Removal of ammonia nitrogen, nitrate, and phosphate from aqueous solution using biochar derived from Thalia dealbata...

Thalia dealbata Fraser-derived biochar was prepared at different carbonization temperatures to remove nutrients in aqueous solution. Thermogravimetry/differential thermogravimetry (TG/DTG) was used to analyze the carbonization and decomposition procedure of Thalia dealbata Fraser. X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), zeta potential, and N₂ adsorption-desorption isotherms were employed to characterize the prepared biochar. The carbonization temperature obviously effected the physical and chemical properties of biochar. The adsorption efficiency of ammonia (NH₄⁺-N), nitrate (NO₃^--N), and phosphate (PO₄^3-) adsorption on biochar was tested. Pseudo-first-order kinetic, pseudo-second-order kinetic, and intra-particle diffusion kinetic models were used to fit adsorption kinetic. Langmuir and Freundlich models were used to fit adsorption isotherms. The theoretical adsorption capacity of NH₄⁺-N, NO₃^--N, and PO₄^3- on biochar was 5.8 mg/g, 3.8 mg/g, and 1.3 mg/g, respectively. This study provides the insights for effect of carbonization temperature on biochar preparation and application.