Eco-friendly remedies for soil contamination: manufacturing and analysis of nanobiochar using sugarcane bagasse and olive mill waste

Soil degradation poses a significant challenge to Egypt’s agriculture, making resource optimization essential. Nanobiochar presents a promising solution for pollutant removal; however, its low yields may hinder commercialization. This study investigates the production of biochar from sugarcane bagasse and olive mill waste, focusing on its composition, morphology, and effectiveness in soil immobilization. Advanced techniques like SEM, TEM, and FTIR were used to characterize the nanobiochar, highlighting its potential as a sustainable solution to soil contamination. The study revealed that ZnCl2 treatment significantly lowers pH, while KOH modification raises it. Surface morphology analysis showed that SCB biochar exhibited a highly porous structure, while OMW biochar had less porous edges and irregular oval-shaped pores. The effects of biochar activation on the availability of heavy metals like Ni, Pb, and Mo (in mg.Kg⁻¹) were also examined. Ni concentrations decreased from 1.27 mg.Kg⁻¹ in untreated biochar (NA) to 0.78 mg.Kg⁻¹ in KOH-treated biochar (KA) and 0.67 mg.Kg⁻¹ in ZnCl2-treated biochar (ZnA). Pb levels dropped from 7.7 mg.Kg⁻¹ in NA to 5.2 mg.Kg⁻¹ in KA and slightly to 4.74 mg.Kg⁻¹ in ZnA. Mo showed a similar trend, with the highest concentration in NA at 1.21 mg.Kg⁻¹, followed by 0.88 mg.Kg⁻¹ in KA and 0.75 mg.Kg⁻¹ in ZnA. Overall, OMW nanobiochar demonstrated a greener, more sustainable solution to soil contamination compared to SCB nanobiochar.