PL
 |
EN
Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl
Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 10

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
1
Plant extract as biodegradable inhibitor for zinc in dilute solution of sulphuric acid
100%
Onukwuli O. D. , Ezeugo J. O.
|
2018
|
tom 109
2
Content available Adsorptive removal of colour pigment from palm oil using acid activated nteje clay. Kinetics, equilibrium and thermodynamics
100%
Ajemba R. O. , Onukwuli O. D.
|
|
tom Vol. 49, iss. 1
369--381
EN
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.
3
Content available Characterization and optimization of spectrophotometric colour removal from dye containing wastewater by Coagulation-Flocculation
100%
Obiora-Okafo I. A. , Onukwuli O. D.
Polish Journal of Chemical Technology
|
2018
|
tom Vol. 20, nr 4
49--59
EN
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.
4
Study on the pore and fibre metric characteristics of natural organic polymer for colour degradation in wastewater: Face-centred central composite design
100%
Obiora-Okafo I. A. , Onukwuli O. D.
World Scientific News
|
2021
|
tom 159
5
Content available Assessing influence of hydrochloric acid leaching on structural changes and bleaching performance of Nigerian clay from Udi
100%
Ajemba R. O. , Onukwuli O. D.
Physicochemical Problems of Mineral Processing
|
2014
|
tom Vol. 50, iss. 1
349--358
EN
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.
6
Corrosion control of aluminium in H2SO4 medium using Kolestran (Cholestyramine) drug as iInhibitor
80%
Udeh B. C. , Onukwuli O. D. , Omotioma M.
World Scientific News
|
2021
|
tom 159
7
Content available Optimization of corrosion inhibition of Picralima nitida leaves extract as green corrosion inhibitor for zinc in 1.0 M HCl
80%
Ezeugo J. N. O. , Onukwuli O. D. , Omotioma M.
World News of Natural Sciences
|
2017
|
tom 15
EN
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.
8
Characterization and optimization study of Epiphyllum oxypetalum extract as corrosion inhibitor for mild steel in 3 M H2SO4 solutions
80%
Emembolu L. N. , Onukwuli O. D. , Okafor V. N.
World Scientific News
|
2020
|
tom 145
9
Content available Synthesis and physico-chemical studies of base catalyzed methanolysis of some virgin tropical seed oils
80%
Esonye C. , Onukwuli O. D. , Ofoefule A. U.
World News of Natural Sciences
|
2017
|
tom 15
EN
The physico-chemical characterization of Prunus amygdalus, Dacryodes edulis and Chrysophillum albidium seed oils were investigated, together with their methyl esters. The vegetable oils were extracted by applying the solvent extraction method, using n-hexane. Prunus amygdalus had the highest oil yield (60.1%), followed by Dyacrodes edulis (55.76 %) and least from Chrysophillum albidium (13.67%). The oils and their biodiesel were then analyzed for acid value, free fatty acid, specific gravity, ash content, iodine value, peroxide value, saponification value, kinematic viscosity, flash point, smoke point, titre value, cloud point, moisture content and refractive index. Accordingly, Dyacrodes edulis seed oil had the highest acid value of 6.57 and required two-step transesterifictaion. The produced biodiesels were discussed in the light of ASTM D 9751, ASTMD 6751 and DIN 14214. These showed yields of 94.36%, 93.03% and 86.49%, cetane numbers of 70.40, 55.20 and 64.57 and calorific values of 31,178.39 KJ/kg, 34,421.50 KJ/kg and 32,838.38 KJ/kg for Prunus amygdalus, Dacryodes edulis and Chrysophyllum albidium, respectively. Other fuel-related properties showed highly improved qualities upon transesterification and compared well with ASTM and EU standards. The overall results showed that the seed oils are viable for biodiesel production.
10
Optimization of Chrysophyllum albidum leaf extract as corrosion inhibitor for aluminium in 0.5 M H2SO4
71%
Ezeugo J. O. , Onukwuli O. D. , Ikebudu K. O. , Ezechukwu V. C. , Nwaeto N. O.
|
|
tom 125
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.