Waste-to-Wealth:\nUnlocking the Potential of Pine Sawdust\nBiochar for Adsorption of Cobalt(II) and Nickel(II) Ions and Sustainable\nElimination of Carbamazepine from Aqueous Solutions

Sustainable waste management is the recycling, reusing,\nand recovery\nof wastes from natural sources. This research studied the conversion\nof Pinus sylvestris residues into sustainable\nbiochars with improved properties for the adsorption of Co(II) and\nNi(II) with further usage of spent biochars in the removal of carbamazepine.\nThe biochars possessed high surface areas and abundant chemical composition\nwith equilibrium adsorption capacities of 0.38 mmol/g for Co(II) and\n0.48 mmol/g for Ni(II), forming cobalt phosphate and nickel hydroxide\non the biochar surface. The laden biochars efficiently removed carbamazepine\nthrough adsorption and under UV light, following a first-order kinetic\nmodel with rate constants ranging from 0.0031 to 0.0042 min<sup>–1</sup> and achieving an efficiency of over 80%. The complex interaction\nmechanisms were responsible for the reduction of the carbamazepine\nconcentration in the studied systems. This research demonstrates that\nwaste wood raw materials can be used as synergistic multifunctional\nmaterials.