本文選題：DGT　切入點：鎘　出處：《沈陽農(nóng)業(yè)大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：Cd是環(huán)境中毒性較強的重金屬元素,土壤中重金屬Cd會對糧食安全和人體健康造成危害,但如何表征Cd的生物有效性,從而以此為基礎(chǔ)建立起土壤-稻米Cd傳輸模型一直是難以解決的科學(xué)問題。薄膜梯度擴散(DGT)是一種新型的重金屬有效態(tài)提取技術(shù),能有效反應(yīng)稻米從土壤中吸收重金屬的情況。本文在大量前期工作的基礎(chǔ)上進一步探究,改進自主材料納米Mg-Al-DTPA-LDHs(以下簡稱DTPA-LDHs)的生產(chǎn)工藝,深入研究DTPA-LDHs的材料性能。并以DTPA-LDHs為結(jié)合相,制成DTPA-LDHs-DGT(以下簡稱新型DGT)。通過新型DGT的研制研究和新型DGT應(yīng)用于土壤-稻米鎘傳輸模型構(gòu)建研究,得出以下結(jié)論:1.DTPA-LDHs材料具有飽和吸附量大、吸附可持續(xù)時間長、pH適用范圍寬、吸附過程不受電解質(zhì)影響等特點。DTPA-LDHs結(jié)合相在顯微鏡下表現(xiàn)均勻,說明納米級材料DTPA-LDHs的性能遠(yuǎn)高于顆粒性材料Chelex 100,適用性更好。2.根據(jù)不同厚度擴散膜DGT對金屬絡(luò)合易解離態(tài)解離性能存在差異這一原理,提出了一套計算金屬解離動力學(xué)及有效態(tài)組分的方法,并將其應(yīng)用于水體Zn、Ni、Fe、Cu、Cd、Mn、Pb等金屬形態(tài)及解離動力學(xué)特征差異計算中。且計算結(jié)果更好地體現(xiàn)出有效態(tài)中絡(luò)合易解離部分的貢獻(xiàn),計算公式假設(shè)參數(shù)少,避免了金屬價態(tài)、有機質(zhì)組分構(gòu)成差異性等因素對有效態(tài)含量計算的影響。3.采用Cubist多元混合線性回歸技術(shù)構(gòu)建土壤-稻米Cd傳輸模型,預(yù)測值與檢測值一致性明顯好于常規(guī)回歸分析。說明Cubist技術(shù)是構(gòu)建土壤-稻米Cd傳輸模型最有效的方法之一。4.DGT技術(shù)可以溶合影響稻米富集Cd的土壤環(huán)境因子。再次構(gòu)建Cubist模型,規(guī)則由7個減少為4個,參數(shù)由6個減少為5個,檢測參數(shù)減少、參數(shù)指征更加明確,模型精度提高。
[Abstract]:CD is a toxic heavy metal element in the environment. CD in soil will cause harm to food security and human health, but how to characterize the bioavailability of CD. Therefore, it is always difficult to solve the scientific problem of establishing a soil-rice CD transport model. The film gradient diffusion (DGTT) is a new technology for the extraction of available heavy metals. It can effectively reflect the absorption of heavy metals from the soil by rice. Based on a lot of previous work, the production process of nano-sized Mg-Al-DTPA-LDHs (DTPA-LDHs) was improved in this paper. The material properties of DTPA-LDHs were studied in depth. DTPA-LDHs-DGTs (hereinafter referred to as new DGTT) were prepared by using DTPA-LDHs as the combination phase. Through the development of new DGT and the application of new DGT to the construction of soil-rice cadmium transport model, The main conclusions are as follows: 1. DTPA-LDHs has the characteristics of large saturated adsorption capacity, long adsorption duration and wide suitable pH range, and the adsorption process is not affected by electrolytes. DTPA-LDHs binding phase is uniform under microscope. The results show that the properties of nano-material DTPA-LDHs are much higher than that of granular material Chelex 100, and the applicability is better. 2.According to the principle that the dissociation properties of DGT with different thickness on the dissociation state of metal complex are different, A set of methods for calculating the dissociation kinetics and effective state components of metals are presented. It has been applied to the calculation of the difference of metal morphology and dissociation kinetics characteristics in water, such as ZnNII / NiFeFeCU / CDMn-Pb and so on. The calculated results better reflect the contribution of the complex dissociation part of the effective state, and the calculation formula assumes less parameters and avoids the metal valence state. The effect of different components of organic matter on the calculation of available state content. 3. A model of CD transport between soil and rice was established by using Cubist multivariate mixed linear regression technique. The results showed that Cubist technique was one of the most effective methods to construct a soil-rice CD transport model. 4. DGT technique could combine the soil environmental factors affecting CD enrichment in rice. Cubist model was constructed again. The rules are reduced from 7 to 4, the parameters are reduced from 6 to 5, the detection parameters are reduced, the parameter indications are more definite, and the precision of the model is improved.
【學(xué)位授予單位】：沈陽農(nóng)業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：X53
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本文編號：1646651