8:2氟调聚醇(8:2FTOH)厌氧生物降解特性

Anaerobic biodegradability of 8:2 fluorotelomer alcohol(8:2 FTOH)

为了阐明厌氧环境下全氟羧酸(PFCAs)等全氟化合物的迁移归趋,研究了8:2氟调聚醇(8:2FTOH)的厌氧降解性能.结果表明,取自市政污水处理厂的污泥在厌氧条件下可还原降解8:2FTOH,并生成氟离子、全氟类和多氟类降解产物,且降解过程可采用双指数衰减模型拟合.在为期120d的培养中,8:2FTOH的摩尔降解率高达(93.2±0.9)%;摩尔回收率则随着培养时间的增加有下降的趋势,由培养初期(1d)的(97.5±5.1)%下降至末期(120d)的(68.9±4.0)%,这说明在培养后期可能产生了未知的降解产物或生成了未知的挥发性产物.8:2不饱和氟调聚酸(8:2FTUA)和全氟辛酸(PFOA)分别是摩尔产率最高的多氟类和全氟类降解产物,分别介于(6.94±0.10)%^(24.2±1.5)%和(2.67±0.22)%^(14.9±1.0)%的范围内.多氟类降解产物的摩尔产率随培养时间的增加先增加后降低,而全氟类降解产物的摩尔产率则随培养时间的增加持续增加,这说明其可能分别为中间降解产物和最终降解产物.

To elucidate the trends and fates of perfluorochemicals such as perfluorocarboxylates (PFCAs) under anaerobicenvironments, the anaerobic biodegradability of 8:2 fluorotemoler alcohol (8:2 FTOH) was studied. The results indicatedthat 8:2 FTOH could be decomposed under anaerobic conditions by sewage sludge collected from a municipal wastewatertreatment plant, and produce fluoride, per- and poly-fluorinated compounds, and the decomposition data perfectly fitted adouble exponential decay model. With an incubation time of 120d, the final molar degradation rate of 8:2 FTOH was up to(93.2±0.9)%, while its molar recoveries decreased with the incubation time, from (97.5±5.1)% at the beginning (1d) to(68.9±4.0)% at the end (120 d). These results indicated that some unknown or volatile products have been generated at thelate of incubation. 2H-perfluoro-2-decenoic acid (8:2 FTUA) and perfluorooctanoic acid (PFOA) were the most abundantof poly- and perfluorinated products with the molar yields ranged from (6.94±0.10 )% to (24.2±1.5)% and from(2.67±0.22)% to (14.9±1.0)%, respectively. With increasement of incubation time, the molar yields of polyfluorinatedproducts firstly increased and then decreased, while the molar yields of perfluorinated products consistently increased,indicated that they might be the intermediate and final biodegradation products, respectively.