School of Physical Sciences
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Browsing School of Physical Sciences by Author "Alisa, C. O."
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Item Open Access Establishing risk assessment from reclaimed Nekede Mechanic Village Owerri, Nigeria(U. P., 2018-09-14) Nkwoada, A. U.; Alisa, C. O.; Amakom, C. M.; Enenebeaku, C. K.The current resettlement of Nekede Auto-Mechanic village by Imo State government of Nigeria created a sparse piece of land awaiting government utilization. Risk assessment was carried out on the land using existing boreholes and soil to determine land utilization potential. Analysis of the physicochemical water parameters showed that there was no contamination of boreholes. The high value of COD correlated with the high levels of Fe in soil and water samples. Heavy metals concentrations showed that Fe was very much present in the soil while Pb, Cd and Cu had reduced concentrations. Risk assessment for the soil samples showed that Fe had the highest mean and median value. The highest mean value for water was Cu metal. Highest variance value was Cu in soil while Pb had the lowest value in water. Hazard quotient of water samples showed that hazards existed for Cd, Cu and Pb but at a moderate level for Fe. Estimated daily/weekly water intake values were all below WHO/FAO standards. The soil enrichment factor showed no enrichment for Pb, minimal enrichment for Cd, moderate enrichment for Cu and significant contamination for Fe. Ecological risk assessments for the heavy metals were at low ecological risk. Potential ecological index depicts Fe and Cd at a considerable level of ecological risk. Likewise, contaminants existed at the nearby Otamiri river due to dredging and nearby waste dumps. The anthropogenic activity at the Otamiri river posed a serious environmental concern if not controlled and reclaimed. Hence, the reclamation of Nekede auto mechanic village will not be suitable for agricultural or recreational purposes.Item Open Access GIS and MATLAB modeling of criteria pollutants: A study of Lower Onitsha Basin during rains(Journal BiNET Scientifc Publishing, 2018-10-14) Anyika, L. C.; Alisa, C. O.; Nkwoada, A. U.; Opara, A. I.; Ejike, E. N.; Onuoha, G. N.The study of air pollutants SO2, NO2 and PM10 in lower Onitsha basin, a densely populated city was performed using GPS and Matlab modeling. The pollutants were studied in nine specific locations for 3 months of rains over 3 consecutive years with each georeferenced. The Matlab pollution model was generated by integrating the spatial database and measured pollution attributes database using a polynomial expression. SO2 highest concentration (141 µg/m3) peaked in Upper Iweka at sampling point 1 before dispersing to lower concentrated regions in Awada and Resthouse. NO2 peaked at 207 µg/m3 in Upper Iweka at sampling point 3 and driven by wind towards Borromeo area to very low concentration of 38 ug/m3. The PM10 peaked in Upper Iweka (180 µg/m3) and driven by rains towards Borromeo before increasing again in concentration levels at Awada. The AQI showed that SO2 pollutants had acceptable air quality at all sampling points while NO2 and PM10 air quality affected sensitive groups. SO2 concentration levels exceeded the National air quality standard in Nigeria (NAQS) while NO2 and PM10 were below the NAQS standard. The GIS plot showed that 3 metrological forces were driving pollutants from Upper Iweka and Awada to other sampling areas in the order of SO2> NO2> PM10. The Matlab wind speed plot showed that there was an upward wind in upper Iweka driving the pollutants towards dispersal at some other region. Thus, Upper Iweka is an active point source pollution area and dispersed to Borromeo and Awada by scavenging rains under prevailing wind speed, wind direction and humidity. Hence calls for improved monitoring and regulation to address poll.Item Open Access Investigation of Aba river contamination using Eichhornia crassipes as bio-indicator(U. P., 2017-06-05) Akagha, C. I.; Ajiwe, V. I. E.; Okoye, P. A. C.; Alisa, C. O.; Nkwoada, A. U.The seasonal variation of heavy metal contamination levels in Aba River of Abia State in Nigeria was investigated using Eichhornia crassipies. Routine sampling was performed on bi-monthly bases to cover the Nigerian Rainy season and Harmattan season. Iron (Fe) showed more abundance with maximum concentration (69.5 mg/kg) mainly in Dec/Jan at UST, PZA, ABT and DST sampling points. The lowest concentration of iron was obtained in Apr/May for UST and DST and in Oct/Nov for PZA and ABT. Manganese showed maximum concentration (7 mg/kg) in the dry season at PZA and NBL during Oct/Nov months. The lowest concentration was in Dec/Jan at UST, PZA and ABT which were Harmattan seasons. The varied concentrations of zinc (Zn) demonstrated no pattern or trend except at Oct/Nov of ABT at value of 9.7 mg/kg, while lead (Pb) metal was significantly identified during the months of Feb/March (end of Harmattan) and April/May (beginning of Rains) during the seasonal study. Chromium metal (Cr) was uniformly distributed but significant at NBL during months of Jun/Jul. Nickel (Ni) metal was detected mainly at UST, PZA and NBL at trace levels. Copper was mainly detected during rainy seasons of Apr/May and Jun/July but remained at low concentrations when compared to other metals. Hence, UST and PZA sampling points contained the most active level of heavy metals, while Harmattan season showed the highest phytochemical activity of the heavy metals. Therefore Eichhornia crassipes showed metal removal in the following order Fe > Mn> Cr > Ni > Pb > Zn > Cd.Item Open Access New amine/phenylglycedyl ether adducts for mild steel protection in 1 M HCl: Experimental and computational study(Wiley-VCH GmbH, 2020) Akalezi, C. O.; Onwumere, F. C.; Alisa, C. O.; Nnanyereugo, M. N.; Oguzie, E. E.The key objective of this study is to ascertain the effect of structure and increased molecular size on the corrosion inhibition potential of two synthesized amines, when compared to their precursor compounds. The product amines were N-(2-hydroxy-3-phenoxy) ethanol amine (NHPE), N,N potentials were assessed using experimental and quantum theoretical modeling and calculations. Some key electronic properties such as highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies, gap energy, dipole moment and sur face area, were calculated and discussed. The various approaches adopted in this study were in reasonable agreement and the following average inhibition efficiency trend was obtained: NNHPE (75.7%)>NHPE (68.3%)> PGE (64.2) >MEA (61.0).Item Open Access Pollution in Nigerian auto-mechanic villages: A review(U. P., 2018) Nkwoada, A. U.; Alisa, C. O.; Amakom, C. M.The increasing number of malfunctioning automobiles with subsequent increase in emission levels and waste handling is an environmental concern in Nigeria. The spills from lubricants, gasoline, diesel and byproducts of used and spent engine oil constitute the major pollutants in auto mechanic villages in Nigeria. Its environmental pollution has been predominant through soil and groundwater contamination and also poses a major anthropogenic threat. The studied heavy metals on contaminated soil showed that studies had focused on common metals of Cu, Cd, Pb and Zn in the east and west regions, while trace metals were studied in the south and radioactive elements in the north. Statistical evaluation showed high occurrences of Cu, Cd, Pb and Zn in the four geo-political zones of Nigeria. The detrimental effects of auto-mechanic village activities were on humans and also disrupted growth and flowering of arable plants. The remediation application showed that soil type and contaminant characteristics play a major role in determining the type of remediation procedure to be applied. Hence, Nigeria should provide standard repairs and services to automobiles in-line with emerging technology and best environmental practices.Item Open Access Spatio-temporal study of criteria pollutants in Nigerian city(U. P., 2020-06-29) Anyika, L. C.; Alisa, C. O.; Nkwoada, A. U.; Opara, A. I.; Ejike, E. N.Aims: An investigation of characteristic long term air pollutants known for temporal and spatial behaviors was conducted due to increased pollution scenarios in Nigerian cities as a result of deprived environmental enforcement of statutory obligations. Study Design: One of the worlds’ most polluted cities (Onitsha lower basin) in Nigeria was selected for spatio-temporal study of three criteria pollutants combined with GIS and MATLAB alongside associated meteorological conditions during harmattan. Methodology: 72-hourly analyses of the nine different locations having 4 sampling sites and 500 meters apart were done from December to February which generated over 19, 440 experimental data per quarter of each annual study. Results: Upper Iweka/Nitel area recorded the highest concentration of SO2 pollutant at (94.2 µg/m3) due to longer residence times and low wind mixing height. Borromeo hospital showed the least active NO2 region but converges at points 1 due to North-east wind dissimilar to sampling points 1 having the lowest PM10 distribution. Measured temperature parameter correlates inversely with relative humidity and precipitation. The GIS spatial representation corresponded to temporal variability of gaseous and particulate pollutants. Conclusion: All sampled areas had AQI above 50; hence the study identified SO2, NO2, and PM10 as Primary pollutants of Onitsha lower basin.Item Open Access Studies on adsorptive behavior of Cd2+ on graphene oxide: Alternative novel approach(U. P., 2018-03-03) Nkwoada, A. U.; Alisa, C. O.; Enenebeaku, C. K.; Oguzie, E, E.Certain adsorptive mechanisms and interactions often exist within linearized kinetic functions which are largely unreported. A novel inverse saturation modeling was applied to evaluate the adsorptive behavior of super-saturation, saturation, and desorptive processes on linear kinetic function plots using pseudo 1st order, pseudo 2nd order, Elovich and Intra-particle diffusion. Graphene oxide was prepared by room temperature synthesis and used as adsorbent over Cd2+ adsorbate. Batch adsorption process was conducted and four error functions were utilized. The sum of squares of the errors and Sum of absolute errors identified pseudo 2nd order as having the least deviation at 0.113 and 0.337 respectively. The modelled pseudo 1st order reaction had R2 = 0.985 while the inverse saturation model had R2 value of 0.998, both been a better data fit than non-modelled pseudo 1st order R2 at 0.917. The slower reaction kinetics in pseudo 1st order was due to supersaturation during adsorption as shown by inverse saturation point. The correlation coefficient of modeled kinetic plot of pseudo 2nd order, Intra particle diffusion and Elovich had R2 = 1. The Elovich inverse saturation plot showed that the graph was an L-isotherm type indicating progressive saturation. The rate determining step experienced by Intra-particle diffusion was accommodated by wide range of inverse saturation plots showing adsorption, supersaturation and desorption as points of greatest influence. The inverse saturation plot of pseudo 2nd order plot had absolute slope of 2.656 and large intercept of 24.815 driving it's faster reaction kinetics. Hence, the inverse saturation point modelling provided a much better interpretation of adsorptive behavior of graphene oxide adsorbent over Cd2+ adsorbate.