Liu, et al (2024) Silicone-modified black peanut shell (BPS) biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More adsorbents: Preparation and their adsorptions for copper(II) from water. Heliyon. https://doi.org/10.1016/j.heliyon.2024.e3516

Water pollution caused by heavy metal ions, particularly copper (II), has become a pressing ecological issue due to its toxic effects on humans and animals. Copper contamination primarily stems from industrial activities such as mining, smelting, and manufacturing. Traditional methods to remove copper from wastewater often suffer from inefficiencies, high costs, and potential secondary pollution. Among various techniques, adsorption stands out for its cost-effectiveness, ease of operation, and environmental friendliness.

Recent research has focused on developing modified biochar adsorbents to enhance copper removal efficiency. A novel approach involves the use of silicone-modified biochar made from waste black peanut shells (BPS). This study explored the preparation and effectiveness of these modified biochar adsorbents (BPS-MBCs) in removing copper (II) from water.

The preparation of BPS-MBCs involves pyrolyzing black peanut shells at 400°C, followed by acid treatment and modification with gamma-amino-propyl triethoxysilane (a type of silicone). This process enhances the specific surface area and porosityPorosity of biochar is a key factor in its effectiveness as a soil amendment and its ability to retain water and nutrients. Biochar’s porosity is influenced by feedstock type and pyrolysis temperature, and it plays a crucial role in microbial activity and overall soil health. Biochar More of the biochar, thereby improving its adsorption capacity for copper (II).

The adsorption performance of BPS-MBCs was analyzed through various models and experiments. Kinetic studies revealed that copper adsorption on BPS-MBCs followed pseudo-second-order kinetics, indicating that chemical adsorption predominates. Intraparticle diffusion and external mass-transfer models helped estimate diffusion coefficients, showing that multiple processes, including physical adsorption, chemical adsorption, and diffusion-chemisorption, play roles in copper removal.

Thermodynamic parameters indicated that copper adsorption on BPS-MBCs is an endothermic and spontaneous process. The maximum adsorption capacity of BPS-MBC-400, a specific variant of the modified biochar, was found to be approximately 284 mg/g at 45°C. This capacity is significantly higher than that of unmodified biochar, underscoring the effectiveness of silicone modification.

Further experiments demonstrated that BPS-MBCs could be effectively regenerated and reused for copper adsorption, maintaining their efficiency over multiple cycles. The adsorption mechanism was primarily driven by weak non-covalent interactions, as suggested by the low sorption energy values obtained from the Temkin and Dubinin-Radushkevich isotherm models.

Characterization techniques such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) provided insights into the structural changes in biochar before and after modification. The incorporation of silicone introduced functional groups that enhanced the biochar’s affinity for copper ions. SEM images confirmed the presence of mesopores, which facilitated better diffusion and adsorption of copper.

The study concludes that silicone-modified biochar from black peanut shells is a promising and sustainable adsorbent for removing copper (II) from wastewater. Its high adsorption capacity, ease of regeneration, and low production cost make it a viable solution for industrial applications. Moreover, the use of agricultural waste as a raw material aligns with environmental sustainability goals by reducing waste and promoting circular economy practices.

Future research could explore the application of this modified biochar for other heavy metals and pollutants, as well as scaling up the production process for commercial use. The continued development of green and efficient adsorbents is crucial for addressing the global challenge of water pollution and ensuring clean water for all.