TY  - JOUR
A1  - Unuabonah, Emmanuel I.
A1  - El-Khaiary, Mohammad I.
A1  - Olu-Owolabi, Bamidele I.
A1  - Adebowale, Kayode O.
T1  - Predicting the dynamics and performance of a polymer-clay based composite in a fixed bed system for the removal of lead (II) ion
JF  - Chemical engineering research and design
N2  - A polymer-clay based composite adsorbent was prepared from locally obtained kaolinite clay and polyvinyl alcohol. The composite adsorbent was used to remove lead (II) ions from aqueous solution in a fixed bed mode. The increase in bed height and initial metal ion concentration increased the adsorption capacity of lead (II) and the volume of aqueous solution treated at 50% breakthrough. However, the adsorption capacity was reduced by almost 16.5% with the simultaneous presence of Ca2+/Pb2+ and Na+/Pb2+ in the aqueous solution. Regeneration of the adsorbent with 0.1 M of HCl also reduced its adsorption capacity to 75.1%. Adsorption of lead (II) ions onto the polymer-clay composite adsorbent in the presence of Na+ and Ca2+ electrolyte increased the rate of mass transfer, probably due to competition between cationic species in solution for adsorption sites. Regeneration further increased the rate of mass transfer as a result of reduced adsorption sites after the regeneration process. The length of the mass transfer zone was found to increase with increasing bed height but did not change with increasing the initial metal ion concentration. The models of Yoon-Nelson, Thomas, and Clark were found to give good fit to adsorption data. On the other hand, Bohart-Adams model was found to be a poor predictor for the column operation. The polymer-clay composite adsorbent has a good potential for the removal of lead (II) ions from highly polluted aqueous solutions.
KW  - Fixed bed
KW  - Adsorption models
KW  - Polymer-clay composite
KW  - Regeneration
KW  - Breakthrough
KW  - Mass transfer zone
Y1  - 2012
U6  - https://doi.org/10.1016/j.cherd.2011.11.009
SN  - 0263-8762
VL  - 90
IS  - 8
SP  - 1105
EP  - 1115
PB  - Inst. of Electr. and Electronics Engineers
CY  - Rugby
ER  - 
TY  - JOUR
A1  - Omorogie, Martins O.
A1  - Babalola, Jonathan Oyebamiji
A1  - Unuabonah, Emmanuel I.
A1  - Gong, Jian Ru
T1  - Kinetics and thermodynamics of heavy metal ions sequestration onto novel
 Nauclea diderrichii seed biomass
JF  - BIORESOURCE TECHNOLOGY
N2  - This study reports the sequestration of Cd(II) and Hg(II) using a new biosorbent. Nauclea diderrichii seed biomass. Experimental data obtained were fitted into kinetic and thermodynamic models. Experimental data fitted best into pseudo-second order kinetic model among others. Results obtained kinetically revealed that the biosorption of Cd(II) and Hg(II) using N. diderrichii seed biosorbent increased with increase in temperature. At the highest temperature, which was 333 K. the highest amount of metal biosorbed, q(e), for Cd(II) and Hg(II) obtained were 6.30 and 6.15 mg/g respectively. The biosorption of Cd(II) was kinetically faster than that of Hg(II), the highest initial biosorption rates for Cd(II) and Hg(II) were 56.19 and 4.39 mg/g min respectively. Thermodynamic parameters obtained by Erying equation from this study revealed that the biosorption process was spontaneous, feasible, endothermic with a decrease in the degree of chaos in the biosorption system. (C) 2012 Elsevier Ltd. All rights reserved.
KW  - Nauclea diderrichii seed biosorbent
KW  - Biosorption
KW  - Kinetics
KW  - Thermodynamics
KW  - Film diffusion
Y1  - 2012
U6  - https://doi.org/10.1016/j.biortech.2012.04.053
SN  - 0960-8524
VL  - 118
IS  - 8
SP  - 576
EP  - 579
PB  - ELSEVIER SCI LTD
CY  - OXFORD
ER  - 
TY  - JOUR
A1  - Omorogie, Martins O.
A1  - Babalola, Jonathan Oyebamiji
A1  - Unuabonah, Emmanuel I.
A1  - Gong, Jian R.
T1  - Hybrid materials from agro-waste and nanoparticles: implications on the kinetics of the adsorption of inorganic pollutants
JF  - Environmental technology
N2  - This study is a first-hand report of the immobilization of Nauclea diderrichii seed waste biomass (ND) (an agro-waste) with eco-friendly mesoporous silica (MS) and graphene oxide-MS (GO+MS ) nanoparticles, producing two new hybrid materials namely: MND adsorbent for agro-waste modified with MS and GND adsorbent for agro-waste modified with GO+MS nanoparticles showed improved surface area, pore size and pore volume over those of the agro-waste. The abstractive potential of the new hybrid materials was explored for uptake of Cr(III) and Pb(II) ions. Analysis of experimental data from these new hybrid materials showed increased initial sorption rate of Cr(III) and Pb(II) ions uptake. The amounts of Cr(III) and Pb(II) ions adsorbed by MND and GND adsorbents were greater than those of ND. Modification of N. diderrichii seed waste significantly improved its rate of adsorption and diffusion coefficient for Cr(III) and Pb(II) more than its adsorption capacity. The rate of adsorption of the heavy metal ions was higher with GO+MS nanoparticles than for other adsorbents. Kinetic data were found to fit well the pseudo-second-order and the diffusion-chemisorption kinetic models suggesting that the adsorption of Cr(III) and Pb(II) onto these adsorbents is mainly through chemisorption mechanism. Analysis of kinetic data with the homogeneous particle diffusion kinetic model suggests that particle diffusion (diffusion of ions through the adsorbent) is the rate-limiting step for the adsorption process.
KW  - adsorption
KW  - graphene oxide
KW  - nanoparticles
KW  - kinetic models
KW  - hybrid materials
Y1  - 2014
U6  - https://doi.org/10.1080/09593330.2013.839747
SN  - 0959-3330
SN  - 1479-487X
VL  - 35
IS  - 5
SP  - 611
EP  - 619
PB  - Routledge, Taylor & Francis Group
CY  - Abingdon
ER  - 
TY  - JOUR
A1  - Omorogie, Martins O.
A1  - Babalola, Jonathan Oyebamiji
A1  - Unuabonah, Emmanuel I.
A1  - Song, Weiguo
A1  - Gong, Jian Ru
T1  - Efficient chromium abstraction from aqueous solution using a low-cost biosorbent: Nauclea diderrichii seed biomass waste
JF  - Journal of Saudi Chemical Society
N2  - Toxic Cr(III) which poses environmental hazard to flora and fauna was efficiently abstracted by low-cost Nauclea diderrichii seed biomass (NDS) with good sequestral capacity for this metal was investigated in this study. The NDS surface analyses showed that it has a specific surface area of 5.36 m(2)/g and pHpzc of 4.90. Thermogravimetric analysis of NDS showed three consecutive weight losses from 50-200 degrees C (ca. 5%), 200-400 C (ca. 35%), >400 degrees C (ca. 10%), corresponding to external water molecules, structural water molecules and heat induced condensation reactions respectively. Differential thermogram of NDS presented a large endothermic peak between 20-510 degrees C suggesting bond breakage and dissociation with the ultimate release of small molecules. The experimental data showed kinetically fast biosorption with increased initial Cr(III) concentrations, indicating the role of external mass transfer mechanism as the rate controlling mechanism in this adsorption process. The Langmuir biosorption capacity of NDS was 483.81 mg/g. The use of the corrected Akaike Information Criterion tool for ranking equilibrium models suggested that the Freundlich model best described the experimental data, which is an indication of the heterogeneous nature of the active sites on the surface of NDS. N. diderrichii seed biomass is an easily sourced, cheap and environmental friendly biosorbent which will serve as a good and cost effective alternative to activated carbon for the treatment of polluted water and industrial effluents. (C) 2012 King Saud University. Production and hosting by Elsevier B.V. All rights reserved.
KW  - Biomass
KW  - Equilibrium
KW  - External mass transfer
KW  - Kinetics
KW  - Adsorption
KW  - Water
Y1  - 2016
U6  - https://doi.org/10.1016/j.jscs.2012.09.017
SN  - 1319-6103
SN  - 2212-4640
VL  - 20
SP  - 49
EP  - 57
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Omorogie, Martins O.
A1  - Babalola, Jonathan Oyebamiji
A1  - Unuabonah, Emmanuel I.
A1  - Gong, Jian R.
T1  - Clean technology approach for the competitive binding of toxic metal ions onto MnO2 nano-bioextractant
JF  - Clean technologies and environmental policy
N2  - The competitive extraction of Cr(III) onto Nauclea diderrichii seed epicarp doped with MnO2 nanoparticles (MnO2 nano-bioextractant (MNB)) in a single and binary batch system was studied. For validity of experimental data, chi square test, root mean square error, sum of the square errors, hybrid fractional error function, Marquart’s percent standard deviation and standard absolute error were used. Among the kinetic models used, pseudo-second-order and Langmuir equations gave the best fits for the experimental data, with qe (mg g) for the uptake of Cr(III) in single metal system onto MNB, then Cr(III) with Cd(II), Pb(II), Hg(II), KCl and CaCl2 in binary metal systems onto MNB were 2.611, then 1.989, 1.016, 2.208, 1.249 and 1.868 from kinetic standpoint, respectively. The initial sorption rates, h (mg/g/min), and half lives, t1/2 (min), for the uptake of Cr(III) in single metal system onto MNB, then Cr(III) with Cd(II), Pb(II), Hg(II), KCl and CaCl2 in binary metal system onto MNB were 3.497, then 2.311, 2.274, 0.242, 2.956, 45.568 and 0.747, then 5.769, 1.766, 12.144, 1.762, and 2.415, respectively. Physicochemical surface analyses such as pH of point of zero charge, Brunauer–Emmett–Teller single point and multi-point techniques for surface area analyses, scanning electron microscopy and transmission electron microscopy were done on MNB and MnO2 nanoparticles in order to understand their surface microstructures. Desorption study showed that MNB can be recycled and used for future study. Hence, MNB showed good potential to remediate Cr(III) from wastewaters and polluted water.
KW  - Nauclea diderrichii
KW  - Nano-bioextractant
KW  - Doping
KW  - Kinetics
KW  - Mass transfer
Y1  - 2016
U6  - https://doi.org/10.1007/s10098-015-1004-z
SN  - 1618-954X
SN  - 1618-9558
VL  - 18
SP  - 171
EP  - 184
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Unuabonah, Emmanuel I.
A1  - Günter, Christina
A1  - Weber, Jens
A1  - Lubahn, Susanne
A1  - Taubert, Andreas
T1  - Hybrid Clay - a new highly efficient adsorbent for water treatment
JF  - ACS sustainable chemistry & engineering
N2  - New hybrid clay adsorbent based on kaolinite clay and Carica papaya seeds with improved cation exchange capacity (CEC), rate of heavy metal ion uptake, and adsorption capacity for heavy metal ions were prepared. The CEC of the new material is ca. 75 meq/100 g in spite of the unexpectedly low surface area (approximate to 19 m(2)/g). Accordingly, the average particle size of the hybrid clay adsorbent decreased from over 200 to 100 pm. The hybrid clay adsorbent is a highly efficient adsorbent for heavy metals. With an initial metal concentration of 1 mg/L, the hybrid clay adsorbent reduces the Cd2+, Ni2+, and Pb2+ concentration in aqueous solution to <= 4, <= 7 and <= 20 mu g/L, respectively, from the first minute to over 300 min using a fixed bed containing 2 g of adsorbent and a flow rate of approximate to 7 mL/min. These values are (with the exception of Pb2+) in line with the WHO permissible limits for heavy metal ions. In a cocktail solution of Cd2+, and Ni2+, the hybrid clay shows a reduced rate of uptake but an increased adsorption capacity. The CEC data suggest that the adsorption of Pb2+, Cd2+, and Ni2+ on the hybrid clay adsorbent is essentially due to ion exchange. This hybrid clay adsorbent is prepared from materials that are abundant and by a simple means that is sustainable, easily recovered from aqueous solution, nonbiodegradable (unlike numerous biosorbent), and easily regenerated and is a highly efficient alternative to activated carbon for water treatment.
KW  - Kaolinite
KW  - Hybrid clay
KW  - Water treatment
KW  - Cation exchange Capacity
KW  - Adsorbent
KW  - Kinetics
Y1  - 2013
U6  - https://doi.org/10.1021/sc400051y
SN  - 2168-0485
VL  - 1
IS  - 8
SP  - 966
EP  - 973
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Unuabonah, Emmanuel I.
A1  - Olu-Owolabi, Bamidele I.
A1  - Taubert, Andreas
A1  - Omolehin, Elizabeth B.
A1  - Adebowale, Kayode O.
T1  - SAPK a novel composite resin for water treatment with very high Zn2+, Cd2+, and Pb2+ adsorption capacity
JF  - Industrial & engineering chemistry research
N2  - A new sulfonated aniline-modified poly(vinyl alcohol)/K-feldspar (SAPK) composite was prepared. The cation-exchange capacity of the composite was found to be S times that of neat feldspar. The specific surface area and point of zero charge also changed significantly upon modification, from 15.6 +/- 0.1 m(2)/g and 2.20 (K-feldspar) to 73.6 +/- 0.3 m(2)/g and 1.91 (SAPK). Zn2+, Cd2+, and Pb2+ adsorption was found to be largely independent of pH, and the metal adsorption rate on SAPK was higher than that on neat feldspar. This particularly applies to the initial adsorption rates. The adsorption process involves both film and pore diffusion; film diffusion initially controls the adsorption. The Freundlich and Langmuir models were found to fit metal-ion adsorption on SAPK most accurately. Adsorption on neat feldspar was best fitted with a Langmuir model, indicating the formation of adsorbate monolayers. Both pure feldspar and SAPK showed better selectivity for Pb2+ than for Cd2+ or Zn2+.
Y1  - 2013
U6  - https://doi.org/10.1021/ie3024577
SN  - 0888-5885
VL  - 52
IS  - 2
SP  - 578
EP  - 585
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Unuabonah, Emmanuel I.
A1  - Taubert, Andreas
T1  - Clay-polymer nanocomposites (CPNs): Adsorbents of the future for water treatment
JF  - Applied clay science : an international journal on the application and technology of clays and clay minerals
N2  - A class of adsorbents currently receiving growing attention is the clay-polymer nanocomposite (CPN) adsorbents. CPNs effectively treat water by adsorption and flocculation of both inorganic and organic micropollutants from aqueous solutions. Some of these CPNs - when modified with biocides - also have the ability to efficiently remove microorganisms such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans from water. CPNs are far more easily recovered from aqueous media than neat clay. They also exhibit far better treatment times than either polymer or clay adsorbents. They have higher adsorption capacity and better life cycles compared with clay alone. CPNs therefore show an excellent potential as highly efficient water and waste treatment agents.
 This article reviews the various CPNs that have been prepared recently and used as adsorbents in the removal of micropollutants (inorganic, organic and biological) from aqueous solutions. A special focus is placed on CPNs that are not only interesting from an academic point of view but also effectively reduce the concentration of micropollutants in water to safe limits and also on new developments bordering on CPN use as water treatment agent that have not yet realized their full potential. (C) 2014 Elsevier B.V. All rights reserved.
KW  - Clay-polymer nanocomposite - CPN
KW  - Micropollutants
KW  - Adsorbent
KW  - Water treatment
KW  - Microorganism
KW  - Desorption
Y1  - 2014
U6  - https://doi.org/10.1016/j.clay.2014.06.016
SN  - 0169-1317
SN  - 1872-9053
VL  - 99
SP  - 83
EP  - 92
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Unuabonah, Emmanuel I.
A1  - Kolawole, Matthew O.
A1  - Agunbiade, Foluso O.
A1  - Omorogie, Martins O.
A1  - Koko, Daniel T.
A1  - Ugwuja, Chidinma G.
A1  - Ugege, Leonard E.
A1  - Oyejide, Nicholas E.
A1  - Günter, Christina
A1  - Taubert, Andreas
T1  - Novel metal-doped bacteriostatic hybrid clay composites for point-of-use disinfection of water
JF  - Journal of Environmental Chemical Engineering
N2  - This study reports the facile microwave-assisted thermal preparation of novel metal-doped hybrid clay composite adsorbents consisting of Kaolinite clay, Carica papaya seeds and/or plantain peels (Musa paradisiaca) and ZnCl2. Fourier Transformed IR spectroscopy, X-ray diffraction, Scanning Electron Microscopy and Brunauer-Emmett-Teller (BET) analysis are employed to characterize these composite adsorbents. The physicochemical analysis of these composites suggests that they act as bacteriostatic rather than bacteriacidal agents. This bacterostactic action is induced by the ZnO phase in the composites whose amount correlates with the efficacy of the composite. The composite prepared with papaya seeds (PS-HYCA) provides the best disinfection efficacy (when compared with composite prepared with Musa paradisiaca peels-PP-HYCA) against gram-negative enteric bacteria with a breakthrough time of 400 and 700 min for the removal of 1.5 x10(6) cfu/mL S. typhi and V. cholerae from water respectively. At 10(3) cfu/mL of each bacterium in solution, 2 g of both composite adsorbents kept the levels the bacteria in effluent solutions at zero for up to 24 h. Steam regeneration of 2 g of bacteria-loaded Carica papaya prepared composite adsorbent shows a loss of ca. 31% of its capacity even after the 3rd regeneration cycle of 25 h of service time. The composite adsorbent prepared with Carica papaya seeds will be useful for developing simple point-of-use water treatment systems for water disinfection application. This composite adsorbent is comparatively of good performance and shows relatively long hydraulic contact times and is expected to minimize energy intensive traditional treatment processes.
KW  - Kaolinite
KW  - Composites
KW  - Bacteria
KW  - Breakthrough time
KW  - Regeneration
Y1  - 2017
U6  - https://doi.org/10.1016/j.jece.2017.04.017
SN  - 2213-3437
VL  - 5
SP  - 2128
EP  - 2141
PB  - Elsevier
CY  - Oxford
ER  -