Equilibrium isotherm investigation on the sequestration of ciprofloxacin from solution via adsorption onto yam peel powder

Abstract

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.