Open Access Original Research Article

Polarographic and Voltammetric Investigation of Sudan I

Yeliz Karaman, Mustafa Uçar, Necati Menek

Chemical Science International Journal, Page 1-12
DOI: 10.9734/CSJI/2018/44596

The voltammetric and polarographic reduction of the 1-phenylazo-2-naphthol (Sudan I) on a hanging mercury drop electrode (HMDE) and static mercury drop electrode (SMDE) has been studied by using several techniques including square-wave voltammetry (SWV), differential pulse polarography (DPP), direct current polarography (DCP) and cyclic voltammetry (CV) in aqueous and ethanolic Britton-Robinson buffer media. The observed shift of the compound reduction peaks to more negative potentials with increasing pH indicates that hydrogen ions are involved in the electrode reaction. The effect of scan rate and pH on the reduction peaks has been studied. From the polarographic and voltammetric data, electrochemical reduction mechanism of the azo dye has been suggested. The reduction of the azo group to amino group in acidic, neutral and basic media was observed

Open Access Original Research Article

Kinetic and Energetic Correlations in the Reaction of Vitamin-C Tablets

Seddique M. Ahmed, Mohamed M. Shahata

Chemical Science International Journal, Page 1-7
DOI: 10.9734/CSJI/2018/45058

The oxidation time based on the fitting of experimental data was taken out. Drawing of the Absorbance (λmax=265 nm) vs. oxidation time (sec) of Vitacid C by K2 CrO4 were studied. Energy consumed during oxidative degradation of vitamin-C(Vit-C) Tablets in aqueous potassium chromate (K2CrO4) medium was studied spectrophometrically at 25°C. The reduction of the absorbance at~ 265 nm with increasing time was scanned. A good linearity (R-square ≥ 0.99). The slope (EC/ppm) vs reductant (Vit-C/ppm) at constant oxidant is about 1.218, while, the slope of EC vs. oxidant (K2CrO4 /ppm) is about 3.653. Calculations suggest that the EC during reduction of Cr (VI) to Cr (III) is about three times of magnitude faster than the oxidation of the Vit - C sample.

Open Access Original Research Article

Structural and Thermal Studies on Racemic PbC4H4O6•2H2O Single Crystal

Takanori Fukami, Shuta Tahara

Chemical Science International Journal, Page 1-9
DOI: 10.9734/CSJI/2018/45004

Single crystals of racemic lead tartrate dihydrate, PbC4H4O6·2H2O, were grown at 308 K by the gel method using silica gel as the growth medium. Differential scanning calorimetry, thermogravimetric-differential thermal analysis, and X-ray diffraction measurements were performed on the single crystals. The space group symmetry (orthorhombic Pbca) and the structural parameters were determined at room temperature. The structure consisted of PbO8 polyhedra, C4H4O6 molecules, two independent H2O molecules, and zig-zag hydrogen-bonded chains along the a- and b-axes linked by O–H···O hydrogen bonds between adjacent molecules. Weight losses due to thermal decomposition of racemic PbC4H4O6·2H2O occurred in the temperature range of 300–1600 K. We suggested that the weight losses in the ranges of 300–900 K and 900–1600 K were caused by the evolution of gases from 2H2O and C4H4O5, and the evaporation of PbO, respectively.

Open Access Original Research Article

Polycyclic Aromatic Hydrocarbons in Water Sample from Dadin Kowa Dam, Gombe State, Nigeria

Z. M. Chellube, J. C. Akan, L. B. Inuwa, A. I. Mohammed

Chemical Science International Journal, Page 1-8
DOI: 10.9734/CSJI/2018/43748

The purpose of this study was to investigate the concentrations of PAHs in water samples from Dadin Kowa Dam, Nigeria and to evaluate the risk associated with the ingestion of the water from the Dam. The concentrations of PAHs varied with the sample site and season; and the levels of PAHs at all site are found to be significantly below the maximum allowable concentrations (MACs) of 0.005 to 3.0 mg/l. The carcinogenic risks were higher than 10−6 threshold values, and the water from Dadin Kowa Dam is considered to pose significant health effects to children and adult. However, the carcinogenicity risks rating decrease in the order of children > adult. The study further demonstrated that Dadin Kowa Dam requires a substantial PAHs pollution control program.

Open Access Original Research Article

Non-linear Regression, a Better Approach for the Optimisation of Hydroquinone, Resorcinol and Catechol Adsorption by Chemically Activated Carbon Based on Monkey Kola (Cola lepidota k. schum) Waste

Nono Nguemjom Patricia, Kamgaing Théophile, Tchuifon Tchuifon Donald Raoul, Doungmo Giscard, Baleba Mbanga Moise Roger, Anagho Solomon Gabche

Chemical Science International Journal, Page 1-18
DOI: 10.9734/CSJI/2018/45320

Activated carbon was prepared from waste of monkey kola by pyrolysis and chemical activation using H3PO4. It was characterised by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and energy dispersive X–ray spectroscopy (EDX). Different physical properties namely bulk density, moisture content, volatile matter content, iodine number, pH of the solution, pHpzc and methylene blue adsorption were also determined. The activated carbon was used as an adsorbent for the removal of hydroquinone, catechol and resorcinol in solution. The process parameters of the sorption system such as pH of the solution, contact time and the amount of adsorbent were studied to understand their effects on pollutants removal. The optimised parameters are found to be pH: between 6 - 8, and the agitation time: 30 minutes. The experimental equilibrium data were analysed using five models (Langmuir, Freundlich, Redlich-Peterson, Sips, Langmuir-Freundlich). Non-linear regression analysis was employed, and three error analysis methods, correlation coefficient (R²), root-mean-square error (RMSE) and non-linear chi-square test (χ²) were considered to identify the best-fit isotherm and the best-fit kinetic model. Among all the adsorption isotherms considered, Langmuir was found to be a perfect representation of the experimental equilibrium data with high R² low RMSE and good χ². Batch kinetic experiments were carried out and experimental kinetics was fitted by non-linear regression. The sorption process was found to follow the pseudo first-order in case of the three pollutants. This study showed that the activated carbon can be used as a good adsorbent for the removal of phenol derivatives from water according to its maximum adsorption capacity which is about 66.57 µmol/g, 10.42µmol/g and 5.47 µmol/g respectively for hydroquinone, catechol and resorcinol.