本文選題：胞外聚合物　切入點(diǎn)：脫氮除磷　出處：《湘潭大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：基于藻類的生物膜技術(shù)具有脫氮除磷的優(yōu)勢,在城鎮(zhèn)污水處理中具有應(yīng)用前景,但污水中的重金屬等毒物可影響藻細(xì)胞及其胞外聚合物(EPS)。EPS是藻類等生物在特定環(huán)境下產(chǎn)生的高分子物質(zhì),具有多種生物作用,而目前對(duì)于EPS在重金屬脅迫藻類脫氮除磷過程的作用及機(jī)制尚不明晰。本文以小球藻(Chlorella vulgaris)為研究目標(biāo),以鎘為重金屬代表,在考察鎘脅迫對(duì)小球藻脫氮除磷效率影響的基礎(chǔ)上,探明鎘脅迫下氮、磷、鎘在EPS及藻細(xì)胞內(nèi)的分布;明確鎘脅迫下EPS的產(chǎn)生特性及其與脫氮除磷效率之間的關(guān)系。論文主要得到了以下的研究結(jié)論:(1)Cd2+對(duì)小球藻生長具有較強(qiáng)的毒性效應(yīng),其96h-EC50值為1.17 mg/L。低濃度的Cd2+(0.1 mg/L)能促進(jìn)小球藻的生長、酯酶活性和脫氮除磷效率,而高濃度的Cd2+(0.5 mg/L)則會(huì)產(chǎn)生抑制效應(yīng)。Cd2+濃度為1.0 mg/L時(shí),6天實(shí)驗(yàn)周期中小球藻的平均生長速率是3.29×105 cells/(mL*d),為無Cd2+對(duì)照組的59.4%。在1.0mg/L Cd2+脅迫下,小球藻對(duì)氨氮(NH4+-N)和正磷酸鹽(PO43--P)去除率仍然能保持在對(duì)照組(分別為68.0%和50.5%)的62.6%和64.9%,單個(gè)藻細(xì)胞對(duì)NH4+-N和PO43--P的去除量也能保持在對(duì)照組的69.3%和62.5%。酯酶活性的實(shí)驗(yàn)結(jié)果表明,EPS對(duì)Cd2+脅迫小球藻脫氮除磷中具有緩解毒性作用。(2)在1.0 mg/L Cd2+脅迫下,溶解態(tài)EPS(S-EPS)中總氮(TN)和總磷(TP)的含量分別減少至6.15 mg/L和1.44 mg/L,相比于對(duì)照組增加了56.8%和30.7%;結(jié)合態(tài)EPS(B-EPS)中TN和TP的平均含量分別為0.27 mg/L和0.18mg/L,比對(duì)照組高26.8%和27.5%;處理組中單個(gè)藻細(xì)胞內(nèi)TN和TP的含量增加至1.39×10-6 mg/L和0.20×10-6 mg/L,為對(duì)照組的82.5%和79.9%。Cd2+在EPS及細(xì)胞內(nèi)的分布表明,EPS(尤其是B-EPS)可作為細(xì)胞的防護(hù)欄障阻止Cd2+進(jìn)入細(xì)胞。在1.0 mg/L Cd2+脅迫下,55.4%的Cd2+分布在B-EPS中,僅有19.5%分布在S-EPS中。此外,Cd2+脅迫減慢了EPS中氮、磷的擴(kuò)散速率以及藻細(xì)胞對(duì)氮、磷的吸收速率,但NH4+-N和PO43--P擴(kuò)散的平均速率仍然分別保持為對(duì)照組的65.8%和64.1%;藻細(xì)胞對(duì)NH4+-N和PO43--P的吸收速率也能保持在對(duì)照組的62.0%和56.2%。(3)1.0 mg/L Cd2+脅迫加速了EPS的產(chǎn)生,實(shí)驗(yàn)周期中第6天時(shí)S-EPS含量達(dá)到15.56×10-7μg/cell,平均B-EPS含量為4.38×10-7μg/cell,比對(duì)照組分別增多了20.0%,30.4%。同時(shí),S-EPS中多糖和蛋白質(zhì)分別達(dá)到9.74×10-7和7.53×10-7μg/cell,比對(duì)照組增多了17.5%和19.3%;B-EPS中多糖和蛋白質(zhì)平均含量分別為5.45×10-7和3.17×10-7μg/cell,較對(duì)照組增加20.3%和33.2%。三維熒光光譜(3D-EEM)表明,S-EPS中含有類色氨酸和類腐殖酸,B-EPS含有類酪氨酸和類色氨酸。Cd2+脅迫下EPS中各組分含量相比于對(duì)照組都有所增加,且S-EPS中的類色氨酸和B-EPS中的類酪氨酸峰位置發(fā)生了紅移現(xiàn)象。傅里葉紅外轉(zhuǎn)換光譜(FTIR)結(jié)果表明,與Cd2+相互結(jié)合的主要官能團(tuán)是S-EPS和B-EPS中的-OH或-NH(3446-3460 cm-1)、蛋白質(zhì)中的C=O(-1642 cm-1),以及S-EPS中多糖上的C-O-C或C-O(-1081 cm-1),且出現(xiàn)了新的官能團(tuán),如屬于蛋白質(zhì)的-NH(1558,1540 cm-1)和C=O(1384 cm-1),說明EPS中的蛋白質(zhì)和多糖是與Cd2+作用的主要成分。在1.0 mg/L Cd2+脅迫下,EPS的產(chǎn)生總量與小球藻脫氮除磷效率之間呈現(xiàn)出良好的正相關(guān)性,其R2值分別為0.9905(NH4+-N)和0.9414(PO43--P)。相比于PO43--P,EPS含量與NH4+-N去除率之間線性關(guān)系更為明顯。
[Abstract]:Biofilm technology of algae with nitrogen and phosphorus removal based on the advantages of application in urban sewage treatment, but the sewage in the heavy metal poison can affect algal cells and extracellular polymers (EPS).EPS is a polymer material such as algae organisms in a particular environment, with a variety of biological effects, but the effect and the mechanism of EPS in heavy metal stress algal nitrogen and phosphorus removal process is still not clear. In this paper, Chlorella (Chlorella vulgaris) as the research object, with the heavy metal cadmium as representative, in the study of cadmium based efficiency of nitrogen and phosphorus removal effect of Chlorella, proven under Cadmium Stress of nitrogen, phosphorus, and distribution of cadmium in EPS in algae cell the relationship between characteristics; clear under cadmium stress EPS and nitrogen and phosphorus removal efficiency. The thesis obtained the following conclusions: (1) Cd2+ has strong toxic effects on the growth of Chlorella vulgaris, 96h-EC The 50 value is 1.17 mg/L. and low concentration of Cd2+ (0.1 mg/L) can promote the growth of Chlorella, esterase activity and nitrogen and phosphorus removal efficiency, and high concentration of Cd2+ (0.5 mg/L) will have the inhibitory effect of.Cd2+ concentration was 1 mg/L, the average growth rate of the 6 day experimental period of C.pyrenoidosa is 3.29 x 105 (cells/ mL*d), no Cd2+ control group 59.4%. in 1.0mg/L under the stress of Cd2+, Chlorella vulgaris (NH4+-N) on ammonia nitrogen and orthophosphate (PO43--P) removal rate remained in the control group (68% and 50.5%) of 62.6% and 64.9%, the experimental results of single algae cell removal on NH4+-N and PO43--P can maintain 69.3% 62.5%. and esterase activity in the control group showed that EPS and Cd2+ stress on nitrogen and phosphorus removal can alleviate the toxic effect of Chlorella. (2) at 1 mg/L under the stress of Cd2+, dissolved EPS (S-EPS) in total nitrogen (TN) and total phosphorus (TP) content decreased to 6.15 mg/L and 1.44 mg/L respectively, phase Than in the control group increased by 56.8% and 30.7%; bound EPS (B-EPS) TN and TP in the average content of mg/L and 0.18mg/L were 0.27, 26.8% higher than the control group and the treatment group was 27.5%; in the individual algal cells within TN and TP increased to 1.39 * 10-6 * 10-6 mg/L and 0.20 mg/L distribution the control group 82.5% and 79.9%.Cd2+ in EPS cells and that EPS (especially B-EPS) can be used as a protective barrier to prevent Cd2+ cells into cells. In 1 mg/L Cd2+ under the stress of 55.4% Cd2+ distribution in B-EPS, only 19.5% of the distribution in S-EPS. In addition, Cd2+ stress slows down the EPS in nitrogen. The diffusion rate of nitrogen and phosphorus and algal cells, the absorption rate of phosphorus, but the average rate of NH4+-N and PO43--P diffusion are still maintained as the control group 65.8% and 64.1%; the absorption rate of algae cells to NH4+-N and PO43--P can be maintained at 62% in the control group and 56.2%. (3) 1 mg/L Cd2+ stress accelerated The production of EPS in the sixth day experimental period, the content of S-EPS was 15.56 * 10-7 g/cell, the average content of B-EPS is 4.38 x 10-7 g/cell, than in the control group were increased by 20%, 30.4%. and S-EPS in protein and polysaccharide were up to 9.74 x 10-7 and 7.53 x 10-7 g/cell more than that of control group. 17.5% and 19.3%; the average B-EPS content of polysaccharide and protein were 5.45 * 10-7 and 3.17 * 10-7 g/cell, increased 20.3% than that in control group and three dimensional fluorescence spectra of 33.2%. (3D-EEM) showed that S-EPS contains tryptophan like and humic acid, B-EPS containing tyrosine and tryptophan were under.Cd2+ stress EPS content compared with the control group increased, and the peak position of tyrosine in S-EPS tryptophan and B-EPS in the red shift phenomenon. Fourier transform infrared spectroscopy (FTIR) results show that the main functional groups combined with Cd2+ and B-EPS in S-EPS -OH or -NH (3446-3460 cm-1), C=O (-1642 cm-1 protein), and S-EPS polysaccharide on C-O-C or C-O (-1081 cm-1), and the emergence of new functional groups, such as belonging to protein -NH (15581540 cm-1) and C=O (1384 cm-1), EPS in protein and polysaccharide the main component of the interaction between Cd2+ and mg/L in 1. Under the stress of Cd2+, EPS between the total nitrogen and phosphorus removal efficiency of Chlorella showed a good positive correlation, the R2 values were 0.9905 (NH4+-N) and 0.9414 (PO43--P). Compared with PO43--P, the linear relationship between EPS content and NH4+-N removal rate is more obvious.

【學(xué)位授予單位】：湘潭大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：X703;X173

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 呂英,張捚,孫寶盛;胞外聚合物對(duì)水中Cu~(2+)的吸附研究[J];工業(yè)用水與廢水;2005年05期

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本文編號(hào)：1570526