Environmentally persistent free radicals (EPFR) are emerging contaminants of health concern. Their levels in the environment are not well known because few studies have optimized EPFR extraction. Therefore, here we studied the extraction and decay of EPFR that are formed on the surfaces of Cu(II)-montmorillonite clay contaminated by polycyclic aromatic hydrocarbons (PAH) including benzo[a]pyrene and anthracene. EPFR were analyzed by electron paramagnetic resonance. Results show that acetone or dichloromethane/acetone effectively extract benzo[a]pyrene-EPFR. By contrast, CCl₄, acetonitrile or methanol do not extract benzo[a]pyrene-EPFR, but extract residual benzo[a]pyrene at 62.2% for CCl₄, 77.8% for acetonitrile and 59.1% for methanol. EPFR concentration decreases with ultrasonic intensity and time, from 60 s at 16 kHz to 1200 s at 40 kHz. The decay of PAH–EPFR in acetone displays two steps, a fast decay from 0 to about 5 h, then a slower decay from 5 to 50 h. The 1/e lifetime during the slow decay period was about 168 h for benzo[a]pyrene-EPFR and 180 h for anthracene-EPFR.

环境持久性自由基（EPFR）是对健康的关注新兴污染物。它们在环境中的含量尚不为人所知，因为很少有研究对EPFR提取进行了优化。因此，在这里，我们研究了被多环芳烃（PAH）（包括苯并[a] py和蒽）污染的Cu（II）-蒙脱土粘土表面上形成的EPFR的提取和衰减。通过电子顺磁共振分析EPFR。结果表明，丙酮或二氯甲烷/丙酮可有效提取苯并[a] py-EPFR。相比之下，CCL ₄，乙腈或甲醇不提取苯并[a]芘EPFR，但提取残余苯并[a]芘在62.2％的CCl为₄，乙腈为77.8％，甲醇为59.1％。EPFR浓度随超声强度和时间而降低，从16 kHz的60 s降低到40 kHz的1200 s。丙酮中PAH-EPFR的衰减显示两个步骤，从0到约5 h快速衰减，然后从5到50 h较慢衰减。苯并[a] py-EPFR在缓慢衰变期间的1 / e寿命约为168小时，蒽-EPFR为180小时。