本文關(guān)鍵詞： 小球藻 Cd~(2+) 毒性效應(yīng) 吸附效能 機(jī)理分析　出處：《哈爾濱工業(yè)大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著近幾十年社會(huì)經(jīng)濟(jì)的快速發(fā)展,環(huán)境問題受到了人們的關(guān)注,特別是近幾年來,中央加大了對(duì)環(huán)境保護(hù)的力度。各種修復(fù)水體污染的方法被研制出來,其中利用藻類等生物修復(fù)水體重金屬污染或者利用藻類生物吸附劑處理污水是一種具有廣泛應(yīng)用前景的技術(shù)。小球藻等綠藻廣泛存在于水體中,并且生長(zhǎng)繁殖速度快,很容易進(jìn)行大規(guī)模養(yǎng)殖,同時(shí)對(duì)重金屬具有一定的吸附能力,可以有效降低重金屬的含量。但是,重金屬對(duì)生活藻類的毒性作用影響了其的正常生長(zhǎng),在一定程度上抑制了藻類在水處理中的應(yīng)用。同時(shí),在重金屬的脅迫下,藻細(xì)胞自身能夠通過一系列生理活動(dòng)來減輕重金屬的毒害作用,這一特點(diǎn)對(duì)于活性藻體在重金屬水體中的應(yīng)用具有重要的實(shí)際意義。另外,死亡的藻體對(duì)重金屬同樣有一定的吸附能力。本研究采用靜態(tài)實(shí)驗(yàn)的方法,選用水體中常見的綠藻(小球藻、斜生柵藻),對(duì)其毒理學(xué)進(jìn)行研究。獲得了Cd2+對(duì)兩種藻的半數(shù)抑制濃度分別為5.94mg/L、4.13 mg/L。同時(shí)對(duì)不同鎘脅迫下的小球藻和斜生柵藻的葉綠素a,胞內(nèi)胞外可溶性糖和蛋白質(zhì)的濃度變化進(jìn)行了比較,獲取了兩種藻類對(duì)Cd2+的耐受性程度,結(jié)果顯示小球藻對(duì)鎘的耐受性更好。另外,鎘的脅迫下,小球藻藻細(xì)胞本身的抗氧化酶發(fā)生了一系列的變化,如SOD隨著鎘濃度先升高后降低等,說明在此過程中,抗氧化酶確實(shí)起到了一定的解毒效果。在吸附實(shí)驗(yàn)中,研究了初始藻細(xì)胞密度,初始重金屬濃度,酸堿性,以及溫度對(duì)生活、死亡小球藻生物吸附效率的影響,結(jié)果顯示小球藻對(duì)鎘具有很好的吸附效能,且生活小球藻的吸附效率要高于死亡小球藻。同時(shí)采用批量平衡法研究了小球藻對(duì)鎘的吸附動(dòng)力學(xué)與熱力學(xué),并采用偽一級(jí)動(dòng)力學(xué)方程、偽二級(jí)動(dòng)力學(xué)方程、Langmuir等溫線方程以及Freundlich等溫線方程對(duì)實(shí)驗(yàn)數(shù)據(jù)進(jìn)行了擬合。結(jié)果顯示:在溶液中性偏酸性的條件下,吸附效果最好,在20-30℃溫度范圍內(nèi)提高溫度有利于吸附的發(fā)生,同時(shí),藻的生物量及鎘的初始濃度都在一定程度上影響到吸附效果。偽二級(jí)動(dòng)力學(xué)方程、Langmuir等溫線方程以及Freundlich等溫線方程都可描述小球藻生物吸附鎘的過程。通過紅外光譜分析,發(fā)現(xiàn)了小球藻在吸附過程中是C-O、C=O、-COOH、-NH-等官能團(tuán)發(fā)揮了重要的作用。
[Abstract]:With the rapid development of social economy in recent decades, people pay more attention to environmental problems, especially in recent years, the central government has stepped up its efforts to protect the environment. Various methods for remediation of water pollution have been developed. Among them, the use of algae and other biological remediation of heavy metal pollution or the use of algae biological adsorbent treatment of sewage is a technology with wide application prospects. Chlorella and other green algae widely exist in the water, and the growth and reproduction speed is fast. It is easy to breed on a large scale and has certain adsorption ability for heavy metals, which can effectively reduce the content of heavy metals. However, the toxicity of heavy metals to living algae affects their normal growth. At the same time, under the stress of heavy metals, algal cells can reduce the toxicity of heavy metals through a series of physiological activities. This feature has important practical significance for the application of active algae in heavy metal water. In addition, the dead algae also has certain adsorption capacity for heavy metals. Chlorella vulgaris (Chlorella vulgaris), which is common in water, The median inhibitory concentration of Cd2 on two species of algae was 5.94 mg / L, 4.13 mg / L, respectively. The chlorophyll a, extracellular soluble sugar and protein of Chlorella vulgaris and S. obliquus under different cadmium stress were also studied. Were compared with each other. The tolerance of two algae to Cd2 was obtained. The results showed that Chlorella microphylla had better tolerance to cadmium. In addition, under cadmium stress, the antioxidant enzymes of Chlorella vulgaris cells had a series of changes. For example, SOD increased first and then decreased with the concentration of cadmium, which indicated that antioxidant enzymes did play a certain detoxification effect in this process. In the adsorption experiment, the initial cell density of algae, the initial concentration of heavy metals, acid and alkalinity, and so on, were studied. And the effect of temperature on the biosorption efficiency of Chlorella mori showed that Chlorella sp. Has a good adsorption efficiency for cadmium. The adsorption efficiency of chlorella was higher than that of dead Chlorella. The adsorption kinetics and thermodynamics of cadmium by Chlorella microphylla were studied by batch equilibrium method, and the pseudo-first-order kinetic equation was used. The pseudo-second-order kinetic equation Langmuir isotherm equation and Freundlich isotherm equation were used to fit the experimental data. Increasing the temperature in the temperature range of 20-30 鈩，

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