Pine-wood derived nanobiochar for removal of carbamazepine from aqueous media: Adsorption behavior and influential parameters

In recent years, application of biochar for removal of pollutants from aqueous solutions has been of interest due to favorable physicochemical properties and availability of feedstock. However, adsorption behavior has been reported only for raw and micro biochar particles and taking advantage of biochar nanoparticles, which offer superior specific surface area, did not receive any attention. The objective of this study was to investigate the adsorption efficiency of produced nanobiochar from pinewood. For this purpose, removal of carbamazepine (CBZ), a globally prescribed pharmaceutical, at very low concentrations (0.5–20ppb) on as-produced nanobiochar with average particle size of 60nm was studied. The results showed that nanobiochar can remove up to 95% of CBZ (74μg CBZ/g nanobiochar) after 3h contact time. Adsorption of CBZ on nanobiochar followed Freundlich isotherm model (R2=0.9822) and pseudo-second order kinetic model (R2=0.9994). It was found that increasing pH from 3 to 8 can enhance the adsorption efficiency by 2.3 folds. Also, due to the presence of surfactant in wastewater, the addition of Tween 80 as a model surfactant was studied in the range of 0 to 1 (Tween 80 to CBZ molar ratio) and the results showed that adsorption efficiency can be enhanced by 57%. Thus, the nanobiochar obtained from pinewood residues can be a promising sorbent for micropollutants.