Organic residues as adsorbent for the removal of ciprofloxacin from aqueous solution

Abstract

Ciprofloxacin was used to study the adsorbent properties of three organic residues: corn cob and rice husk. The study encompassed measuring the effect of the biomass dose, pH, contact time, temperature and initial concentration of the drug. The optimal dose of the adsorbent was established in 2 and 6 g L−1 for the corn cob and rice husk, respectively. The pH strongly affects the adsorption of ciprofloxacin; the optimum pH for the absorption of ciprofloxacin onto the three biomasses is 6. The experiments show a rapid adsorption that hits equilibrium in 60 min for the rice husk and 40 min for corn cob. The temperature has little in fluence with a tendency to a decrease in the percentage of removal when the temperature increases. The removal percentage of ciprofloxacin reaches 56.3% for corn cob and 59.7% for rice husk given an ambient temperature of 20 °C and a ciprofloxacin concentration of 5 mg L−1. The experimental adsorption data can be fitted well by the Freundlich model and the kinetic data by a pseudo second order model. The obtained results suggest that maize and rice husk can be used as low-cost biosorbents for the removal of ciprofloxacin from aqueous solutions.