A recent study explored how biochar, a carbon-rich material, can effectively remove aromatic organic pollutants from the environment through a combination of sorption and degradation processes. Researchers Quan Chen, Hongjuan Feng, and their team conducted experiments and theoretical calculations to examine the removal of monocyclic 2,6-dimethylphenol (DMP) and bicyclic bisphenol A (BPA) using both raw and modified biochars.

The study found that biochar’s ability to remove these pollutants is influenced by the interaction between sorption and degradation. Higher sorption of aromatic organics generally leads to increased degradation by biochar. However, the number of aromatic rings in the pollutant plays a critical role: more rings result in higher sorption but lower degradation rates. This interplay between sorption and degradation was found to be governed by various mechanisms, including π-π interactions, hydrophobic effects, and hydrogen bonding, identified through molecular dynamic simulations.

Furthermore, density functional theory (DFT) calculations revealed that specific sites on the biochar, such as graphitic nitrogen, defects, and functional groups like carboxyl and hydroxyl, are pivotal for the degradation process. The study also showed that while DMP undergoes both free radical and electron transfer degradation pathways, BPA is primarily degraded through free radical pathways.

By combining experimental results with theoretical insights, the research provides a comprehensive understanding of the mechanisms behind the removal of aromatic contaminants by biochar. This knowledge is crucial for developing effective biochar-based strategies for environmental remediation.