Thermodynamic assessment of Tetrabromobisphenol A (TBBPA) persistence over time in freeze-thaw aged biochar and its environmental significance

Over extended periods of application, a beneficial carbon material, biochar, undergos a series of physical and chemical changes collectively referred to as the aging process, which result from exposure to various environmental factors. The potential long-term threats to the local environment are tied to the influence of interactions between biochar and contaminants, such as Tetrabromobisphenol A (TBBPA). The objective is to examine the thermodynamic changes in freeze-thaw cycles to explore the long-term behaviors of with biochar-contaminants under environmental interactions. The results revealed that freeze-thaw aging and the involvement of dissolved organic matters (DOMs) were the major factors affecting the immobilization behaviors of biochar, shifting the interactive energy from −2.92 ∼ 13.75 to −18.04 ∼ 76.39 KJ/mol. The surface functionality of the biochar underwent significant alterations, with DOMs and TBBPA in long-term applications. As the migration of TBBPA on biochar culminates in a dissipation process, The study also revealed that the energy required for TBBPA dissipation was higher in a freeze-thaw environment and in systems enriched with DOMs elevating from 33.29 ∼ 75.97–53.75 ∼ 76.39 KJ/mol. In comparison, the high pyrolyzed surface showed low variations as alteration from 39.25 ∼ 58.08–32.10 ∼ 69.76 KJ/mol. This implies that in regions where biochar is applied to soils rich in biomass and nutrients, a more substantial energy is necessary to overcome the dissipation of TBBPA compared to regions with less fertile soils. The findings of this study suggest that the enrichment of contaminants may be facilitated in areas where biochar is applied to nutrient-rich soils.