Engineered biochar turns sunlight into a powerful cleanup tool

Researchers have developed engineered biochar combined with artificial humic substances that significantly enhance sunlight-driven chemical reactions, presenting a novel solar-powered approach to environmental pollution cleanup. By synthesizing humic substances from pine sawdust through controlled hydrothermal treatment, the team created hybrid materials with tunable molecular structures that exhibit much stronger electron-donating properties under sunlight compared to conventional biochar. This engineering enables the biochar to actively drive reduction reactions critical to metal cycling and contaminant transformation in natural settings. Testing with silver ion reduction demonstrated that materials treated at higher temperatures (notably 340°C) achieved reduction efficiencies over nineteen times greater than those treated at lower temperatures. This improvement is attributed to increased phenolic functional groups that generate reactive superoxide radicals under sunlight, facilitating ligand-to-metal charge transfer. Additionally, the biochar dynamically releases dissolved organic molecules when exposed to light, further amplifying photochemical activity and indicating that biochar is an active participant in environmental redox processes rather than a passive sorbent. This