【摘要】：多氯聯(lián)苯(polychlorinated biphenyls,PCBs)由于具有良好的阻燃性、熱穩(wěn)定性、化學(xué)惰性和高電阻率,曾被大量生產(chǎn)并被廣泛運(yùn)用于工業(yè)生產(chǎn),又由于其具有持久性、高毒致癌性及生物積累性,成為斯德哥爾摩公約首批優(yōu)先控制的12種持久性有機(jī)污染物之一。PCBs在進(jìn)入環(huán)境后,會受多種環(huán)境因素的影響,在不同介質(zhì)中發(fā)生一系列的轉(zhuǎn)化,最后趨于平衡,其中水體PCBs污染與人類生產(chǎn)生活關(guān)系最為密切。本文以獲得的一株P(guān)CBs降解菌為生物材料,研究了短期活體和死體菌株在不同培養(yǎng)時(shí)間對2,4,4'-TCB的生物去除作用并對去除條件進(jìn)行優(yōu)化;探究了短期活體菌株對TCB的去除機(jī)制及不同條件下的生物吸附和生物降解能力;探討了長期菌體對TCB的生物吸附和生物降解機(jī)制,研究了活體菌株對不同氯代PCBs同系物的生物吸附和生物降解作用。具體實(shí)驗(yàn)結(jié)果如下:1、附著劍菌(Ensifer adhaerens R2)活菌及滅菌處理對2,4,4'-TCB均有較高的去除效率,滅菌處理去除效果更佳。R2對2,4,4'-TCB的去除可在2h內(nèi)達(dá)到平衡,溫度、OD值、金屬離子均會影響去除效果。2、短期實(shí)驗(yàn)中(24h),R2活菌對溶液中2,4,4'-TCB的去除作用包括生物吸附和生物降解,生物吸附相對貢獻(xiàn)更大;R2的滅活處理對TCB的去除機(jī)制為生物吸附,并且吸附效率高于活菌處理。R2活菌對TCB的去除在2h即可達(dá)到平衡,單因素條件下,pH值為7.5,溫度為30℃,添加0.05mol/L的Ca2+、Mg2+可使活菌對2,4,4'-TCB的降解達(dá)到最優(yōu);pH值為6.0、35℃、OD為0.8、添加1mol/L的Ca2+、Mg2+處理可使活菌對2,4,4'-TCB的吸附達(dá)到最優(yōu)。3、長期實(shí)驗(yàn)中(16d),實(shí)驗(yàn)前期R2活菌生物吸附所占比列更大,后期生物降解占據(jù)主導(dǎo)地位。菌體分泌的多糖、蛋白、脂質(zhì)均參與了 TCB的吸附。菌體分泌的可溶性EPS中多糖產(chǎn)量隨時(shí)間呈升高趨勢,不溶性EPS中多糖及蛋白呈降低趨勢。菌體SOD、POD活性隨時(shí)間呈上升趨勢,最高分別可達(dá)575.21 U/g、1052.63U/(g.min);菌體PPO活性呈先升高后平穩(wěn)的趨勢,最高可達(dá)2631.58 U/(g·min);菌體INT活性呈先升高后略微降低的趨勢。4、探討了活菌對不同氯代同系物的去除機(jī)制,結(jié)果表明,氯取代數(shù)越高,越易被菌體吸附,越難被降解。
[Abstract]:Polychlorinated biphenyls (polychlorinated biphenyls,PCBs) have been widely used in industrial production because of their good flame retardancy, thermal stability, chemical inertia and high electrical resistivity, and because of their persistence, high toxicity, carcinogenicity and bioaccumulation, polychlorinated biphenyls (polychlorinated biphenyls,PCBs) have been widely used in industrial production. PCBs is one of the first 12 persistent organic pollutants under priority control under the Stockholm Convention. After entering the environment, PCBs will undergo a series of transformations in different media under the influence of a variety of environmental factors. Water PCBs pollution is most closely related to human production and life. In this paper, a strain of PCBs degrading bacteria was used as biomaterial to study the biological removal effect of short term live and dead strains on 2O4O4TCB and optimize the removal conditions. The removal mechanism of TCB and the ability of biosorption and biodegradation under different conditions were investigated. The mechanism of TCB biosorption and biodegradation by long term bacteria was studied. The bioadsorption and biodegradation of different chlorinated PCBs congeners by live strains were studied. The experimental results are as follows: 1. The removal efficiency of active bacteria and sterilizing bacteria from (Ensifer adhaerens R2 is higher than that of sterilizing treatment, and the removal efficiency of sterilizing treatment is better, and the removal of TCB by R2 can reach equilibrium within 2 hours. Temperature, OD value and metal ions all affected the removal efficiency. 2. In the short-term experiment (24 h), the removal effects of R2-live-bacteria on the removal of 2C4O4TCB in solution included biosorption and biodegradation, and the relative contribution of biosorption was greater. The removal mechanism of TCB by the inactivation treatment of R2 was biosorption, and the adsorption efficiency was higher than that of the live bacteria treatment. The removal of TCB by R2 could reach equilibrium within 2 hours. Under the condition of single factor, the pH value was 7.5 and the temperature was 30 鈩，

本文編號：2426454