Applied Chemistry

The depletion of high grade reserves coupled with increasing market pressure for improved product quality has forced phosphate producers to re-examine their process flow-sheets and evaluate alternate or supplement processing routes. The world is rich in phosphate resources, but most of these resources are of middle and low grade ores, in the same time it is difficult to obtain high grade concentrate with high recovery using traditional separation methods. As a result of increasing complex mineralogy, steadily decreasing ore grades and ever increasing economic and environmental problems, the mineral processing industry over the past decade had to evolve appropriate means to beneficiate low grades phosphate ores deposits. Some of the important emerging trends and the evolutionary changes which have occurred in mineral processing technology are reviewed. New treating methods such as column flotation, nano-bubble flotation technique, application of amphoteric collectors, bio-processing, and application of surface modification using enzymes help to beneficiate low grade phosphate ores.

Heavy metals may be harmful to humans through ingestion of medicinal plants containing metals through atmospheric pollution, pesticides and chemical fertilizers root uptake, ingestion of plants splashed with contaminated soil. Metals of concern are arsenic (As), cadmium (Cd), copper (Cu), Mercury (Hg) and lead (Pb). Removal of the heavy metal ions from contaminated medicinal plants Indigofera tinctoria and Acalypha indica by adsorption technique. It is the best, economically viable and efficient method. It, therefore, becomes necessary to remove these heavy metals from medicinal plants by an appropriate treatment before consuming.

Solvent extraction of lanthanum(III) and vanadium(V) from their aqueous solutions with chloroform solution of 1-phenyl-3-methyl-4-butanoylpyrazol-5-one (the ligand) was studied. The effects of ligand (extractant) concentrations and the pH of the metal aqueous solutions on the solvent extraction were evaluated in terms of their distribution coefficients (D) and the equilibrium constants (Kex) were determined. The values of the slopes of the plots of log D versus log [HBPy(org)] and that of log D versus pH showed that approximately 3 moles of the HBPy ligand reacted with one mole of La3+ while 2 moles of the same ligand reacted with VO2+ during the extraction process. The average logarithms of the equilibrium constant (Kex) values obtained for the metals at the different HBPy concentrations and buffer 4 are -7.40 (La) and -5.14 (V); while those obtained at the different pH and a constant extractant concentration of 0.02 M are La(BPy)3 = -0.49; and VO2(BPy)2 = -1.39; showing that the ligand is an efficient extractant for V(V) and La(III) ions from their aqueous solutions. The study has shown that separation of the La(III) and V(V) ions in their mixture is possible by the adjustment of the extractant concentrations and the pH of the aqueous solution of such mixture.

The mixed-ligand complexes, [Cu(bipy)2 (4-methylimidazole-5-carboxaldehyde)(ClO4)2 1 and Cu(bipy)2(indole-3-carboxaldehyde)](ClO4)2 2 were synthesized and characterized by employing elemental analyses, metal analyses, infrared and UV-Vis spectroscopy, room temperature magnetic susceptibility measurements, conductivity measurements and theoretical studies. The elemental and metal analyses show good agreement which support the formulation for the prepared complexes while the infrared spectroscopy revealed the coordination through both the nitrogen atom of the imidazole ring and the oxygen atom of the aldehyde group for 1. In complex 2, the coordination was through the oxygen atom only. The electronic transitions observed in the UV-Vis region show the various intraligand transitions and the d-d transitions at 14,347cm-1 with a shoulder at 11,115 cm-1 for 1 and for 2 the bands are 13,642 cm-1 and 11,494 cm-1. The magnetic moments 1.44B.M (1) and 1.34B.M (2) show antiferromagnetic properties of the complexes. From the theoretical studies, the Binding energies (Stabilization Energies) are found to be -33.85 (-466.46) kcal/mol and -32.73 ( -465.17) kcal/mol for 1 and 2 respectively. Therefore, the theoretical calculations corroborated the formation of a six –coordinate complex in 1 and a five –coordinate geometry around the Cu ion in 2. The conductivity measurement revealed that the complexes are 1:2 electrolytes.

A spectrophotometric method for the analysis of phorate (organophosphorus insecticide) is described. The analysis is based on the oxidation of organophosphorus pesticide with slight excess of N-bromosuccinimide (NBS) and the unconsumed NBS was determined with rhodamine B on a spectrophotometer (Genesis IOS V1.200) at ?max. 553nm. Beer’s law was obeyed in the concentration range of 0.10 to 1.00ppm. The method was successfully applied for the determination of phorate in vegetable samples. The validity of the proposed method was assessed by comparing it with the high performance liquid chromatographic method (HPLC) through statistical analysis. There was no significant difference between the two methods. In the absence of sophisticated equipment like high performance liquid chromatograph and gas liquid chromatograph, the proposed method could be used for pesticide residues analysis.

The presence of pathogens in drinking water may result from source water contamination by human and animal activities, followed by improper or insufficient treatment. The study was conducted to assess the bacteriological quality of water produced at the Kwanyako Water Treatment Plant in the Central the Region of Ghana. Triplicate water samples of Raw and Final water were collected in sterile 500ml polypropylene bottles, and analysed for thermotolerant coliform (TTC) using the Most Probable Number (MPN) method to determine the bacteriological quality of water before and after treatment. The study was carried out for a period of 6 months (September, 2013 to February 2014). TTC was positive for all Raw water samples but negative for all Final water samples. This implied that, the water produced at the Treatment plant is efficiently treated and poses no health threat.

Styrene-divinylbenzene copolymer is a special macroporous strong base anion resin crosslinked with divinylbenzene that is specially selective for hydrophobic anions. It shows good mechanical strength and an excellent resistance to osmotic and thermal shock. The amination reactions were done by chloro dimethyl ether solvent at 45°C. TGA and FTIR techniques were used to investigate the thermo gravimetric analysis and structures of obtained resins, respectively. The exchange capacities of anion exchange resins (X-16) are 312 meq/100g as determined by titration method. Then the structure of PS-DVB resin was investigated by scanning electron microscope (SEM) technique. The SEM images showed that the porous structure of PS-DVB resin was approximately intact after amination reaction.

Chemistry of natural product has contributed significantly towards the improvement of modern medicine. Custard apple (Annona squamosa ) is a nutritional rich fruit and is largely valued for its taste. It is known to have some active ingredients which kills lung, colon, breast and pancreatic cancer cells. Therefore, consumption of this fruit is known to have aided in anti-cancer activities. The investigation is carried out to find the chemical composition, phytochemical analysis and evaluation of crust, pulp and the seed of custard apple. The chemical characteristics such as pH, titratable acidity, total sugar and lipids are also verified. The results revealed that seed, pulp and crust contains adequate amount of vitamin C, citric acid, carbohydrate, protein etc. The phytochemical analysis revealed that custard apple contains tannins, flavonoids, cardiac glycosides and steroids. Standard GC analysis of seed oils contain certain types of essential oils which are mainly aiding in anti-inflammatory, anti-cancer and anti-microbial properties. The antioxidant activity is evaluated using DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) assay. The presence of anthocyanins may also offer anti-cancer, anti-inflammatory and anti-viral benefits of custard apple.

Abstract The development of nanotechnology is making the interest of researchers towards the synthesis of nanoparticles for the bioapplication. Metal oxides such as ZnO have received increasing attention as antibacterial materials in recent years because of their stability under harsh processing conditions, and also because they are generally regarded as safe materials for human beings and animals. Zinc activates 300 enzymes, and it plays a role in many another phenomenons like growth, membrane stability, bone mineralization, tissue growth, and repair, wound healing and cell signaling. Many studies have shown that ZnO nanoparticles have enhanced antibacterial activity. Use of plant and plant materials for the synthesis of Zinc nanoparticles is relatively new and exciting research field. Various plants were used for the synthesis of nanoparticles using green synthesis method

The present maniscrupt aimed to improve the castable refractory castable concretes. Thus, kaolin-based refractory castables investigated were carefully prepared. They are composed of 90 wt. % well-graded (coarse, medium, and fine) kaolin aggregate, 10 wt. % binding matrix and adequate amount of distilled water. The binder mixture was calcium aluminate cement (CAC) containing 80 % Alumina and magnesium-aluminate spinel (MA- spinel) or mullite either preformed or insitu. The castable batches were cast into cubes (25 x 25 x 25 mm), cured for 7 days under water, and followed by drying at 110ºC for 24 hrs. The samples were then subjected to firing at 1550°C for a soaking time of 1 hr. The phase composition of the prepared castable samples were investigated by using X-Ray diffraction (XRD) analysis, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, differential thermal analysis (DTA) and thermal gravimetric analysis (TGA). Results of these investigations confirm each other.