Sources of the sixteen polycyclic aromatic hydrocarbons (PAHs) in the United States Environmental Protection Agency priority pollutants list were determined in sediments of Kolo Creek using diagnostic ratios of parent PAHs[phenanthrene/phenanthrene ? anthracene; fluoranthene/fluoranthene ? pyrene; benz(a) anthracene/ benz(a) anthracene ? chrysene and indeno(1,2,3-d)pyrene/ indeno(1,2,3-cd)pyrene ? benzo(ghi)pyrelene]. The study was conducted over four seasons (dry, late dry, rainy and late rainy seasons). Applying cross plots of the diagnostic ratios revealed that PAHs in Kolo Creek sediment have pyrogenic origins except in the rainy season that had petrogenic origins. Comparison of diagnostic ratio values obtained from this study with literature values enabled the further classification into types of pyrogenic and/or petrogenic sources. While the pyrogenic sources of PAHs were mainly as a result of Grass/Wood combustion, the petrogenic PAHs were as result of drained diesel and lubricating oil. The predicted sources corresponded with the prevailing human activities in the vicinity, especially samples collected near a petrol station and an abattoir. This study further affirms the simplicity and accuracy of the use of diagnostic ratios for PAHs source prediction.
The flood in 2012, which was recorded as the most devastating in the past 40 years in Nigeria, that caused colossal loss in material wealth, could also be a source of heavy metal pollution, especially at the lower reaches of the flood where deposition of flood transported materials occurs. Heavy metals (Fe, Ni, Cd, Cr, Zn, Cu and Pb) concentrations were determined in soil samples from two locations, an area submerged by the flood water (flooded) and an area at a higher elevation than the flood water (unflooded), which served as the control. The soil pH, texture, Total Organic Carbon, and Cation Exchange Capacity were also determined. Standard laboratory methods were employed for all the analyses. The soil in this study was characterized as sandy/clay/loam soil following the particle size analysis, with an average pH of 4.6 in the flooded soils and 6.5 in the unflooded soils. Total Organic Carbon (TOC) ranged from (0.936-1.989)% in the flooded soil and (0.663-0.939)% in the unflooded soil. Cation Exchange Capacity (CEC) was higher in the flooded soil (1.936-3.234) meq/100 g, than in the unflooded soil (1.164-1.722) meq/100 g. The results of
The effect of common acids, anions, and auxiliary complexing agents in the solvent extraction of Fe 2+ from aqueous solutions into chloroform solutions of 4,4´-(1E,1E´)-1,1´-(ethane-1,2-diylbis(azan-1-yl-1ylidene))bis alone and in the presence of of 1-(3-hydroxy-5-methyl-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl) butan-1-one (HBuP) was studied. Colorimetric method of analysis using 1,10phenanthroline was used to determine concentrations of Fe 2+ in aqueous solutions after extraction and percentage extraction determined by difference. Separation factors βXY were calculated using data from previous studies using same organic phases to determine theoretical conditions for separating Fe 2+ from Ni 2+ , Pb 2+ , and UO2 2+ . All acids gave > 90% extraction of Fe 2+ at most concentrations with HNO3 and H3PO4 giving the highest percentage extraction of 99.93% at 0.01M and 0.1M respectively in the mixed ligands H2BuEtP/HBuP organic system. H3PO4 also gave best extraction of 99.3% at 0.1M in ligand H2BuEtP alone system. Although all anions used for study also gave > 90% extraction of Fe 2+ at different concentration in both types of organic phases, CHCOO -, PO4 3-, Brand tartrate ions gave the best extraction of Fe 2+ with H2BuEtP. Acids and anions behave as salting out agents or masking agents at different concentrations.
Water hyacinth (Eichhornia crassipies) has proved to be a menace in water bodies and studies are on, in the direction of solving this problem; one of which is to discover economic uses of water hyacinth. Adsorption of heavy metals and dyes from aqueous solutions by activated carbon derived from water hyacinth is one of such studies. In this study, dried and pulverized water hyacinth shoot was used for the sorption studies. This is in the bid of eliminating the rigours of producing activated carbon, thereby saving time and cost. The adsorption capacity of water hyacinth shoot for Methylene Blue dye was studied as a function of initial metal ion concentration in a batch system. Results showed that adsorption increased with methylene blue dye concentration. Seven adsorption isotherms, namely Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Florry-Huggins, Harkins-Jura and Henry's isotherms were applied to the adsorption data. Isotherm parameters showed that all the isotherms correlated well with the adsorption data. The maximum adsorption capacity of Methylene Blue dye to the dried water hyacinth shoot was found to be 58.14mg/g. The use of dried water hyacinth shoot would appreciably save the time and cost for producing activated carbon but not without some compromise of efficiency.
Generation-3 polyamidoamine (PAMAM) dendrimer was implanted on silica to produce a very good adsorbent (G-3 PAMAM-SGA). The composite was characterized and used for the removal of Cd(II) ions from aqueous solution. Kinetic data fit the Lagergren pseudo-second-order model and also follow the intraparticle diffusion kinetic model to an extent, which is an indication that the sorption process is controlled by both mechanisms: intraparticle/film layer and adsorption inside the pores/crevices of the composite. Equilibrium sorption data of Cd(II) on G-3 PAMAM-SGA fit the Freundlich isotherm (R2 = 0.9993) which is indicative of multilayered adsorption that occurred on heterogeneous surfaces. The ΔG° values for all temperatures studied were negative, which indicated a spontaneous and feasible process. The result implies that G-3 PAMAM-SGA is a promising adsorbent for microscale scavenging of Cd(II) ions in aqueous solutions.
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