F. E. Okieimen

University of Benin, Benim, Edo, Nigeria

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Publications (85)99.76 Total impact

  • Raymond A. Wuana, Felix E. Okieimen, Blessing Ogoh
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    ABSTRACT: Chemical fractionation patterns and plant tissue concentrations were used to assess nickel, copper, zinc, cadmium, and lead phytoavailability to maize in a soil amended with metal salts or poultry manure. A sandy loam was treated with 80–400 mg kg−1 doses of a quinternary mixture of the metal nitrates either directly or as spiked poultry manure. The European Communities Bureau of Reference sequential extraction procedure partitioned the metals among three operationally defined pools in the soil. Metal mobilities were lower in the poultry manure–amended than the metal salt–treated soil, indicating the manure's ability to fix the metals in soil. Pot experiments revealed high metal transferabilities with no apparent phytotoxic symptoms in maize at the doses applied, suggesting some degree of tolerance to the metals. Heavy-metal concentrations in maize increased linearly with metal doses in metal salt–treated soil, but were less phytoavailable in soil amended with poultry manure. Heavy-metal concentrations in maize were reasonably predicted from soil parameters using stepwise multivariate regression models. The findings are useful in the assessment and remediation of heavy metal–contaminated soils.
    Communications in Soil Science and Plant Analysis 11/2012; 43(20). · 0.42 Impact Factor
  • Raymond A. Wuana, Felix E. Okieimen
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    ABSTRACT: Scattered literature is harnessed to critically review the possible sources, chemistry, potential biohazards and best available remedial strategies for a number of heavy metals (lead, chromium, arsenic, zinc, cadmium, copper, mercury and nickel) commonly found in contaminated soils. The principles, advantages and disadvantages of immobilization, soil washing and phytoremediation techniques which are frequently listed among the best demonstrated available technologies for cleaning up heavy metal contaminated sites are presented. Remediation of heavy metal contaminated soils is necessary to reduce the associated risks, make the land resource available for agricultural production, enhance food security and scale down land tenure problems arising from changes in the land use pattern.
    ISRN Ecology. 10/2011; 2011.
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    ABSTRACT: The development of high-performance composite materials from locally sourced and renewable materials was investigated. Rubber seed oil polyurethane resin synthesized using rubber seed monoglyceride derived from glycerolysis of the oil was used as matrix in the composite samples. Rubber seed oil-based polyurethane composite reinforced with unidirectional sisal fibers were prepared and characterized. Results showed that the properties of unidirectional fiber-reinforced rubber seed oil-based polyurethane composites gave good thermal and mechanical properties. Also, the values of tensile strengths and flexural moduli of the polyurethane composites were more than tenfold and about twofold higher than un-reinforced rubber seed oil-based polyurethane. The improved thermal stability and the scanning electron micrographs of the fracture surface of the composites were attributed to good fiber–matrix interaction. These results indicate that high-performance “all natural products” composite materials can be developed from resources that are readily available locally.
    Materials & Design. 10/2010;
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    ABSTRACT: Cow dung used as soil amendments and a sequential chemical speciation (six steps) procedure were used to predict the uptake of Cr, Cu and As by maize (Zea mays) plant in chromated copper arsenate (CCA) contaminated soil. A pot experiment containing the contaminated soil samples with different percentage levels of amendments and control (no amendment) was set up. The relative concentrations of the metals in the CCA contaminated soil were established as Cr 265.84 mg/kg, Cu 155.82 mg/kg and As 33.09 mg/kg. However, with the use of speciation and calculations based on mobility factor (M f), the relative toxicity of the metals in the soil was established as As (60%) > Cr (19%) > Cu (8%). The amendment, rich in organic matter raised the pH level of the soil, demobilized the metals rendering them unavailable through bounding resulting into relatively lower uptake by plants in soils with amendment when compared with plants in the control pots.
    International Journal for Biotechnology and Molecular Biology Research. 10/2010; 1:65-73.
  • D. Balköse, T. O. Egbuchunam, F. E. Okieimen
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    ABSTRACT: Soaps are a class of surface active compounds derived from natural oils and fats. Double decomposition reactions permit the synthesis of metallic soaps, which are long-chain carboxylates of metal ions, from alkaline ones such as sodium, potassium or ammonium soaps. Metallic soaps are commercially important as they find use in diverse applications such as driers in paints or inks, components of lubricating greases, heat stabilizers for plastics (especially PVC), catalysts and water proofing agents, fuel additives and cosmetic products amongst others. Many of these applications are related to the thermal properties of these compounds and the thermal behaviour of metal soaps in terms of decomposition processes is of great importance. Rubber seed oil (RSO) which is an unsaturated triglyceride abundantly available in Nigeria, India and Australia is an excellent starting material for metal soaps. In this study rubber seed oil having 2.2% myristic acid, 7.6% palmitic acid, 10.7% stearic acid, 20.61% oleic acid, 36.62% linoleic acid, 22.5% linolenic acid was used in making barium, calcium, cadmium and zinc soaps. The thermal behaviour of soaps (Ba, Ca, Cd and Zn) of rubber seed oil for use as additives in the processing of poly(vinyl chloride) (PVC) was investigated by thermal gravimetry and differential scanning calorimetry. The stability of the soaps was examined by thermogravimetry up to 873 K at a constant heating rate of 10 °C min−1. The soaps were found to be thermally stable up to 473 K as they recorded less than 5% mass loss at this temperature with values of apparent activation energy for decomposition varying from 52 to 96 kJ mol−1. Differential scanning calorimetric studies of the soaps revealed melting and decomposition behaviour of metal soaps.
    Journal of Thermal Analysis and Calorimetry 08/2010; 101(2):795-799. · 1.98 Impact Factor
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    R. A. Wuana, F. E. Okieimen, J. A. Imborvungu
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    ABSTRACT: Changes in heavy metal speciation and uptake by maize in a soil before and after washing with chelating organic acids, citric acid, tartaric acid and ethylenediaminetetraacetic acid were assessed. A sandy loam was collected from the vicinity of the Benue industrial layout, Makurdi, Nigeria and spiked with a quinternary mixture of nickel, copper, zinc, cadmium and lead nitrates to achieve higher levels of contamination. Batch soil washing experiments performed on 1.0 g portions of the spiked soil using 0.05 M chelating agents at a solid:liquid ratio of 1:25 showed that washing efficiencies varied in the order: ethylenediaminetetraacetic acid> citric acid> tartaric acid with metal extraction yields typically following the sequence, copper> nickel> zinc> cadmium> lead. Sequential extractions proposed by the European Communities Bureau of Reference method used to assess the redistribution of heavy metal forms in the soil showed that apparent metal mobilities were reduced upon soil washing. Citric acid removed most of the metals hitherto associated with the exchangeable and reducible fractions; tartaric acid, the exchangeable metal pools; and ethylenediaminetetraacetic acid, the non-residual metal pools. Heavy metal assay of harvested biomass of maize grown on unwashed and washed soil samples indicated that metal transfer coefficients, decreased in the order of treatment: ethylenediaminetetraacetic acid <citric acid <tartaric acid <unwashed soil. Ethylenediaminetetraacetic acid and citric acid appeared to offer greater potentials as chelating agents to use in remediating the high permeability soil. Tartaric acid, however, is recommended in events of moderate contamination.
    International journal of Environmental Science and Technology 06/2010; · 1.84 Impact Factor
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    E U Ikhuoria, A S Folayan, F E Okieimen
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    ABSTRACT: Graft copolymers of starch and acrylonitrile were synthesized in aqueous solution. Ceric ammonium ion was used to initiate the graft copolymerization. Ten grades of graft copolymers were synthesized-five by varying the initial concentration of the monomer and the other five by varying the initial concentration of the initiator. Evidence of graft copolymerization of the hydrolyzed products was obtained from the IR analyses. Some grafting parameters such as % grafting ratio and % conversion were favoured by initial increase in the monomer concentration. However, these parameters were observed to decrease at much higher concentrations (>3 M). Evidence of hydrolysis shows that the grafted copolymers could be used as flocculants.
    International Journal for Biotechnology and Molecular Biology Research. 04/2010; 1:10-14.
  • Chemical Industry and Chemical Engineering Quarterly 01/2010; 16(1):19-30. · 0.53 Impact Factor
  • T. O. Egbuchunam, F. E. Okieimen, D. B. Balköse
    International Journal of Engineering Research in Africa. 01/2010; 1:47-56.
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    Ekebafe L.O, Imanah J.E, Okieimen F.E
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    ABSTRACT: Samples of rubber seed shells were carbonized at varying temperatures (100, 200, 300, 400, 500, 600, 700 and 800 °C) for three hours each and sieved through a 150 μm screen. The portion of the rubber seed shell carbon that passed through the screen was characterized in terms of loss on ignition, surface area, moisture content, pH, bulk density, and metal content and used in compounding natural rubber. The characterization shows that the pH, conductivity, loss on ignition and the surface area increases with the increases of the heating temperature, unlike the bulk density which decreases. The compound mixes were cured using the efficient vulcanization system. Cure characteristics of compounds and physico-mechanical properties of the vulcanisates were measured as a function of filler loading along with that of N330 carbon-black filled natural rubbers. The results showed that the cure times, scorch times and the torque gradually increased, with increasing the filler content for rubber seed shell carbon-filled natural rubber, with the filler obtained at carbonizing temperature of 600 °C tending to show optimum cure indices. The physicomechanical properties of the vulcanisates increase with filler loading. The reinforcing potential of the carbonized rubber seed shell carbon was found to increase markedly for the filler obtained at the temperature range of 500-600 °C and then decreases with further increase in temperature.
    Chemical Industry and Chemical Engineering Quarterly 01/2010; · 0.53 Impact Factor
  • MALOMO D, A. K. AKINLABI, F. E. OKIEIMEN, EGHAREVBA F
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    ABSTRACT: Blends of natural rubber (NR) and low molecular weight natural rubber (LMWNR) were compounded using three different mixing schemes by adopting the semi-efficient sulphur vulcanization compounding formulation. In scheme 1, the natural rubber and LMWNR were first mixed before adding the compounding ingredients. In scheme 2, the compounding ingredients were first mixed with the NR before adding the LMWNR and in scheme 3 the compounding ingredients were first mixed with the LMWNR before adding the NR. Properties of the vulcanizates from the three mixing schemes viz-a-viz: chemical resistance, ageing and physico-mechanical properties were investigated and compared. The physico-mechanical results of all the vulcanizates were found to be within the accepted level for NR compounds. The ageing results from all the mixing schemes were found impressing. Vulcanizates from mixing scheme 1 restricted penetration of petroleum fuels and organic solvents best, followed by scheme 2 and the least was scheme 3. The activation energy and free energy change were found to be highest with scheme 1, thereby making mixing scheme 1 being more technologically advantageous than other mixing schemes.
    Chemical Industry and Chemical Engineering Quarterly. 01/2010;
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    ABSTRACT: Rice husks carbon was prepared and evaluated for the single and competitive aqueous phase adsorption of hardness causing ions. The precursor (rice husks) was ammonium chloride-activated at 30 ± 1oC for 12h followed by carbonization at 350oC for 1h. The portion of carbon that passed through a 300μm sieve and retained on a 90μm sieve was characterized in terms of percent attrition, pH, bulk density, porosity, surface area and total acidic surface groups. The attributes of the rice husk carbon compared favourably with those of a commercial grade carbon (Thermax). Single solute equilibrium adsorption of Ca2+ and Mg2+ ions was satisfactorily described (but more so for Mg2+) by the single component Langmuir, Freundlich and Tempkin isotherms. Ca2+ ion appeared to be more quantitatively adsorbed than Mg2+during competitive adsorption. Better correlations were, however, found between experimental and predicted amounts adsorbed for Mg2+than Ca2+. The adsorption of both ions obeyed pseudo-second order kinetics and followed the intraparticle diffusion mechanism. These findings are of importance to simple water treatment schemes that utilize the principle of activated carbon adsorption. Keywords: Competitive adsorption, rice husk carbon, isotherms, and kinetics.
    Journal- Indian Chemical Society of Nigeria. 09/2009; 34(1):2009.
  • F. E. Okieimen, T. O. Egbuchunam, D. B. Balköse
    Advanced Materials Research 01/2009;
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    ABSTRACT: Epoxidized rubber seed oil (4.5% oxirane content, ERSO) was prepared by treating the oil with peracetic acid generated in situ by reacting glacial acetic acid with hydrogen peroxide. The thermal behavior of the ERSO was determined by differential scanning calorimetry. The effect of the epoxidized oil on the thermal stability of poly (vinyl chloride) (PVC) plastigels, formulated to contain dioctyl phthalate (DOP) plasticizer and various amounts of the epoxidized oil, was evaluated by using discoloration indices of the polymer samples degraded at 160°C for 30 min and thermogravimetry at a constant heating rate of 10°C/min up to 600°C. The thermal behavior of the ERSO was characterized by endothermic peaks at about 150°C, which were attributed to the formation of network structures via epoxide groups, and at temperatures above 300°C, which were due to the decomposition of the material. Up to 50% of the DOP plasticizer in the PVC plastisol formulation could be substituted by ERSO without a marked deleterious effect on the consistency of the plastigel formed. In the presence of the epoxidized oil, PVC plastigel samples showed a marked reduction in discoloration and the number of conjugated double bonds, as well as high temperatures for the attainment of specific extents of degradation. These results showed that the ERSO retarded/inhibited thermal dehydrochlorination and the formation of long (n > 6) polyene sequences in PVC plastigels. The plasticizer efficiency/permanence of ERSO in PVC/DOP plastigels was evaluated from mechanical properties' measurements, leaching/migration tests, and water vapor permeability studies. The results showed that a large proportion of DOP could be substituted by ERSO in a PVC plastisol formulation without deleterious effects on the properties of the plastigels. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers.
    Journal of Vinyl and Additive Technology 05/2008; 14(2):65 - 72. · 1.11 Impact Factor
  • F. E. OKIEIMEN, T. O. EGBUCHUNAM, BALKÖSE D
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    ABSTRACT: Novel formulations of PVC plastisols based on blends of bio-based and synthetic plasticizers were prepared and characterized. A traditional phthalate plasticizer, dioctylphthalate, was replaced in the plastisols studied by the epoxidized rubber seed oil (4.5 % oxirane content). The plastisols formed were processed into plastigels and characterized in terms of permanence properties using leaching and migration tests and water vapour barrier properties. It was found that the permanence properties of PVC/DOP plastigels were maintained in the presence of up to 50 % ERSO, and that blending with DOP did not impair the water barrier properties of PVC plastigels.
    Chemical Industry and Chemical Engineering Quarterly. 01/2008;
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    F. E. Okieimen, T. O. Egbuchunam, D. Balköse
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    ABSTRACT: Novel formulations of PVC plastisols based on blends of bio-based and syn- thetic plasticizers were prepared and characterized. A traditional phthalate plasticizer, dioctylphthalate, was replaced in the plastisols studied by the epo- xidized rubber seed oil (4.5 % oxirane content). The plastisols formed were processed into plastigels and characterized in terms of permanence properties using leaching and migration tests and water vapour barrier properties. It was found that the permanence properties of PVC/DOP plastigels were maintained in the presence of up to 50 % ERSO, and that blending with DOP did not im- pair the water barrier properties of PVC plastigels.
    Chemical Industry & Chemical Engineering Quarterly - CHEM IND CHEM ENG Q. 01/2008; 14(1):11-15.
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    ABSTRACT: This article reports on the physico-mechanical properties, chemical resistance, aging properties, sorption, diffusion, and permeability of ketones (cyclohexanone and acetone) through vulcanizates from blends of natural rubber (NR) and epoxidized low molecular weight natural rubber (ELMWNR) compounded by three different mixing schemes. The compounding ingredients were mixed with the two mentioned rubbers using three different mixing schemes by adopting a semi-efficient sulphur vulcanization compounding formulation. In Scheme 1, the natural rubber and ELMWNR were first mixed before adding the compounding ingredients. In Scheme 2, the compounding ingredients were first mixed with the NR before adding the ELWMNR and in Scheme 3, the compounding ingredients were first mixed with the ELMWNR before adding the NR. The physico-mechanical results of the vulcanizates showed that changes in the mixing schemes significantly influence the tensile properties of the vulcanizates. The tensile strength of the vulcanizates prepared with mixing Scheme 2 were 4.3 MPa lower than vulcanizates from Scheme 1, whereas Scheme 3 was lower than Scheme 1 with 8.5 MPa. The aging results of the vulcanizates from all the mixing schemes were found impressing. The activation energy and free energy change were highest for Scheme 1 whereas the extent of cyclohexanone and acetone penetrations were the lowest with Scheme 1, signifying well crosslinked and ketone resistant vulcanizates.
    International Journal of Polymeric Materials 10/2007; 56(10):1023-1039. · 1.87 Impact Factor
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    ABSTRACT: Activated carbon powder was obtained by treating coconut fibre with ammonium chloride and carbonized at 400 o C. The powdered activated carbon was sieved. The portion that passed through a 212 um and retained on a 90 um mesh size was used for this study. The treatment was done to increase the surface area and the adsorption site of the carbon. The activated carbon was characterized in terms of pH, surface area, loss on ignition, moisture content and bulk density. The adsorption pattern of soluble petroleum fraction (kerosene and diesel) on coconut fibre carbons as a function of time was studied. The removal of diesel and kerosene from aqueous solutions measured by changes in the chemical oxygen demand shows that removal efficiency was less than 45% corresponding to about 6.8 mg/l/g decreases in chemical oxygen demand (COD). The removal of diesel and kerosene from aqueous solution followed a psuedo first order rate law.
    International Journal of Physical Sciences. 03/2007; 2:47-49.
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    ABSTRACT: This article reports on the physico-mechanical properties, chemical resistance, aging properties, sorption, diffusion, and permeability of aldehydes (acetaldehyde and formaldehyde) through vulcanizates from blends of natural rubber (NR) and low molecular weight natural rubber (LMWNR) compounded by three different mixing schemes. The compounding ingredients were mixed with the two mentioned rubbers using three different mixing schemes by adopting the semi-efficient sulphur vulcanization compounding formulation. In scheme 1, the natural rubber and LMWNR were first mixed before adding the compounding ingredients. In scheme 2, the compounding ingredients were first mixed with the NR before adding the LWMNR and in scheme 3, the compounding ingredients were first mixed with the LMWNR before adding the NR. The physico-mechanical results of the vulcanizates showed that changes in the mixing schemes significantly influence the tensile properties of the vulcanizates. The tensile strengths of the vulcanizates prepared with mixing scheme 2 were 3.5 MPa lower than vulcanizates from scheme 1, whereas scheme 3 was lower than scheme 1 by 7.8 MPa. The aging result of the vulcanizates from all the mixing schemes were found to be similar. The activation energy and free energy change were highest with scheme 1 whereas the extent of acetaldehyde and formaldehyde penetrations were lowest with scheme 1, signifying a well crosslinked and aldehyde-resistant vulcanizate.
    International Journal of Polymeric Materials 03/2007; 56:273-289. · 1.87 Impact Factor
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    ABSTRACT: Vulcanizates from blends of natural rubber and thioglycolic acid modified, epoxidized, low-molecular-weight natural rubber filled with mixtures of carbon black and carbonized rubber seed shell, with semiefficient sulfur vulcanization recipes, were critically investigated and characterized. The investigated properties were the processing and rheological properties (the cure rate, cure time, scorch time, total oscillating disc rheometry torque, and Mooney viscosity), physicomechanical and chemical properties, solvent resistance, solubility, and swelling properties. On the basis of the investigated properties, it was observed that the carbonized rubber seed shell acted as a plasticizer and not as a reinforcing filler such as carbon black. The replacement of carbon black with up to 20% carbonized rubber seed shell produced vulcanizates having processing advantages in time gain and energy consumption, with their physical, chemical, and mechanical properties around the acceptable level for natural rubber compounds but lower than the properties obtained for a 100% carbon black filled vulcanizate. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
    Journal of Applied Polymer Science 02/2007; 104(5):2830 - 2838. · 1.40 Impact Factor