Enhanced Surface Properties of Biochar Using Activation Strategies for Sustainable Dye Removal: A Review

ABSTRACT Water pollution due to hazardous dyes is a severe issue that requires investigation through sustainable and cost‐effective approaches. In the current scenario, biochar, a carbon‐rich material derived from biomass, has found significant importance as an alternative to traditional adsorbents like activated carbon. The wastewater treatment efficacy depends on the structural properties of biochar, such as porosity, surface functional groups, and its mechanism, including physical adsorption, ion exchange, and electrostatic attraction. The current review explores various biochar activation methods, including physical (steam and gasification), chemical (acid, base, oxidant, and salt), and biological (bacterial, fungal, and enzymatic), which are used to increase the adsorption efficiency. However, large‐scale production of activated biochar faces many challenges related to quality and sustainability. The application of artificial intelligence (AI) and machine learning (ML) presents new opportunities for optimizing activation parameters and improving predictive modelling. Furthermore, adopting a circular economy approach through biochar reuse in soil remediation, energy recovery, and industrial interdependence can enhance sustainability. Despite promising advancements, research gaps remain in standardizing activation protocols, ensuring long‐term stability, and developing policy frameworks for large‐scale implementation. Addressing these challenges is critical for advancing biochar as a viable solution for dye removal in wastewater treatment.