Biochar catalytic architectures for pesticide degradation: Design, mechanisms and soil detoxification: Bridging the lab-field gap. A critical review

Biochar-based catalytic systems have emerged to be promising materials that combine adsorption and catalytic degradation for pesticide remediation. However, they are under a non-linear relationship for good sorption and effective mineralization, which is also influenced by soil organic matter (SOM), soil pH, microbial interactions and catalyst ageing. This review critically reviews the recent advances in the rational design of biochar catalytic architectures like metal-modified, photocatalytic heterojunctions, carbon hybrids and bio-hybrids, and the dominant mechanisms such as Reactive Oxygen Species (ROS) generation, interfacial electron transfer, surface complexation, and the soil-specific factors that govern the field performance of biochars. Laboratory efficiencies are in the range 95–99.7%, while field results are in the range 37–99.7% and often drop over time as a result of SOM competition, radical scavenging and material ageing. This review provides a comprehensive conceptual framework between the structural characteristics of biochar, the catalytic mechanism, and its environmental behavior, and we provide an overview of important challenges including metal leaching, long-term stability, scalability, and the data-driven framework (machine-learning) and design principles necessary to bridge the laboratory-field divide. A practical roadmap for site-specific and environment-friendly biochar catalysts for sustainable soil detoxification is presented at the end of the review.