生物炭对土壤微生物及其强化修复多环芳烃污染的影响与机理研究

发布时间：2018-05-17 19:36

本文选题：生物炭 + 微生物固定化　；参考：《上海交通大学》2015年博士论文

【摘要】：论文以水稻秸秆、稻壳和牛粪为原料,在350和500℃条件下限氧热解制备生物炭的基础上,研究了生物炭对土著微生物生态效应影响,并采用末端限制性多态分析(T-RFLP)和荧光定量PCR(q PCR)技术,对土壤微生物多样性及功能基因进行定量分析。在此基础上,以持久性有机污染物多环芳烃(PAHs)为研究对象,采用微生物固定化技术,将自主筛选的PAHs降解菌固定于生物炭上,开展了生物炭固定化微生物对复合污染土壤中16种PAHs生物修复及其作用机理研究。为生物炭强化和刺激土著微生物修复PAHs污染土壤提供科学依据,论文对于发展污染土壤原位生物修复技术,阐明生物炭固定化降解菌强化修复PAHs污染土壤机理及其生态效应具有重要的理论和现实意义,主要研究结果如下:1.对生物炭主要元素和理化性质研究表明,牛粪、稻壳和水稻秸秆生物炭表面存在羰基(C=O)、羧基(-COOH)、羟基(-OH)、醚(-O-)、芳香族C=N键和N-H3键等主要官能基团。生物炭除了含有大量C元素以外,还含有N、P、Ca、Na、Mg、K及Mn、Zn、Cu等微量元素;供试6种生物炭均呈碱性,水稻秸秆生物炭RS500的p H值最高,为10.50;500℃热解温度制备的生物炭中的C元素和灰分含量高于350℃制备的生物炭;相同热解温度条件下,稻壳和水稻秸秆生物炭中的C/N大于牛粪生物炭。2.生物炭对土壤蔗糖酶活性具有显著的刺激作用,对放线菌具有抑制作用,对土壤磷酸酶、脲酶活性、细菌和真菌数量、CO2和N2O的释放量的影响与施炭量和生物炭制备温度密切相关,其中,在添加4%生物炭的土壤中,生物炭对土壤细菌生长具有显著的刺激作用;500℃热解制备生物炭对土壤中细菌的刺激作用要大于350℃热解制备的生物炭。生物炭对土壤N2O释放的影响具有典型hormesis效应特征。3.生物炭处理土壤中细菌群落发生了显著变化,主要形成5个类群;所有供试生物炭处理土壤中nir S基因拷贝数增加了67.22~70.18%;生物炭处理对土壤中微生物群落的多样性和amo A基因拷贝数的影响与生物炭制备温度、原料和施炭量密切相关。其中,施炭量为4%时,350℃低温热解制备的生物炭显著提高土壤微生物的多样性。除DM350和RH350两个处理外,土壤中amo A基因拷贝数比对照减少了93~98.10%。生物炭对土壤细菌16S r DNA和PAH-RHDαGP基因拷贝数量增加具有刺激作用。其中,低温生物炭处理的刺激作用大于高温热解制备的生物炭。处理土壤中PAH-RHDαGP基因拷贝数量增加最多的是水稻秸秆RS350,其拷贝数达到1.73×107 copies g-1 dry soil。4.生物炭对PAHs复合污染土壤中amo A基因的拷贝数具有抑制作用,抑制率最大的是水稻秸秆生物炭RS500;然而,PAH-RHDαGP和nir S基因的数量则显著增加。其中,生物炭对污染土壤amo A基因的拷贝数的抑制率达到23.53~85.13%,PAH-RHDαGP基因拷贝数量增加最多的是水稻秸秆RS350生物炭,拷贝数达到1.73×107 copies g-1 dry soil;相同处理条件下,在500℃高温热解生物炭处理土壤中nir S基因的拷贝数大于350℃低温热解制备的生物炭,增加最多是水稻秸秆生物炭RS350处理,为对照土壤的2.9倍,拷贝数达到6.45×107 copies g-1 dry soil。5.采用富集培养方法,筛选和分离到1株能在重金属存在条件下对PAHs具有高效降解作用的降解菌,经形态学观察和16S r DNA分子鉴定,属于贪铜菌属,将其命名为B35。6.低温生物炭固定化B35菌剂对培养基中PAHs的吸附与降解作用大于高温生物炭处理。相同热解制备温度条件下,植物类的稻壳和水稻秸秆生物炭固定化降解菌剂对PAHs的吸附作用大于牛粪类。固定化菌剂对PAHs吸附作用的大小依次为:稻壳生物炭RH350水稻秸秆生物炭RS350牛粪生物炭RM350稻壳生物炭RH500牛粪生物炭DM500水稻秸秆生物炭RS500。对PAHs的降解效率最高的是稻壳生物炭RH350菌剂,降解率达到31.34%。7.不同生物炭固定化菌剂对不同分子量PAHs均具有吸附与降解作用,不同环PAHs之间存在显著差异。除水稻秸秆生物炭RS500外,所有生物炭固定化菌剂对4环PAHs吸附率均高于2~3环PAHs,平均吸附率分别为44.98%和24.50%,热解温度对不同生物炭固定化菌剂吸附5~6环PAHs的影响差异比2~4环的差异大。350℃热解制备的生物炭固定化菌剂对2~4环PAHs的降解率高于500℃热解制备的生物炭固定化菌剂。其中,对2~3环、4环和5~6环PAHs的上海交通大学博士学位论文平均降解率分别为:15.03%、25.08%和10.08%。降解率最高分别达到23.33%、36.50%和22.75%。8.与培养基中生物炭固定化菌剂PAHs吸附作用相同,350℃低温制备的生物炭固定化菌剂对污染土壤PAHs的吸附和降解率高于高温500℃制备的生物炭处理,并且对2~4环PAHs的吸附作用大于5~6环。其中,吸附作用最强的是水稻秸秆生物炭RS350处理,吸附率达到22.80%。9.生物强化和生物刺激协同作用是生物炭固定化B35降解菌剂修复PAHs污染土壤的重要作用机理。不同生物炭固定化菌剂对污染土壤中PAHs的修复作用的大小依次为:水稻秸秆生物炭RS350稻壳生物炭RH350牛粪生物炭RM350稻壳生物炭RH500牛粪生物炭DM500水稻秸秆生物炭RS500。
[Abstract]:In this paper, rice straw, rice husk and cow dung were used as raw materials. On the basis of bio carbon preparation by limiting oxygen pyrolysis at 350 and 500 degrees, the effects of biological charcoal on the ecological effects of indigenous microorganisms were studied. The microbial diversity and functional genes of soil microbial diversity and functional genes were quantified by terminal restricted polymorphism analysis (T-RFLP) and fluorescence quantitative PCR (Q PCR) technique. On this basis, based on the persistent organic pollutants polycyclic aromatic hydrocarbons (PAHs) as the research object, the microbial immobilization technology was used to immobilize the independent PAHs degrading bacteria on biochar, and the mechanism of the biological charcoal immobilized microorganism to repair 16 kinds of PAHs species in the contaminated soil was carried out and the mechanism of biological charcoal enhancement and stimulation was studied. The aboriginal microorganism provides scientific basis for the remediation of PAHs contaminated soil. This paper is of great theoretical and practical significance to the development of in situ bioremediation technology of contaminated soil and clarifying the mechanism and ecological effects of Biocharcoal immobilized degradation bacteria to strengthen the remediation of PAHs contaminated soil. The main fruits are as follows: 1. main elements and physicochemical properties of biological charcoal Studies have shown that there are carbonyl (C=O), carboxyl (-COOH), hydroxyl (-OH), ether (-O-), aromatic C=N and N-H3 key on the surface of biological charcoal of cow dung, rice hull and rice straw. Biological charcoal also contains N, P, Ca, Na, Mg, Mg, Ca, Na, and other trace elements in addition to a large number of C elements; the 6 kinds of biological charcoal are alkaline and rice straw organisms. The P H value of carbon RS500 is the highest, which is 10.50. The C element and ash content in the Biocharcoal prepared at 500 C is higher than that of the biological carbon prepared at 350 C. Under the same pyrolysis temperature, the C/N in the rice husk and rice straw bio carbon is greater than that of the cow dung biological charcoal.2. Biocharcoal, which has a significant stimulating effect on the activity of the soil sucrase, and the actinomycetes have a significant effect on the activity of the actinomycetes. The effects of inhibition on soil phosphatase, urease activity, bacteria and fungi, the release of CO2 and N2O are closely related to the amount of carbon and the preparation temperature of biological carbon. In the soil adding 4% biological charcoal, biological carbon has significant stimulation for the growth of soil bacteria, and the pyrolysis of biochar at 500 degrees centigrade to stimulate the bacteria in the soil The effect of bio carbon on the release of soil N2O has a typical hormesis effect characteristic of the soil N2O release. The bacterial community in the soil treated by.3. biological charcoal has changed significantly, mainly formed 5 groups, and the copy number of NIR S gene in the soil of all the tested biochar treated soil increased by 67.22~70.18%; Biocharcoal treatment of soil The diversity of microbial communities in the soil and the effect of AMO A gene copy number are closely related to the preparation temperature of biological carbon and the amount of carbon applied in the soil. Among them, the Biocharcoal prepared by low temperature pyrolysis at 350 centigrade can significantly improve the diversity of soil microorganism. The amo A gene copy number in soil is less than that of the control, except DM350 and RH350. 93~98.10%. bio carbon has a stimulating effect on the increase of the copy number of 16S R DNA and PAH-RHD alpha GP in soil bacteria. Among them, the stimulation effect of low temperature biochar treatment is greater than that of high temperature pyrolysis. The maximum number of PAH-RHD alpha GP gene copies in the soil is increased by the rice straw RS350, and the copy number is 1.73 * 107 copies G. -1 dry soil.4. biochar could inhibit the copy number of AMO A gene in the PAHs compound contaminated soil, and the maximum inhibition rate was the rice straw bio carbon RS500; however, the number of PAH-RHD a GP and NIR S genes increased significantly. The copy number increased most because of the rice straw RS350 biological carbon, the copy number reached 1.73 * 107 copies g-1 dry soil. Under the same treatment conditions, the copy number of NIR S gene in the soil treated at 500 C high temperature pyrolytic biochar was greater than the low temperature pyrolytic carbon from 350 C, and the most increased is the rice straw bio carbon RS350 treatment, which was the control soil. 2.9 times of the soil, the copy number reached 6.45 * 107 copies g-1 dry soil.5., and the enrichment culture method was used to screen and isolate 1 degrading bacteria which could effectively degrade PAHs under the presence of heavy metals. By morphological observation and 16S R DNA molecular identification, it belonged to the genus cupric, and named it as a B35.6. low temperature biological charcoal immobilized B35 microbial agent. The adsorption and degradation of PAHs in the medium is greater than that of high temperature biochar treatment. Under the same pyrolysis temperature conditions, the adsorption of rice husk and rice straw bio carbon immobilized microbial agent on PAHs is greater than that of cow dung. The size of the adsorption of PAHs by immobilized bacteria is the following: Rice hull bio carbon RH350 rice straw biology Carbon RS350 cow dung biological charcoal RM350 rice husk biological charcoal RH500 cow dung biological carbon DM500 rice straw bio carbon RS500. degradation efficiency of PAHs is the highest in rice hull Biocharcoal RH350 bacteria, degradation rate to 31.34%.7. different biological charcoal immobilized bacteria have adsorption and degradation of different molecular weight PAHs, there is significant difference between different loop PAHs. Except for rice straw biological carbon RS500, all Biocharcoal immobilized bacteria have higher adsorption rates for 4 ring PAHs than 2~3 ring PAHs, and the average adsorption rate is 44.98% and 24.50% respectively. The difference of the pyrolysis temperature on the adsorption of 5~6 ring PAHs with different Biocharcoal immobilized bacteria is greater than that of 2~4 ring. The degradation rate of PAHs was higher than that of Biocharcoal immobilized bacteria prepared by pyrolysis at 500 C. The average degradation rate of Shanghai Jiao Tong University doctorate in the Shanghai Jiao Tong University was 15.03%, 25.08% and 10.08%. respectively reached 23.33%, 36.50% and 22.75%.8., respectively, and PAHs adsorption of Biocharcoal immobilized bacteria in the medium, respectively. The adsorption and degradation rate of Biocharcoal immobilized bacteria on contaminated soil PAHs was higher than that prepared at 500 C at 350 C, and the adsorption of 2~4 ring PAHs was greater than that of 5~6 ring. Among them, the strongest adsorption was RS350 treatment of rice straw biological carbon, the adsorption rate was 22.80%.9. biofortified and biostimulation Co The same effect is the important mechanism of the biological charcoal immobilized B35 degradation bacteria for the remediation of PAHs contaminated soil. The size of the remediation of PAHs in contaminated soil by different Biocharcoal immobilized bacteria is in turn: rice straw biological carbon, RS350 rice hull, RH350 cattle manure, RM350 rice husk, RH500 cattle dung, Biocharcoal, Biocharcoal and rice straw biology Carbon RS500.
【学位授予单位】：上海交通大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：X53;S154.3

【参考文献】