From non-conventional agricultural waste into sustainable and eco-friendly activated carbon through specified thermo-chemical protocol

The preparation of eco-friendly activated carbons (ACs) has gained significant attention due to their enhanced ability to remove a wide range of pollutants from water. Agricultural waste materials are promising precursors for the preparation of ACs due to their abundant availability and low cost. For the first time, this study is dedicated to preparing activated carbon from the useless leaves of sugar beet (LSB). This was conducted by thermo-chemical activation using H₃PO₄ as a robust activating agent. The activation process was carried out in a programmable furnace at a fixed temperature of 550 °C for 2 h. Different ratios of H₃PO₄ (85%) and pristine LSB (0.5:1, 1:1, 2:1, and 3:1) were used to produce four synthesized ACs, which were labeled as AC_(0.5:1), AC_(1:1), AC_(2:1) and AC_(3:1), respectively, for evaluating the impact of the impregnation ratios on the properties of these synthesized ACs. The as-synthesized ACs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FTIR), and Brunauer–Emmett–Teller surface area (S_BET) analysis. Among all the prepared ACs, AC_(2:1) showed the highest degree of amorphicity, which resulted in the highest S_BET value of 700.71 m²/g. This high surface area suggests a magnificent porous structure and surface chemistry of the synthesized AC, making it suitable for various environmental applications. The study shows that the thermo-chemical activation of sugar beet leaves with H₃PO₄ can produce a highly competent AC with excellent characteristics that can be used in waste management, water purification, and other related applications. Overall, this study highlights the potential of using useless LSB as a sustainable source of AC production and provides new insights into the preparation and characterization of eco-friendly ACs.