TY - JOUR A1 - Ugwuja, Chidinma G. A1 - Adelowo, Olawale O. A1 - Ogunlaja, Aemere A1 - Omorogie, Martins O. A1 - Olukanni, Olumide D. A1 - Ikhimiukor, Odion O. A1 - Iermak, Ievgeniia A1 - Kolawole, Gabriel A. A1 - Günter, Christina A1 - Taubert, Andreas A1 - Bodede, Olusola A1 - Moodley, Roshila A1 - Inada, Natalia M. A1 - Camargo, Andrea S.S. de A1 - Unuabonah, Emmanuel Iyayi T1 - Visible-Light-Mediated Photodynamic Water Disinfection @ Bimetallic-Doped Hybrid Clay Nanocomposites JF - ACS applied materials & interfaces N2 - This study reports a new class of photocatalytic hybrid clay nanocomposites prepared from low-cost sources (kaolinite clay and Carica papaya seeds) doped with Zn and Cu salts via a solvothermal process. X-ray diffraction analysis suggests that Cu-doping and Cu/Zn-doping introduce new phases into the crystalline structure of Kaolinite clay, which is linked to the reduced band gap of kaolinite from typically between 4.9 and 8.2 eV to 2.69 eV for Cu-doped and 1.5 eV for Cu/Zn hybrid clay nanocomposites (Nisar, J.; Arhammar, C.; Jamstorp, E.; Ahuja, R. Phys. Rev. B 2011, 84, 075120). In the presence of solar light irradiation, Cu- and Cu/Zn-doped nanocomposites facilitate the electron hole pair separation. This promotes the generation of singlet oxygen which in turn improves the water disinfection efficiencies of these novel nanocomposite materials. The nanocomposite materials were further characterized using high-resolution scanning electron microscopy, fluorimetry, therrnogravimetric analysis, and Raman spectroscopy. The breakthrough times of the nanocomposites for a fixed bed mode of disinfection of water contaminated with 2.32 x 10(7) cfu/mL E. coli ATCC 25922 under solar light irradiation are 25 h for Zn-doped, 30 h for Cu-doped, and 35 h for Cu/Zn-doped nanocomposites. In the presence of multidrug and multimetal resistant strains of E. coli, the breakthrough time decreases significantly. Zn-only doped nanocomposites are not photocatalytically active. In the absence of light, the nanocomposites are still effective in decontaminating water, although less efficient than under solar light irradiation. Electrostatic interaction, metal toxicity, and release of singlet oxygen (only in the Cu-doped and Cu/Zn-doped nanocomposites) are the three disinfection mechanisms by which these nanocomposites disinfect water. A regrowth study indicates the absence of any living E. coli cells in treated water even after 4 days. These data and the long hydraulic times (under gravity) exhibited by these nanocomposites during photodisinfection of water indicate an unusually high potential of these nanocomposites as efficient, affordable, and sustainable point-of-use systems for the disinfection of water in developing countries. KW - disinfection KW - nanocomposite material KW - multidrug-resistant Escherichia coli KW - water KW - reactive oxygen species Y1 - 2019 U6 - https://doi.org/10.1021/acsami.9b01212 SN - 1944-8244 SN - 1944-8252 VL - 11 IS - 28 SP - 25483 EP - 25494 PB - American Chemical Society CY - Washington, DC ER - TY - JOUR A1 - Unuabonah, Emmanuel Iyayi 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 Iyayi 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 - Babalola, Jonathan Oyebamiji A1 - Omorogie, Martins Osaigbovo A1 - Babarinde, Adesola Abiola A1 - Unuabonah, Emmanuel Iyayi A1 - Oninla, Vincent Olukayode T1 - OPTIMIZATION OF THE BIOSORPTION OF Cr3+, Cd2+ AND Pb2+ USING A NEW BIOWASTE: Zea mays SEED CHAFF JF - Environmental engineering and management journal N2 - This study highlights the potential use of yellow Zea mays seed chaff (YZMSC) biomass as a biosorbent for the removal of Cr3+, Cd2+ and Pb2+ ions from aqueous solutions. Fourier transformed Infrared analysis of the biomass suggests that YZMSC biomass is basically composed of cellulose and methyl cellulose. The biosorption capacities, q(max), of YZMSC biomass for Cr3+, Cd2+ and Pb2+ are 14.68, 121.95 and 384.62 mg/g respectively. Biosorption equilibrium was achieved at 20, 30 and 60 min for Cr3+, Cd2+ and Pb2+ respectively. YZMSC biomass was found to have higher biosorption capacity and overall kinetic rate of uptake for Pb2+ than for Cd2+ and Cr3+. However, Cr3+ had better initial kinetic rate of uptake by the biomass than Pb2+ and Cd2+. The Freundlich equilibrium isotherm model was found to describe equilibrium data better than Langmuir model suggesting that biosorption of these metal ions could be on more than one active site on the surface of YZMSC biomass. Kinetic study predicted the pseudo-second kinetic model as being able to better describe kinetic data obtained than either modified pseudo-first order or Bangham kinetic models. Biosorption of Cr3+, Cd2+ and Pb2+ onto YZMSC biomass was endothermic in nature with large positive entropy values. Biosorption of these metal ions onto YZMSC biomass was observed to be feasible and spontaneous above 283 K. Optimization of biomass weight for the removal of these metal ions suggest that 384 kg, 129 kg and 144 kg of YZMSC biomass is required for the removal of 95% of Cr3+, Cd2+ and Pb2+ metal ions respectively from 100 mg/L of metal ions in 10 tonnes of aqueous solutions. KW - biomass KW - biosorption KW - optimization KW - yellow Zea mays Y1 - 2016 SN - 1582-9596 SN - 1843-3707 VL - 15 SP - 1571 EP - 1580 PB - Gh. Asachi Universitatea Tehnică IaÅŸi CY - Iasi ER - TY - JOUR A1 - Unuabonah, Emmanuel Iyayi 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 - TY - JOUR A1 - Unuabonah, Emmanuel Iyayi A1 - Nöske, Robert A1 - Weber, Jens A1 - Günter, Christina A1 - Taubert, Andreas T1 - New micro/mesoporous nanocomposite material from low-cost sources for the efficient removal of aromatic and pathogenic pollutants from water JF - Beilstein journal of nanotechnology N2 - A new micro/mesoporous hybrid clay nanocomposite prepared from kaolinite clay, Carica papaya seeds, and ZnCl2 via calcination in an inert atmosphere is presented. Regardless of the synthesis temperature, the specific surface area of the nanocomposite material is between approximate to 150 and 300 m(2)/g. The material contains both micro- and mesopores in roughly equal amounts. X-ray diffraction, infrared spectroscopy, and solid-state nuclear magnetic resonance spectroscopy suggest the formation of several new bonds in the materials upon reaction of the precursors, thus confirming the formation of a new hybrid material. Thermogravimetric analysis/differential thermal analysis and elemental analysis confirm the presence of carbonaceous matter. The new composite is stable up to 900 degrees C and is an efficient adsorbent for the removal of a water micropollutant, 4-nitrophenol, and a pathogen, E. coli, from an aqueous medium, suggesting applications in water remediation are feasible. KW - 4-nitrophenol KW - Carica papaya seeds KW - clay KW - E. coli KW - micro/mesoporous KW - nanocomposite KW - water remediation Y1 - 2019 U6 - https://doi.org/10.3762/bjnano.10.11 SN - 2190-4286 VL - 10 SP - 119 EP - 131 PB - Beilstein-Institut zur Förderung der Chemischen Wissenschaften CY - Frankfurt, Main ER - TY - JOUR A1 - Ofomaja, Augustine Enakpodia A1 - Unuabonah, Emmanuel Iyayi T1 - Kinetics and time-dependent Langmuir modeling of 4-nitrophenol adsorption onto Mansonia sawdust JF - Journal of the Taiwan Institute of Chemical Engineers N2 - Often time's adsorption of large molecules onto untreated lignocellulosic materials is viewed as a two stage process and has frequently been characterized only by kinetic models while the rate limiting step of adsorption is determined only at various stages of the adsorption process. In this study the kinetics and the contribution of diffusion processes to 4-nitrophenol adsorption onto untreated sawdust was examined and the overall rate limiting step evaluated. The adsorption profile showed an initial rapid uptake of 4-nitrophenol which decreased and became almost constant after 5 min of contact. Analysis of the adsorption profile with the intraparticle diffusion equation and fractional 4-nitrophenol uptake with time showed that the profile can be divided into three different stages. The rate determining step of 4-nitrophenol adsorption was then evaluated based on the activation energies of each processes along with their activation parameters (Delta G*, Delta H* and Delta S*). The results revealed that external mass transfer was the overall rate limiting step with activation parameters E-a = 21.11, Delta H* = 23.75 and Delta S* = 144.97. Time dependent Langmuir modeling was carried out to optimize process parameters. (c) 2013 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved. KW - Untreated agricultural wastes KW - Activation parameters KW - Diffusion processes KW - Double exponential model KW - 4-Nitrophenol KW - Adsorption Y1 - 2013 U6 - https://doi.org/10.1016/j.jtice.2012.12.021 SN - 1876-1070 VL - 44 IS - 4 SP - 566 EP - 576 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Omorogie, Martins O. A1 - Babalola, Jonathan Oyebamiji A1 - Unuabonah, Emmanuel Iyayi 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 Iyayi 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 - Unuabonah, Emmanuel Iyayi 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 -