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 - 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 - 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 - Unuabonah, Emmanuel Iyayi A1 - Agunbiade, Foluso O. A1 - Alfred, Moses O. A1 - Adewumi, Thompson A. A1 - Okoli, Chukwunonso P. A1 - Omorogie, Martins O. A1 - Akanbi, Moses O. A1 - Ofomaja, Augustine E. A1 - Taubert, Andreas T1 - Facile synthesis of new amino-functionalized agrogenic hybrid composite clay adsorbents for phosphate capture and recovery from water JF - Journal of Cleaner Production N2 - New hybrid clay materials with good affinity for phosphate ions were developed from a combination of biomass-Carica papaya seeds (PS) and Musa paradisiaca (Plantain peels-PP), ZnCl2 and Kaolinite clay to produce iPS-HYCA and iPP-HYCA composite adsorbents respectively. Functionalization of these adsorbents with an organosilane produced NPS-HYCA and NPP-HYCA composite adsorbents. The pH(pzc) for the adsorbents were 7.83, 6.91, 7.66 and 6.55 for iPS-HYCA, NPS-HYCA, iPP-HYCA and NPP-HYCA respectively. Using the Brouer-Sotolongo isotherm model which best predict the adsorption capacity of composites for phosphate, iPP-HYCA, iPS-HYCA, NPP-HYCA, and NPS-HYCA composite adsorbents respectively. When compared with some commercial resins, the amino-functionalized adsorbents had better adsorption capacities. Furthermore, amino-functionalized adsorbents showed improved adsorption capacity and rate of phosphate uptake (as much as 40-fold), as well as retain 94% (for NPS-HYCA) and 84.1% (for NPP-HYCA) efficiency for phosphate adsorption after 5 adsorption-desorption cycles (96 h of adsorption time with 100 mg/L of phosphate ions) as against 37.5% (for iPS-HYCA) and 35% (for iPP-HYCA) under similar conditions. In 25 min desorption of phosphate ion attained equilibrium. These new amino-functionalized hybrid clay composite adsorbents, which were prepared by a simple means that is sustainable, have potentials for the efficient capture of phosphate ions from aqueous solution. They are quickly recovered from aqueous solution, non-biodegradable (unlike many biosorbent) with potentials to replace expensive adsorbents in the future. They have the further advantage of being useful in the recovery of phosphate for use in agriculture which could positively impact the global food security programme. (C) 2017 Elsevier Ltd. All rights reserved. KW - Composite adsorbents KW - Sustainable KW - Phosphate recovery KW - Water KW - Desorption kinetics Y1 - 2017 U6 - https://doi.org/10.1016/j.jclepro.2017.06.160 SN - 0959-6526 SN - 1879-1786 VL - 164 SP - 652 EP - 663 PB - Elsevier CY - Oxford ER -