Comparative dissolution of natural goethite samples in HCl and HNO3

The dissolution of goethite samples in mineral acids from to extreme parts of Nigeria (Osogbo and Kaduna) have been investigated. The rate of dissolution was found to be slightly faster in HCl than HNO3. The higherrate of dissolution in HCl could be attributed to the complexing ability of Cl- in addition to the H+ effect while lowering effect by NO3- was attributed to adsorption of NO3 on to the goethite surface. Mononuclear complexes, especially bidentate of oxyanion are found to accelerate dissolution as opposed to binuclear complexes. A binuclearbidentate surface complex formation between NO3 - and Fe3+ was therefore proposed to account for the inhibition observed. The possible formation of Fe—Cl reduces both the surface positive charge and the repulsion between the oxide surface and protons in solution. This produced accelerated proton dissolution. The effect of temperature on theinitial dissolution rate fit into Arrhenius equation, with Kaduna goethite exhibiting higher rate than Osogbo type in both acids. The activation energies for Kaduna goethite sample are 66.11 and 82.43 kJmol-1 in 0.1M HCl and 0.1M HNO3 respectively while for Osogbo goethite sample are 54.60 and 76.32 kJmol-1 in 0.1M HCl and 0.1M HNO3 respectively. The frequency factors of 8.4 x 10-4 & 11.17 x10-4 and 5.0 x 10-5 and 3.09 x 10-3 for Kaduna and Osogbo goethite samples were obtained. @JASE

Adsorption of Rhodamine B Dye from Aqueous Solution on Irvingia gabonensis Biomass: Kinetics and Thermodynamics Studies

Raw Irvingia gabonenses (dika nut) (DN) and its acid-treated form(ADN) were used for the uptake of rhodamineB(RhB) dye from aqueous solution. The adsorbents were characterized by Fourier transform infrared (FTIR) spectroscopy, Brunauer–Emmett– Teller (BET) surface area analysis and scanning electron microscopy (SEM). The adsorbents were found to have characteristic functional groups such as –OH, C-N and C=O. SEM revealed that acid treatment resulted in the development of several pore sizes. Sorption data fitted the Freundlich adsorption isothermbetter than the Langmuir isotherm.The maximum sorption capacities, qmax, obtained from the Langmuir adsorption isotherm were 212.77 and 232 mg g–1 for DN and ADN, respectively. The pseudosecond- order kinetics model was observed to fit the adsorption data. Solution pH and temperature significantly influenced the adsorption process and negative values of ΔG° suggest that the sorption process was spontaneous and feasible. Intraparticle diffusion mainly controlled the uptake of RhB onto DN and ADN; however, boundary layer diffusion also occurred in the RhB-ADN system. The desorption efficiency of RhB from the adsorbents was tested with a number of eluents. The eluents were found to follow the order: H2O>CH3COOH>HCl and CH3COOH>HCl>H2O for DN and ADN, respectively.KEYWORDS Irvingia gabonenses, adsorption, rhodamine B, thermodynamics, kinetics, biomass

Determination of Sulphur (IV) Oxide in Ilorin City, Nigeria, During Dry Season

Ambient concentrations of sulphur (IV) oxide (SO2) have been determined in the city of Ilorin, Nigeria between mid February and mid Novembers 2003. SO2 levels were found to vary significantly with the traffic density and human activities. There was a significant difference (P = 0.05) between the SO2 concentrations at two sites (high and low traffic volume areas); however, there was no significant difference (P= 0.05) between high traffic/medium population density and medium traffic/high population density areas. The regression analysis indicated a strong correlation (r= 0.94) between the concentration of SO2 pattern and the hourly average traffic volume in all the sites. Average level found for the city was 59.3 ± 1.9ppb, which falls within the limits of the United States Environmental Protection Agency guidelines for air quality standards. Atmospheric pollution being one of the most dominant problems associated with urbanization, urban areas are associated with high density of industries and transport networks, among other infrastructure, which generate a wide range of air pollutants .@JASE

Monitoring of sulfur dioxide in the guinea savanna zone of Nigeria: implications of the atmospheric photochemistry

The level of sulfur(IV) oxide (SO2) in the tropospheric environment of Ilorin is presented using three urban classes and a control site from 2003-2006 wet and dry seasons. The mean concentrations over the years during wet and dry seasons were 1.29 ± 0.17 and 7.17 ± 0.87 (ppb), respectively. The wet season concentration was 15.25% lower than the dry season due to rain attenuation. The mean values at the control site for two seasons were one order of magnitude lower than those in the urban sites. The overall average concentration over Ilorin city was 4.23 ± 0.52 ppb. The value is comparable with other cities of the world and is within the limit of the United State Environmental Protection Agency (USEPA) Guidelines for Air Quality Standards. SO2 levels were found to varied significantly with vehicular intensity, other anthropogenic activities also decreased drastically during wet season. There was a significant difference (p = 0.05) between SO2 concentration with high and low traffic flow count; however, there was no difference (p = 0.05) between high traffic/medium population and medium traffic/high population density areas. The regression analysis indicated a correlation between SO2 and the hourly traffic volume in almost all the sites

Heavy Metals Distribution and Speciation in Soils around a Mega Cement Factory in North-Central Nigeria

Surface and sub-surface soils were sampled in the neighbourhood environment of an ultra-modern and largest cement factory in Nigeria. The five geochemical fractions investigated were exchangeable, carbonate, Fe-Mn oxide, organic matter and residual. All fractions were subsequently analyzed for lead (Pb), copper (Cu), zinc (Zn), manganese (Mn) and iron (Fe) using atomic absorption spectrophotometer. The average total metals concentrations (mg/Kg) in the surface soil were 1063.8± 261 for Fe, 30.29 ± 19.25 for Mn, 24.15 ± 21.69 for Cu, 15.08 ± 11.95 for Pb and 8.54 ± 3.18 for Zn. Relatively lower mean concentrations were measured in the sub-surface soil samples. The percent distribution concentration of the various metals in the residual fraction ranged from 0.23 to 69.48% for Pb, 0.85 to 75.30% for Cu, 36.02 to 83.86% for Zn, 12.97 to 44.04% for Mn and 18.11 to 57.25% for Fe. Factor analysis revealed that while Pb, Cu and Zn would majorly be of anthropogenic origin, Mn and Fe are mainly of natural origin. Pb was found to be the most mobile with mobility factor of 71.8% while Fe has the least mobility factor of 3.62%. Regression analysis (r2 = 0.71) further showed that Cu is correlated with Pb. Soil pollution indices revealed that the surface soil is slightly contaminated in lead and zinc, and moderately contaminated in copper.Key words: Heavy metals speciation, Mobility factor, Soil pollution, Cement industr

The effect of two African mineral dyes on the activity of alkaline phosphatase in the skin and serum of albino rats

The effect of two African mineral dyes Yombo tumtum (YT) and Yombo fita (YF) on the activity of alkaline phosphatase (ALP) in the skin and serum of albino rats was investigated. The chemical analyses of the dyes were first carried out using solubility test, pH determination and X-ray fluorescence (XRF) elemental analysis. Six different concentrations (0.05, 0.15, 0.25, 0.5, 0.75 and 1.00%) of each dye were prepared using hydrogen peroxide as solvent. A total of 70 albino rats (Rattus norvegicus) were used for the study. The rats were grouped into 14 of 5 rats and were maintained on commercial feed for a period of 30 days, during which the experiment lasted. Group I served as the first control and the animals had distilled water applied on their heads. Group 2 which served as the second control contained rats on whose heads were applied the dissolving solvent i.e. hydrogen peroxide. Rats in group 3 to 8 had the various concentrations of YT (black) dye applied on their heads, while those in groups 9 to 14 had the various prepared concentrations of YF (white) dye applied on their heads. At the end of the experiment, blood samples were collected and portion of the head skin where the dyes were applied was cut. The activity of ALP was thereafter determined in the serum and skin of the experimental animals. The results revealed a significant decrease (

Biosorption of chromium(VI) using immobilized Bacillius subtilis and Pseudomonas aeruginosa

Heavy metals like chromium do contaminate the environment that comprises of soil, water and air. It affects the growth of flora and fauna which in turn affect human health negatively. Chromium could also bio-accumulate in plants and animals and this becomes dangerous for survival of human if adequate steps are not taken for treatment of industrial and agricultural wastes. Therefore, the batch removal of Cr (VI) from environment water bodies becomes necessary. Its removal from aqueous solution using immobilized Bacillus subtilis (IBBS), Pseudomonas aeruginosa (IPBS), mixed biomass (IMBS) and Alginate alone (IABS) was carried out. The conditions of influence of initial Cr (VI) concentrations, solution pH, contact time, biomass dosage and temperature were studied. The sorption kinetic models of Cr (VI) onto the biosorbents were examined with pseudo first-order, pseudo second-order, and Elovich kinetics respectively. It was found that the experimental conditions affected the extent of removal of Cr (VI) from aqueous solution. The higher the initial concentration, the larger the amount of Cr (VI) removed while the higher the temperature the lesser the amount removed. The optimum contact time and adsorbent dose for effective removal of Cr (VI) from aqueous solution were found to be 60 mins and 0.01 g respectively. Pseudo second-order kinetic model best correlates the experimental data. Among isotherm models studied, Freundlich adsorption isotherm model gave the best fit.Key Words: Chromium (VI), Adsorption Kinetics, Adsorption Isotherms, Spectrophotometric Determination, Immobilized Biosorbent

The Effect of Two African Mineral Dyes on the Activity of Alkaline Phosphatase in the Skin and Serum of Albino Rats

The effect of two African mineral dyes Yombo tumtum (YT) and Yombo fita (YF) on the activity of alkaline phosphatase (ALP) in the skin and serum of albino rats was investigated. The chemical analyses of the dyes were first carried out using solubility test, pH determination and X-ray fluorescence (XRF) elemental analysis. Six different concentrations (0.05, 0.15, 0.25, 0.5, 0.75 and 1.00%) of each dye were prepared using hydrogen peroxide as solvent. A total of 70 albino rats ( Rattus norvegicus ) were used for the study. The rats were grouped into 14 of 5 rats and were maintained on commercial feed for a period of 30 days, during which the experiment lasted. Group I served as the first control and the animals had distilled water applied on their heads. Group 2 which served as the second control contained rats on whose heads were applied the dissolving solvent i.e. hydrogen peroxide. Rats in group 3 to 8 had the various concentrations of YT (black) dye applied on their heads, while those in groups 9 to 14 had the various prepared concentrations of YF (white) dye applied on their heads. At the end of the experiment, blood samples were collected and portion of the head skin where the dyes were applied was cut. The activity of ALP was thereafter determined in the serum and skin of the experimental animals. The results revealed a significant decrease (p<0.05) in the activity of ALP as the concentration of the dye increased in both the serum and ski

Biodegradation of hydrocarbon compounds in Agbabu natural bitumen

The recovery of an environment polluted by petroleum and allied hydrocarbons through bioremediation is being embraced globally as the best technology of removing hydrocarbon pollutants from environment. Infrared spectral changes and gravimetric analysis from the preliminary biodegradability study carried out on Agbabu Natural Bitumen showed the vulnerability of the bitumen to some bacteria: Pseudomonas putrefaciens, Pseudomonas nigrificans, Bacillus licheniformis, Pseudomonas fragi and Achromobacter aerogenes. This study investigates the ability of P. putrefaciens, P. nigrificans, B. licheniformis, P. fragi and A. aerogenes to degrade the aliphatic and polycyclic aromatic hydrocarbon fractions of Agbabu natural bitumen. Samples of the bitumen were separately inoculated with each of the bacteria for 14 days and the hydrocarbon profiles before and after inoculation were quantified using gas chromatography technique. The total aliphatic hydrocarbon compounds (C11 - C29) in the bitumen degraded by P. putrefaciens and P. nigrificans was slightly higher than that in the undegraded bitumen, while the concentration of compounds (C11 - C29) found in samples of the bitumen degraded by B. licheniformis, P. fragi and A. aerogenes was less than what was contained in the undegraded bitumen. Also the even-odd carbon-ratios of the degraded bitumen were higher than unity while these were less than unity in the undegraded bitumen. The polycyclic aromatic hydrocarbons (PAHs) profile in the bitumen degraded samples also differed from that of undegraded bitumen. A substantial reduction in the concentration of some PAHs was found in the bitumen samples following their degradation by the bacteria strains, typically from 55.98 to 30.79%, thus suggesting the possibility of using the bacteria strains for bioremediation process.Keywords: Agbabu, bitumen, bacteria, biodegradability, hydrocarbonsAfrican Journal of Biotechnology, Vol 13(11), 1257-126

Assessment of Asa river: impact of waste discharge from soft drink plant into Asa river, Ilorin, Nigeria

Some physical and chemical analysis was carried out on samples collected at various distances from the effluent discharge from a soft drink plant in Ilorin into Asa River. The pH was found to range between 7.2-7.8 with a mean temperature of 25.25°C. Experimental results obtained on replicate samples showed that the standard deviation was generally below 10%. The total organic matter ranged between 21-22.9% while the nitrate concentration ranged between 5.81- 15.41 mg/l; these were high and could lead to eutrophication of the water body into which it empties. The cation and anion concentrations all fall within safe limits except for zinc and in some cases, NO3- concentrations which was higher than the standard set by regulatory bodies. A Pearson\'s correlation study showed correlations between different parameters at both 1% and 5% probability levels. Journal of Applied Sciences and Environmental Management Vol. 9(1) 2005: 187-19