Self-assembly of needle-like layered double hydroxide (LDH) nanocrystals on hydrochar: characterization and phosphate removal ability

Abstract

Ongoing efforts are being made to develop biochar materials that can enhance phosphate sorption for application as a mitigation method to prevent phosphorus transport. Layered double hydroxides (LDHs) embedded in a biochar matrix by liquid-phase deposition has been shown to have high phosphate adsorption capabilities, but this pyrolysis-based technique is complex and costly. This study successfully prepared a hydrochar–LDH nanocomposite material using a one-step hydrothermal method. Morphological analysis indicated that needle-like nano-sized LDH crystals were well formed within the hydrochar matrix. The hydrochar–LDH nanocomposite demonstrated rapid phosphate sorption kinetics and a maximum sorption capacity of 386 mg g⁻¹, which is comparable to the biochar–LDH nanocomposites prepared by liquid-phase deposition. The comparable sorption capacity of the hydrochar–LDH nanocomposite presents an attractive phosphate sorbent material that can be produced using a cost-effective, simple procedure.