多种土壤对双酚A的吸附行为及吸附预测模型的构建

发布时间：2018-01-09 19:09

本文关键词：多种土壤对双酚A的吸附行为及吸附预测模型的构建　出处：《华中农业大学》2015年硕士论文　论文类型：学位论文

【摘要】：吸附解吸是内分泌干扰物在土壤环境中行为和归宿的两个主要过程。内分泌干扰物在土壤中的吸附解吸影响着它在土壤中的迁移、降解和生物利用等过程。了解内分泌干扰物在多种土壤中的吸附解吸行为,并且建立一种快速预测不同土壤对内分泌干扰物吸附行为的模型,对于预测和评价内分泌干扰物对土壤、地下水存在的潜在危害、开展土壤修复具有十分重要的意义。本文采用批量平衡吸附法,研究了低浓度内分泌干扰物双酚A(bisphenol A)在七种地带性土壤和五种非地带性土壤中的吸附行为,主要考察了吸附动力学、等温线、热力学等特性;探讨了环境因素如:p H、温度、离子强度等对土壤吸附双酚A的影响;结合SPSS统计分析软件研究了土壤的不同性质参数对吸附行为的影响程度,并通过多元逐步回归分析建立了土壤对双酚A吸附行为的预测模型;运用红外光谱技术,考察了土壤在吸附双酚A前后官能团的变化特征;并初步探讨了双酚A与土壤的结合机理。主要研究内容和结果如下:1.研究了双酚A在供试土壤表面的吸附动力学机制。双酚A在土壤中吸附量随时间增加而增加,最后趋于稳定,吸附分为快吸附和慢吸附两个过程,24 h内可达吸附平衡。吸附动力学用二级动力学、Elovich方程和抛物线扩散方程拟合,结果表明二级动力学拟合效果较好,R2均大于0.92。它表明吸附过程比较复杂,化学吸附是速控步骤。2.应用吸附-解吸化学方法和傅里叶变换红外光谱(FTIR)分析,系统探讨了双酚A在土壤表面的吸附-解吸特征,初步揭示了其吸附机理。双酚A在十二种土壤中的等温吸附方程均可用线性方程和Freundlich方程拟合。采自华中农业大学水稻田土对双酚A的吸附量最大,桃园地土的吸附量最小。吸附系数最大者是最小者的3.03倍。用Ca Cl2溶液和磷酸缓冲盐溶液,连续解吸吸附在土壤表面的双酚A分子,计算通过静电作用和配位交换作用吸附的双酚A所占比例。结果表明静电作用吸附所占比例为3.4%-11.8%,配位交换作用所占比例为2.9%-13.2%。两者总共所占比例10.1%-21.9%。说明静电作用和配位交换作用吸附不是土壤吸附双酚A的主要作用力。FTIR结果表明,氢键作用参与了土壤对双酚A的吸附。3.环境影响因素试验表明,除长沙红壤和华中农业大学茶园地土外,其余土壤在酸性条件下(p H 3-5)吸附量较大,随着p H增加,吸附量逐渐降低,在p H=6-8左右,吸附量趋于平衡,随着p H进一步增加,吸附量急剧下降,这与土壤表面所带电荷和双酚A在不同p H条件下的解离程度有关。随着电解质Ca Cl2浓度的增加,土壤对双酚A的吸附量均呈增加趋势,表明Ca2+的存在促进了土壤对双酚A吸附。去有机质之后的土壤与原土比较,去有机质土壤对双酚A的吸附量明显降低,表明有机质含量是影响土壤对双酚A吸附的重要因素。除武汉黄棕壤外,其余土壤对双酚A的吸附量均随温度增加而降低,表明温度升高不利于吸附反应的进行。4.吸附热力学实验表明,双酚A在土壤表面的吸附自由能(△G)为负值,表明吸附为自发过程,且△G的绝对值均小于40 k J/mol,说明主要发生物理吸附;吸附焓变值△H(除武汉黄棕壤)小于零,说明吸附是放热反应,这与温度变化对吸附的影响一致;吸附的熵变值△S均小于零,说明吸附过程是一个熵减小的过程。双酚A在土壤中的吸附主要是一个自发、放热、熵减小的物理吸附过程。5.运用SPSS统计分析软件研究了土壤各种性质参数对双酚A吸附的影响程度。简单相关分析得出,土壤对双酚A吸附能力与土壤有机质含量(SOM)高度相关,与阳离子交换量(CEC)中度相关,与p H和粘粒含量弱相关,与电导率(EC)和比表面积(SSA)几乎不相关。偏回归分析表明,土壤有机质是影响双酚A吸附的最主要因素,这与一元线性回归结果一致。多元逐步回归分析结果显示,有机质含量是主导土壤对双酚A吸附的关键因素,随着土壤有机质含量增加,其吸附能力增强。并通过多元逐步回归分析建立了土壤对双酚A吸附行为预测模型,揭示了双酚A在不同土壤中的吸附系数与SOM间存在的定量关系,具有较强的理论指导意义。
[Abstract]:Adsorption and desorption are the two main processes of endocrine disruptors behavior in the soil environment and the destination. The adsorption and desorption of endocrine disrupting chemicals in soils affects its migration in soil, degradation and biological processes. Understanding of endocrine disruptors in a variety of soil adsorption desorption behavior, and establish a rapid prediction model of soil the adsorption behaviors of endocrine disruptors, for the prediction and evaluation of endocrine disruptors on Soil and groundwater potential hazards exist, has very important significance to carry out soil remediation. In this paper, using batch equilibrium adsorption method of low concentration of bisphenol A (bisphenol A) in seven soil and five non zonal soil the adsorption behavior of the main effects of adsorption isotherms, kinetics, thermodynamics and other characteristics; discusses the environmental factors such as: P H, temperature, ionic strength and so on The effect of soil adsorption of bisphenol A; the influence degree of different parameters with SPSS statistical analysis software to study the soil adsorption behavior, and through multivariate analysis established a prediction model of soil on the adsorption behavior of bisphenol A by using stepwise regression; infrared spectroscopy, investigated the changes in soil characteristics before and after adsorption of bisphenol A and functional groups; preliminary study on the binding mechanism of bisphenol A and soil. The main research contents and results are as follows: 1. research on bisphenol A in the tested soil surface. The adsorption kinetics mechanism of adsorption increased with time of bisphenol A in the soil, and finally tends to be stable, the adsorption is fast adsorption and slow adsorption process of two, 24 h up to grade two. The adsorption equilibrium of kinetics of adsorption kinetics, the Elovich equation and parabolic diffusion equation, results show that the better the two level dynamic fitting effect of R2 was greater than 0.92., it shows that the adsorption. The process is more complex, the chemical adsorption is the rate controlling step of.2. adsorption desorption chemical method and application of Fu Liye transform infrared spectroscopy (FTIR) analysis system, discusses the characteristics of adsorption desorption of bisphenol A in surface soils, reveal the mechanism of adsorption of bisphenol A in twelve kinds of soil. The isothermal adsorption equation of linear equations can and the Freundlich equation. The maximum adsorption capacity of paddy mining from Huazhong Agricultural University soil of bisphenol A, the adsorption capacity of Taoyuan land is the smallest. The maximum adsorption coefficient is 3.03 times the minimum. With the Ca Cl2 solution and phosphate buffer salt solution, adsorption of bisphenol A in continuous solution molecular soil surface, calculated by the electrostatic interaction bisphenol A and ligand exchange interaction adsorption proportion. The results show that the electrostatic adsorption of the proportion of 3.4%-11.8%, the ligand exchange accounted for the proportion of total 2.9%-13.2%. of the two 10.1%-21.9%. The main force of.FTIR electrostatic interactions and ligand exchange adsorption is not soil adsorption of bisphenol A results show that the hydrogen bonding in the experiment soil.3. environmental impact factors on the adsorption of bisphenol A, in addition to Changsha red and Huazhong Agricultural University tea garden soil, the soil under acidic conditions (P H 3-5) larger adsorption amount. With P H increased, adsorption capacity gradually decreased, in P H=6-8, adsorption equilibrium, with the P H further increased, adsorption capacity decreased sharply, and the soil surface charge and bisphenol A in different P under the condition of H from solution degree. With the increase of electrolyte Ca concentration of Cl2, the adsorption capacity of soil to bisphenol A increased, showed that Ca2+ promoted the adsorption of bisphenol A to soil organic matter. After compared with the original soil, soil organic matter to the adsorption of bisphenol A was significantly reduced, showed that the content of organic matter The amount of soil is an important factor affecting the adsorption of bisphenol A. In addition to Wuhan yellow brown soil, the adsorption capacity of bisphenol A on the rest of the soil were decrease with the increasing temperature, that temperature is not conducive to the adsorption reaction of.4. adsorption experiments showed that the adsorption of bisphenol A in soil surface free energy (G). That shows that the adsorption is a spontaneous process, and the absolute value of G was less than 40 K J/mol, the main physical adsorption; adsorption enthalpy value Delta H (except Wuhan yellow brown soil) is less than zero, indicating that the adsorption is an exothermic reaction, and the effect of temperature on the adsorption; variable Delta S is less than zero adsorption the entropy, which means that the adsorption process is a process of entropy decrease. The adsorption of bisphenol A in soil is a spontaneous, exothermic, entropy decreases the physical adsorption process of.5. using SPSS statistical analysis software to study the influence of various parameters on the soil properties of bisphenol A adsorption process . simple correlation analysis showed that the soil adsorption capacity of bisphenol A and the content of soil organic matter (SOM) are highly correlated, and cation exchange capacity (CEC) and P H are moderate, and the content of clay weak correlation, and electrical conductivity (EC) and specific surface area (SSA) almost no correlation. Partial regression analysis showed that soil organic matter is the main factor affecting the adsorption of bisphenol A, and the linear regression results. Multiple stepwise regression analysis showed that the content of organic matter is a key factor leading to soil adsorption of bisphenol A, with the increase of soil organic matter content, enhanced its adsorption capacity. And through multivariate analysis was established on the soil the adsorption behavior of bisphenol A prediction model of stepwise regression, reveals the existence of the quantitative relationship between adsorption coefficient and SOM bisphenol A in different soils, has a strong theoretical significance.

【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53

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