No abstract

No abstract

No abstract

This study evaluated the performance of an Unmodified Ugwuoba-montmorillonite Clay (UUC) and the Acid Modified Ugwuoba-montmorillonite Clay (AMUC) of Nigerian origin as low-cost materials for attenuation of Methylene Blue (MB). Batch sorption methodology was applied in adsorption and desorption studies. AMUC was found to have higher adsorption of MB than UUC under all experimental conditions. Optimum experimental conditions were achieved at pH 8.0, adsorbent particle size 100 μm, MB concentration 200 mg/L and contact time of 60 and 90 min for AMUC and UUC, respectively. Equilibrium isotherm analysis was performed by the application of the Langmuir, Freundlich, Flory-Huggins, Tempkin, Dubinin-Radushkevich and Scatchard isotherm models. The Langmuir isotherm was found to be applicable (R2of 0.999) in the sorption of MB on UUC while the Freundlich gave the best fit (R2 of 0.990) for AMUC. Kinetic analysis was evaluated by the Pseudo First Order (PFO), Pseudo Second Order (PSO), Elovich, Bangham, Intraparticle diffusion and liquid film diffusion models. The PSO model was found to be applicable in the kinetics with an initial sorption rate of 0.647 and 1.477mg g-1 min-1 for the respective adsorbents. Thermodynamics revealed a spontaneous, feasible and exothermic adsorption process, while desorption studies showed a physical adsorption mechanism.

In this work, the adsorption of ciprofloxacin onto yam peel biosorbent was studied by batch method. The equilibrium isotherm analysis of the adsorption process was evaluated to provide insight into the removal mechanism. A decrease in the percentage removal (75.0 – 60.8%) and an increase in adsorption capacity (6.0 – 24.3 mg/g) with an increase in ciprofloxacin concentration from 20 – 100 mg/L was obtained. The isotherm was analyzed by the Langmuir, Temkin, Freundlich, and Scatchard models, and the best fit was obtained for the Freundlich model with a R2 of 0.9918. The separation factor in the range of 0.238 – 0.609 and the Freundlich adsorption intensity of 1.492 indicated a favorable adsorption of ciprofloxacin on yam peel. A monolayer adsorption capacity of 42.81 mg/g was obtained for yam peel which was higher than other efficient adsorbents. The Scatchard model gave a linear fit to the uptake data with R2 of 0.9653 and sum square error of 0.008. The isotherm analysis revealed complex adsorption involving multi mechanisms in the overall process. The results of this investigation showed that yam peel could be utilized as an efficient agricultural waste for the adsorption of ciprofloxacin from wastewater.