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以天然海水为实验介质,研究了季铵盐的生物降解、光降解和水解特性。结果表明,季铵盐的生物降解速率与水样含菌量相关,降解曲线呈阶梯三段式,中段细菌因受季铵盐杀灭/抑制作用含菌量降低,导致季铵盐的降解趋缓,192 h的降解率为8.93%。不同光源和温度对季铵盐的光降解速率和水解速率影响较大,kuv/kvis=188,k40℃/k20℃=4.58。季铵盐的降解主要由光降解贡献,20℃时自然光降解的k分别是生物降解和水解的1.96和4.5倍。季铵盐在海水中的生物降解、自然光降解和水解动力学均符合一级动力学模型,20℃时其速率常数k分别为0.00046、0.0009和0.0002,半衰期t1/2分别为62.8 d、32.1 d和126.0 d,降解半衰期较长,在海洋环境中的残留持久性需重视。
With natural seawater as the experimental medium, the biodegradation, photodegradation and hydrolysis of quaternary ammonium salts were studied. The results showed that the biodegradation rate of quaternary ammonium salt was related to the content of bacteria in the water sample, the degradation curve showed a ladder three-stage model, and the bacteria in the middle stage had a decrease in bacteria content due to quaternary ammonium killing / inhibition. Slow, the degradation rate of 192 h was 8.93%. Different light sources and temperature have a great influence on the photodegradation rate and hydrolysis rate of quaternary ammonium salt, kuv / kvis = 188, k40 ℃ / k20 ℃ = 4.58. The degradation of quaternary ammonium salt is mainly contributed by photodegradation, k of natural photodegradation at 20 ℃ is 1.96 and 4.5 times that of biodegradation and hydrolysis, respectively. The biodegradation, natural photodegradation and hydrolysis kinetics of quaternary ammonium salt in seawater are in accordance with the first-order kinetic model. The rate constants k at 20 ℃ are 0.00046, 0.0009 and 0.0002 respectively, and the half-lives t1 / 2 are 62.8 and 32.1 d And 126.0 d, the longer half-life of degradation and the persistence of residues in the marine environment should be emphasized.