Open Access Original Research Article

Synthesis and Characterization of Nano Structured Zinc(II) Cysteine Complex under Ultrasound Irradiation

Maryam Ranjbar, Nasrin Shahsavan, Mohammad Yousefi

Chemical Science International Journal, Page 111-121
DOI: 10.9734/ACSJ/2012/1617

Cysteine and zinc oxides are important materials that have a wide range of applications especially in biomedical sciences. In this study, synthesis and characterization of nano structured Zn(II) complex of cysteine, (cysteine = 2-amino-3-mercaptopropanoic acid), in two different particle sizes, has been investigated. The reaction of Zinc(II) acetate and KI with cysteine ligand under ultrasonic irradiation, leads to the formation of nano sized Zn(II) cysteine complex. Particle sizes of the product have been decreased after thermal treatments in an autoclave. The hexagonal micro crystalline zinc oxide, has been prepared using Zn(II) cysteine complex as precursor. Characterization of the Zn(II) complex, has been performed using elemental analysis, FTIR spectroscopy, energy dispersed X-ray analysis (EDAX), scanning electron microscopy (SEM), thermal analysis (TG/DTA) and gel-permeation chromatography (GPC). Based on the results, chemical formula for the Zn(II) cysteine complex is proposed as [ZnI2(C3H5NO2S)]n. Scanning electron microscopy (SEM) analysis has demonstrated nano particles Zn(II) complex with average diameter of about 38-54 nm. Hexagonal ZnO micro structures were characterized by FTIR, X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDAX) techniques.

Open Access Original Research Article

Corrosion Inhibition of Aluminium in Acidic Medium by Different Extracts of Ocimum gratissimum

I. J. Alinnor, P. M. Ejikeme

Chemical Science International Journal, Page 122-135
DOI: 10.9734/ACSJ/2012/1835

Aims: This study is aimed at using plant extracts to prevent corrosion of aluminium in acidic medium. The inhibition efficiency of different extracts of 1M HCl, ethanol and distilled water were determined.
Study Design: Gravimetric method was used for the analysis.
Place and Duration of Study: Department of Chemistry, Federal University of Technology, Owerri, Nigeria, between March and November, 2011.
Methodology: Aluminium sheets of AA1060 and purity 98.98% was used. Each sheet was mechanically press-cut into coupons of dimension 3 cm x 3 cm. The solvents used for extraction of ocimum gratissimum leaf were 1M HCl, ethanol and distilled water, respectively. A hole with diameter 0.5 cm was drilled in each aluminium coupon and suspended in beakers containing test solution using glass hook. The weight loss was determined by retrieving coupons from test solutions at intervals. The coupons were weighed after retrieving. The different in weight was taken as weight loss of aluminium.
Results: The percentage of inhibition efficiency (% I.E) was calculated at 303 K and 333 K, respectively. The result indicates that % I.E increases as concentration of inhibitor increases. The trend of inhibition efficiency was in order: Distilled H2O > C2H5OH > 1M HCl. The result indicates that increase in temperature decreases inhibition efficiency and degree of surface coverage. The result shows that apparent activation energy Ea increases as inhibitor concentration increases. The activation energy of distilled water extract range between 45.02 to 79.90 kJ/mol. While the activation energies of ethanol and 1 M HCl extracts of the inhibitor ranges between 35.12 to 72.93 kJ/mol and 26.60 to 65.25 kJ/mol, respectively. The experimental data obtained corroborated with Langmuir and Flory Huggins adsorption isotherms.
Conclusion: This study indicates that different extracts of Ocimum gratissimum inhibits aluminium surface in presence of 1M HCl. The result of the analysis shows that inhibition efficiency and degree of surface coverage decreases as temperature increases. The activation energy of different extracts increases as concentration of inhibitor increases. The negative values of ∆Gads shows that adsorption of inhibitor on surface of aluminium is spontaneous.

Open Access Original Research Article

Preparation and Characterization of Activated Carbons Obtained from Maize Cobs by Zinc Chloride Activation

J. M. Ketcha, D. J. D. Dina, H. M. Ngomo, N. J. Ndi

Chemical Science International Journal, Page 136-160
DOI: 10.9734/ACSJ/2012/1806

Aims: To set up high adsorbent materials at lower cost from agricultural wastes in this case maize cobs and to characterize these materials.
Study Design: Determination of the textural and physicochemical properties of the prepared materials.
Place and Duration of Study: Technological University of Chalmers, Nuclear Chemistry Laboratory, Goteborg, Sweden, between November 2010 and January 2011.
Methodology: Five activated carbon samples of maize cobs were prepared by chemical activation with zinc chloride (ZnCl2). They were characterized and the values of their textural (SEM images and XRD patterns) and physicochemical properties (specific surface area, pore volume, pore size and functional groups) were determined and compared with those of a commercial activated carbon of animal origin.
Results: The results showed that the part of the cob used, the residence time, the quantity and the state of the activating agent affected the activated carbon produced. Thus, the carbon material obtained from the woody belt (hard part of the cob) showed the most significant properties with a specific surface area of 701.68 m2/g and a porous volume of about 0.39 cm3/g. On the other hand, samples obtained from the soft part of the cob mixed with small particles of woody belt, gave low specific surface area (0.43-11.62 m2/g) and porous volumes (0.00028-0.11 cm3/g). In addition, all these chars presented acidic functions at their surfaces.
Conclusion: The study revealed that maize cobs particularly the hard part of the cobs, an agricultural waste, can be used as raw material for the preparation of activated carbon.

Open Access Original Research Article

Determination of Angiotensin-Converting Enzyme Inhibitor, Perindopril Erbumine, in Bulk and Tablet Dosage Form with HPLC

Chatragadda Nagalakshmi, Avula Prameela Rani, Sunkara Bhawani, Chandra Bala Sekaran

Chemical Science International Journal, Page 161-176
DOI: 10.9734/ACSJ/2012/2045

Aim: To develop and validate a simple HPLC method for the determination of perindopril erbumine (PDE) in bulk and tablets.
Place and Duration of Study: Rainbow Pharma Lab, Hyderabad, India, between April and June 2012.
Methodology: The separation of PDE was carried out on a Zorbax XDB C8 (250 mm × 4.6 mm I.D., 5 μm particle size) analytical column. The mobile phase was phosphate buffer (pH 4.5)-acetonitrile (60:40 v/v). The flow rate and wavelength were set to 1.3 mL/min and 242 nm, respectively. As per ICH guidelines, the proposed method was validated. The developed method was successfully applied for the estimation of PDE in tablets and results were compared statistically with the official method.
Results: The developed method showed a linear response from 8 to 80 μg/mL, with a regression coefficient (R2) of 0.9996. The LOD and LOQ were 2.4 and 8μg/mL, respectively. The selectivity studies showed that the method was selective and free from interfering common excipients. The intra- and inter-day RSD were in the range of 0.043-0.234% and 0.180-0.654%, respectively. The results of recovery studies were good. The stability data of the PDE indicate that the drug was stable for 72 hours.
Conclusion: The developed method was linear, sensitive, selective, precise, accurate and robust, being suitable for routine quality control analyses of PDE.

Open Access Original Research Article

Modification in Properties of Fly Ash through Mechanical and Chemical Activation

Anita Sharma, Khushboo Srivastava, Vijay Devra, Ashu Rani

Chemical Science International Journal, Page 177-187
DOI: 10.9734/ACSJ/2012/2052

This paper is a critical overview on chemical, structural, and morphological changes in fly ash properties with mechanical activation using high energy planetary ball mill and chemical activation by digesting with various mineral acids (HCl, HNO3, H2SO4 and HClO4) at 110ºC. Mechanical activation results in increase in silica percentage, amorphous nature, specific surface area and surface roughness, as evident by analytical measurements using XRF, XRD, FT-IR, BET surface area and SEM techniques. The chemical activation of Fly ash performed by different acids results in increased silica content and surface area due to leaching of several metal ions from silico-aluminate skeleton. The surface silanol groups responsible for generating Brönsted acidity are enhanced as evident by pyridine adsorbed FT-IR. Activation with HClO4 is also evident to generate surface active Lewis acid sites due to formation of Al-OH phases on the surface. The mechano-chemical activation can generate sufficient activity on fly ash surface rendering its potential application in heterogeneous acid catalysis.