure and composite membranes to explore the complete understanding of diffusion and solubility of CO2 through membranes. Pure cellulose acetate (CA) and cellulose acetate-titania nanoparticle (CA-TiO2) composite membranes were fabricated and characterised using SEM and FTIR analysis. The results indicated that the blended CA-TiO2 membrane adsorbed more quantity of CO2 gas as compared to pure CA membrane. The high CO2 adsorption capacity may enhance the diffusion and solubility of CO2 in the CA-TiO2 composite membrane, which results in a better CO2 separation. The experimental data was modelled by Pseudo first-order, pseudo second order and intra particle diffusion models. According to correlation factor R(2), the Pseudo second order model was fitted well with experimental data. The intra particle diffusion model revealed that adsorption in dense membranes was not solely consisting of intra particle diffusion.

Effect of concentration of Surfactant on the Exfoliation of Graphite to Graphene in Aqueous Media

Graphite was exfoliated to graphene by tip sonic using sodium cholate as a surfactant in the presence of Millipore water as a medium. The use of water as a solvent for exfoliation purposes is very important due to its environmentally friendly nature and almost no cost, contrary to organic media. Two different concentration ratios of surfactants are used in the present work. As a result, graphene dispersions with two different concentrations of 5 mg/ml and about 7 mg/ml respectively were obtained in aqueous media. It was observed that the optimum concentration of surfactant has an effective role in the exfoliation of graphite to graphene. Concentrations of graphene dispersions were studied through UV spectroscopy, while Raman spectroscopy, Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) were used to study the quality of the exfoliated graphene flakes.

Effects of selected size of graphene nanosheets on the mechanical properties of polyacrylonitrile polymer

Mechanical properties of polyacrylonitrile (PAN) polymer can be significantly improved by the incorporation of graphene nano-sheets of different sizes. The graphite was exfoliated to graphene using sonic tip in the presence of N-methyl pyrrolidinone (NMP) as a solvent. Exfoliated graphene was separated from unexfoliated graphitic crystallites using selected speed (rpm) of centrifuge for specific time. The exfoliated graphene nano-sheets were classified into two different groups on the basis of flake size, (i.e. 1 μm and 3.5 μm). Then these graphene sheets were incorporated into PAN to study the effects of their flake size on mechanical properties. Different mechanical properties such as Young’s modulus, ultimate tensile strength (UTS) and elongation at break (dL at break) were studied. Young’s modulus and UTS improved more than 45 % and 25 %, for 3.5 μm graphene flake size respectively. While more than 40 % and 21 %, improvement in modulus and UTS for 1 μm graphene sheet were observed respectively.

Liner Material's Output Characteristics of Explosively Formed Projectiles (EFPs)

The output considerations: velocity, pressure, density, internal energy, temperature and L/D ratio of explosively formed projectiles (EFPs) were investigated. The internal energy of the EFPs was inversely proportional to the density of the liner material. The shock pressure generated and its fluctuations were highest for Fe and Ta liner materials respectively. The least pressure variations were observed for Cu along its axial direction with highest length to diameter (L/D) ratio to supports deeper penetration. The maximum difference between numerical simulation and experiment was 9.7 % for Cu EFP.

Influence of Amphiphilic Plasticizer on Properties of Thermoplastic Starch Films

ABSTRACT Thermoplastic starch powders and films were produced by using different combinations of hydrophilic (malic acid and water) and amphiphilic (isoleucine and butyric acid) plasticizers. Spray drying was used to produce thermoplastic starch powder followed by compression molding for the development of films. In all plasticized formulations, the rate of retrogradation was inhibited until the seventh day. The crystallinity and moisture sensitivity of the freshly prepared films were dependent on amphiphilic plasticizer quantity in formulation. Fourier transform infrared spectroscopy and thermogravimetric analysis showed an effective interaction of starch with isoleucine. Isoleucine formulated films showed the highest tensile strength, whereas malic acid-rich films showed better strain values. GRAPHICAL ABSTRACT

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.