Effects of Pyrogenic Carbon on the Photolysis of Sugar Cane Mill Mud

Black carbon, including char, is ubiquitous in soils from the incomplete combustion of biomass. Because chars are conductive, various redox and photocatalysis pathways are possible to transform biomass on surface soils. This study investigated the effects of wavelengths, conductive black carbon, and factory source on photolysis of the sugar processing byproduct (mill mud). During the course of photolysis, a new shortwave UV (250 nm) peak formed from mill mud extract if 700 °C biochar (20 wt %) was present. Generalized and moving window 2D correlation spectroscopy showed the greatest impact of photolysis on aromatic structures earlier (0.5 wk) in the 2-wk reaction. Conductive (700 °C but not 300 °C) biochar, electrochemically resembling graphite, putatively induces quinone-like structures capable of redox catalysis and photosensitization. Biochar-mediated photochemical production of aromatic structures could impact carbon cycles and nutrient availability, especially through sorption on nutrient-laden mineral surfaces.