以SiO2为载体模拟固体土壤环境,研究了邻苯二酚(CT)-Fe2O3/SiO2和CT-CuO/SiO2体系中持久性自由基(PFRs)的形成机制、特征及其对邻苯二酚降解的影响.实验发现,相对于CT-SiO2体系,CT-Fe2O3/SiO2和CT-Cu O/SiO2体系中邻苯二酚和过渡金属相互作用,还原后的过渡金属与自由基结合形成了以半醌自由基为主的更稳定的PFRs,其g值为2.0040—2.0055.在较低浓度时,这种PFRs阻碍了CT的降解,改变了其环境行为,增大了其环境风险.
This work studied the formation mechanism and characteristics of PFRs in the system of catechol( CT)-Fe2O3/ SiO2 and CT-CuO / SiO2. Importantly,the impact of PFRs on CT degradation was investigated. Compared to CT-SiO2 particles,more stable PFRs were observed during the interaction between CT and transition metal on the surface of 1% Fe2O3/ SiO2 or 1% Cu O / SiO2 particles. These PFRs are mostly semiquinone free radicals with a g factor of 2.0040—2.0055. The generation of Fe( Ⅱ)-PFRs or Cu( I)-PFRs decreased the degradation of CT in the lower concentration and thus might alter CT environmental behavior and increase its environmental risk.