Low-cost silica xerogels as potential adsorbents for ciprofloxacin removal

Abstract

Ciprofloxacin, a second generation fluoroquinolone antibiotic, is one of the top pharmaceutical contaminants in water and many approaches have been developed for the removal of ciprofloxacin in wastewater. In this study, ciprofloxacin adsorption is carried out using a low-cost silica xerogel synthesized by a simple sol-gel method. The effect of pH, contact time, initial concentration of ciprofloxacin and temperature on the adsorption of ciprofloxacin by the silica xerogel is investigated. At optimum adsorption conditions, the experimental data fits well to a Langmuir isotherm and a pseudo-second-order kinetic model. The maximum ciprofloxacin adsorption capacity is determined as 24.45 mg g−1. Thermodynamic parameters show that ciprofloxacin adsorption by the silica xerogel is a spontaneous endothermic process. Moreover, reusability experiments reveal that the silica xerogel can be effectively used several times for ciprofloxacin adsorption. The promising results indicate that the silica xerogel can be regarded as potential adsorbent for ciprofloxacin removal.