Metal oxide-biochar composites have emerged as a promising solution for water and soil remediation. While 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 has been used for various environmental applications, its limitations in contaminant immobilization and water treatment have led to the development of composites that incorporate metal oxides. Recent studies highlight how functionalizing biochar with metal oxides, such as Fe, Zn, and Ce, enhances its surface area and chemical properties, improving the adsorption and removal of pollutants.

The synthesis of these composites often involves methods like direct 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, chemical precipitation, and impregnation with metal salts. The resulting materials have shown significant efficiency in removing contaminants such as heavy metals and organic pollutants from both water and soil. For instance, metal-biochar composites achieve removal rates as high as 100% for some inorganic contaminants and 98.9% for lead in soil. They work through mechanisms like electrostatic attraction, complexation, and oxidation/reduction reactions.

Despite their potential, challenges remain. Issues such as the environmental risks of metal leachingLeaching is the process where nutrients are dissolved and carried away from the soil by water. This can lead to nutrient depletion and environmental pollution. Biochar can help reduce leaching by improving nutrient retention in the soil.   More, high production costs, and the need for more sustainable synthesis methods need to be addressed. Future research should focus on life cycle assessments, large-scale applications, and leveraging machine learning to optimize synthesis processes.

In conclusion, metal oxide-biochar composites represent a promising and sustainable technology for addressing water and soil pollution. However, further research is required to fully unlock their potential for industrial applications.