Batch adsorption studies on the removal of ciprofloxacin hydrochloride from aqueous solution using ZnO nanoparticles and groundnut (Arachis hypogaea) shell powder: a comparison

The present study pertains to batch studies on the removal of ciprofloxacin from aqueous solution using groundnut (Arachis hypogaea) shell powder and ZnO nanoparticles. An attempt has been made to compare the adsorption capacities of the two adsorbents. Nanoparticles synthesised by precipitation method have an average size of 68.61 nm as obtained from XRD and TEM data. Groundnut shell powder has been characterised by proximate and sieve analyses. Studies at varying pH 1-14, contact time, 15-180 min, and adsorbate concentration 10-100 mg/L, show maximum removal of 85.4% at pH 4 for ZnO nanoparticles and 79.6% at pH 6 for groundnut shell powder, for a contact time of 150 min and drug concentration 100 mg/L for both the adsorbents. Isotherm analyses show that favourable adsorption occurs which is physical in nature, is monolayer and there is a uniform distribution of adsorbate on the adsorbent surface. Results indicate that Freundlich, Langmuir and Temkin isotherms are obeyed. Kinetic studies indicate that pseudo-first-order kinetics is followed in both cases.