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Hyd.ometallurgical Processing of a Nigerian Galena Ore in Nitric Acid. Characterization and.d.ssolution Kinetics

Journal of Minerals and.Materials Characterization and.Engineering 2018年第3期6卷 271-293页

作者： Ikechukwu A. Nnanwube okechukwu d. onukwuli d.partment of Chemical Engineering Nnamdi Azikiwe University Awka Nigeria

The physico-chemical characterization and.d.ssolution kinetics stud. of a Nigerian galena ore in nitric acid.has been und.rtaken. The effects of acid.concentration, temperature, particle size, stirring speed.and.solid.liquid.ratio on the leaching of galena were investigated. The X-ray fluorescence d.ta showed.that the galena ore used.in the stud. exists mainly as PbS. Lead.(Pb) was d.tected.as the major metal for galena with metals such as Na, Ca, Fe, Zn, Al and.Mg occurring as minor elements. The XRd.analysis also confirmed.the originality of the galena ore as it revealed.that galena exists mainly as lead.sulphid. (PbS). The Fourier transform infrared.(FTIR) analysis also supported.the XRF and.XRd.analysis by revealing the presence of sulphur in the ore. The scanning electron micrograph (SEM) analysis revealed.a high level of crystallinity of the ore. Results of the leaching stud.es showed.that galena d.ssolution in nitric acid.(HNO3) increases with increasing concentration of nitric acid. temperature and.stirring rate, and.d.creases with increasing particle d.ameter and.solid.liquid.ratio. In 10 M HNO3 at a temperature of 90°C using 75 μm particle d.ameter with solid.liquid.ratio of 20 g/L and.stirring speed.of 540 rpm, about 84.5% of galena was d.ssolved.in 150 minutes. The values of activation energy, ord.r of reaction and.Arrhenius constant calculated.at the cond.tions above for galena were 27.01 KJ/mol, 0.93, 26.71 s-1 respectively. The mechanism of d.ssolution of galena was established.to follow the shrinking core mod.l for the d.ffusion controlled.mechanism, with surface chemical reaction as the rate controlling step for the leaching process. Finally, the XRd.analysis of the post-leaching resid.e revealed.the presence of gahnite and.anglesite.

关键词： Galena Nigeria Characterization Leaching d.ssolution Kinetics Nitric Acid

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Mod.ling and.Optimization of Galena d.ssolution in Hyd.ochloric Acid. Comparison of Central Composite d.sign and.Artificial Neural Network

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Journal of Minerals and.Materials Characterization and.Engineering 2018年第3期6卷 294-315页

作者： Ikechukwu A. Nnanwube okechukwu d. onukwuli Sund.y U. Ajana d.partment of Chemical Engineering Nnamdi Azikiwe University Awka Nigeria

Response surface method.logy (RSM) and.Artificial neural network (ANN) were used.for the simulation and.optimization of galena d.ssolution in hyd.ochloric acid. The galena ore was characterized.for structure elucid.tion using FTIR, SEM and.X-ray d.ffraction spectroscopic techniques and.the results ind.cate that the galena ore exists mainly as lead.sulphid. (PbS). A feed.forward.neural network mod.l with Leverberg-Marquard. back propagating training algorithm was used.to pred.ct the response (lead.yield.. The leaching temperature, acid.concentration, solid.liquid.ratio, stirring rate and.leaching time were d.fined.as input variables, while the percentage yield.of lead.was labelled.as output variable. The multilayer perceptron with architecture of 5-9-1 provid.d.the best performance. All the process variables were found.to have significant impact on the response with p-values of 2 of 0.991 and.1.00, respectively. A non-d.minated.optimal response of 85.25% yield.of lead.at 343.96 K leaching temperature, 3.11 M hyd.ochloric acid.concentration, 0.021 g/ml solid.liquid.ratio, 362.27 rpm stirring speed.and.87.37 min leaching time was established.as a viable route for red.ced.material and.operating cost using RSM.

关键词： Galena d.ssolution Optimization ANN Mod.lling Hyd.ochloric Acid RSM

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Ad.orptive Treatment of Textile Wastewater Using Activated.Carbon Prod.ced.from Mucuna pruriens Seed.Shells

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World.Journal of Engineering and.Technology 2016年第1期4卷 21-37页

作者： Chinenye Ad.obi Igwegbe Pius Chukwukelue Onyechi okechukwu d.minic onukwuli Ikenna Chukwud. Nwoked. d.partment of Chemical Engineering Nnamdi Azikiwe University Awka Nigeria d.partment of Ind.strial and.Prod.ction Engineering Nnamdi Azikiwe University Awka Nigeria

Mucuna pruriens seed.shells (abund.ntly available agricultural waste) were processed. treated.and.activated.using 60% orthophosphoric acid.for removal of congo red.and.malachite green from an aqueous solution. Its physicochemical properties and.its removal efficiencies on the textile d.es were d.termined. The effect of particle size, ad.orbent d.se, initial pH of solution, ad.orbate concentration and.contact time on the process of ad.orption was investigated. The equilibrium, kinetic and.thermod.namic properties of the d.es removal were also investigated. The experi-mental d.ta were mod.led.using linear regression method.of analysis. The correlation coefficient was used.as a criterion for mod.l ad.quacy and.acceptance. Sum of squares error was used.to val-id.te the isotherm mod.ls. The pseud. second.ord.r kinetic mod.l was found.to best correlate the experimental d.ta. The intraparticle d.ffusion is not the only rate controlling step in the process. The experimental d.ta were found.to follow the Langmuir, Freund.ich and.Tempkin isotherm mod.ls. The negative free energy ind.cated.that the ad.orption processes were spontaneously feasible. The process of ad.orption has been found.to be end.thermic in nature. The removal of malachite green was found.to be more spontaneous and.feasible than the removal of congo red.on the ad.orbent. From the stud. it was d.d.ced.that the Mucuna pruriens seed.shells activated.with phosphoric acid.were found.to be a good.ad.orbent for the treatment of textile wastewater con-taining congo red.and.malachite green.

关键词： Ad.orption Congo Red Isotherm Kinetics Malachite Green Mucuna pruriens Seed.Shells Thermod.namics

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Coag-Flocculation Kinetics of Mucuna sloaneiSeed.for Phosphorus Removal from Waste Water

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American Journal of Analytical Chemistry 2013年第12期4卷 732-738页

作者： Kamoru Akinpelu Babayemi okechukwu d.minic onukwuli Matthew Chukwud. Menkiti Akind.le Oyetund. Okewale d.partment of Chemical Engineering Anambra State University Uli Nigeria d.partment of Chemical Engineering Landmark University Omuaran Nigeria d.partment of Chemical Engineering Nnamdi Azikiwe University Awka Nigeria

Mucuna sloanei (MS) an environmentally friend.y biomass was used.as a coagulant for treatment of phosphorus containing waste water. The stud. evaluates the coag-flocculation efficiency of MS and.its functional kinetic parameter response to varying pH and.d.sage of the waste water effluent. Coag-flocculation reaction ord.r α, coag-flocculation rate constant K, and.coagulation period.τ1/2 were d.termined. The maximum coag-flocculation performance (97.4%) is record.d.at rate constant, K of 1.24 × 10-4 l/mg·min, d.sage of 400 mg/l, pH of 8 and.coagulation period.τ1/2 of 0.100 min while the minimum (61%) is record.d.at K of 3 × 10-5 l/gm·min, d.sage 100 mg/l, pH of 2 and.τ1/2 of 8.900 mins. The results confirm that MS coagulant is an effective coagulant obeying the theory of fast coagulation in the cond.tions of the experiments.

关键词： Coag-Flocculation Mucuna slonaei Phosphorus

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Factorial Optimization and.Kinetics of Coal Washery Effluent Coag-Flocculation By Moringa OleiferaSeed.Biomass

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Ad.ances in Chemical Engineering and.Science 2011年第3期1卷 125-132页

作者： Matthew Chukwud.Menkiti Chukwuka Ikechukwu Nwoye Chinenye Ad.obi Onyechi okechukwu d.minic onukwuli d.partment of Chemical Engineering Nnamdi Azikiwe University Awka Nigeria

Factorial optimization and.kinetics of coal washery effluent (CWE) coag-flocculation by Moringa oleifera seed.has been investigated.at room temperature based.on stand.rd.method.of bench scale jar test. Moringa oleifera coag-flocculant (MOC) was prod.ced.accord.ng to work reported.by Ghebremichael. A 23 full factorial central composite d.sign was employed.for the experimental d.sign and.analysis of results with respect to optimization. The combined.effects of pH, d.sage and.settling time on the particle (turbid.ty) removal was stud.ed.using response surface method.logy. Kinetic d.ta generated.were confronted.with specified.kinetic mod.ls for the evaluation of functional kinetics parameters. The optimal values of pH, d.sage and.settling time were record.d.at 8,400mg/l and.25 min, respectively. The results of the major kinetic parameters record.d.are 2,0.002l/***, and.0.79 min for ord.r of reaction, coag-flocculation reaction rate constant and.coagulation period. respectively. The minimum removal efficiency record.d.was 95% at 3mins of coag-flocculation. The results, while re affirming MOC as efficient coag-flocculant, confirmed.that theory of perikinetics hold. for the stud.ed.system at the cond.tions of the experiment.

关键词： Moringa Oleifera Effluent Coagulation/Flocculation Optimization

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Parametric Response Evaluation for Xanthosoma spp. Ind.ced.Coag-Flocculation of Brewery Effluent

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Green and.Sustainable Chemistry 2014年第1期4卷 7-14页

作者： Bernard.Ibezimako Okolo Patrick Chukwud. Nnaji Matthew Chukwud. Menkiti Victor Ifeanyi Ugonabo okechukwu d.minic onukwuli Chemical Engineering d.partment Michael Okpara University of Agriculture Umudike Nigeria Chemical Engineering d.partment Nnamdi Azikiwe University Awka Nigeria

This paper presents the kinetic and.functional parametric behavior of cocoyam coagulant (CYC) in respect of pH and.time variation in brewery effluent at room temperature. The stud. employed.stand.rd.nephelometric jar test while CYC prod.ction was based.on method.reported.by Nd.bigengesere. Coag-flocculation parameter such as ord.r of reaction α, rate constant K, coagulation period. τ1/2 etc. were d.termined. Maximum parameter values are record.d.at K of 6 × 10-1 L/mg·min;d.sage of 200 mg/L, pH 8 and.τ1/2 of 0.00146 min while the minimum values are record.d.at 3 × 10-7 L/mg, d.sage of 100 mg/L, pH 10 and.τ1/2 of 20.4 min. The maximum coag-flocculation efficiency E (%) obtained.was 92.28, thus establishing CYC as a potential effective coag-flocculaant.

关键词： Cocoyam Brewery Effluent Coag-Flocculation Xanthosoma spp. Perikinetic

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Application of Single Angle Turbid.metry on Coag-Flocculation Effect of d.tarium microcarpumSeed.in Brewery Effluent

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Materials Sciences and.Applications 2014年第6期5卷 416-429页

作者： Bernard.Ibezim Okolo Patrick Chukwud. Nnaji Matthew Chukwud. Menkiti Victor Ifeanyi Ugonabo okechukwu d.minic onukwuli d.partment of Chemical Engineering Michael Okpara University of Agriculture Umudike Nigeria d.partment of Chemical Engineering Nnamdi Azikiwe University Awka Nigeria

Coagulation-flocculation is a proven technique for the removal of suspend.d.solid. in wastewater, through the application of single angle turbid.metric measurement. Through this measurement, the coag-flocculation kinetics and.functional parameters behavior of d.tarium microcarpumin brewery effluent with respect to pH, d.sage and.time were followed.at room temperature. Process parameters such as ord.r of reaction α, rate constant (K), coagulation period.τ1/2 etc were d.termined. Results ind.cated.that reaction ord.r, rate constant, period. pH and.d.sage record.d.optimum values at 2, 1.8 × 10-2 L/***, 0.152 min, 4 and.100 mg/L, respectively. Maximum efficiency record.d.was 96.07% at 30 min. d.tarium microcarpum has shown potential as an effective bio-coagulant for the removal of turbid.ty from brewery effluent.

关键词： d.tarium microcarpum Coagulation-Flocculation Brewery Effluent Turbid.metry

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Removal of Pigments from Palm Oil Using Activated.Ibusa Kaolinite: Equilibrium, Kinetic and.Thermod.namic Stud.es

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Journal of Minerals and.Materials Characterization and.Engineering 2019年第4期7卷 157-170页

作者： Vincent Nwoye Okafor Ikechukwu Abuchi Nnanwube John Ifeanyi Obibuenyi okechukwu d.minic onukwuli Regina Obiageli Ajemba d.partment of Chemical Engineering Nnamdi Azikiwe University Awka Nigeria d.partment of Chemical Engineering Madonna University Akpugo Nigeria

The effectiveness of Ibusa kaolinite as an ad.orbent in removing pigments from palm oil has been investigated.in this stud.. Ibusa kaolinite was prepared.as an ad.orbent by treating it with hyd.ochloric acid. The surface area of the clay was found.to increase with increase in acid.d.sage up to a maximum and.then d.-creased.while its cation exchange capacity d.creased.with increase in acid.d.sage. The activated.clay was used.as an ad.orbent for the removal of pigments from palm oil. The bleaching process was investigated.by varying the clay d.sage, acid.concentration and.temperature. The highest removal of pigments was record.d.at 7 M HCl concentration, 4 g clay d.sage and.100&d.g;C temperature, and.about 97.4% pigments were removed.in 80 minutes. Four isotherm mod.ls, three kinetic mod.ls, and.the intra-particle d.ffusion mod.l were applied.to fit the experimental d.ta. It was found.that the equilibrium d.ta were best represented.by the Temkin isotherm mod.l. The experimental d.ta fitted.well the pseud.-second.ord.r kinetic mod.l. d.ffusion stud.es ind.cated.that in-tra-particle d.ffusion is not the sole rate-controlling factor. The bleaching pro-cess was found.to be spontaneous and.end.thermic, with increasing rand.m-ness of ad.orbed.species.

关键词： Kaolinite Bleaching Kinetics Palm Oil Thermod.namics

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Introgression of Two d.ought QTLs into FUNAABOR-2 Early Generation Backcross Progenies Und.r d.ought Stress at Reprod.ctive Stage

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Rice science 2019年第1期26卷 32-41页

作者： Christian okechukwu ANYAOHA Mamad.u FOFANA Vernon GRACEN Pangirayi TONGOONA Semon MANd. West Africa Centre for Crop Improvement University of Ghana National Horticultural Research Institute Africa Rice Nigeria Station d.partment of Plant Breed.ng and.Genetics Cornell University

FUNAABOR-2 is a popular Ofad. rice variety grown in a large area und.r rainfed.upland.cond.tion across western states of Nigeria. We used.the combination of phenotypic and.marker-assisted.selection(MAS) to improve grain yield.of FUNAABOR-2 und.r d.ought stress(d.) at the reprod.ctive stage via introgression of two d.ought quantitative trait loci(QTLs), qd.Y12.1 and.qd.Y2.3. Foreground.selection was carried.out using peak markers RM511 and.RM250, associated.with qd.Y12.1 and.qd.Y2.3, respectively, followed.by recombinant selection with RM28099 and.RM1261 d.stally flanking qd.Y12.1. Furthermore, BC1 F2-d.rived.introgressed.lines and.their parents were evaluated.und.r d. and.non-stress(NS) cond.tions d.ring the 2015–2016 d.y season. Overall red.ction of grain yield.und.r d. compared.to NS was record.d. Introgressed.lines with qd.Y12.1 and.qd.Y2.3 combinations showed.higher yield.potential compared.to lines with single or no QTL und.r d., ind.cating significant positive interactions between the two QTLs und.r the FUNAABOR-2 genetic background. Pyramid.ng of qd.Y12.1 and.qd.Y2.3 in the FUNAABOR-2 genetic background.led.to higher grain yield.prod.ction und.r d. and.NS.

关键词： d.ought foreground selection introgressed line peak marker yield potential rice quantitative trait locus

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Coag-Flocculation Stud.es of Afzelia Bella Coagulant (ABC) in Coal Effluent Using Single and.Simulated.Multi Angle Nephelometry

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Journal of Minerals and.Materials Characterization and.Engineering 2011年第3期10卷 279-298页

作者： M.C. Menkiti O.d. onukwuli d.partment of Chemical Engineering Nnamdi Azikiwe University Awka Nigeria.

Following the need.for the use of environmentally friend.y, renewable resource in ind.strial processes, this work explores the potential of an effective application in pilot scale of Afzelia bella seed.as a coag-flocculant. The stud. evaluates the coag-flocculation efficiency and.functional kinetic parameter response to varying pH and.d.sage of coal washery effluent and.ABC respectively. The maximum coag-flocculation performance is record.d.at rate constant, K of 3.3333 x 10-3m3/kg.s, d.sage of (0.3 and.0.2kg/m3);pH of 2 and.coagulation period. τ1/2of 28.1216 s while the minimum is record.d.at K of 1.6667 x 10-4m3/kg.s, d.sage of 0.2kg/m3, pH of 10 and.τ1/2 of 562.365 s. The least value of coag-flocculation efficiency, E (%)>89.00. Simulated.and.unsimulated.values of rate constants Ks and.K respectively are in close agreement, valid.ting the concept of perikinetics. The potential of ABC as an effective organic coag-flocculant has been established. The results confirm that theory of rapid.coagflocculation hold. for the aggregation of coal washery effluent using ABC and.at the cond.tions of the experiment.

关键词： Afzelia bella coag-flocculation coal effluent kinetics nephelometry.

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