CHEMICALLY MODIFIED BIOCHARS FOR THE REMOVAL OF IBUPROFEN AND DICLOFENAC FROM WATER

Abstract

Non-steroidal anti-inflammatory drugs like ibuprofen and diclofenac are recognized as contaminants of emerging concern since they have been found in various environmental matrices and have long-lasting ecotoxic impacts on biotic components of the ecosystem. Owing to their persistence in wastewater treatment, their elimination is desirable. Adsorption is one of the most promising methods for the removal of pollutants from water. In present research, three different biochars were prepared from pine cones, apricot shells and walnut shells at 500 °C and 800 °C via pyrolysis, which were chemically modified with ZnCl2 and FeCl3 mineral salts. Batch adsorption studies were performed to assess the effect of biochar dose, initial concentration and contact time. Results showed that FeCl3 modified walnut biochar, removed a higher percentage (78.30%) of diclofenac. Contrarily, ZnCl2 modified pine cone biochar removed higher percentage (75.97%) of ibuprofen from water at a dose of 5 g/L among other biochars. Monolayer and multilayer adsorption on the biochars was predicted by Langmuir and Freundlich isotherm models, which best fitted the sorption data. The adsorption kinetics data of ibuprofen and diclofenac fitted well to the power function, Elovich and pseudo-second-order models suggesting a variety of mechanisms were likely at play in the adsorption of ibuprofen onto biochars. This study demonstrates that modified biochars have the ability to adsorb emergent pollutants such as ibuprofen and diclofenac from water.