Effect of Concentration of AgNO3 on the Rate of Formation of a Complex Salt, [Co(H3)6](NO3)3 and Estimation of Molar Concentration of the Complex

Different molar concentrations of AgNO3 (0.10 M, 0.15 M, 0.20 M, 0.25 M and 0.30 M) were prepared and 50.00cm3 of 0.20 M of [CO(NH3)6]Cl3 A new complex was formed  and , the time taken as well as the rate at which the complex was formed were determined for each reaction. The insoluble component (AgCl) and soluble component (new complex) formed were separated from the reaction mixture by filtration. The residue (AgCl) was dried between filter papers in fume cupboard while the filtrate, which contained the new complex was first evaporated and finally crystallized by cooling under tap. The weights and molar concentrations of AgCl and new complex formed were determined. Confirmatory tests of the substituted anions (NO-3 and Cl-) were conducted. The work showed that the times taken for the formation of the new complex and AgCl  were 32 sec, 27 sec, 21 sec, 16 sec and 12 sec. for 0.10 M, 0.15 M, 0.20 M, 0.25 M and 0.30 M of AgNO3 respectively; the corresponding rates (cm3/sec) were 1.56, 1.85, 2.38, 3.22 and 4.20, respectively; the weights of the AgCl and new complex formed were 27.27g and 58.99g, respectively; the molar concentrations of AgCl and new complex obtained were 0.19 mol/dm3 and 0.17 mol/dm3 and; the qualitative analyses of the swapped anions confirmed the presence of NO-3 in the new complex and Cl- in AgCl. Keywords: Complex salts; substitution reactions; rate of reaction; crystallization; precipitation

Efficacy of Organic Nutritive Additives on the Quantity and Fuel Value of Biogas from Donkey Dung as Alternative Source of Gaseous Fuel

Five (5) different slurries of donkey dung were prepared by dissolving 20.00g of ground donkey dung in 125.00cm3 distilled water. Each of the slurries was placed in a 500cm3 Buchner flask (as a reactor).The reactors were made in triplicate and, labeled A, B, C, D and control. A quantity of 0.15g each of blood meal (as source of proteins), ethanoic acid, ground nut oil and sugar was added to A, B, C and D, respectively while the control reactor was kept unaided (without additive).  The slurries were subjected to anaerobic  microbial decomposition at 33oC for 30 consecutive days.  The biogas (gaseous product) generated in each reactor was collected over brine (28% NaCl) and, the average daily and total volumes of biogas for each reactor was purified by absorption process using appropriate absorbents and subsequently dried by passing over activated silica gel.  The work showed that the mean total volumes of the gaseous product collected from A, B, C, D and control reactor were 49.52dm3, 49.66dm3, 49.88dm3, 52.44dm3 and 48.52dm3, respectively; the percentages of the fuel contents of the mean total columes of biogas collected (based on the respective CH4 contents of the gaseous products) from A, B, C, D and control wee 60.78%, 60.62%, 60.42%, 64.75% and 60.39%, respectively; the increase in the volumes of the gaseous product in A, B, C and D were 1.00dm3, 1.14dm3, 1.36dm3, and 3.02dm3, respectively and; the percentages of the increase in the fuel value in A, B, C and D were 0.39%, 0.23%, 0.03%, and 4.36%, respectively. Keywords: Donkey dung; organic nutritive additives; biogas; gaseous fuel;   fuel value

Effects of Concentration and Catalyst on the Kinetics of Biogas Production from Cattle Dung at Thermophilic Temperature

Five different reactors (Ra, Rb, Rc, Rd and Re) of equal capacity (500cm3 each) were constructed and connected to a gas-collecting device. For the investigation of the effect of concentration on biogas production (uncatalysed reaction), different concentrations of reactant (20g/250cm3, 30g/250cm3, 40g/250cm3, 50g/250cm3 and 60g/250cm3) prepared from cattle dung were respectively placed in Ra, Rb, Rc, Rd, and Re, and anaerobically fermented at thermophilic temperature (370C) for 16days. For the investigation of the combined effect of concentration and catalyst (catalysed reaction), parallel set ups were made, but in this case, 1.0g, 1.5g, 2.0g, 2.5g, and 3.0g of yeast were respectively added to the reactants (slurries) in Ra, Rb, Rc, Rd, and Re, which were also anaerobically fermented at 370C for 16days. The reactors and their contents for both the catalyzed and uncatalyzed reactions were made in triplicate and the mean (average) volume of biogas collected in each of the reactors were evaluated. The average volumes of biogas obtained were used for the kinetics studies, where the rate of biogas production, the rate constant for biogas formation from the substrate (cattle dung), the rate of catalyst substrate unstable complex formation, the fraction of total catalyst that involved in the formation of complex with substrate, the concentration of excess (free) catalyst in the slurry, the rate of substrate transformation into biogas and the saturation constant of the catalyst added to each slurry was evaluated using the appropriate equations. The research revealed that, addition of catalyst to the slurries,  enhanced biogas production; at a certain point, the volume of biogas produced, the rate of biogas formation, the rate of catalyst substrate unstable complex formation and the rate of substrate transformation into biogas were directly proportional to the concentrations of the reactants and catalyst; the rate constants for reactions (catalyzed and uncatalyzed) were inversely proportional to the concentrations of reactants and the catalyst added; the fractions of the total catalyst that involved in the formation of unstable complex  with substrate in Ra, Rb, Rc, Rd, and Re were 0.95g, 0.97g, 0.98g, 0.98g, and 0.98g, respectively; the concentrations of the excess catalyst in Ra, Rb, Rc, Rd, and (g/cm3) were 0.05, 0.53, 1.02, 1.52 and 2.02, respectively and; the saturation constants (g/g) of the catalyst added to the slurries in Ra, Rb, Rc, Rd, and Re were 0.0476, 0.0484, 0.0488, 0.0490, and 0.0492, respectively. The research also revealed that the reactions (catalyzed and uncatalyzed) carried out obeyed first order rate law equation. Key-words: Biogas; cattle dung; anaerobic fermentation; concentration; catalyst; thermophilic temperature

Gaseous fuel production by anaerobic fungal degradation of banana leaves

Anaerobic biodegradation of banana leaves by cellulolytic fungus (yeast) was carried out at optimum operational conditions of temperature (330C), PH (7.3) and slurry concentration (4g/25cm3). The organic component of the gaseous fuel generated was analysed using flame ionization detector (FID). The analysis revealed that the gaseous fuel was rich in methane (CH4).Keywords: Anaerobic biodegradation; Micro-organisms; gaseous fuel (biogas)

Effect of reagent type on the froth floatation of Sokoto phosphate ore

Effect of reagent type on the froth floatation of Sokoto phosphate ore for its beneficiation has been established. The samples of the Sokoto phosphate mineral ore used for the research work were sourced from mining locations in Dange-Shuni, Bodinga, Yabo, Wurno, and Rabbah Local Government Areas of Sokoto State. Size-Assay analysis conducted on scrubbed Sokoto Phosphates nodules revealed that nodules had a size distribution with 80% passing 29.3 mm. Flotation Tests using AERO704 (fatty Acid), Alkyl Hydroxamates, Melamine as collectors (alone or mixed with diesel), MIBC as frother, Calcium Hydroxide and Sulphuric Acid as pH regulators and Dextrin, Sodium Silicate and Aluminium Chloride as depressants produced poor P2O5 separation in the flotation products due to very poor liberation associated with very fine mineral grains. Based on the results obtained, AERO704 Collector gave the best result with aP2O5 recovery pH of 10

Extract of Combretum micranthum as corrosion inhibitor for Al – Si – Mg alloy in simulated sea water environment

The leaf extract  of  Combretum micranthum (CM) was  tested  as  green  corrosion  inhibitor for Al-Si-Mg alloy in 3.5wt% NaCl solution using gravimetric and linear polarization methods at 300C, 500C and 700C, from 1, 2, 3, 4, 5 hours of exposure time with concentration of the extract 0, 0.2, 0.4, 0.6, 0.8 and 1.0 v/v  respectively. The result obtained indicate that the leaf extract of CM is a good corrosion inhibitor in the simulated sea  water medium. The inhibition efficiency of the extract increased with an increase in concentration of the CM extract and decreased with increase in temperature. On the other hand, inhibition efficiency (IE%) synergistically decreased on addition of surfactant (Monoethylamine). The adsorption of the inhibitor on Al-Si-Mg surface is exothermic, Spontaneous and is best described by Langmuir, Freundlick and El-Awady adsorption models. The calculated values of activation energy, enthalpy of activation entropy of activation, free energy of process is by physical adsorption. Equally, methanol extract CM is a good adsorption inhibitor for the corrosion of Al-Si-Mg in 3.5wt% NaCl solution. Tafel polarization analysis indicates that the studied plant extract is a mixed type inhibitor. http://dx.doi.org/10.4314/njt.v35i4.2

Effect of particle size on the froth floatation of Sokoto phosphate ore

Effect of particle size on the froth floatation of Sokoto phosphate ore for its beneficiation has been investigated and established. The research has been conducted using various reagents, pH(s) at different sieve size fractions. Bench scale flotation tests were carried out on -250+180μm, -180+106μm, -106+75μm, -75+45μm and -45+38μm particle size fractions after screening in order to determine the optimum flotation feed size distribution using 1 liter Denver flotation cell. The results of the scoping flotation studies using a conditioning Pulp Density of 60%Solids, pH9, 800g/t reagent dosage for AERO704 Promoter (Fatty Acid) and flotation pulp density of 28.5% Solids show that +106μm particle size gave the highest assay content of 20.4% P2O5 with a recovery of 76.2% compared to +38μm (19.9%P2O5 and recovery of 43.2%) and +180μm (19.4%P2O5 and 24.1% recovery) in their floats (concentrates) but with no perfect separation as the tailings fraction also contained similar grades with slight differences

Effect of Pre-Ageing Thermal Conditions on the Corrosion Properties of Antimony-Modified Al-Si-Mg Alloy

The purpose of this investigation was to evaluate the effect of pre-ageing thermal conditions on the corrosion properties of antimony-modified Al-Si-Mg alloy.The alloy was subjected to a Single Thermal Ageing Treatment; STAT (T6 temper-solution heat treatment and ageing) and Double thermal ageing treatment; DTAT (T7 temper- solution heat treatment and ageing for stabilization). These consist of solution heat treatment (SHT) at 540oC for 1hr, water quenched followed by an artificial ageing; DTAT and STAT. For the single thermal ageing treatment (STAT), quenched samples were aged at temperatures of 1800C for 2hrs, before cooling in air. In the double thermal ageing treatment (DTAT), quenched samples were pre-aged at a temperature of 90oC, 105oC and 120oC for 1- 5 hrs. This was followed by ageing at 180oC for 2hrs before cooling in air. The corrosion characteristic of the as-cast, Single Thermal Ageing Treatment (STAT) and Double Thermal Ageing Treatment (DTAT) were evaluated using weight loss and linear polarization techniques in a static 3.5%NaCl solution. From the results, the corrosion rate decreases with increasing pre-ageing time and temperatures. Equally, from the linear polarization data/curves, the corrosion rate of the treated alloy decreases at all ageing temperatures along with the ageing time. The Optical Microscope (OM) results of as-corroded samples revealed that the alloy suffers pitting/uniform corrosion. The corrosion behaviour of the DTAT samples in simulated seawater showed an excellent improvement in corrosion resistance than the as-cast and conventional STAT alloy.http://dx.doi.org/10.4314/njt.v34i4.

Median lethal dose (LD50) evaluation of some polyherbal formulations marketed in northern Nigeria

The polyherbal preparations reported here are traditionally used in Northern Nigeria for the treatment of wide range of illnesses. The aim of this study was to evaluate the acute toxicity potential of 70% ethanol extracts of forty polyherbal products by determining their median lethal dose (LD50) estimates intraperitoneally and orally using the Lorke’s method in mice. Overall 90% of the extracts indicated values that were either less toxic or slightly toxic intraperitoneally, while 10 % had values that were practically non toxic using the same route. Oral administration of the extracts showed that 25% had values that were only slightly toxic while 75 % of the herbal products had median lethal dose values that were practically non toxic. From our results this could imply that most of the extracts tested may be safe for oral use and this could explain the continuous use of the polyherbal preparations by the local people in traditional management of various ailments in the Northern part of Nigeria.Keywords: Herbal products, AcuteToxicity, Lorke’s method, Northern Nigeri

Preliminary studies on the behavioural effects of the methanol extract of Leonotis nepetifolia Linn stem in mice

Background: Leonotis nepetifolia Linn (Lamiaceae) is used in traditional medicine for its calming (tranquilizing) effects. The aim of this study was to determine whether there is any scientific justification for this use. To achieve this purpose, we investigated the behavioural effects of the methanol extract of Leonotis nepetifolia stem (37.5, 75 and 150 mg/kg) in mice.Methods: Acute toxicity studies were carried out on the methanol stem extract of Leonotis nepetifolia to determine the LD50. The behavioural tests employed were diazepam-induced sleep onset and duration, hole board assay for exploratory activity, mouse beam walk assay for motor coordination, and the staircase test for the detection of anxiolytic compounds. Preliminary phytochemical screening was also carried out on the extract.Results: The intraperitoneal LD50 value was found to be 3.8 g/kg. The results showed that the extract significantly prolonged the duration of diazepam-induced sleep at the highest dose (150 mg/kg). There was no observable effect on exploratory activity and motor coordination at the doses tested (37.5, 75 and 150 mg/kg). The extract, however, at 150 mg/kg elicited a significant decrease in the number of rearings in the staircase test, an effect also observed in the group of mice injected with an anxiolytic dose of diazepam. The preliminary phytochemical  screening revealed the presence of alkaloids, saponins, glycosides and   triterpenoids.Conclusion: The results obtained suggest that the crude methanol extract of Leonotis nepetifolia stem possesses some biologically active constituents with potential anxiolytic activity and thus may justify its traditional use as a tranquilizer.Keywords: behavioural; exploratory; Leonotis nepetifolia; motor coordination; anxiolyti