Removal of ofloxacin hydrochloride and paracetamol from aqueous solutions: Binary mixtures and competitive adsorption

Abstract

The presence of pharmaceutical compounds in water bodies has raised serious concerns about their effect on the environment as well as human health. Ofloxacin hydrochloride (OFL), a fluroquinolone antibiotic and paracetamol (PCM), an analgesic are examples of commonly found drugs in wastewater. The present study aims to investigate the potential use of rice husk ash for the removal of these drugs from water. Rice husk ash was obtained by burning rice husk at 700˚C and characterized by FTIR, XRD, SEM, BET and EDX. Effect of factors influencing adsorption like adsorbate concentration, contact time, pH and sorbent dosage were evaluated. Batch studies have been conducted in order to obtain an optimum set of conditions for the maximum adsorption of OFL and PCM at varying drug concentrations of 10–100 mg L−1, contact time of 15 min–180 min and pH ranging from 2 to 12 as per the nature of the drug under study. Equilibrium data were subjected to kinetics and equilibrium studies to get the adsorption rate constant and maximum capacity of sorbent. Isotherm studies show that the maximum adsorption capacity for OFL is 7.34 mg g−1 and that for PCM is 7.65 mg g−1. The influence of one drug on the uptake of the other from binary solutions at varying concentration ratios of OFL and PCM in the ratios 1:0, 1:1, 1:2 and 1:3 has also been investigated for every fixed concentration of primary drug (i.e. 10 mg L−1, 50 mg L−1 and 100 mg L−1).