Heavy metals such as copper, often discharged from industrial processes and agricultural activities, pose significant environmental and health risks due to their toxicity, particularly in the soluble form of Cu (II). This study investigates the effectiveness of biochar produced from date palm leaf midrib waste via a two-step pyrolysis process, as a sustainable and economical adsorbent for removing Cu (II) from aqueous solutions The biochar was characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), and Brunauer–Emmett–Teller (BET) surface area analysis. Adsorption experiments were conducted to evaluate the effects of pH, adsorbent dosage, contact time, and initial Cu (II) concentration. The maximum adsorption capacity was observed at pH 6, with a capacity of 70 mg/g. The adsorption data were best described by the pseudo-second-order kinetic model, indicating chemisorption as the primary mechanism. Thermodynamic studies indicated that the adsorption process was spontaneous and exothermic, with a Gibbs free energy change (ΔG) of −1.245 kJ/mol at 25 °C, enthalpy change (ΔH) of −15.71 kJ/mol, and entropy change (ΔS) of 48.36 J/mol·K. Reusability tests demonstrated that the biochar retained over 85% of its initial adsorption capacity after five cycles, with capacities of 60 mg/g in the first cycle, decreasing to 52 mg/g by the fifth cycle. This study highlights the potential of biochar derived from date palm waste as an efficient, sustainable adsorbent for the removal of Cu (II) from wastewater, contributing to both environmental management and waste valorization. Future research should focus on optimizing the biochar production process and exploring its application for the removal of other contaminants.

This study addresses the environmental and health hazards posed by Pb(II) and iodine, two significant contaminants. The objective was to explore the adsorption of these substances from aqueous solutions using biochar derived from the leaf midribs of the date palm through a slow pyrolysis process. The pyrolysis was conducted in two stages within a vacuum furnace: initially at 300 °C for 1 h followed by overnight cooling, and then at 600 °C with a similar cooling process. The resulting biochar was characterized for its microstructural features and functional groups using scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. It exhibited a porous structure with large numbers of pores (20 to 50 μm in size) and functional groups including O-H, C-H, and C=C, which are integral to its adsorption capabilities. For the adsorption studies, a 100 ppm Pb(II) ion solution was treated with varying amounts of biochar (20, 40, 60, and 80 mg) for 24 h. In parallel, iodine adsorption was tested, with biochar quantities ranging from 0.1 to 0.4 g/50 mL. Both treatments were followed by filtration and analysis using atomic absorption spectroscopy to determine the remaining concentrations of Pb(II) and iodine. The study also explored the effect of varying incubation periods (up to 30 h) on iodine adsorption. The results were significant; 100% adsorption of Pb(II) was achieved with the addition of 60 mg of biochar per 10 mL of solution. In contrast, for iodine, a maximum adsorption of 39.7% was observed with 30 mg or 40 mg of biochar per 50 mL. These findings demonstrate the potential of date palm-derived biochar as an effective and sustainable material for the removal of Pb(II) and iodine from contaminated water, offering valuable insights for environmental remediation strategies.

This study explores the adsorption efficiency of biochar derived from palm trees and Ficus nitida for the removal of various contaminants, including Cu(II), Pb(II), iodine, and chlorpyrifos from aqueous solutions. Biochar was prepared using a two-step pyrolysis process for date palm biochar and single-step pyrolysis for Ficus nitida biochar. Characterization techniques such as SEM, EDX, and FTIR revealed a significant surface area and a variety of functional groups in both types of biochar, essential for effective adsorption. The date palm biochar exhibited superior adsorption capacities for Cu(II) and Pb(II) ions, achieving efficiencies up to 99.9% and 100%, respectively, due to its high content of oxygen-containing functional groups that facilitated strong complexation and ion exchange mechanisms. Conversely, Ficus nitida biochar demonstrated a higher adsorption capacity for iodine, reaching 68% adsorption compared to 39.7% for date palm biochar, owing to its greater surface area and microporosity. In the case of chlorpyrifos, Ficus nitida biochar again outperformed date palm biochar, achieving a maximum adsorption efficiency of 87% after 24 h of incubation, compared to 50.8% for date palm biochar. The study also examines the effect of incubation time on adsorption efficiency, showing that the adsorption of chlorpyrifos by date palm biochar increased significantly with time, reaching a maximum of 62.9% after 48 h, with no further improvement beyond 12 h. These results highlight the importance of biochar characteristics, such as surface area, pore structure, and functional groups, in determining adsorption efficiency. The findings suggest that optimizing pyrolysis conditions and surface modifications could further enhance the performance of biochar as a cost-effective and sustainable solution for water purification and environmental remediation.