Rohama Gill

Fabrication of covalently bonded nanostructured thin films of epoxy resin and polydimethylsiloxane for oil adsorption

Abstract Thin films of architectures PEI(CNERa/PDMS)n, PEI(CNERb/PDMS)n, (PEI/CNERb)n and PEI(CNERb/NH2-MMT/PEI)n have been fabricated via covalent layer-by-layer technique. Different film deposition parameters such as solvent type, polymer concentration, polymer ratio and dipping time have been optimized to achieve a uniform growth of layers. The effect of polymer concentration and dipping time on film thickness was also studied via ellipsometer. The optimized ratio of polymer concentration was 1:1 and 1:2 for PEI(CNERa/PDMS)n and PEI(CNERb/PDMS)n, respectively. AFM analysis indicated that the films were homogeneous while contact angle measurements revealed that although films were hydrophobic in nature yet they have wetting property due to the presence of hydroxyl groups formed during curing process. These epoxy-based multilayers have shown significant oil adsorption capacity. All the fabricated films qualify scotch tape test and were found resistant towards strong acids, bases and organic solvents.

Exclusion of Zn(II) from aqueous solution using corncob (Zea mays stalk) after chemical modifications with inorganic acids and bases

AbstractIn the conducted research, corncob powder was pretreated with inorganic acids and bases. The consequence of different parameters such as initial metal concentration, pH, and contact time on Zn(II) biosorption from aqueous solution was deliberated. The order of maximum Zn(II) uptake qmax (mg g−1) for different pretreated and raw corncob powder was Ba(OH)2 (128.9) > H3PO4 (124.07) > NaOH (118.737) > H2SO4 (114.8) > HCl (93.41) > Al(OH)3 (87.9) > Native (86.74). The percentage of Zn(II) removed on corncob biomass increased with increase in pH reaching a maximum at pH 5.5. Kinetics of Zn(II) biosorption described that Zn(II) sorption rate was high in first 15–30 min and equilibrium was established after 120 min. The maximum adsorption data of native and pretreated biomass was investigated using Langmuir, Freundlich equilibrium, and Pseudo-first and second-order kinetic models. It was accomplished that structural modifications onto corncob powder lead to the formation of novel biomasses with increased ...

Electroconductive Composites from Polystyrene Block Copolymers and Cu–Alumina Filler

Technological advancements and development of new materials may lead to the manufacture of sustainable energy-conducting devices used in the energy sector. This research attempts to fabricate novel electroconductive and mechanically stable nanocomposites via an electroless deposition (ELD) technique using electrically insulating materials. Metallic Cu is coated onto Al2O3 by ELD, and the prepared filler is then integrated (2–14 wt %) into a matrix of polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene-graft-maleic anhydride (PS-b-(PE-r-B)-b-PS-g-MA). Considerable variations in composite phases with filler inclusion exist. The Cu crystallite growth onto Al2O3 was evaluated by X-ray diffraction (XRD) analysis and energy dispersive spectrometry (EDS). Scanning electron microscopy (SEM) depicts a uniform Cu coating on Al2O3, while homogeneous filler dispersion is exhibited in the case of composites. The electrical behavior of composites is enhanced drastically (7.7 × 10−5 S/cm) upon incorporation of Cu–Al2O3 into an insulating polymer matrix (4.4 × 10−16 S/cm). Moreover, mechanical (Young’s modulus, tensile strength and % elongation at break) and thermal (thermogravimetric analysis (TGA), derivative thermogravimetry (DTG), and differential scanning calorimetry (DSC)) properties of the nanocomposites also improve substantially. These composites are likely to meet the demands of modern high-strength electroconductive devices.

CHAPTER 6:Adsorption and Desorption on Nanostructured Materials

Release of toxic pollutants from industries, whether in the form of liquids or gases, has adversely affected the quality of the environment. To remediate the environment from such pollutants, a large number of conventional methods and advanced technologies have been developed and adopted. Amongst these innumerable methods, adsorption has emerged as one of the most significant processes to remove pollutants of a diverse nature. The present work is based on the ability of nanostructured materials as adsorbents for various gaseous and liquid pollutants. The mechanism of adsorption and desorption is elaborated along with factors that are responsible for the occurrence of such processes. The role of nano-sized carbonaceous, metallic, magnetic, metal oxides, clays, silicon and polymer-based materials, is highlighted as advanced nanosorbents to eradicate pollutants such as noxious gases, organic/inorganic chemicals, dyes, heavy metals, etc. released in the environment as a result of anthropogenic activities.

Synthesis and characterization of cyclotetrakis(μ-oxo-dimethylaminoethanolato-κN: κO)tetrakis(iodozinc) toluene solvate and Bis(dimethylaminoethanol)cadmium(II)iodide

Abstract Two new metal(II) complexes formulated as [ZnI(dmae)]4·2(C7H8) 1 and CdI2(Hdmae)2 2 have been synthesized by using N,N-dimethylaminoethanol, a N,O donor ligand and characterized by melting point, elemental analysis, FT-IR spectroscopy, mass spectrometry and single crystal X-ray diffraction analysis. Complex 1 crystallizes in tetragonal I4(1)/a space group with μ2–O bridge between zinc atoms. The zinc atom is four coordinated with Zn–O 1.9315(13) and 1.9606(14) Å. The complex 2 is mononuclear with distorted octahedral geometry around the Cd(II) and contains two bidentate chelating Hdmae ligands and two iodine atoms, with Cd–O and Cd–N distances of 2.498(2) and 2.400(2) Å, respectively, and the weak O–H···I hydrogen bonds like interactions link the molecules to generate a 1D supramolecular structure.