A review on biochar composites for soil remediation applications: Comprehensive solution to contemporary challenges

Biochar has emerged as a promising material for solving many environmental challenges. It's derived from biomass pyrolysis and acts as a carbon shuttle between the atmosphere and soil. It also serves as a fertility agent and can remove contaminants from soil. This review aims to understand the effect of the choice of preparation methods and process parameters like temperature, feedstock, and additives on the characteristics of biochar. A detailed investigation into how biochar modifications enhance biochar properties and stability has been provided. Mechanisms of biochar composite applications for remediation of contaminated soil, carbon sequestration, and soil fertility enhancement through analysis of relevant research studies have been presented. Further, an effort has been made to discuss and suggest possible optimization of biochar preparation to achieve multiple goals in soil collectively. Specifically, the role of adding metal compounds, minerals, and ions has been explored. Challenges and conflicting research findings have also been mentioned based on the available literature. This paper majorly focuses on the need to address contemporary challenges like climate change, soil toxicity, and fertility loss holistically and sustainably using biochar composite application in soil. Future research in this field must include biochar applications in temporal and spatial aspects for optimal use.