Vol. 29, No. 2 (Nov 2018)
1. The Enhancement of Electrical Conductivity and Tensile Properties of Conductive Poly (Vinyl Chloride) / Poly (Ethylene Oxide) / Polyaniline (PAni) Conductive Composite Films: The Effect of Polyaniline Loading and Ethylene Dimethacrylate (EDMA) (Mohammed Izzuddeen Mohd Yazid, Supri A Ghani, AF Osman, and MD Siti Hajar)
Abstract: The effect of ethylene dimethacrylate (EDMA) as surface modifier and polyaniline (PAni) loading on poly (vinyl chloride) (PVC) / poly (ethylene oxide) (PEO) matrix was investigated. PVC/PEO conductive composite films with different PAni loading were fabricated using solution casting technique. The inclusion of EDMA exhibited higher tensile strength, modulus of elasticity and electrical properties for all filler loadings of PVC/PEO/PAni conductive composite films. The scanning electron microscopy (SEM) morphology indicated that the inclusion of EDMA in conductive films provided decent fillers dispersion in the PVC/PEO phases. The structural modifications, if occurred, will be interpreted with the assistance of FTIR spectroscopy.
2. Improvement in Corrosion Resistance of Aluminium alloy by Permanganate-based Conversion Coating (Makanjuola Oki, Adeolu Adesoji Adediran, Bamidele Ogunsemi, Olayinka Agboola Saheed Olayinka and Oyeyemi Ogunsola)
Abstract: This investigation on permanganate based conversion coating describes a chromate-free coating and efforts at reducing the environmental foot prints of metal finishing industries. A golden coloured coating on aluminum specimen was obtained from the permanganate coating (PMC) bath with nominal pH of 7.9. Results from scanning electron microscopy (SEM) examination showed that the conversion coatings are continuous and the surfaces of the specimens treated in the coating bath are composed of irregularly shaped and mud-cracked coating materials. The coatings, as revealed from energy dispersive spectroscopy (EDX) analyses in the SEM are composed essentially of aluminium, oxygen and manganese compounds which are likely to be hydrated. Accelerated corrosion tests in near neutral 3.5% sodium chloride solution and natural exposure tests revealed that the replacement of chromate with permanganate improved paint adhesion and corrosion resistance on aluminium substrates. Furthermore, the results indicated that the corrosion resistance of the permanganate based conversion coating matched those from the traditional chromate coating bath, but for the corrosion resistance after application of a top coat of lacquer, the former was adjudged better than the later.
3. Liquid-Liquid Extraction and Recovery of Pd (II) from Nitric Acid Medium Using Green Diesel as Extractant (B.A. Masrya, M.M. Zeida, A.T. Kassema, H.G. Noweira, E.A. Saadb and J.A. Daouda)
Abstract: A cheap method for the extraction of palladium from HNO3 solution by green Diesel as extractant in kerosene was investigated. Several parameters such as extractant, nitrate, hydrogen ion, nitric acid and metal ion concentration, phase ratio and thermodynamic parameters were studied. The extracted species was deduced using the slope analysis method and IR measurements. The results showed that the extraction efficiency of Pd(II) is 95% with 10% (v/v) Diesel in kerosene , and 97% was recovered from the loaded organic solution using 0.05M thiourea or ammonium thiocyante solutions as stripping agents. The maximum loading capacity of Diesel was found to be 2 × 10-2 moles of Pd (II) per mole extractant. The effect of diluents on the extraction of Pd(II) from nitric acid solution by green Diesel indicated that, under the used experimental conditions, kerosene gave the highest extraction percent compared to cyclohexane, benzene, toluene, chloroform and carbon tetrachloride. Extraction of Pd(II) from different acidic media was also carried out and the extraction percent was found to decrease in the order: H2SO4 > HNO3 >HCl. The possibility of extraction and recovery of palladium from the sulphate leach solution of spent automotive catalyst was explored and a modified process is proposed and evaluated.
4. Effects of Ferric Chloride and Polyaniline Addition on the Properties of Polyethylene Oxide / Polyvinyl Chloride / Polyaniline Conductive Films (Mohammed Izzuddeen Bin Mohd Yazid, Supri Abdul Ghani, Azlin Fazlina Osman and Siti Hajar Binti Mohd Din)
Abstract: Polyethylene oxide (PEO) / Polyvinyl chloride (PVC) blends with 2.5 wt% – 10 wt% polyaniline (PAni) loadings were fabricated with and without the presence of ferric chloride (FeCl3). PEO/PVC/PAni and PEO/PVC/PAni-FeCl3 conductive films were prepared by solution casting method using tetrahydrofuran as the solvent at ambient temperature. The tensile properties, electrical conductivity and structure/morphology of the conductive films were analyzed and discussed in this paper. The results indicated that the tensile strength and elongation at break decreased but the Young’s modulus increased with PAni loading. Meanwhile, PEO/PVC/PAni-FeCl3 conductive films showed lower tensile strength and Young’s modulus but higher elongation at break in comparison with PEO/PVC/PAni conductive films. The agglomeration of PAni at higher loadings was revealed by SEM study. However, this study found that higher loading of PAni increased the electrical conductivity of the films and further improved with the addition of FeCl3. The FTIR study revealed the structure of the films with the effect of PAni as filler and FeCl3 as the oxidizing agent.
5. Preparation of amidoxime adsorbent by radiation induced grafting of acrylonitrile on polyethylene film and its application in Cr(VI) removal (Nazia Rahman, Nirmal Chandra Dafader, Abdur Rahim Miah, Md. Ferdous Alam and Shahnaz Sultana)
Abstract: Pre-irradiation technique was applied to graft acrylonitrile (AN) onto polyethylene film. The graft yield was optimized with respect to radiation dose, monomer concentration and reaction time. H2SO4 was added to the monomer solution to improve the graft yield. Highest graft yield obtained was 120 % at 70 kGy radiation dose, 60% monomer concentration and 4 h reaction time using H2SO4 as additive. The AN grafted films were modified with hydroxyl amine hydrochloride to prepare amidoxime adsorbent. The prepared adsorbent was characterized by using FTIR, NMR, TGA and DMA. The prepared amidoxime adsorbent showed high affinity towards Cr(VI) adsorption. Adsorption capacity was studied under different conditions: contact time, pH and initial metal ion concentration. The highest adsorption capacity obtained was 200 mg/g of adsorbent after 72 h contact time at pH 1.5 and initial metal ion concentration 200 ppm. Pseudo-first-order and pseudo-second-order equations were used for interpretation of kinetic adsorption data. The equilibrium experimental data of Cr(VI) adsorption were also fitted with Langmuir isotherm model. Desorption and reuse of the adsorbent film was studied. The adsorbent showed no significant loss of adsorption capacity upon repeated use.
6. A New Treatment to Compute the Track Parameters in PADC Detector using Track Opening Measurement (Saeed Hassan Saeed Al-Nia’emi)
Abstract: In this paper, a new treatment (or method) has been presented to calculate the parameters of the etched track and its shape development after irradiating the polyallyldiglycol carbonate (PADC) detector CR-39 by alpha particles using the direct measurement of the track opening diameters. The method is based on a concept that the track diameter grow rate VD and the track etch rate VT are not constants with the progressing of the etching process. Some of the equations used in the case of VD to be a constant have been modified as a function of the etching time to be more suitable for the case. Certain boundary conditions have been extracted from previous works that based on the measurement of the track lengths directly from the track’s images, to use them in the equations that were applied to figure out the track parameters in the present work. A CR-39 detector was irradiated with alpha particles of energies of 1.53, 2.35, 3.06, 3.80 and 4.44 MeV under normal incidence using 1Ci 241Am source of 5.485 MeV. The irradiated detectors were etched chemically with an aqueous 6.25 N solution of NaOH at 70oC. The track parameters and the profile development, as well as the V(R’) function, were determined. The results obtained by this method through using the track diameters information were showed a good agreement with previous works that used the direct measurement of the track lengths.
7. Soybean oil bleaching by adsorption onto bentonite/iron oxide nanocomposites (Mohammad Ghorbanpour)
Abstract: The bleaching process of soybean oil using commercial bentonite and Bentonite/iron oxide composites has been studied. X-ray diffraction (XRD), BET surface area measurement and scanning electron microscopy (SEM) were used to characterize the composites generated. SEM results shows that the porosity of bentonite after alkaline ion exchange process can be enhanced by the opening of the bentonite’s flakes. BET shows that the flakes’ structure was more opened and the porosity was increased from 179.58 m2/g for bentonite to 202 m2/g for 3 min ion exchanged sample. Changes in basal reflection in XRD peak validated the presence of iron oxide particles. The experimental results indicate that composite prepared for 1 min show the same efficiency in bleaching crude soybean oil with the bentonite. The greatest reduction in bleaching capacity in soybean oil was achieved using the composite prepared for 3 min. The highest transparency, 1.5-fold in red and 1.25-fold in yellow greater than that of neutralized oil, was obtained with the alkaline ion exchange composite prepared for 3 min. Hence, this process gives a good adsorbent with better bleaching properties than commercial bentonite.
8. Effect of Frequency and Number of Piezoelectric Probes in Sonication-Assisted Exfoliation of Graphite Layers into Graphene Oxide (Aminah Nur Aisyah, Achmad Ainul Fikri, Suhufa Alfarisa, Agus Purwanto, Sumarna, Wipsar Sunu Brams Dwandaru)
Abstract: A self-custom-made ultrasound generator using piezoelectric probes has been constructed to reduce graphite layers via liquid-phase exfoliation into graphene oxide (GO) material. The ultrasound frequency and the number of piezoelectric probes are varied with values of 20 kHz, 30 kHz, and 35 kHz, and 1 probe, 2 probes, and 3 probes, respectively. The solutions obtained from the sonication process show a temperature increase of 1 or 2 oC compared to room temperature. Color changes of the solution before sonication, after sonication, and after being left overnight are also exhibited; that is from dark, dark blue, to grayish blue, respectively. The solutions are then characterized using UV-Vis spectrophotometer and scanning electron microscope (SEM). The UV-Vis results show the presence of GO material at an absorbance peak of 270 nm. Increasing the frequency and number of the probes decreases the absorbance peaks of the solutions. The best GO sample solution is obtained for an ultrasound frequency of 35 kHz and using 3 piezoelectric probes. Images from SEM show rod-like carbon materials stacked on top of each other in the form of flower-like structures. The widths of these rod-like materials vary from 1 to 2 microns; whereas the thicknesses of these materials are around 300 nm to 1.5 microns.
9. Study of ethanol vapor sensing behavior by Polypyrrole-Multiwall carbon nanotubes nanocomposites (Sanjay G. Bachhav, Dilip R. Patil)
Abstract: Polypyrrole-multiwall carbon nanotubes (PPy/MWCNT) nanocomposites were synthesized by in-situ chemical oxidative polymerization method. The MWCNTs were functionalized prior to the formation of nanocomposites. These nanocomposites were characterized by Field Emission Scanning Electron microscopy (FE-SEM), X-Ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR) and thermogravimetric analysis (TGA) to study the effect of incorporation of functionalized MWCNT in polypyrrole matrix. The results showed the successful formation of PPy/MWCNT nanocomposite and there is significant interaction between PPy and MWCNTs. The response of the prepared PPy/MWCNT nanocomposites sensors was studied in the form of sensitivity towards ethanol vapors. Results showed that the response increases with ethanol concentration and it is also affected by the MWCNT content in PPy matrix.
10. Catalytic Hydrogenation of Hydrocarbons for Gasoline Production (M.D. Garba and A. Galadima)
Abstract: The persistent growth in the global population has also accounted for the continuous increase in the used of gasoline-based automobile engines. Although the application of gasoline additives such as tetraethyl lead (TEL), oxygenates and metal carbonyls like methyl cyclopentadienyl manganese tricarbonyl (MCT) have been considered suitable for gasoline quality upgrading, the numerous challenges that include environmental pollution and destruction to catalytic converters attributed to search for better valorisation options. The hydrogenation of hydrocarbon fractions from petroleum refining is a forefront issue recently adopted by the refineries worldwide. The process involved the incorporation of suitable catalytic systems under hydrogen atmosphere to upgrade hydrocarbons into similar derivatives of better gasoline properties. The paper carefully tailored a series of recently published literature on the various aspect of the hydrogen process with emphasis to catalyst design and testing, mechanisms, industrial perspective and challenges. Areas for further investigations were also discussed.