Adsorption Kinetics and Equilibrium of Ciprofloxacin from Aqueous Solutions Using Corylus avellana (Hazelnut) Activated Carbon

The adsorption of Ciprofloxacin (CIP) from aqueous solutions by hazelnut shell activated carbon (HSAC) was studied in a batch adsorption system. Factors influencing CIP adsorption such as contact time (10-180 min), initial CIP concentration (25–200 mg/L), pH (3–11), adsorbent dosage (0.3–3.0 g/L) and temperature (293–323 K) were investigated. The adsorption process was relatively fast and equilibrium was established about 60 min. Maximum adsorption of CIP occurred at around pH 6. A comparison of the kinetic models on the overall adsorption rate showed that the adsorption system was best described by the pseudo second-order kinetics. The adsorption equilibrium data fitted best with the Langmuir isotherm and the monolayer adsorption capacity of CIP was determined as 61.25, 67.39, 73.64 mg/g at 273, 298 and 323 K, respectively. Thermodynamic parameters were calculated for the CIP–HSAC system and the positive value of ΔH0 (3.064 kJ/mol) and negative values of ΔG0 showed that the adsorption was endothermic, spontaneous and physical in nature.