本文選題：生物表面活性劑 + 皂角苷��； 參考：《江西理工大學(xué)》2017年碩士論文

【摘要】：近年來,由于稀土資源的大規(guī)模開發(fā),以及農(nóng)用稀土的使用,導(dǎo)致稀土元素礦區(qū)及周邊土壤環(huán)境中累積,由于植物吸收利用導(dǎo)致農(nóng)產(chǎn)品稀土超標(biāo),并且通過食物鏈傳遞引起人體健康風(fēng)險(xiǎn)。目前污染土壤治理技術(shù)中,土壤淋洗具有見效快、徹底移除污染物等優(yōu)點(diǎn),使其在污染土壤的治理領(lǐng)域具有良好的應(yīng)用前景。淋洗劑的選擇與開發(fā)是土壤淋洗技術(shù)應(yīng)用最關(guān)鍵的問題,生物表面活性劑具有低毒性、可生物降解、對(duì)土壤破壞小等優(yōu)點(diǎn),成為土壤淋洗技術(shù)研究重點(diǎn)。本文以La、Ce、Y和Eu為目標(biāo)污染物,探討皂角苷對(duì)土壤中稀土元素的淋洗效果及作用機(jī)理。采用振蕩淋洗實(shí)驗(yàn),探討皂角苷濃度、淋洗液pH、土液比、淋洗時(shí)間等因素對(duì)淋洗效果的影響。通過土柱淋洗實(shí)驗(yàn),探討皂角苷對(duì)土壤中稀土元素La、Ce、Y和Eu的動(dòng)態(tài)淋洗效果。通過分析皂角苷在土壤中的吸附行為、紅外光譜分析、離子交換平衡實(shí)驗(yàn)等探討皂角苷與稀土元素的作用機(jī)理。主要研究結(jié)論如下:(1)通過振蕩淋洗實(shí)驗(yàn),得出淋洗污染土壤中La、Ce、Y和Eu的最適條件:皂角苷濃度為25 g·L-1、pH=5.5、土液比為1:40、淋洗時(shí)間為6h、無電解質(zhì)共存,皂角苷對(duì)La、Ce、Y和Eu的淋洗率分別為58.05%、57.78%、64.43%、91.97%。(2)土柱淋洗實(shí)驗(yàn)的結(jié)果表明,皂角苷對(duì)土壤中的稀土有較好的淋洗效果。25g·L-1皂角苷溶液對(duì)La、Ce、Y和Eu的淋洗效率分別為35.26%、26.07%、31.48%和30.85%,累積淋洗量分別為58.60 mg·kg-1的La、51.16 mg·kg-1的Ce、24.66mg·kg-1的Y和34.47 mg·kg-1的Eu。四種元素的土柱淋洗效果均低于振蕩淋洗效果。通過淋洗前后土壤中稀土元素形態(tài)分析,皂角苷淋洗主要去除稀土的弱酸可提取態(tài),其次為可還原態(tài)。淋洗后土壤中的稀土從與土壤結(jié)合較松散的形態(tài)轉(zhuǎn)化為土壤結(jié)合較緊密的結(jié)合形態(tài),增加了土壤的稀土元素的穩(wěn)定性,降低了稀土在土壤中的生物利用性及其潛在危害。(3)通過對(duì)比皂角苷與稀土元素反應(yīng)前后的紅外光譜圖,證明了皂角苷與稀土元素通過皂角苷分子中的羧基基團(tuán)與稀土離子反應(yīng)生成了新的配位化合物,并通過離子交換平衡法測定了皂角苷與La、Ce、Y、Eu生成了配位比為1:1的配位化合物。皂角苷吸附土壤中稀土元素的機(jī)理可以被歸納為降低界面張力、增溶、配位等多種作用的結(jié)合。
[Abstract]:In recent years, the large-scale development of rare earth resources, as well as the use of rare earth in agriculture, has led to the accumulation of rare earth elements in the mining area and the surrounding soil environment. Because of the absorption and utilization of the plants, the rare earth of the agricultural products is exceeding the standard, and the health risk of the human body is transmitted through the food chain. The selection and development of the leaching agent is the most important problem in the application of soil leaching technology. The bioactive agent has the advantages of low toxicity, biodegradation and small damage to soil, which has become the key point of soil leaching technology. This paper is based on La, Ce, Y. And Eu as the target pollutant, the effect and mechanism of the leaching of rare earth elements in soil by saponins were discussed. The influence of factors such as the concentration of saponins, pH, soil liquid ratio and leaching time on the leaching effect were investigated by oscillatory leaching experiment. The dynamic drenching of La, Ce, Y and Eu in soil was investigated by soil column leaching experiment. The main research conclusions are as follows: (1) the optimum conditions for La, Ce, Y and Eu in contaminated soil are obtained by oscillating leaching experiments: the concentration of saponin is 25 g. L-1, pH=5.5, and soil. The liquid ratio is 1:40, the leaching time is 6h, no electrolyte coexist, the leaching rate of saponins to La, Ce, Y and Eu are 58.05%, 57.78%, 64.43%, 91.97%. (2) soil column leaching experiment results show that saponin has better leaching effect on rare earth in soil.25g. L-1 saponins solution to La, Ce, Y and Eu leaching efficiency is 35.26%, 26.07%, 31.48% respectively. And 30.85%, the cumulative leaching amount is 58.60 mg. Kg-1 La, 51.16 mg. Kg-1 Ce, 24.66mg. Kg-1 Y and 34.47 mg. Kg-1 Eu. four elements of the soil column washing effect is lower than the oscillation leaching effect. Original state. After leaching, the rare earth in soil is converted from a loose combination with the soil into a compact combination of soil combination, which increases the stability of the rare earth elements in the soil and reduces the bioavailability and potential hazards of rare earth elements in the soil. (3) by comparing the infrared spectra before and after the reaction of saponins and rare earth elements, it is proved that A new coordination compound was formed by the reaction of saponin and rare earth elements through the carboxyl groups of saponin molecules with rare earth ions. The coordination compounds of saponins with La, Ce, Y and Eu were determined by the ion exchange equilibrium method. The mechanism of the adsorption of rare earth elements in soil by saponins can be induced to reduce the interface. The combination of various functions, such as tension, solubilization, coordination and so on.
【學(xué)位授予單位】：江西理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：X53

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

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本文編號(hào)：1986178