Guava leaves as adsorbent for the removal of emerging pollutant: Ciprofloxacin from aqueous solution

Abstract

In this work, the feasibility of using guava leaves powder (GLP) as an adsorbent to remove ciprofloxacin (CIP) from aqueous solution was investigated. The effectiveness of GLP to remove CIP was studied under different experimental conditions. The optimum pH for the adsorption of CIP was found to be pH 4. The adsorption trend was rapid at the initial stage and equilibrium was achieved in 60 min. The percentage uptake of CIP decreased with increasing initial CIP concentration. The adsorption kinetics was found to conform well to the pseudo-second order kinetic model. Characterisation of GLP was carried out by using field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and Fourier-transform infrared (FTIR) spectrophotometry. Both Langmuir and Freundlich isotherm models were applied to describe the equilibrium adsorption data of CIP onto GLP. The maximum adsorption capacity (qm) was found to be 232.56 mg g-1. By applying Plackett-Burman design, contact time and pH were found to be the influential parameters in affecting the uptake of CIP onto GLP.