Functionalized biochar for plasticizer remediation in aquatic systems: synergistic adsorption and advanced oxidation strategies

Abstract

Biochar-based treatment strategies have received growing interest; however, no comprehensive review has systematically assessed the mechanisms and performance of functionalized biochar for plasticizer remediation. This review critically compares pristine biochar and its advances in biochar modifications for plasticizer adsorption. Additionally, it unveils how functionalized biochar integrates with advanced oxidation processes (AOPs) to achieve synergistic adsorption and degradation of plasticizers in water. As different studies have used varying initial concentrations, a direct comparison is not appropriate. Therefore, the partition coefficient (PC) was determined to enable a normalized and insightful comparison. The modified biochar exhibited higher PC values (0.179–42.7 L g−1) than pristine biochar (0.082–1.852 L g−1), highlighting the enhancement of adsorption capacity through targeted modifications. The pine cone-derived pristine biochar demonstrated the highest PC (2.56 L g−1). Further, nitrogen-doped (N-doped) biochar exhibited superior adsorption for DEP (32.3 L g−1) and DBP (42.7 L g−1). For degradation, persulfate-based AOP achieved rapid plasticizer degradation (∼99% within minutes) under different conditions with rapid persulfate activation. Plasticizer mitigation in aquatic systems using biochar remains constrained by inconsistent performance due to variability in feedstock, modification methods, and experimental conditions, which limits reliable comparisons across studies. Therefore, addressing these inconsistencies is crucial for optimizing the performance of biochar in real-world water remediation systems.