Efficient removal of methyl orange from aqueous solution using amidoxime adsorbent

The amidoxime adsorbent was prepared by radiation grafting of acrylonitrile on non-woven polyethylene followed by chemical treatment with hydroxyl amine hydrochloride. The prepared amidoxime adsorbent was used for adsorption of methyl orange (MO) from aqueous solution. The effect of different conditions such as contact time, pH and initial metal ion concentration on the adsorption capacity was investigated. Pseudo-first-order and pseudo-second-order equations were used to study the kinetic adsorption data. A Langmuir isotherm model was used to investigate the equilibrium experimental data. The monolayer saturation adsorption capacity of the adsorbent for MO, as determined from the Langmuir equation, was 142 mg/g of the adsorbent. Moreover, desorption and reuse of the adsorbent film showed satisfactory results. Large-scale recycling of the adsorbent will reduce the production cost, and thereby make the practical application of the adsorbent economically feasible.

Abbreviations: Acrylonitrile - AN, Polyethylene - PE, Methylene Orange - MO     

Structural and magnetic properties of LaFe0.5Cr0.5O3 studied by neutron diffraction, electron diffraction and magnetometry

The structural and magnetic properties of the perovskite type compound LaFe_0.5Cr_0.5O₃ have been studied by temperature dependent neutron powder diffraction and magnetization measurements. Rietveld refinement of the neutron diffraction data shows that the compound crystallizes in an orthorhombic perovskite structure with a random positioning of the Fe and Cr cations at the B sublattice. The magnetic structure at 10 K is a collinear antiferromagnetic one with the magnetic moment per site being equal to 2.79(4) μ_B. Magnetisation measurements confirm the overall antiferromagnetic behaviour. Moreover, it indicates a weak uncompensated magnetic moment close to the transition temperature T_N ≈ 265 K. This moment can be described by a magnetic cluster state, which remains up to 550 K. Electron diffraction patterns along with high-resolution transmission electron microscopy images reveal that the crystallites are composed by domains of different orientation, which share the same cubic perovskite sub-cell reflections.     

Effect of crosslinking monomers on the performance of electron beam-induced biodegradable Bionolle–rubber blends

To find out the better crosslinking monomer for vulcanization of natural rubber under electron beam (EB) radiation, the dry rubber was masticated with different polyfunctional monomers like TMPTA, NVP, and ethylene glycol diacrylate of different numbers of CH₂ CH₂ O group, such as 1G, 3G, 7G, and 10 G. The masticated films were irradiated with different doses under EB at 10 kGy/pass. The highest tensile strength (25 MPa) of the rubber was observed in the presence of TMPTA (3phr) at 150 kGy dose. The gel content of the rubber increased with an increase of dose. Bionolle was mixed with the masticated rubber containing 3 phr TMPTA at different proportions; films of these blends along with Bionolle were irradiated under EB with different doses. The concentration of rubber in Bionolle and radiation dose were optimized. The elastomer with 5% masticated showed the highest tensile strength (62 MPa). The gel content of the blends was found to increase with an increase of radiation dose as well as rubber concentration in Bionolle. The elastomers or blends were found to possess good thermal properties. The elastomers exhibited a much lower loss of tensile strength due to the thermal aging compared with pure Bionolle. The elastomers sustained their original shape for 300 min at 180°C, whereas Bionolle sustained its shape for only 3 min at 120°C under the same load (50 g). Among all the elastomers, 5% rubber containing elastomer was found to be better in all respects. It was observed from scanning electron microscopy and differential scanning calorimetry studies that 5% rubber is well mixed with Bionolle. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 799–807, 2001     

Moisture diffusivity and shrinkage of broad beans during bulk drying in an inert medium fluidized bed dryer assisted by dielectric heating

Drying behavior of broad beans (Vicia faba) was studied in a pilot scaled fluidized bed dryer with inert particles assisted by dielectric heating. The effective diffusion coefficient of moisture transfer was determined by Fickian method at four different air drying temperatures of 35, 45, 55 and 65 °C. Correlations for moisture diffusivity as a function of moisture content and temperature of the drying medium were developed. The values of moisture diffusivity were obtained within the range of 1.27 × 10^?9–6.48 × 10^?9 m²/s and the activation energies for FBD and FBD + DE were found to be 27.71 and 17.10 kJ/mol, respectively. The shrinkage behavior of the broad beans was also investigated by considering the volume ratio of (V/V_O) to be function of moisture content alone and fitting a polynomial of the third order. The dielectric heating power was also found to be effective on the rate of drying.     

Site-occupation behavior and solid-solution hardening effect of rhenium in Mo5SiB2

The site-occupation behavior of Re in Mo₅SiB₂ (T₂) was studied both theoretically and experimentally, and the effect of Re on the solid-solution hardening of T₂ was investigated by taking into account the off-stoichiometry of the T₂ phase. Mo–Si–B quaternary alloys containing 1.4 at.% Re were produced using a conventional Ar arc-melting technique, and the cast samples were homogenized at 1800 °C for 24 h in an Ar atmosphere. High-resolution high-angle annular dark-field scanning transmission electron microscopy observations strongly suggest that Re preferentially occupies the Mo sites in the Mo–B layers of the T₂ unit cell, which was confirmed by the site-occupation behavior predicted by first-principles calculations. Nanoindentation measurements indicate that the hardness of the T₂ phase is affected by both the off-stoichiometry and Re addition.     

Comparative Studies of Mechanical and Interfacial Properties Between Jute Fiber/PVC and E-Glass Fiber/PVC Composites

Composites (50 wt% fiber) of jute fiber reinforced polyvinyl chloride (PVC) matrix and E-glass fiber reinforced PVC matrix were prepared by compression molding. Mechanical properties such as tensile strength (TS), tensile modulus (TM), bending strength (BS), bending modulus (BM) and impact strength (IS) of both types of composites was evaluated and compared. Values of TS, TM, BS, BM and IS of jute fiber/PVC composites were found to be 45 MPa, 802 MPa, 46 MPa, 850 MPa and 24 kJ/m², respectively. It was observed that TS, TM, BS, BM and IS of E-glass fiber/PVC composites were found to increase by 44, 80, 47, 92 and 37.5%, respectively. Thermal properties of the composites were also carried out, which revealed that thermal stability of E-glass fiber/PVC system was higher. The interfacial adhesion between the fibers (jute and E-glass) and matrix was studied by means of critical fiber length and interfacial shear strength that were measured by single fiber fragmentation test. Fracture sides after flexural testing of both types of the composites were investigated by Scanning Electron Microscopy.     

Improvement of Leather Surface by UV Curing

Leather surface has been modified with UV-cured film of urethane triacrylate in the presence of variable concentrations of mono-functional monomers such as N-vinyl pyrrolidone (NVP) and ethyl hexyl acrylate (EHA). Incorporation of small amounts of plasticizer into the formulation has substantially enhanced both tensile strength and elongation of the coated leather. Addition of a difunctional monomer such as tripropyl glycol diacrylate (TPGDA) to the system has increased the tensile property further.     

The Preparation and Characterization of Silk/Gelatin Biocomposites

There is a growing interest in the use of composite materials. Silk fiber/gelatin biocomposites were fabricated using compression molding. The fiber content in the composite varied from 10–30 wt%. Composite containing 30 wt% silk showed the best mechanical properties. Tensile strength, tensile modulus, bending strength, bending modulus and impact strength, hardness of the 30% silk content composites were found 54 MPa, 0.95 GPa, 75 MPa and 0.43 GPa and 5.4 kJ/m², 95.5 Shore A, respectively. Water uptake properties at room temperature, accelerated weathering aging, irradiation, thermomechanical analysis, and degradation in soil were carried out in this experiment.     

Study on the Water-Aging Properties of Gelatin-Glucose and Gelatin-Urea Films: The Effect of Gamma Radiation

Thin gelatin films (about 0.25 mm thickness) were prepared from granular gelatin via casting. The mechanical properties of gelatin films such as tensile strength (TS), elongation at break (Eb%), water uptake and water aging properties were investigated. To improve the water aging properties of gelatin films, gelatin-glucose and gelatin–urea films were prepared. Effect of gamma radiation on the tensile properties, water uptake and water aging properties of gelatin-glucose and gelatin-urea films were also studied. The results of the investigation show that both glucose and urea can improve the water stability of the gelatin films.     

Influence of Codiluent on the Properties of Radiation-Cured Films

A number of formulations were developed using urethane diacrylate oligomer in combination with a series of monofunctional and multifunctional reactive diluents possessing diverse glass transition temperatures from ?50°C to 250°C. Films prepared with these formulations were cured under ultraviolet (UV) radiation; their properties, such as hardness, gel content, tensile characteristics, etc., were determined and compared with those of the films cured by electron beam (EB) radiation. Effect of comonomer diluents was investigated in these cases. A good correlation was observed between these properties and the glass transition temperature (T _g) of the copolymer (cured film), prepared under radiation with urethane acrylate, monomer, and comonomer.