Papers by edidiong asuquo
ChemEngineering
An agricultural residue, white yam (Dioscorea rotundata) tuber peel (YTBS), was used for the remo... more An agricultural residue, white yam (Dioscorea rotundata) tuber peel (YTBS), was used for the removal of Cd(II) ion from an aqueous solution using a batch method. The adsorbent was characterized using FTIR, TGA, SEM, EDX, N2 BET, XRD, and XRF. The optimization of sorption variables such as pH, contact time, adsorbent dose, and initial metal ion concentration at 25 °C were also carried out. The results indicated the dependence of sorption on the adsorbate pH and adsorbent dose, while the adsorption system reached equilibrium in 180 min. The sorption kinetics was fitted to three models (pseudo first order, pseudo second order, and Elovich) to validate the kinetics, and the pseudo first order was the best model for the description of Cd(II) uptake. Equilibrium isotherm modelling was also carried out using the Langmuir, Freundlich, and Temkin models, with the Langmuir isotherm giving the best fitting to the experimental results. The maximum loading capacity (qmax) of the adsorbent for Cd...
Journal of Environmental Chemical Engineering, 2017
In this study, cadmium and lead ions removal from aqueous solutions using a commercial activated ... more In this study, cadmium and lead ions removal from aqueous solutions using a commercial activated carbon adsorbent (CGAC) were investigated under batch conditions. The adsorbent was observed to have a coarse surface with crevices, high resistance to attrition, high surface area and pore volume with bimodal pore size distribution which indicates that the material was mesoporous. Sorption kinetics for Cd(II) and Pb(II) ions proceeded through a two-stage kinetic profile-initial quick uptake occurring within 30 minutes followed by a gradual removal of the two metal ions until 180 minutes with optimum uptake (q e,exp) of 17.23 mgg-1 and 16.84 mgg-1 for Cd(II) and Pb(II) ions respectively. Modelling of sorption kinetics indicates that the pseudo first order (PFO) model described the sorption of Pb(II) ion better than Cd(II), while the reverse was observed with respect to the pseudo second order (PSO) model. Intraparticle diffusion modelling showed that intraparticle diffusion may not be the only mechanism that influenced the rate of ions uptake. Isotherm modelling was carried out and the results indicated that the Langmuir and Freundlich models described the uptake of Pb(II) ion better than Cd(II) ion. A comparison of the two models indicated that the Langmuir isotherm is the better isotherm for the description of Cd(II) and Pb(II) ions sorption by the adsorbent. The maximum loading capacity (q max) obtained from the Langmuir isotherm was 27.3mgg-1 and 20.3mgg-1 for Cd(II) and Pb(II) ions respectively.
Journal of Environmental Chemical Engineering, 2016
Sorption of cadmium (II) ion from aqueous solution onto sweet potato (Ipomoea batatas L.) peel ad... more Sorption of cadmium (II) ion from aqueous solution onto sweet potato (Ipomoea batatas L.) peel adsorbent: characterisation, kinetic and isotherm studies.
AFRICAN JOURNAL OF BIOTECHNOLOGY
This paper discusses the kinetics of lead (II) and Nickel (II) ions adsorption from aqueous solut... more This paper discusses the kinetics of lead (II) and Nickel (II) ions adsorption from aqueous solutions using chemically modified and unmodified agricultural adsorbents at 28°C, pH 6.2 and 0.01M NaCl ionic strength. The removal of the two metals were found to increase with increase in chemical modification, the sequence being 1.0MOPF>0.5MOPF>UOPF. In addition Nickel (II) had a higher percentage removal than lead (II). The intraparticle diffusion rate constant (Kid) were determined to be 63.023 min-1 (Ni2+) and 38.212 min-1 (Pb2+) for the 1.0MOPF adsorbent. The results show that the intraparticle diffusion model fits the sorption of lead (II) with higher coefficient of determination (r2) than Nickel (II), thereby indicating that the intra-particle diffusion may be the rate limiting step for Pb2+ sorption. The results from this study indicates that a good adsorbent for the removal of Ni2+ and Pb 2+ can be obtained from both chemically modified and unmodified oil palm fruit fibre.
European Journal of Scientific Research
The kinetics of Pb 2+ sorption from aqueous solutions using mercaptoacetic acid modified and unmo... more The kinetics of Pb 2+ sorption from aqueous solutions using mercaptoacetic acid modified and unmodified oil palm fruit fibre was investigated. Sorption capacity, q t increased following the trend; 1.0MOPF> 0.5 MOPF> UOPF and maximum sorption was attained in 120 minutes. Kinetic modeling of the sorption data using the pseudo-first order, pseudo-second order, Elovich, mass transfer and intraparticle diffusivity models was carried out. The pseudo-second order equation was the best fitting model with r 2 0.99. Thereby indicating that sorption of Pb 2+ on the adsorbents followed a pseudo-second order mechanism.
The use of sawdust meal in the adsorption of metal ions in a mixture of Hg (II), As (III) and Pb ... more The use of sawdust meal in the adsorption of metal ions in a mixture of Hg (II), As (III) and Pb (II) was investigated. Whereas particle sizes of adsorbent affected the adsorption of As (III) and Pb (II), it did not affect the adsorption of Hg (II) ion. The removal efficiencies of the metal ions was very high (99.99%). Modification by thiolation and carboxymethylation did not significantly affect the adsorption capacity of the adsorbent. The sorption process was modeled using pseudo-first and pseudo-second order kinetic equations with the later giving a good fit with rate constant (k2) of 3.33x10-22 g/mg-min and R2 value of 1.00 for the three metal ions and the three adsorbent types. The adsorption in a mixture of metal ions caused a leveling effect on the sorption capacity of the sawdust meal. Therefore, the sorption efficiency of each metal ion was influenced by the presence of other metal ions. This study significantly reveals the presence of other heavy metals, as design paramet...
A comparison was made on the sorption efficiency of an unmodified(UGC) and chemically modified(TG... more A comparison was made on the sorption efficiency of an unmodified(UGC) and chemically modified(TGC) guinea corn waste used to remove Pb2+ from aqueous solutions. The removal efficiencies of the two adsorbents were: 71.2% and 73.3% for the UGC and TGC adsorbents respectively. Also an analysis of six kinetic models: pseudo-second order, pseudo-first order, Elovich, intraparticle diffusivity, mass transfer and intraparticle diffusion equations was also used to characterize the metal ion transport mechanism. The sorption of Pb2+ was found to best fit the pseudo-second order equation. Thereby indicating that the sorption of Pb2+ followed a second order mechanism with chemical sorption as the rate limiting step. The two adsorbents were found to be efficient in the sorption of Pb(II) ions.
Global Journal of Environmental Sciences, 2008
Journal of Applied Science, Engineering and Technology, 2009
The desorption of Ni 2+ from three oil palm fruit fibre adsorbents (UOPF, 0.5MOPF and 1.0MOPF) us... more The desorption of Ni 2+ from three oil palm fruit fibre adsorbents (UOPF, 0.5MOPF and 1.0MOPF) using five desorbing solutions showed a desorption efficiency following the trend, 0.1M HCl > 0.1MH 2 SO 4 > 0.1MHNO 3 > 0.1MNaOH >hot deionized H 2 O. The Elovich desorption constant, β values for the 0.1MHCl desorbent were: 6.45 X10-1 , 5.57 x 10-1 and 4.34 x 10-1 g. mg-.min-1 for UOPF,0.5MOPF and 1.0MOPF adsorbents respectively. The surface residence time ح values for the 0.1MHCl desorbent were; 32.3, 28.6 and 26.8 seconds for UOPF, 0.5MOPF and 1.0MOPF adsorbents respectively. Kinetic modeling analysis of the Elovich and pseudo-first order desorption equations, indicates that the latter model described the desorption of Ni 2+ better.
International Journal of Natural and Applied Sciences, 2006
ABSTRACT The kinetics of desorption of lead (II) ion from metal loaded adsorbent of mercaptoaceti... more ABSTRACT The kinetics of desorption of lead (II) ion from metal loaded adsorbent of mercaptoacetic acid modified and unmodified oil palm (Elaeis guineensis) fruit fiber was studied using different solutions, at different contact times. At the end of 25 minutes, 79.19%, 75.99%, 57.14%, 50.56% and 32.72% of Pb2+ were desorbed using 0.2 MHcl, 0.1 M H2S04, 0.1 MHNO3, 0.1 MNaOH and hot deionized H20 respectively for the 1.0 MOPF adsorbent. Desorption kinetic modeling of Pb2+ using the Elovich desorption and Pseudo-first Order Rate desorption equations showed that the latter described the kinetics of Pb2+ better. The desorption rate instant, β for 0.1 MHCl solution were: 7.27 x 10-1, 6.49 x 10-1 and 5.11 x 10-1, mg.g-1, .min-1, for UOPF, 0.5 MOPF and 1.0 MOPF adsorbents respectively. The surface residence time ح values for the 0.1 MHCl solutions were 24.83, 46.70 and 29.80 seconds for UOPF, 0.5 MOPF and 1.0 MOPF adsorbents respectively
Indian Journal of Chemical Technology, 2008
This study examines the sorption kinetics of Pb (II) and Cd (II) ions from aqueous solutions usin... more This study examines the sorption kinetics of Pb (II) and Cd (II) ions from aqueous solutions using unmodified and chemically modified oil palm fruit fibre. Four different models of the pseudo-second order equation were used to characterize the metal ion sorption kinetics. The results indicate that different kinetic parameters were obtained from the four forms of the pseudo-second order equations. The chemical modification of the adsorbent increased the equilibrium sorption capacity with maximum values of 5.579 mg/g for Pb(II) and 7.980 mg/g for Cd(II) for the 1.0 MOPF adsorbents. The coefficient of determination (r 2) was used to analyse the different pseudo second order equations with the best fit for each of the different metal ions.
Tsinghua Science & Technology, 2007
The kinetics of the sorption of Cd 2+ and Cr 3+ from aqueous solutions by mercaptoacetic acid mod... more The kinetics of the sorption of Cd 2+ and Cr 3+ from aqueous solutions by mercaptoacetic acid modified and unmodified oil palm fruit fibre adsorbents were investigated. The results indicate that sorption equilibrium was reached within 60 min for both metals. Also, the removal efficiency of the three adsorbents was observed to increase for both metals with stronger treatments with mercaptoacetic acid. This may be attributed to the influence of the thiolation of the adsorbents. Furthermore, Cr 3+ had higher removal percentages than Cd 2+ for all the adsorbents. The sorption mechanism based on the intraparticle diffusion model shows that Cd 2+ sorption is better described than Cr 3+. The intraparticle diffusion rate constants, K id , for Cd 2+ are 62.04 min −1 (untreated), 67.01 min −1 (treated with 0.5 mol/L mercaptoacetic acid), and 71.43 min −1 (treated with 1.0 mol/L mercaptocacetic acid) while those for Cr 3+ are 63.41 min −1 (untreated), 65.79 min −1 (0.5 mol/L acid treated), and 66.25 min −1 (1.0 mol/L acid treated).
Journal of Applied Sciences, 2006
World, 2010
... This was taken as the normal pH range for ordinary soils that favour plant and micro-organism... more ... This was taken as the normal pH range for ordinary soils that favour plant and micro-organisms. The mean values of soil pH ranged from 5.88 to 9.31. ... J Environ Qual. 32:129 137. Udosen, ED, Udoessien, EI and Ibok, UJ (1990). ...
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Papers by edidiong asuquo