Hajar El Ouahabi, Oussama Bayessi, Ammar Mouaky, Ayoub Hirt, Samir Rachidi
In the face of accelerating climate risks and resource depletion, pyrolytic biochar has emerged as a multifunctional carbon material with applications extending beyond soil amendment. Its tunable structure and surface chemistry make it a promising platform for carbon sequestration, environmental remediation, and sustainable energy technologies. This review critically examines recent advances in tailoring biochar properties through feedstock selection and pyrolysis parameters, with emphasis on its dual roles in wastewater treatment and electrochemical energy storage. We highlight how structural tunability, high surface reactivity, and electrical conductivity enable biochar to function as both an efficient adsorbent and a cost-effective electrode material. Beyond summarizing current applications, we identify key challenges in scalability, standardization, and environmental safety, and propose strategies for integrating biochar into circular economy and carbon market frameworks. By synthesizing insights across agriculture, water treatment, and energy technologies, this work outlines a roadmap for positioning biochar as a pivotal climate-smart material for the coming decades.