重金属对厌氧污泥电子传递体系活性影响研究

Effects of Heavy Metallic Ions on Electron Transport System Activity of Anaerobic Sludge

以2-氯酚(2-CP)厌氧降解污泥电子传递体系(ETS)活性为考察对象,研究了3种典型重金属元素Cu2+、Cd2+、Ni2+对ETS活性的影响,并比较了驯化过程对提高厌氧微生物抗重金属毒性的作用.重金属离子对厌氧污泥呼吸活性的抑制作用发生很快,在0.25 h内就已表现出来,并随金属浓度的增加而加剧.驯化前,3种金属的作用均表现为抑制,抑制作用的强弱顺序为Ni2+>Cd2+>Cu2+,抑制强度与金属离子在水溶液中的含量成正相关关系.采用低浓度金属离子驯化的方法可以有效改善重金属毒性.驯化后,Cu2+毒性的降幅约为10%,Cd2+毒性的最大降幅超过40%,Ni2+对污泥ETS活性的作用则基本表现为促进,最佳促进浓度约为70 mg/L.Ni2+对ETS活性的特殊激活作用可能与其能形成正四面体结构的络合物有关.驯化作用对改善金属毒性的效果:Ni2+>Cd2+>Cu2+.

The influence of Ni^2＋ , Cd^2＋ and Cu^2＋ on electron transport system （ETS） activity of anaerobic 2-chlorophenon degradation sludge, as well as the effect of acclimation on microbial resistance to metallic toxicity, was investigated. The inhibitive effect of heavy metals on ETS activities acted within 0.25 h, and metallic toxicity aggravated with the increasing amount of metallic ions. The relative strength of inhibition was Ni2^＋ 〉 Cd^2＋ 〉 Cu^2＋ and was mainly dependent on the metallic ion concentration in solution. Acclimation with metals of low concentration was proved to be a good way to improve the microbial resistance to heavy metals. After domestication, the toxicity of Cu^2＋ decreased 10%, and the maximum decreasing percentage of Cd^2＋ inhibition was more than 40%, while the effect of Ni^2＋ transferred to be in favor of ETS activity with the optimal concentration of 70 mg/L. The particularly active effect of Ni^2＋ was probably due to the capability of Ni^2＋ to form regular tetrahedron chelate compounds. The relative amelioration of microbial resistance was Ni^2＋ 〉 Cd^2＋ 〉 Cu^2＋ .