LAUSR

Abstract In the present paper column studies for the removal of ciprofloxacin hydrochloride from aqueous solution using vertical and sequential bed adsorption columns using ZnO nanoparticles and groundnut shell powder (GSP) as adsorbents have been discussed. Bed depth service time model (BDST) has been used to determine the column parameters i.e length of the column, bed depth and flow rate. Studies at varying drug concentrations and flow rates have been carried out at pH 4 for ZnO nanoparticles and 6 for groundnut shell powder i.e the pH where maximum adsorption of ciprofloxacin has been found to occur in batch studies using ZnO nanoparticles and groundnut shell powder. The bed capacity for ZnO nanoparticles has been found to be 6.1 mg/g and 6.24 mg/g using a vertical bed and sequential bed column respectively and for groundnut shell powder it is 5.59 mg/g and 6.29 mg/g for a feed concentration of 80 mg/L and flow rate 5 ml/min. at 298 K temperature. Analyses of breakthrough curves show that the time taken by columns for 50% breakthrough and 90% exhaustion increases with increase in the feed concentration and flow rate. The Thomas model and Yoon-Nelson models are in good agreement with experimental data. It is found that the bed capacity for sequential column, which is easier to handle and use, is slightly better than that of vertical column and can be considered for use in small scale industries.