Modified Biochar Derived from Grass Jelly Tree Waste as a Potential Adsorbent for Ibuprofen Adsorption from Water

Ibuprofen, abbreviated to IBP, is a widely used non-steroidal anti-inflammatory drug that can find its way into the environment via hospital and medical wastes, municipal wastewater, and through veterinary usage. IBP is harmful to aquatic life with long lasting effects and as such its release can pose an environmental hazard. Therefore, this study focussed on determining the potential of modified biochar derived from a by-product of the food industry, namely grass jelly tree waste, as an effective adsorbent for removing IBP from aqueous solutions. The modified biochar could be prepared by pyrolysis at 700 °C for 1 hour, then phosphoric acid modification was achieved by soaking for 24 hours, followed by washing with water until neutral. This modified biochar exhibited a specific surface area (SSA) of 111 m2/g, a total pore volume of 0.097 cm3/g with an average pore diameter of 3.49 nm. Adsorption parameters such as contact time, solution pH, concentration and temperature were studied. Batch adsorption experiments indicate that the modified biochar is highly efficient in removing IBP, with equilibrium rapidly being reached after 2 hours. Kinetic studies demonstrated that the adsorption of IBP on modified biochar fitted better to the pseudo-second order kinetic model than the pseudo-first order model. The Sips isotherm model which is a combination of Langmuir and Freundlich models demonstrated a superior fit of adsorption behaviour with the maximum adsorption capacity for IBP being 200.73 mg/g at optimal pH (pH 2). The thermodynamic parameters show that the adsorption is spontaneous, exothermic, and results in increased disorder. Thus, the use of grass jelly tree waste in the production of biochar can be a sustainable and economical approach for converting this industrial waste into a useful adsorbent for the remediation of pharmaceutical contaminated water.