Pritpal Singh

Hygrothermal Effects on Chopped Fibre/Woven Fabric Reinforced Epoxy Composites. Part A: Moisture Absorption Characteristics:

Diffusion of water in epoxy composites with different sequential arrange ments of woven roving (WR) and chopped strand mat (CSM) reinforcements was studied on immersion in water at 298 K and 323 K. Laminates with CSM as skin layers showed higher diffusivity and equilibrium moisture content than WR as skin layers. The diffusion parameters obtained from the experiment conducted up to saturation limits of 323 K showed good correlation with the data computed using a moisture absorption programme written on lines suggested by G. S. Springer. Hence data at lower temperatures are also generated by using the above programme, thus shortening the time to reach saturation levels.

Fabrication of a mercury(II) ion selective electrode based on poly-o-toluidine–zirconium phosphoborate

This work covers various aspects of a new ion selective electrode for mercury(II) ions, designed by incorporation of poly-o-toluidine (PTD) into zirconium phosphoborate (ZrPB) ion exchanger. The designed sensor showed pretty good detection ability towards Hg2+ ions in comparison to alkali, alkaline earth, transition and even some heavy metal ions. The crystallinity and morphology of the synthesized composite has been explored using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. A linear near Nernstian response for Hg(II) ions with a slope of 28.0 mV per decade over a wide concentration range (1 × 10−7 M to 1 × 10−1 M) has been observed. The limit of detection is 7.08 × 10−8 M (0.014 ppm). Moreover, the electrode showed significantly the same results in the pH range 2.5–10.0, a fast response time of 6 s and a life-time of at least 6 months without any divergence in potential. It has been successfully applied as an indicator electrode in potentiometric titrations, and quantitative estimation of Hg(II) ions in tap water, CFL unit waste water and thermometer unit waste.

Hygrothermal Effects on Chopped Fibre/Woven Fabric Reinforced Epoxy Composites. Part B: Degradation Studies

Studies were conducted on the degradation of short beam shear (SBS) and impact strength (Izod) properties of glass epoxy composite specimens with sequential ar rangements of woven roving (WR) and chopped strand mat (CSM) reinforcements, (Figure 1 of Part A) immersed in water at two different temperatures (298 K, 323 K). It was found that composites with higher fibre content, though possessed of a higher ini tial shear strength, degraded faster than those with low fibre content. This was attributed to a thin resin layer separating the glass layers and a consequential increased surface area around the fibres for the moisture absorption. Further, it was noted that while the impact strength too degraded with exposure period, the degradation patterns are almost identical in all types of laminates within the limits of fibre resin ratio chosen.

Electrochemical behavior of a membrane based on zirconium(IV) phosphoborate nanocomposite and its application in dye removal

A new hybrid ion-exchange membrane was prepared from a novel composite obtained by dispersion of polyaniline into an inorganic matrix of zirconium(IV) phosphoborate employing a sol–gel method. The composite was characterized by FTIR, XRD, SEM, TEM and TGA/DTA analysis. Membrane potential, transport number, permselectivity and fixed charge density were studied as a function of electrolytic concentration, in order to explore the electrochemical behavior of the prepared membrane. Values for all these electrochemical properties were found to increase upto a mean concentration for each electrolyte and declined thereafter. All these electrochemical properties have higher values for monovalent alkali metal cations than those for bivalent alkaline earth metal cations. The nanocomposite worked well to hamper the growth of both G− and G+ bacterial cultures of Escherichia coli and Bacillus strains to a remarkable level. The nanocomposite was also evaluated for adsorptive removal of methylene blue from aqueous solutions. Maximum adsorption was achieved at pH 11 with an adsorbent dosage of 20 mg for a 1.6 mg/100 mL dye solution in an interval of 3.5 h. Up to 99% dye was recovered upon elution and the regenerated column was efficiently used a number of times. Promising results obtained in dye removal by adsorption and antimicrobial activity encourage the use of such composites in water purification.

Photocatalytic degradation of methyl orange using TiO2/SnO2 binary nano composite

Removal of organic dyes effluents in water, which is a major source of environmental pollution, has become a important area of research these days. In the present study, photocatalytic degradation of hazardous dye methyl orange (MO) using binary TiO2/SnO2 nanocomposite has been studied. Nanocomposite in a TiO2:SnO2 ratio of 95:5 has been synthesized from TiO2 (anatase) and SnO2 (rutile) nanoparticles using hydrothermal method. The synthesis of composite has been confirmed using various characterizations. The phase structure, particle size, surface morphology and optical properties have been estimated using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), Fourier transform infrared spectroscopy (FT-IR) analysis and UV-Visible spectroscopy. The binary nanocomposites degraded the hazardous dye methyl orange with high speed as compare to pure TiO2 nanoparticles, under UV-light illumination. Addition of SnO2 to TiO2 leads to enhanced degradation capacity owing to formation of intermediate band gap. The photocatalytic activity of compound has also been compared with previously reported anatase TiO2 nanoparticles.Removal of organic dyes effluents in water, which is a major source of environmental pollution, has become a important area of research these days. In the present study, photocatalytic degradation of hazardous dye methyl orange (MO) using binary TiO2/SnO2 nanocomposite has been studied. Nanocomposite in a TiO2:SnO2 ratio of 95:5 has been synthesized from TiO2 (anatase) and SnO2 (rutile) nanoparticles using hydrothermal method. The synthesis of composite has been confirmed using various characterizations. The phase structure, particle size, surface morphology and optical properties have been estimated using X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), Fourier transform infrared spectroscopy (FT-IR) analysis and UV-Visible spectroscopy. The binary nanocomposites degraded the hazardous dye methyl orange with high speed as compare to pure TiO2 nanoparticles, under UV-light illumination. Addition of SnO2 to TiO2 leads to enhanced degradation capacity owing to formation of...

Study of photocatalytic and antibacterial activities of graphene oxide nanosheets

AbstractGraphene oxide (GO) is a biocompatible material that is easily dispersible in water making its mixing easy with ceramic or polymer matrixes while trying to enhance their properties. In the present study, the photocatalytic and antibacterial activities of GO have been studied. GO has been synthesized by modified Hummer’s method. The synthesized material has been characterized using X-ray diffraction, Raman spectroscopy, high-resolution transmission electron microscopy (HR-TEM), Fourier transform infrared spectroscopy (FT-IR) and UV-visible spectroscopy. HR-TEM confirmed the formation of GO nanosheets. It has been observed that GO nanosheets with excellent morphology exhibit efficient photocatalytic activity towards Congo red (CR) dye. Using advanced oxidation process, toxic organic dye CR is oxidized through reaction with reactive oxidative species generated by GO photocatalyst under UV-light irradiation. The study reflects new possibilities of GO for degradation of toxic organic pollutants. The effect of GO dose has also been studied and the reaction has been evaluated to be first order. Antibacterial activity of GO has been evaluated via well diffusion assay by growing Escherichia coli and Bacillus on LB agar plates. Graphical abstractᅟ

Synthesis and characterization of a tin(IV) antimonophosphate nano-composite membrane incorporating 1-dodecyl-3-methylimidazolium bromide ionic liquid

The fabrication of polyvinyl chloride (PVC) based cation exchange nano-composite membranes by the solution casting technique using tetrahydrofuran as solvent and tin(IV) antimonophosphate as cation exchanger has been achieved. An ionic liquid (IL), 1-dodecyl-3-methylimidazolium bromide, [C12mim][Br], was used as a filler additive, which has been found to affect the properties of the composite membrane. From X-ray diffraction (XRD), it has been observed that membrane with a mass ratio of tin(IV) antimonophosphate (exchanger) : PVC (binder) : IL of 1 : 1 : 0.3 (M-3) has higher crystallinity than other membranes having a composition of 1 : 1 : 0.1 (M-1), 1 : 1 : 0.2 (M-2), 1 : 1 : 0.4 (M-4), and 1 : 1 : 0.5 (M-5). The nano-composite membranes are composed of interconnecting networks of near spherical to hexagonal nano-particles of 30–40 nm with nanophase separations at the surface, specifically in the case of M-3. An increase in the concentration of the IL in the casting solution led to a decrease in water content of the membrane and ion exchange capacity (IEC). The membrane potential, transport number, permselectivity and fixed charge density have been found to be higher for monovalent metal ions as compared to that of bivalent metal ions. The membrane M-3 has shown the best results among the investigated membranes.

Nanocomposite zirconium phosphoborate ion-exchanger incorporating carbon nanotubes with photocatalytic activity

ABSTRACT A new form of nanocomposite zirconium phosphoborate (ZrPB) ion exchanger incorporating multi-walled carbon nanotubes (CNTs) has been fabricated and studied. Commercial purity CNTs were used as dopant in ZrPB matrix. The topography and morphology of the composite has been explored with the help of scanning electron microscopy and transmission electron microscopy. The microscopy results confirm the spherical nature and 2–5 nm size of ZrPB particles. CNTs are well reinforced evenly in ZrPB matrix. Multifunctionality of the nanocomposite ion exchange material has been studied for electrochemical characteristics as well as for photocatalytic degradation of methylene blue dye.