Investigating innovative techniques for biochar modification to enhance the removal of heavy metals from aqueous environments: a comprehensive review. - Kumar, Prashant; Singhania, Reeta Rani; Sumathi, Yamini; Kurrey, Nawneet Kumar; Chen, Chiu-Wen; Patel, Anil Kumar; Dong, Cheng-Di (Clean Technologies & Environmental Policy, 2025)