DTPA-LDHs-DGT开发及应用于土壤—稻米镉传输模型构建研究

发布时间：2018-03-22 02:23

  本文选题：DGT　切入点：镉　出处：《沈阳农业大学》2017年硕士论文　论文类型：学位论文

【摘要】：Cd是环境中毒性较强的重金属元素,土壤中重金属Cd会对粮食安全和人体健康造成危害,但如何表征Cd的生物有效性,从而以此为基础建立起土壤-稻米Cd传输模型一直是难以解决的科学问题。薄膜梯度扩散(DGT)是一种新型的重金属有效态提取技术,能有效反应稻米从土壤中吸收重金属的情况。本文在大量前期工作的基础上进一步探究,改进自主材料纳米Mg-Al-DTPA-LDHs(以下简称DTPA-LDHs)的生产工艺,深入研究DTPA-LDHs的材料性能。并以DTPA-LDHs为结合相,制成DTPA-LDHs-DGT(以下简称新型DGT)。通过新型DGT的研制研究和新型DGT应用于土壤-稻米镉传输模型构建研究,得出以下结论:1.DTPA-LDHs材料具有饱和吸附量大、吸附可持续时间长、pH适用范围宽、吸附过程不受电解质影响等特点。DTPA-LDHs结合相在显微镜下表现均匀,说明纳米级材料DTPA-LDHs的性能远高于颗粒性材料Chelex 100,适用性更好。2.根据不同厚度扩散膜DGT对金属络合易解离态解离性能存在差异这一原理,提出了一套计算金属解离动力学及有效态组分的方法,并将其应用于水体Zn、Ni、Fe、Cu、Cd、Mn、Pb等金属形态及解离动力学特征差异计算中。且计算结果更好地体现出有效态中络合易解离部分的贡献,计算公式假设参数少,避免了金属价态、有机质组分构成差异性等因素对有效态含量计算的影响。3.采用Cubist多元混合线性回归技术构建土壤-稻米Cd传输模型,预测值与检测值一致性明显好于常规回归分析。说明Cubist技术是构建土壤-稻米Cd传输模型最有效的方法之一。4.DGT技术可以溶合影响稻米富集Cd的土壤环境因子。再次构建Cubist模型,规则由7个减少为4个,参数由6个减少为5个,检测参数减少、参数指征更加明确,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.
【学位授予单位】：沈阳农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X53
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本文编号：1646651