Sorptive removal of ibuprofen from water by natural porous biochar derived from recyclable plane tree leaf waste

To remove ibuprofen (IBP) in water efficiently and economically, plane tree leaf-derived biochar (P-BC) as a new adsorbent was prepared via pyrolysis at 600 degrees C. Textural characterizations of P-BC exhibited a porous structure and abundant hydroxyl groups. The results of FTIR and XPS indicated that -OH functional groups played a key role in the adsorption process. Batch adsorption studies were carried out at pH values of 2 to 8, adsorbent dosage of 0.1 to 2.0 g/L and initial concentrations of 500 to 5000 mu g/L. Adsorption results showed that P-BC (1.0 g/L) could remove as much as 96.34% of ibuprofen (2000 mu g/L) in a strong acidic environment (i.e. pH 2). The adsorption of ibuprofen by P-BC was found to be more consistent with the pseudo-second order kinetic model and Langmuir isothermal model with higher correlation coefficients of 0.999 and 0.996, respectively. Its maximum adsorption capacity was up to 10,410 mu g/g. A mechanism analysis demonstrated that the -OH functional groups on the surface of P-BC could form hydrogen bonds with IBP as donors and acceptors, respectively. It played a predominant role in removing IBP. In particular the fabricated P-BC is an effective and recyclable sorbent and its efficiency in removing ibuprofen can still reach more than 70% after five regenerations. The total production cost of P-BC is 4.05 USD / kg, which is equivalent to the treatment cost of only 0.004 USD/L wastewater. The results revealed that P-BC is an environment-friendly, low-cost and efficient adsorbent for removing IBP from water.