Biodegradation Mechanisms of Linear Alcohol Ethoxylates under Anaerobic Conditions

详细信息    查看全文

• 作者：Martin Huber ; Ulrich Meyer ; and Paul Rys
• 刊名：Environmental Science & Technology
• 出版年：2000
• 出版时间：May 1, 2000
• 年：2000
• 卷：34
• 期：9
• 页码：1737 - 1741
• 全文大小：272K
• 年卷期：v.34,no.9(May 1, 2000)
• ISSN：1520-5851

文摘

The anaerobic biodegradation mechanisms of linearalcohol ethoxylates (LAE) were studied in incubationexperiments with anoxic sewage sludge. Sophisticatedanalytical techniques were applied, such as solid-phaseextraction (SPE) followed by reversed phase high performanceliquid chromatography (HPLC) procedures based on thederivatization of LAE and poly(ethylene glycol) (PEG). Duringthe degradation of LAE C₁₂(EO)_~9, a technical dodecanolethoxylate with an average of nine ethoxy (EO) units, andLAE C₁₂(EO)₈, a single ethoxymer, alcohol ethoxylateswith shortened EO chains were released as the first identifiablemetabolites, but no PEG products were observed. Fromour results it was concluded that the first step of anaerobicmicrobial attack on the LAE molecule is the cleavage ofthe terminal EO unit, releasing acetaldehyde stepwise, andshortening the ethoxy chain until the lipophilic moiety isreached. In contrast to the aerobic degradation pathway,where central scission prevails (the cleavage of theether bond between alkyl and ethoxy chains), such a primaryattack on the surfactant molecule is very unlikely in ananaerobic community of fermenting bacteria.