Research Outputs

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http://hdl.handle.net/20.500.11837/3244

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Browsing Research Outputs by Subject "Adsorption"

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    Influence of different chaotropic salts on etched mesoporous silica nanoparticles for the removal of bacteria DNA conveying antibiotic resistance genes from hospital wastewater
    (Elsevier, 2022-08-15) Ezeuko, S.; Ojemaye, O.; Okoh, OO.; Okoh, A.
    The adsorption of bacteria DNA onto mesoporous silica nanoparticles in their original state has been a great challenge due to the high negative charge exhibited by both the DNA and silica surface. The aim of this study is to mediate bacteria DNA onto synthesized mesoporous silica nanoparticles (E-MSN) in combination with different chaotropic salts. E-MSN was synthesized via chemical etching techniques using sodium dodecyl sulfate (SDS) as an etchant. SDS was used to remove unwanted layers and provides a convenient platform for underlining mesopore with different chaotropic salts. Scanning electron microscopy (SEM) coupled with energy-dispersive xray spectroscopy (EDX), Fourier-transformed infrared spectroscopy (FTIR), x-ray diffraction spectroscopy (XRD), and point of zero charges (PZC) results showed that synthesized etched mesoporous silica nanoparticles have a crystalline, non-spherical shape and elemental composition of silica at approximately 2 Kev, functional groups that depict silica particles. Molecular characterization of extracted genes showed that Enterococcus faecium harbors tetA, tetM, and ermB in 201bp, 158bp, and 320bp, with the DNA purity ranging from 1.7 to 1.9. DNA adsorption was studied as a function of operating parameters in different solutions of chaotropic salts (sodium chloride (NaCl), 2 M guanidine HCl (CH5N3.HCl), and urea ((NH3)2CO). Among the different chaotropic salts used to compliment the silica nanoparticles, 2 M guanidine HCl exhibited the highest percentage (%) removal efficiency (90%) compared to urea (75%) and sodium chloride (70%) in simulated water and hospital wastewater. Experimental results revealed that the pseudo-second-order kinetic and Sips isotherm is the best fit for the adsorption process. Therefore, mesoporous silica nanoparticles enhanced by different chaotropic salts in this study showed that this material might be promising and economical for the uptake of bacteria DNA conveying antibiotics resistance genes from hospital wastewater.
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    The effectiveness of silver nanoparticles as a clean-up material for water polluted with bacteria DNA conveying antibiotics resistance genes: Effect of different molar concentrations and competing ions
    (Elsevier, 2022-07-22) Ezeuko CS; Ojemaye O; Okoh OO; Okoh A
    This study employed silver nanoparticles to remove DNA conveying antibiotic resistance genes from water. Three different molar concentrations of silver nanoparticles represented as BD1 (0.1M), BD2 (0.5 M), and BD3 (1.0 M) were synthesized as adsorbents and evaluated in a batch adsorption system for the removal of bacteria DNA conveying antibiotic resistance genes from simulated aqueous solution. The authenticity of the adsorbents was confirmed by characterization techniques using Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) coupled with energy-dispersive x-ray spectroscopy (EDX), and x-ray diffraction spectroscopy (XRD) indicated the successful synthesis of these AgNPs. Adsorption studies involving the different operating conditions on the synthesized materials showed that pH affects the removal of DNA with increased removal efficiency observed at acidic pH (removal percentage ranging from 50.26-87.61%, 65.80-87.79%, and 69.23-87.92% for BD1, BD2, and BD3 respectively). Maximum adsorption equilibrium was achieved after 180, 195, and 225 mins for BD1, BD2, and BD3. The isotherm study revealed that Langmuir model is the best fit compared to Freundlich model with highest correlation coefficient and reduced Chi-square (X2) of R2 = 0.97625 and X2 = 0.12142, R2 = 0.96049 and X2 = 0.24403, R2 = 0.85108 and reduced X2 = 1.00914 for BD1, BD2, and BD3 respectively. The kinetic study for the adsorption process indicates that the adsorption of bacteria DNA onto AgNPs obeyed pseudo-second-order with the highest R2 values (ranging from 0.90 to 0.98). Similarly, competing ions (cations and anions) influenced the adsorption capacity in this study. Therefore, this study concludes that AgNPs demonstrated effectiveness in removing bacteria DNA-conveying ARGs from water and will serve as an excellent option to tackle the menace of ARGs in water.