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Wyszukujesz frazę "Onukwuli, O. D." wg kryterium: Autor

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    Wyświetlanie 1-8 z 8
    Tytuł:
    Plant extract as biodegradable inhibitor for zinc in dilute solution of sulphuric acid
    Autorzy:
    Onukwuli, O. D.
    Ezeugo, J. O.
    Powiązania:
    https://bibliotekanauki.pl/articles/1163555.pdf
    Data publikacji:
    2018
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Picralima nitida leaf
    Zinc
    corrosion
    inhibition
    inhibitor
    Opis:
    The inhibitive action of the ethanol extract of oil from Picralima nitida leaf, towards acid corrosion of zinc, is tested using weight loss, and thermometry methods. It was found that the extract acted as a good corrosion inhibitor for zinc corrosion in 0.5 M H2SO4 solution. The inhibitive action of the extract was discussed in view of Langmuir adsorption isotherm. It was revealed that the adsorption of the extract on zinc surface is governed by spontaneous process. The inhibition efficiency (IE) increases in line with corresponding increase in extract concentration. The temperature effect of the corrosion inhibition on the IE was studied. Revelation from the studies indicates that the presence of extract increases the activation energy of the corrosion reaction. Furthermore, from the calculated thermodynamic parameters, it was observed that Picralima nitida extract provides a good protection to zinc against pitting corrosion in chloride ion containing solutions.
    Źródło:
    World Scientific News; 2018, 109; 195-210
    2392-2192
    Pojawia się w:
    World Scientific News
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Assessing influence of hydrochloric acid leaching on structural changes and bleaching performance of Nigerian clay from Udi
    Autorzy:
    Ajemba, R. O.
    Onukwuli, O. D.
    Powiązania:
    https://bibliotekanauki.pl/articles/110317.pdf
    Data publikacji:
    2014
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    acid leaching
    adsorption
    bleaching
    hydrochloric acid
    isotherm
    Opis:
    Clay from Udi in Nigeria was mined, ground, and acid-leached at different concentrations of hydrochloric acid to produce adsorbents of varying properties. The raw and acid-leached samples were characterized using x-ray fluorescence (XRF) and Fourier transforms infra-red spectroscopy (FTIR) to examine the structural modifications in the clay as a result of acid-leaching. The analysis showed that the acid-leaching process caused several modifications of the clay samples. The surface area, Si/[Al + Fe + Mg] ratio, adsorption capacity were found to have increased in the acid-leached samples. The acid-leached samples were tested in order to ascertain their performance in bleaching palm oil and it was observed that the bleaching efficiency increased from 29.8% to 66.7%. The acid-leached sample prepared with 7M hydrochloric acid yielded an adsorbent that was efficient in bleaching palm oil under the experimental conditions. The isotherm analysis showed that the bleaching process followed the Freundlich equation.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2014, 50, 1; 349-358
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Adsorptive removal of colour pigment from palm oil using acid activated nteje clay. Kinetics, equilibrium and thermodynamics
    Autorzy:
    Ajemba, R. O.
    Onukwuli, O. D.
    Powiązania:
    https://bibliotekanauki.pl/articles/110649.pdf
    Data publikacji:
    2013
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    adsorption
    kinetics
    isotherm
    activation
    colour pigment
    palm oil
    bleaching
    Opis:
    The kinetics of colour pigment removal from palm oil using acid activated clay from Nteje has been investigated. To determine the equilibrium adsorption capacity, the effects of temperature, contact time, adsorbent dosage and particle size were studied. The experimental adsorption data were analyzed using pseudo-first order, pseudo-second order, and Elovich kinetic models. The pseudo-second order model fitted very well to the kinetic experimental data. Equilibrium isotherms were analyzed by Lang-muir and Freundlich adsorption models. The data was in line with the Freundlich isotherm indicating a monolayer adsorption. The activation energy was calculated as 12 kJ/mol, and other thermodynamic parameters were determined as ΔS° = 0.063 J/mol, ΔH° = –34.994 J/mol, and ΔG° = –58.606 kJ/mol. These values indicate that the adsorption of colour pigment from palm oil onto acid activated clay was exothermic and can be attributed to physico-chemical adsorption process.
    Źródło:
    Physicochemical Problems of Mineral Processing; 2013, 49, 1; 369-381
    1643-1049
    2084-4735
    Pojawia się w:
    Physicochemical Problems of Mineral Processing
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Characterization and optimization of spectrophotometric colour removal from dye containing wastewater by Coagulation-Flocculation
    Autorzy:
    Obiora-Okafo, I. A.
    Onukwuli, O. D.
    Powiązania:
    https://bibliotekanauki.pl/articles/779809.pdf
    Data publikacji:
    2018
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    coagulation-flocculation
    natural organic polymer
    fibre-metric analysis
    spectrophotometer
    face-centred central composite design
    Opis:
    The performance of Vigna unguiculata coagulant (VUC) for colour removal from acid dye was investigated in this study. The proximate, structure and morphology of the coagulant were investigated using standard official methods, Fourier-Transform Infrared (FTIR) spectrometer and scanning electron microscopy (SEM), respectively. Response surface methodology (RSM) using face-centred central composite design (FCCD) optimized four process variables including pH, coagulant dosage, dye concentration and time. The colour removal efficiency obtained from the optimization analysis was 99.26% at process conditions of pH 2, coagulant dosage 256.09 mg/l, dye concentration 16.7 mg/l and time 540 min. The verification experiments agreed with the predicted values having a standard error value of 1.96%. Overlay contour plot established optimum areas where the predicted response variable is in an acceptable range (≥ 70%) with respect to optimum conditions. The FCCD approach was appropriate for optimizing the process giving higher removal efficiency when compared to the main effect plots.
    Źródło:
    Polish Journal of Chemical Technology; 2018, 20, 4; 49-59
    1509-8117
    1899-4741
    Pojawia się w:
    Polish Journal of Chemical Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Deployment of Antepsin (Sucralfate) as Corrosion Inhibitor of Mild Steel in H2SO4 Medium: Chemical and Electrochemical Studies
    Autorzy:
    Udeh, B. C.
    Onukwuli, O. D.
    Omotioma, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1839460.pdf
    Data publikacji:
    2021
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Antepsin
    Corrosion
    H2SO4
    Inhibitor
    Mild Steel
    Opis:
    This study presents the deployment of antepsin (sucralfate) as corrosion inhibitor of mild steel in H2SO4 medium. Chemical (gravimetric) and electrochemical (potentiodynamic polarization and electrochemical impedance spectroscopy) techniques were used in the corrosion control investigation. The antepsin drug was characterized by gas chromatography mass spectrophotometer (GCMS) and Fourier transform infrared (FTIR) spectroscopy. Effects of inhibitor concentration, temperature and time on weight loss, corrosion rate, inhibition efficiency and degree of surface coverage were examined. Thermodynamic and adsorption properties of the corrosion inhibition process were determined. Inhibition efficiency was optimized using central composite design tool of Design Expert software version 12. Potentiodynamic polarization and electrochemical impedance spectroscopy were employed to determine the type and effectiveness of the inhibitor. As a confirmatory test, scanning electron microscopy (SEM) was employed to examine the surface morphology of the mild steel samples. Analysis of the results showed that major constituents of antepsin include tetradecanoate, metronidazole, hexadecanoic acid, methyl ester and 11-octadecenoic acid. The predominant functional groups include; C=O stretch, C-H bend and symmetric and asymmetric =C-O-C. Adsorption of the molecules of antepsin on the surface of the mild steel was spontaneous and occurred in agreement with physical adsorption. A quadratic model adequately described the relationship between inhibition efficiency and corrosion control variables of concentration of the inhibitor, temperature and time. Optimum inhibition efficiency of antepsin was obtained as 86.75%. Chemical and electrochemical results agreed that antepsin is suitable for corrosion control of mild steel in H2SO4 solution. Antepsin acted as mixed-type inhibitor (controlled both cathodic and anodic reactions).
    Źródło:
    World News of Natural Sciences; 2021, 37; 117-134
    2543-5426
    Pojawia się w:
    World News of Natural Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Characterization and Optimization study of Epiphyllum oxypetalum extract as corrosion inhibitor for mild steel in 3 M H2SO4 solutions
    Autorzy:
    Emembolu, L. N.
    Onukwuli, O. D.
    Okafor, V. N.
    Powiązania:
    https://bibliotekanauki.pl/articles/1030954.pdf
    Data publikacji:
    2020
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Acid corrosion
    Epiphyllum oxypetalum extract
    Optimization
    Photochemical
    Response Surface Methodology
    Opis:
    This study investigated characterization of Epiphyllum oxypetalum (EO) leaf extracts and optimization of process variables on inhibition of mild-steel in 3 M H2SO4 aggressive environment. Response Surface Methodology (RSM) was employed to examine the influence of process variables namely acid concentration (1.0 – 3.0 mols), inhibitor concentration (0.2 – 1.0 g/l), time (1–10 hr) and temperature (303 -343K) on inhibition efficiency. The results of phytochemical screening showed that organic components present in EO extract as a good inhibitor. Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) studies established the presence of active compounds and adsorption of leaf extracts on metal surface. The experimental data was statistically analyzed and regression equations for corrosion rate and inhibition efficiency generated. The optimum conditions were achieved at acid concentration of 1.00 mol, inhibitor concentration of 0.055 g/l temperature of 333K, and time of 2.750 hr. The optimization results revealed that inhibition efficiency of 82.93 % was obtained at optimum combination of the extract concentration, the acid concentration, the temperature and the immersion time. The inhibitive potentials of EO extract was found to impede the localized and uniform corrosion of mild steel in acidic media, showing that the Epiphyllum oxypetalum leaf extract is a good inhibitor for mild steel in acidic solutions.
    Źródło:
    World Scientific News; 2020, 145; 256-273
    2392-2192
    Pojawia się w:
    World Scientific News
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optimization of corrosion inhibition of Picralima nitida leaves extract as green corrosion inhibitor for zinc in 1.0 M HCl
    Autorzy:
    Ezeugo, J. N. O.
    Onukwuli, O. D.
    Omotioma, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1113582.pdf
    Data publikacji:
    2017
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Picralima nitida
    Zinc
    corrosion
    inhibitor
    optimization
    Opis:
    Herein, the optimization of inhibitive action of the ethanol extract of oil from Picralima nitida leaves, towards acid corrosion of zinc, was tested using weight loss and thermometry methods. We found that the extract acts as a good corrosion inhibitor for zinc corrosion in 0.1 M HCl solutions. The inhibition action of the extract was discussed in view of Langmuir adsorption isotherm. This revealed that spontaneous processes govern the adsorption of the extract on zinc surface. Herein, the inhibition efficiency (IE) increases in line with corresponding increase in extract concentration. The temperature effect of the corrosion inhibition on the IE was also studied. This indicated that the presence of the extract increases the needed activation energy of the corrosion reaction. Furthermore, in our work, an optimal inhibition efficiency IE (%) of 86.78 was obtained at optimum inhibitor concentration of 1.2 gl-1, optimum temperature and time of 313 k and 8 hrs, respectively. From the calculated thermodynamic parameters, it can be said, then, that Picralima nitida extract provides good protection to zinc against pitting corrosion in chloride ion containing solutions.
    Źródło:
    World News of Natural Sciences; 2017, 15; 139-161
    2543-5426
    Pojawia się w:
    World News of Natural Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optimization of Chrysophyllum albidum leaf extract as corrosion inhibitor for aluminium in 0.5 M H2SO4
    Autorzy:
    Ezeugo, J. O.
    Onukwuli, O. D.
    Ikebudu, K. O.
    Ezechukwu, V. C.
    Nwaeto, L. O.
    Powiązania:
    https://bibliotekanauki.pl/articles/1075618.pdf
    Data publikacji:
    2019
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Aluminium
    Chrysophyllum albidum
    corrosion
    electrochemical
    optimal
    Opis:
    Inhibition of Chrysophyllum albidum leave (CAL) extract toward 0.5 M H2SO4 corrosion of aluminium was optimized applying response surface methodology. Corrosion analysis was carried out using weight loss and electrochemical techniques. The results of the various analyses of the leave extracts acted as a good corrosion inhibitor for aluminium in 0.5 M H2SO4. Inhibition efficiency increases as the extract concentration increased. Results of molecular dynamic simulations of the active constituents of the extracts confirmed the adsorption potentials of the ethanol extracts of CAL. Optimal inhibition efficiency of 78.43(%) was obtained at optimum inhibitor concentration of 1.00 g/l, 11.71hs and temperature of 303.60k
    Źródło:
    World Scientific News; 2019, 125; 32-50
    2392-2192
    Pojawia się w:
    World Scientific News
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-8 z 8

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