Study on photodegradation of typical new brominated flame retardants on soil minerals and actual soil

The photodegradation process of hexabromobenzene (HBB) adsorbed on four soil minerals and actual soil was studied under simulated sunlight irradiation. The results showed that the photodegradation of HBB on all soils was in accordance with the pseudo-first-order kinetic process. In different soil types, the order of photodegradation rate from fast to slow was silica gel (simulated soil mineral system) > montmorillonite > kaolinite > Sanya soil > quartz sand > Haikou soil. The higher the thickness of soil laying, the lower the photodegradation efficiency of HBB. The photodegradation rate in the system with humic acid (HA) decreased significantly, and the higher the HA concentration, the more obvious the inhibition effect. The photodegradation products of HBB were identified by GC-MS, mainly the formation of debromination products, and the degradation pathway was reduction debromination.