- Antibacterial Activity of Copper-doped Montmorillonite Nanocomposites
Prepared by Alkaline Ion Exchange Method
Hamideh Pourabolghasem, Mohammad Ghorbanpour and Razieh Shayegh
Abstract:
The antibacterial activity of copper-doped montmorillonite nanocomposites (Cu-MMT) has been investigated. Copper loaded clay nanocomposites have been synthesised by alkaline ion exchange processes in media containing copper sulfate at 550°C. Characterisation studies on the composites were done by X-ray diffractometry (XRD), SEM and absorption spectra analysis. SEM results indicated the diffusion of copper to the inner montmorillonite layer and opening of presenting cracks on its surface. The XRD analysis showed the presence of copper oxide (CuO) structure intercalated within the clay mineral layers. The antimicrobial effects of doped montmorillonite powders against pathogen bacterial strains Escherichia coli and Staphylococcus aureus were tested in broth media. Quantitative test in liquid media clearly showed that copper-doped samples had viable cells reduction ability for testing strains. The excellent antimicrobial activity of the composites was observed on S. aureus. In addition, the composite showed good stability in water and good promise for use in water treatment..
- An Evaluation of Sodium Ethyl Xanthate for the Froth Flotation Upgrading of
a Carbonatitic Copper Ore
Abraham Adewale Adeleke, Meso Florence Mokgethwa and Peter Mandonidis
Abstract:
The carbonatitic Palabora copper ore was ground to the less energy intensive coarse size consisting of 45% passing 75 µm in a ball mill for 20 min and froth floated in a 4.5 l Denver cell at varying dosages of the highly selective sodium ethyl xanthate (SETX) at 200, 250, 300, 350 and 400 g/t. The concentrates were collected every 15 s at varying scraping times of 3, 7 and 10 min. The results obtained showed that that the highest recovery of 86.1% was obtained at the 300 g/t SETX dosage with the lowest grade of 11.29%, while the highest grade of 13.95% occurred at the lowest recovery of 78%. The dosages of SETX used for the flotation was found to be generally higher than that of sodium iso-propyl xanthate (SIPX) used for another copper ore of non-carbonatitic origin. However, the successful flotation of the ore ground coarser than the conventional practice of 80% passing 75 µm is economically significant in view of the potential power conservation obtainable.
- Properties of Recycled High Density Polyethylene (RHDPE)/Ethylene Vinyl
Acetate (EVA) Blends: The
Effect of Blends Composition and Compatibilisers
A. R. H. Fatimah, Supri Abdul Ghani and Z. Firuz
Abstract:
Recycled high density polyethylene (RHDPE)/ethylene vinyl acetate (EVA) blends with
different blend compositions and compatibilisers were prepared by using melt blending technique in
Brabender Plasticorder at temperature 160°C and rotor speed of 50 rpm for 10 min. The
compatibilisation of RHDPE/EVA blends were enhanced by the addition of 6 phr of polyethylene-
grafted-maleic anhydride (PE-g-MAH) and caprolactam-maleic anhydride (CL-MAH) as compatibilisers.
The tensile properties, swelling behaviour, morphology and infrared spectroscopy analysis were
studied. The tensile properties and morphology analysis showed that RHDPE/EVA blends became softer
with the increasing EVA content. The results also revealed that there was good compatibility
between RHDPE/EVA blends with addition of PE-g-MAH and CL-MAH lead to improvement in tensile
properties and swelling behaviour of the blends compared to RHDPE/EVA blends without the presence
of compatibilisers. SEM morphology displayed better interfacial adhesion due to good dispersion and
interaction between RHDPE and EVA phases into each other caused by the compatibilisation effect of
PE-g-MAH and CL-MAH. Fourier transformed infrared spectroscopy (FTIR) revealed the structure of the
polymer blend with the addition of CL-MAH and PE-g-MAH as compatibilisers.
- Enhanced Band Gap Energy and Electrochromic Behaviour of Selenium
Incorporated Copper Thin Film
J. Peter, P. Karpagavinayagam and C. Vedhi
Abstract:
Selenium incorporated copper (CuSe) thin films are deposited on indium tin oxide (ITO)
substrate by cyclic voltammogram of 5.0 ml of 0.1 M CuSO4 and 2 ml of 0.05 M selenium dioxide at
potential range from –0.8 V to 0.7 V vs. Ag/AgCl in pH 1.0. The adherent nature, electroactivity
and stability of the CuSe thin film were found to be good. The transmittance and absorption of thin
films was analysed through UV-Vis spectra. An energy gap of 1.78 eV is obtained for CuSe thin films
by extrapolating the linear portion of the curves h? versus (ah?)2. X-ray diffraction patterns
revealed that the deposited films possess cubic structure with lattice constant (a) value 80.892Å.
Surface morphology of thin film shows uniform granular mixed texture-like structure. The sizes of
the grains are found to be in the range between 53.33 nm and 93.33 nm. The film composition was
investigated using an EDX micro analytic unit attached with scanning electron microscope. The in-
situ spectroelectrochemical behaviour of CuSe thin film at various applied potentials in 0.1 M
H2SO4. CuSe thin film exhibits dual colour chromic behaviour from contrast red colour to contrast
yellows colour. The electrochromic device shows good optical contrast, coloration efficiency,
response time and stability.
- Measurement of Shielding Effectiveness of Building Blocks against 662 Kev Photons
Oluwaseun Adedoyin and Abiodun Ayodeji
Abstract:
This study uses building blocks as a shield for gamma energy source of 662 KeV from Cs-
137. The attenuation from the block is compared with those obtained when conventional shields like
iron, lead and concrete are used as shield for Cs-137. This was done with the aim of finding out
the level of shielding and the thickness of building block needed to confer same level of shielding
as the already mentioned conventional shields. Results obtained using a gamma spectrometer with a
NaI(Tl) detector showed that the Half Value Thickness (HVT) of Building block, Concrete, Iron and
Lead were 5.1420 cm, 3.8043 cm, 1.1908 cm, and 0.5581 cm respectively. With the results from this
work, a shield of 37 cm building block (though bulky in size) will attenuate the source and can be
used as a substitute for lead which would require a 4.4 cm thickness.
- Tensile and Thermal Properties of Crosslinked Chitosan/Empty Fruit Bunch
Biofilms by Phthalic
Anhydride
Salmah Husseinsyah, Chan Ming Yeng and Mohamad Arine Aizeq Ahmad Amirudin
Abstract:
Chitosan (CS) has high potential applications in packaging, agriculture and food.
However, the cost of chitosan is higher. Therefore, the addition of agriculture waste such as empty
fruit bunch (EFB) in CS was studied in order to reduce the cost of CS. The CS/EFB biocfilms were
prepared through solvent casting method. This research paper study the effect of phthalic anhydride
(PA) crosslinking agent on tensile, morphological and thermal properties of CS/EFB biofilms. The
results indicated that the tensile strength and elongation at break of uncrosslinked CS/EFB
biofilms decreases but the modulus of elasticity increases as increasing EFB content. In addition,
the glass transition temperature (Tg) of CS/EFB biofilms increased with EFB content. On the other
hand, the crosslinked CS/EFB biofilm with PA showed higher tensile properties such as tensile
strength, elongation at break and modulus of elasticity in comparison with uncrosslinked biofilms.
While, the Tg of crosslinked CS/EFB biofilms higher than uncrosslinked biofilms due to formation of
amide linkages. The formation of amide bonds between CS and PA were demonstrated in FTIR result.
The better filler dispersion and filler-matrix adhesion were proven by Scanning electron microscopy
(SEM). Furthermore, the percentage gel fraction of both uncrosslinked and crosslinked CS/EFB
biofilms increased with increasing of EFB content. On the other hand, the crosslinked CS/EFB
biofilms exhibited higher gel fraction than uncrosslinked biofilms due to the formation of amide
crosslinkages in crosslinked biofilms.
- The Synthesis and Characterisation of 2-methyl-N-((4-methylpyridine-2-yl)
carbamothiol)
Benzamide: Its Preparation with Antibacterial Study
Farook Adam, Nur Nadia Fatihah, Nadiah Ameram, Sreeramanan Subramaniam
and Safiah Ahmad Mubarrakh
Abstract:
The compound, 2-methyl-N-((4-methylpyridin-2-yl)carbamothioyl)benzamide was derived from
ortho-toluylchloride and 2-amino-4-picoline. It was fully crystallised and characterised on the
basis of elemental analysis, X-ray crystallography and spectroscopic techniques namely infra-red,
Uv-Vis and nuclear magnetic resonance. The melting point was in the range of 164.9°C–165.8°C. The
Fourier transform infrared (FTIR) analysis shows the following vibrational frequencies for ?(N-H),
?(C=O), ?(C-N) and ?(C=S) at 3237 cm–1, 1683 cm–1, 1329 cm–1 and 1154 cm–1 respectively. 1H NMR
results showed chemical shifts at 9.140 ppm and 12.983 ppm for the two N-H protons. Single crystal
X-ray diffraction studies on the compound showed it to be a rigid molecule due to the presence of
internal hydrogen bonding. The compound shows antibacterial activity towards gram positive and gram
negative bacteria.
- Ultrasound-assisted Extraction of Oil from Calophyllum inophyllum Seeds:
Statistical Optimisation using Box-Behnken Design
Faiznur Mohd Fuad and Khairiah Abd. Karim
Abstract:
Ultrasound-assisted extraction (UAE) of oil from Calophyllum inophyllum Linn seeds was
studied and the effects of four factors (extraction time, ultrasound power, extraction temperature,
liquid to solid (L/S) ratio) on the oil yield were optimized by using a statistical tool.
Specifically, the optimisation was carried out by employing a Box-Behnken statistical experimental
design. The experimental data were fitted to a quadratic model using multiple regression analysis
giving high determination coefficient value (R2) of 0.984. The predicted oil yield was optimum
(56.2%) when the extraction were conducted for 21 min, 210 W ultrasound power, 42°C extraction
temperature and 21 ml/g L/S ratio. Based on the model summary statistics, the experimental values agreed closely with the predicted values, indicating an excellent fit of the model used. The results indicated that Response Surface Methodology (RSM) was effective for optimising the UAE
conditions of oil from C. inophyllum seeds.
- Corn Cob as a Potential Feedstock for Slow Pyrolysis of Biomass
Nur Syairah Mohamad Aziz, Adilah Shariff, Nur Ismiza Ismail and
Nurhayati Abdullah
Abstract:
The aim of this study is to investigate the characteristic of corn cob as a biomass
feedstock for slow pyrolysis process. This was achieved by using proximate, elemental and
thermogravimetric (TG) analysis as well as heating value, pH and lignocellulosic determination.
Proximate analysis was performed using ASTM E1756-01, ASTM E1755-01 and ASTM E872-82. Proximate
analysis showed that the corn cob feedstock contained 87.76 mf wt% of volatile matter, 1.05 mf wt%
of ash content and 11.09 mf wt% of fixed carbon. The elemental analysis revealed that corn cob
feedstock contain less than 1 mf wt% of nitrogen and sulfur. The percentages of cellulose,
hemicelluloses and lignin of corn cob feedstock are 45.88%, 39.40% and 11.32% respectively. The
weight loss of corn corn cob feedstock was prominent in the temperature range of 250°C–350°C. Two
distinct peaks of DTG curve indicate the difficulty of corn cob feedstock to degrade due to its
high fixed carbon content. The overall findings showed that corn cob is suitable to be used as the
feedstock for slow pyrolysis because of its high volatile matter and low percentages of nitrogen
and sulfur. Its high fixed carbon makes it a potential feedstock for the slow pyrolysis of
biomass.
- Heavy Metal Profile of Shilajit Samples Obtained from Gilgit and Chellas,
Pakistan (Short Communication)
Muhammad Rahim, Imdadullah Mohammadzai, Waseem Hassan and
Nazir Ahmad
Abstract:
Shilajit is considered as one of the wonder medicines of Ayurveda. It is an important
drug of the ancient Hindu material medica and is to this day used extensively for a variety of
diseases. However, there are a number of reports which have associated metal poising with
traditional use of herbal medicine including Shilajit. The study was designed in this regard to
determine the prevalence and concentration of heavy metals in Shilajit obtained from natural
valleys of Gilgit (sample A) and Chellas (sample B) which are commonly used in Pakistan.
Determination of heavy metals was carried out using atomic absorption spectrophotometry. Iron,
zinc, chromium, manganese, cobalt and lead were detected in both samples with percentage of these
metals in sample A were 0.19680%, 0.08705%, 0.01138%, 0.0026%, 0.00051% and 0.00008%,
respectively. While sample B contains these metals in the following percentages: 0.03210%,
0.00213%, 0.00154%, 0.00147%, 0.00055% and 0.00023% respectively. Our data indicated that the metal
concentration in both tested samples are within permissible level as prescribed by world health
organization and are not associated with detrimental health effects.
