Study of the Inhibitive and Adsorptive Properties of Mild Steel in H2SO4 - Boscia senegalensis Plant Environment

The inhibitive and adsorption properties of ethanol extract of Boscia senegalensis for the corrosion of mild steel in H2SO4 were investigated using weight loss, linear polarization, and scanning electron microscopy techniques. From the result, it was found that the corrosion rate of mild steel to decrease with an increase in the concentration of the inhibitor as well as increase with an increase in temperature of the environment. The inhibition efficiency of the inhibitor increases with increasing concentration but decreases with increasing temperature. The inhibition potential of ethanol extract of Boscia senegalensis is attributed to the presence of saponnin, tannin, phlobatanins, anthraquinone, cardiac glycosides, flavanoid, terpene, and alkaloid in the extract. The adsorption of the inhibitor on mild steel surface was found to be exothermic, spontaneous and is best described by Freundlich and Temkim adsorption model. The calculated values of activation energy, enthalpy of activation, entropy of activation, free energy of adsorption and the trend in the variation of inhibition efficiency with temperature, the mechanism of adsorption of the inhibitor by physical adsorption. Ethanol extract of Boscia senegalensis is a good adsorption inhibitor for the corrosion of mild steel in H2SO4. Tafel polarization analyses indicated that studied plant extract is a mixed type inhibitor. Keywords: boscia senegalensis; polarization; adsorption.

Preliminary Studies on the Development of Monoclonal Antibodies Against Mycelia of Ganoderma boninense, the Causal Pathogen of Basal Stem Rot of Oil Palm

This study aimed to raise specific MAbs against G. boninense, the causal pathogen of basal stem rot (BSR) of oil palm. Crude mycelium extract of G. boninense was used as immunogen to generate MAbs. Mycelium was harvested from liquid culture and freeze-dried followed by re-suspension in phosphate buffer saline (PBS). Two 10-week old BALB-C mice were immunized with the mycelial extract. The mice were boosted once before harvesting their spleens for fusion. The MAbs were fused with myeloma cells from BALB-C mice. Initial screening was carried out using plate-trapped antigen enzyme-linked immunosorbent assay (PTA-ELISA) with mycelial immunogen of G. boninense. The MAbs with positive signals were verified via secondary screening and cloned for cross-reactivity test. Cross-reactivity testing was carried out with 2 other fungi namely; Trichoderma and Botrytis along with 2 different species of Ganoderma commonly found in oil palm plantations namely; G. zonatum, and G. miniatocinctum. This study found that the MAbs raised against G. boninense were not specific as the MAbs gave positive signals through the cross-reactivity test with all fungi tested in the cross-reactivity. Future work would be using these MAbs in a co-immunization program whereby the generated Ganoderma sp generic monoclonal antibody will be pre-mixed with the G. boninense mycelium immunogen to allow reduction in the potential cross-reactivity of newly generated antibodies with Ganoderma sp. Our efforts are also currently directed at optimizing the immunogen preparation for the production of MAbs specific to G. boninense

Studies on the Inhibitive Properties of Boscia senegalensis in Aluminium-HCl environment

The extracts of Boscia senegalensis was study as corrosion inhibitors for Aluminium in 1M HCl environment using gravimetric and linear polarization methods. The result shows that the extract inhibits the corrosion of aluminium by elongating the latency periods of the metal beyond in the absence of the inhibitor. The results from gravimetric measurements illustrate increase in inhibition efficiency with increment in extract concentration. Linear polarization plots show that the mode of inhibition was mixed type. The observed decrease in corrosion rate was due to adsorption of the extracts on the surface of the metal which obey the Langmuir adsorption isotherm. Adsorption of the extract depends on its chemical composition which showed the presence of various phytochemicals like flavonoids, steroids, tannins and phenolic compounds etc. which has oxygen atoms with lone pair electrons for co-ordinate bonding with metal.

The Effect of Dielectric Constant On The Kinetics of Reaction Between Plasma Albumin And Formaldehyde In Ethanol- Water Mixtures.

This study determined the effect of increased concentration of ethanol solution on the rate of the reaction between plasma albumin and formaldehyde. It was design to investigate the kinetics of reaction between plasma albumin and low concentrations of formaldehyde  under  pseudo-first order conditions of formaldehyde. The reaction was studied at constant conditions at various dielectric constants and temperatures of   1%, 5%, 15%,20% and 200C  250C, 300C  and 370C respectively. The rate constant as a function of different permittivity in ethanol-water  mixtures  was  determined at constant  conditions.  The dielectric constant of the reaction medium was altered by the addition of the varying amounts of  ethanol  – water mixtures (1- 25% v/v) in a cuvette  and  the absorption  of  0.51 x10-4 mol dm-3 plasma albumin and 0.27 x10-1 formaldehyde- plasma  mixtures  at 235 nm were measured. The values of dielectric constants for different aqueous ethanol- mixtures were taken from literature. The values of rate constants of the reaction of between plasma albumin and formaldehyde were found to decreased with the increase in the concentration of ethanol and the reaction was a second order or bimolecular . The Activation energy and  the  thermodynamic parameters (Gibbs free energy, enthalpy and entropy changes of the reaction)  decreased with  decrease  in dielectric constant of the  medium, that is with  increase in the proportion of the ethanol component  in the solvent mixtures.   The dependence of lnk2 vs. reciprocal dielectric constant (1/D ) of this reaction was found  be linear  with  three  linear portions indicating three zones, that is  three mechanistic changes. Also the correlations between lnk2 and the mole fractions of water and ethanol  ( ?H2O and  ?EtOH) have  shown  that there  was  an increase in rate of the studied reaction in  water but a  decrease  in rate in ethanol mole  fraction.  This leads us to suggest that the reaction rates were slowed by progressive addition of ethanol . A steady decrease in rate constant with decrease in dielectric constant values was observed with a statistically significant p-value =  0.0013 on a two tailed correlation analysis  at 95% confidence assurance. Key Words; dielectric constant, kinetics ,  plasma albumin,   formaldehyde ,   ethanol- water mixtures.

Preliminary Study on the Kinetics and Mechanism of the Oxidation of Naphthol Green B by Dichromate Ion in Aqueous Hydrochloric Acid Medium

- The kinetics of the oxidation of naphthol green B (NGB3-) by Cr2O7 2- has been studied in aqueous hydrochloric acid medium at an ionic strength, I = 0.50 mol dm-3 (NaCl), H+ =1.0 10-4 mol dm-3 (HCl) and T = 25 1C. The redox reaction displayed a stoichiometry of 1:1 and obeys the rate law: -dNGB3-/dt = k2NGB3-]Cr2O7 2- . The second order rate constant increases with increase in acid concentration and in the ionic strength of reaction medium. The rates of reaction displayed a positive salt effect. Addition of acrylonitrile to a partially reacted mixture in the presence of excess methanol did not lead to gel formation. Added cations and anions inhibited the naphthol green B - Cr2O7 2- reaction. Results of the Michaelis – Menten plot gave no evidence of intermediate complex formation during the course of the reaction. Based on the results obtained, the reaction is believed to proceed through the outersphere mechanistic pathway

Non-medical use of pharmaceutical drugs and motivation for change among street youth in Kano, Nigeria

Non-medical use of pharmaceutical drugs among the young Nigerian population is an increasing public health concern. There is a dire need for a  robust understanding of the problem as well as factors affecting behaviour change. This study investigated factors influencing non-medical use of pharmaceutical drugs, consequences, and motivation to stop use among street youth in Kano, Nigeria. Twenty-nine street youth selected through the snowballing sampling technique were involved in focus group discussions. Participants aged between 18 and 29 years. Sensation seeking, mood-altering, confidence, and energy boost were upheld as the major reasons for drug use; while poor health outcomes, financial problems, and  interpersonal dysfunction were the main consequences discussed by the focus group. Many of the participants indicated the intention to stop drug use but expressed concern about difficulties in accessing treatment. Preventive and psycho-social treatment measures for non-medical use of pharmaceutical drugs targeting this group should be made accessible and affordable. Keywords: motivation for change, non-medical use, pharmaceutical drugs, street yout

Kinetics and Mechanism of the Oxidation of Orange II by Chlorate Ion in Aqueous Hydrochloric Acid

Communication in Physical Sciences 2020, 5(2):165-170 Authors: B. Myek, S. O. Idris, A. D. Onu and M. K. Yakubu Received 05 March 2020/Accepted 03 May 2020 The kinetics of the oxidation of orange II (OR-) by ClO3-was studied in aqueous hydrochloric acid where the ionic strength and other parameters of the reaction mixture was, I = 0.50 mol dm-3 (NaCl), [H+] = 5.0 10-2 mol dm-3 (HCl) and T = 21 +/_ 1o C. The redox reaction displayed a stoichiometry of 1:2 and obeys the rate law given as,−????[????????−]/???????? = ????[????][????????][???????????? ]. The observed second order rate constant was found to increases with increase in hydrogen ion concentration. The rates of reaction displayed a zero salt effect and was inhibited by some added cations and anions. From the Michaelis-Menton Buck plot, there was no evidence for the formation of intermediate during the course of the reaction. Based on the results obtained, the outersphere mechanism was proposed for the reaction.&nbsp

Theoretical and Experimental Inhibitive Properties of Mild Steel in HCl by Ethanolic Extract of Boscia senegalensis

The experimental aspect of the corrosion inhibition potentials of Boscia senegalensis was carried out using gravimetric and linear polarization techniques techniques as well as scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), whereas the theoretical aspect was done by using the Density functional theory (DFT) calculations to performed and model the electronic structures of some extract constituents, including Physiosorptive interactions with the Fe surface. The analyses of the experimental results showed that the inhibition efficiency increased with increase in concentration of the inhibitor and decreased with increase in temperature. The efficiency of the extract in HCl (70%).  Thermodynamic parameters revealed that the adsorption of extract onto the metal surface was spontaneous, exothermic and supported the Physical adsorption process. FTIR results showed that the inhibition mechanism was by absorption process, through the functional groups present in the extract and that of the inhibited. Surface morphology also revealed that corrosion product confirmed the protection offered by the extract on the surface of the metal immersed in the acid media. The data obtained were fitted into various adsorption isotherms though the Freundlich isotherm was found to be best fit. Keywords: Inhibition, density functional theory, corrosion, boscia senegalensis

Kinetics and mechanistics steps to the electron transfer reaction of peroxo-bridged binuclear cobalt(III) complex of succinimide by glycine in aqueous acidic medium

ABSTRACT. The kinetics and mechanistic steps to the electron transfer reaction of the peroxo-bridged binuclear cobalt(III) complex of succinimide [(suc)(en)2Co(O2)Co(en)2(suc)2+] hereafter called peroxo-bridged dicobalt(III) complex ‘[Co(O2)Co2+]’ by glycine have been carried out spectrophotometrically at λ = 420 nm and T = 26 ± 1 oC, [H+] = 1 x 10-3 M and ᶙ = 0.5 M (NaCl) in aqueous acidic medium. The reaction was found to be first order with respect to [Co(O2)Co2+] and [(Gly] and experimental data indicates a second-order overall. The reactions obeyed the general rate law: (d[Co(O2)Co2+]/dt) = (a +b)[H+])[Co(O2)Co2+][Gly]. Varying hydrogen ion concentration accelerated the reaction rate and shows first-order dependence while the reactions also affected by changes in the ionic strength of the reaction medium by giving a non-negative salt effect in the course of the reaction. Free radicals were not detected in the reactions. Spectroscopic investigation and Michaelis-Menten plots suggest the absence of intermediate complex formation. The experimental result obtained in this system is concluded in favor of the outer-sphere mechanism.                     KEY WORDS: Cobalt(III) complex, Kinetic, Electron transfer, Spectroscopic, Mechanistic steps, Michaelis-Menten, Glycine   Bull. Chem. Soc. Ethiop. 2021, 35(2), 425-434. DOI:  https://dx.doi.org/10.4314/bcse.v35i2.1

High Energy X-Ray Dosimetry Using (ZnO)0.2(TeO2)0.8 Thin Filmbased Real-time X-Ray Sensor

This study reports the dosimetric response of a (ZnO)0.2(TeO2)0.8 thin film sensor irradiated with high-energy X-ray radiation at various doses. The spray pyrolysis method was used for the film deposition on soda-lime glass substrate using zinc acetate dehydrate and tellurium dioxide powder as the starting precursors. The structural and morphological properties of the film were determined. The I-V characteristics measurements were performed during irradiation with a 6 MV X-ray beam from a Linac. The results revealed that the XRD pattern of the AS-deposited thin film is non-crystalline (amorphous) in nature. The FESEM image shows the non-uniform shape of nanoparticles agglomerated separately, and the EDX spectrum shows the presence of Te, Zn, and O in the film. The I-V characteristics measurements indicate that the current density increases linearly with X-ray doses (0-250 cGy) for all applied voltages (1-6 V). The sensitivity of the thin film sensor has been found to be in the range of 0.37-0.94 mA/cm2 /Gy. The current-voltage measurement test for fading normalised in percentage to day 0 was found in the order of day 0 > day 15 > day 30 > day 1 > day 2. These results are expected to be beneficial for fabricating cheap and practical X-ray sensors