Tabana, Kupa, & Tichapondwa (2025) Adsorption of hexavalent chromium from wastewater using magnetic 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 derived from peanut hulls. Physics and Chemistry of the Earth, Parts A/B/C. https://doi.org/10.1016/j.pce.2024.103815

Peanut hulls, a common agricultural byproduct, have emerged as a promising solution for wastewater treatment. Researchers have developed magnetic biochar from these shells to remove harmful hexavalent chromium (Cr(VI)) from water. Chromium, often found in industrial waste, is a hazardous pollutant linked to cancer and organ damage, necessitating innovative removal strategies.

This biochar is created through pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More, a process that heats organic material in low-oxygen conditions. To enhance its adsorption and separation abilities, peanut hulls are treated with ferric chloride and magnesium chloride. Optimal production involves heating the material at 300°C for two hours, with specific ratios of metal additives. Under these conditions, the biochar achieves a high adsorption efficiency, removing up to 98% of Cr(VI).

The study shows that the biochar’s performance is best in acidic conditions (pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More 3) and at a dosage of 5 g/L. Its effectiveness is attributed to its mesoporous structure and strong magnetic properties, which simplify the separation of the material from treated water. Unlike conventional adsorbents, this magnetic biochar offers a sustainable, cost-effective alternative that is easy to recycle and reuse.

With its capacity to handle toxic pollutants and minimize secondary waste, this magnetic biochar exemplifies how waste can be turned into a valuable resource, offering a scalable, eco-friendly approach to water purification.