降级(电信)
水解
化学
水溶液
生物降解
聚二甲基硅氧烷
废水
动力学
碱性水解
化学分解
溶解度
核化学
色谱法
有机化学
废物管理
分解
工程类
物理
电信
量子力学
计算机科学
作者
Gaëlle Ducom,Baptiste Laubie,Aurélie Ohannessian,Claire Chottier,Patrick Germain,Vincent Chatain
摘要
Accelerated degradation tests were performed on polydimethylsiloxane (PDMS) fluids in aqueous solutions and in extreme chemical conditions (pH 2-4 and 9-12). Results confirmed that silicones can be degraded by hydrolysis. Higher degradation levels were achieved in very acidic and alkaline conditions. Degradation products are probably polar siloxanols. In alkaline conditions, the counter-ion was found to have a strong influence on degradation level. Degradation kinetic studies (46 days) were also performed at different pH values. Supposing zeroth-order kinetics, degradation rate constants at 24 °C were estimated to 0.28 mgSi L(-1) day(-1) in NaOH solution (pH 12), 0.07 mgSi L(-1) day(-1) in HCl solution (pH 2) and 0.002 mgSi L(-1) day(-1) in demineralised water (pH 6). From these results, the following hypothesis was drawn: PDMS hydrolysis could occur in wastewater treatment plants and in landfill cells. It may be a first step in the formation of volatile organic silicon compounds (VOSiCs, including siloxanes) in biogas: coupled to biodegradation and (self-) condensation of degradation products, it could finally lead to VOSiCs.
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