Bio-oxidation of a low grade chalcopyrite ore by mixed culture of acidophilic bacteria

A study on the extent of biooxidation of a low grade Chalcopyrite ore using a mixed acidophilic bacterial consortium predominantly of the Acidithiobacillus ferrooxidans strain has been carried out.  The influence of additive and pH on the bio-oxidation of the ore has been examined. The results of the investigations showed that bio-oxidation was enhanced by the addition of nutrient broth at lower pH. The enhancement in biooxidation of a chalcopyrite ore was 54% and 19% with and without addition of broth in 10 days incubation time, respectively. The study showed that at a lower pH (≤ 4.0), the biooxidation of the ore was higher in presence of broth. Consequently, in presence of nutrient broth, the concentration of Fe and Cu leached were 1200 mg/L and 350 mg/L; and without nutrient broth yielded 580 mg/L and 220 mg/L, respectively within 10 days of incubation and decreases afterwards

Application of nano zinc oxide (nZnO) for the removal of triphenyltin chloride (TPT) from dockyard wastewater

The use of triphenyltin chloride (TPT), a persistent organic pollutant, as a biocide has led to serious contamination of the marine environment. The potential of nano zinc oxide (nZnO) for the removal of TPT from contaminated dockyard wastewater was investigated. The adsorption of TPT onto nZnO has been found to depend on the adsorbent dose, contact time, pH, stirring speed, and temperature. Equilibrium data fitted well with the Freundlich model and the experiments showed that 97.0% TPT removal was achieved by treating 0.643 mg·l-1 TPT contaminated dockyard wastewater with 0.5 g nZnO at optimal conditions. The kinetic data for the adsorption process obeyed a pseudo second-order kinetic model, suggesting that the adsorption process is chemisorption. The nZnO investigated in this study showed good potential for the removal of TPT from contaminated dockyard wastewater systems

Quantitative Leaching of a Spent Cell Phone Printed Circuit Board by Hydrochloric acid

This paper presents a kinetic data on the hydrometallurgical recovery of some metal ions from a printed circuit board (PCB) of a spent cell phone by hydrochloric acid leaching. The effects of acid concentration, temperature and particle diameter on the dissolution efficiency at various leaching time intervals were examined. The results of the leaching investigations showed that the powdered cell phone dissolution increases with increasing acid concentration, system temperature with decreasing particle diameter at 360 rpm. With 2M HCl solution, about 88.49% of the sample was dissolved within 120 minutes using 0.075-0.112 mm particle diameter at 800 C. The results of the study indicated that the dissolution reaction could be represented by a shrinking core model with surface chemical reaction. A value of 0.61, 60.67 kJ/mol and 12.9s-1 were calculated as reaction order, activation energy and frequency factor, respectively for the dissolution process.http://dx.doi.org/10.5937/metmateng1402119

Preparation of TiO2-activated kaolinite composite for photocatalytic degradation of rhodamine B dye

ABSTRACT. Rhodamine B (RhB) is one of the prominent dyes discovered to be carcinogenic and mutagenic substance present in the ecosystem. Alteration of the characteristics of TiO2 through modification with clay influences the behavior of some organic molecules at its surface, and thus its photocatalytic properties. This study investigates the photocatalytic degradation of RhB using TiO2-activated kaolinite composite (TiO2-AKC). TiO2-AKC was prepared in absolute ethanol and characterized using SEM, EDX, TEM, BET and FTIR. The photodegradation of RhB using TiO2-AKC at room temperature under visible-light was studied at various time intervals and the concentration of RhB was monitored using Ultraviolet-Visible spectrophotometer. Characterisation of TiO2-AKC revealed an adequate distribution of TiO2 over the AKC surface, with an enhanced surface area (TiO2-AKC 808 m2g-1, TiO2 50.0 m2g-1, AKC 20.6 m2g-1) necessary for effective degradation. The degradation was efficient in TiO2-AKC than in sole TiO2 resulting in 99.51% and 88.35%, respectively. The experimental data was analysed using zeroth and first order kinetics, parabolic diffusion, and modified Freundlich model. The degradation kinetics conforms to first order kinetics in TiO2-AKC and sole TiO2. The mechanism of the degradation using TiO2-AKC fit into modified Freundlich model and parabolic diffusion model while sole TiO2 was best described by parabolic diffusion model.                 KEY WORDS: Kaolin, Kinetics, Organic dyes, Photodegradation, Pollutants, Titanium(IV) oxide Bull. Chem. Soc. Ethiop. 2022, 36(1), 13-24.                                                                    DOI:   https://dx.doi.org/10.4314/bcse.v36i1.2                                     &nbsp

Leaching of a Nigerian Columbite in Hydrochloric Acid: Dissolution Kinetics

Abstract This paper presents the kinetics of dissolution of a Nigerian colu mb ite mineral ore sample in hydrochloric acid med ia. The effects of acid concentration, process temperature, stirring rate and particle size on the dissolution rate were examined. Experimental results showed that the columbite dissolution increases with increasing acid concentration, temperature, stirring speed and decreases with particle size. W ith 4.0 M HCl solution, about 15.37% of colu mbite was dissolved within 120 minutes using < 0.15 mm particle size at a temperature of 80℃ and a stirring speed of 360 rp m. The result of the study indicated that the leaching data fitted a diffusion model. Values of 0.5, 22.40 kJmo l -1 and 1.51 X 10 -5 min -1 were calculated as reaction order, activation energy and Arrhenius constant, respectively for the dissolution process

Upgrading of a Nigerian Ixiolite ore to Columbite by Sulphuric acid treatment

A quantitative leaching of a Nigerian Ixiolite ore in sulphuric acid medium was carried out and the effect of some parameters such as acid concentration, temperature and particle size was evaluated as a function of time. The experimental results obtained showed that the Ixiolite dissolution increases with increasing acid concentration, temperature, leaching time and, decreases with particle size. With 3 mol/L H2SO4 solution, 71.14% of the ore reacted within 120 minutes at 80 °C.The kinetics of dissolution of the mineral was also examined and the observed effects of the operating variables on the leaching rate were consistent with the diffusion controlled kinetic model. The calculated activation energy for the leaching process was 24.40 kJ/mol with the reaction order of 0.5, supported the proposed model. Detailed characterization of the ore before and after leaching were carried out. At optimal leaching conditions, thermodynamic feasibility of the conversion of raw Ixiolite to Columbite of industrial value, as confirmed by X-ray diffraction (XRD) technique is possible

Role of Low Environmental Temperature in Peptic Ulcer Development

Peptic ulcers are described as acid-induced lesions found in the stomach and duodenum caused by the imbalance between the defending factors of the mucosa and the attacking factors such as hydrochloric acid in gastric juice, with Helicobacter Pylori (H. Pylori) and Non-Steroidal Anti-Inflammatory Drugs NSAIDs. They exhibit seasonal patterns in their occurrence, with higher occurrence in winter and spring and a low occurrence in summer. Temperature plays a major role in their occurrence, some of which have resulted in increased morbidity in some number of diseases, such as gastrointestinal bleeding, caused by an increase in air pressure, dry air (relative humidity) occurring from cold air, and also its actions on the protective effect helicobacter pylori in the human body. Their actions excite the adrenal gland marrow and the sympathetic nerve, causing rapid secretion of adrenaline and non-adrenaline, angiotensin II and endothelin, resulting in damage to the mucosa epithelial, caused by the contraction effect of the adrenal agents on the duodenal mucosa and blood vessel. It causes low expression of Epidermal Growth Factor Receptor (EGFR), Epidermal Growth Factor (EGF), Heat Shock Protein (HSP) 70, Occludin, Nitric Oxide Synthase (NOS), in the gastric mucosa, in extremely cold temperature than those in extremely hot temperature, increasing the gastric acid secretion in extremely cold temperature than in extremely hot temperature. Therefore, this review aims to give general insight into the role of low temperature in peptic ulcer development and further consideration in the treatment of peptic ulcer diseases

Upgrading of a Nigerian Ixiolite ore to Columbite by Sulphuric acid treatment

A quantitative leaching of a Nigerian Ixiolite ore in sulphuric acid medium was carried out and the effect of some parameters such as acid concentration, temperature and particle size was evaluated as a function of time. The experimental results obtained showed that the Ixiolite dissolution increases with increasing acid concentration, temperature, leaching time and, decreases with particle size. With 3 mol/L H2SO4 solution, 71.14% of the ore reacted within 120 minutes at 80 °C.The kinetics of dissolution of the mineral was also examined and the observed effects of the operating variables on the leaching rate were consistent with the diffusion controlled kinetic model. The calculated activation energy for the leaching process was 24.40 kJ/mol with the reaction order of 0.5, supported the proposed model. Detailed characterization of the ore before and after leaching were carried out. At optimal leaching conditions, thermodynamic feasibility of the conversion of raw Ixiolite to Columbite of industrial value, as confirmed by X-ray diffraction (XRD) technique is possible

Rifampicin-monoresistant Mycobacterium tuberculosis among the patients visiting chest clinic, state specialist hospital, Akure, Nigeria

Background:Tuberculosis (TB), one of the most important contagious diseases, is a leading cause of death due to a single pathogen worldwide. Co-infection of people living with HIV with M. tuberculosis has been shown to increase the mortality rate in sub-Saharan Africa.Methods:This present study was carried out to establish the rifampicin resistant profiles among the patients attending chest clinic, state specialist hospital, Akure. We enrolled clinical samples submitted between January 2013 and December 2013 for this study. The sputum samples were analyzed using GeneXpert.Results:Of the 135 sputum processed by GeneXpert, 48 (35.6%) contained Mycobacteria tuberculosis (MTB) and 9 (18.8%) were rifampicin resistant Mycobacteria tuberculosis. Patients within the age group of 24-32 years showed the highest resistant to RIF 6 (12.5%).Conclusion:This study has helped to establish that there is presence of rifampicin resistant Mycobacterium tuberculosis in Akure, Ondo state, Nigeria and most of them were observed among patients who default treatment. This is considered as a threat to TB control programme in Akure, Nigeria and it is recommended that strategies should be put in place in order to ensure patients’ compliance and monitoring of patients’ response to TB treatment.