Advances in biochar composites for environmental sustainability

The rapid degradation of the environment, which includes water pollution and soil depletion, presents significant challenges to global sustainability efforts. According to a United Nations report, approximately 2 billion people do not have access to safe drinking water associated with declining soil quality which threatens agricultural productivity. In order to tackle these pressing societal issues, it is essential to focus on creating adaptable materials for remediation and sustainable resource management. Concurrently, the scientific community is confronted with the task of harmonising the effectiveness, financial feasibility and ecological footprint of these technologies. Here, we review the preparation methods and applications of biochar composites with a focus on pyrolysis, co-precipitation and ball milling techniques. The study highlights biochar composites achieve removal rates exceeding 98% for toxic metals like Cr(VI) and Pb(II) and improve soil fertility through nutrient retention mechanisms. Biochar composites exhibit promising potential in the energy sector for enhancing supercapacitor and lithium-ion battery performance. Breakthroughs in microwave-assisted pyrolysis have led to the development of energy-efficient synthesis methods, while innovative co-precipitation techniques have been discovered for pollutant adsorption. However, despite these promising developments, the high preparation costs and material stability challenges have limited large-scale implementation. Our analysis provides a roadmap for future research on low-cost synthesis methods and long-term stability. Ultimately, biochar composites can play a pivotal role in environmental remediation, energy storage and sustainable agriculture.