甲基硅氧烷在污水处理厂中的环境行为

Environmental behavior of siloxane in wastewater treatment plants

硅氧烷由硅氧原子交替排列形成主链骨架,由于它们的高疏水性、润滑性、稳定性,被广泛地应用于润滑剂、密封剂以及个人护理品、化妆品等,并逐步扩大应用到纺织品以及表面涂层材料。而挥发性甲基硅氧烷在环境中具有持久性、生物富集性且部分具有生殖毒性,因此引起人们的广泛关注。本文归纳了国内外有关挥发性甲基硅氧烷的使用和分布状况,概述了硅氧烷在污水处理厂中的环境行为与归趋。目前,污水处理厂中硅氧烷的去除主要以吸附为主(去除率高达90%以上),其余的部分主要以大气挥发及生物降解的方式散失,且生物降解的机制尚不明晰,提出未来应从污泥中硅氧烷的转化规律及生物降解机制的角度开展进一步深入研究。

Silicon atom and oxygen atom are arranged alternately in the formation of the main chain skeleton of siloxane. Due to the characteristics of high hydrophobicity, lubricity and stability, siloxane is widely employed as a raw material in lubricants, sealants, cosmetics and personal care products etc., and it is also applied in producing textile goods and superficial coating materials frequently. It is the environmental characteristics of high persistence, biological enrichment and reproductive toxicity that have drawn increasing attention to volatile methyl siloxane（VMS） during the past few years. This study outlines the context of the utilization and distribution of VMS, and its environmental behavior and fate in water treatment plants（WWTPs） are also discussed both at home and abroad. The current removal method of VMS adopted by WWTPs is primarily via absorption which contributes to over 90% of the reduction of that in influent. The majority of the rest is further eliminated by atmospheric volatilization and biodegradation. However, the mechanism of the biodegradation of VMS in water environment currently remains unclear, and it is suggested that the further study should place more attention to the analysis of the principle of the transformation and the mechanism of biodegradation of VMS in sludge.