含膨胀晶层矿物纳米复合物对邻苯二甲酸酯的吸附作用
发布时间：2018-11-12 18:19
【摘要】：本文利用含膨胀晶层矿物及其有机插层纳米复合物对水溶液中的邻苯二甲酸酯进行了吸附实验研究。根据含膨胀晶层矿物层间水化阳离子层的可交换性和吸附性,采用水解-插层复合法,用具有相同结构但不同烷基碳链长度的系列季铵盐制备CnTA+/蒙脱石纳米复合物和CnTA+/蛭石纳米复合物,并对水溶液中4种邻苯二甲酸酯类物质进行吸附实验。通过XRD、FT-IR等分析测试手段及物理性能测试对CnTA+/蒙脱石、蛭石纳米复合物进行分析表征,考察了吸附反应时间、初始p H值和反应温度对吸附效果的影响,并探讨了季铵盐烷基碳链链长和用量对制得的CnTA+/蒙脱石、蛭石纳米复合物吸附水溶液中邻苯二甲酸酯类物质效果的影响。通过对吸附结果进行吸附热力学和动力学方程拟合,揭示吸附反应机理。结果表明:相同用量的季铵盐制备的CnTA+/蒙脱石、蛭石纳米复合物的层间距d0 0 1值随季铵盐的链长增长而增大;相同链长的季铵盐制备的CnTA+/蒙脱石、蛭石纳米复合的层间距d0 0 1值随用量的增加而增大。季铵盐阳离子在蒙脱石、蛭石层间因用量及烷基碳链长度的不同而形成不同的排布模式。经有机插层后的CnTA+/蒙脱石、蛭石纳米复合物对PAEs的吸附能力大于原蒙脱石、蛭石。随着季铵盐的用量和季铵盐烷基碳链链长的增加,CnTA+/蒙脱石纳米复合物和CnTA+/蛭石纳米复合物对PAEs的去除率先增加后减小。经1.0CEC季铵盐用量插层后的纳米复合物对PAEs的吸附效果最好。PAEs在CnTA+/蒙脱石纳米复合物和CnTA+/蛭石纳米复合物上的吸附与PAEs物质分子大小及疏水性有关。其中吸附量随着吸附时间的增加而增加,CnTA+/蒙脱石纳米复合物和Cn TA+/蛭石纳米复合物对PAEs的吸附作用基本不会受到初始p H的影响。温度对吸附效果有一定影响,但影响不大。随着温度的升高吸附去除率减小。采用Langmuir吸附等温模型以及Freundlich吸附等温模型对吸附结果进行拟合,两种等温吸附模型均对吸附过程进行拟合。PAEs在钠蒙脱石和蛭石原样上的吸附主要是以表面吸附为主,其中还包括离子交换吸附等化学吸附。在CnTA+/蒙脱石、蛭石纳米复合物上的吸附主要是有机质的分配作用,表面吸附也是吸附的机制之一。吸附过程不能用拟一级动力学吸附模型进行拟合,但符合拟二级动力学吸附模型。
[Abstract]:In this paper, the adsorption of phthalates in aqueous solution was studied by using expanded crystal layer minerals and their organic intercalation nanocomposites. According to the exchangeability and adsorbability of the hydrated cationic layer between the mineral layers containing expanded crystal layer, the hydrolysis-intercalation composite method was adopted. CnTA / montmorillonite nanocomposites and CnTA / vermiculite nanocomposites were prepared by using a series of quaternary ammonium salts with the same structure but different alkyl carbon chain lengths. The adsorption experiments of four phthalate esters in aqueous solution were carried out. CnTA / montmorillonite and vermiculite nanocomposites were characterized by XRD,FT-IR and physical properties. The effects of adsorption time, initial pH value and reaction temperature on the adsorption were investigated. The effects of alkyl chain length and amount of quaternary ammonium salt on the adsorption of phthalates in aqueous solution by CnTA / montmorillonite and vermiculite nanocomposites were investigated. The adsorption reaction mechanism was revealed by fitting the adsorption thermodynamic and kinetic equations. The results showed that the interlayer spacing of CnTA / montmorillonite prepared with the same amount of quaternary ammonium salt increased with the increase of chain length of quaternary ammonium salt. For CnTA / montmorillonite prepared by quaternary ammonium salt with the same chain length, the interlayer spacing of vermiculite nanocomposite increased with the increase of dosage. Quaternary ammonium salt cations in montmorillonite and vermiculite layers have different distribution patterns due to different dosage and length of alkyl carbon chain. After organic intercalation of CnTA / montmorillonite, the adsorption ability of vermiculite nanocomposites to PAEs was higher than that of original montmorillonite and vermiculite. With the increase of quaternary ammonium salt content and alkyl chain length of quaternary ammonium salt, the removal of PAEs by CnTA / montmorillonite nanocomposites and CnTA / vermiculite nanocomposites increased first and then decreased. The adsorption of PAEs on CnTA / montmorillonite nanocomposites and CnTA / vermiculite nanocomposites was related to the molecular size and hydrophobicity of PAEs. The adsorption capacity increased with the increase of adsorption time. The adsorption of PAEs by CnTA / montmorillonite nanocomposites and Cn TA / vermiculite nanocomposites was not affected by the initial pH. Temperature has a certain effect on adsorption, but it has little effect. The adsorption removal rate decreases with the increase of temperature. Langmuir adsorption isotherm model and Freundlich adsorption isotherm model were used to fit the adsorption results. The adsorption process was fitted by two isothermal adsorption models. The adsorption of PAEs on sodium montmorillonite and vermiculite samples was mainly surface adsorption. It also includes chemical adsorption such as ion exchange adsorption. In CnTA / montmorillonite, the adsorption on vermiculite nanocomposites is mainly due to the distribution of organic matter, and surface adsorption is one of the mechanisms of adsorption. The adsorption process can not be fitted by the pseudo-first-order kinetic adsorption model, but it accords with the pseudo-second-order kinetic adsorption model.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X592;O647.3
[Abstract]:In this paper, the adsorption of phthalates in aqueous solution was studied by using expanded crystal layer minerals and their organic intercalation nanocomposites. According to the exchangeability and adsorbability of the hydrated cationic layer between the mineral layers containing expanded crystal layer, the hydrolysis-intercalation composite method was adopted. CnTA / montmorillonite nanocomposites and CnTA / vermiculite nanocomposites were prepared by using a series of quaternary ammonium salts with the same structure but different alkyl carbon chain lengths. The adsorption experiments of four phthalate esters in aqueous solution were carried out. CnTA / montmorillonite and vermiculite nanocomposites were characterized by XRD,FT-IR and physical properties. The effects of adsorption time, initial pH value and reaction temperature on the adsorption were investigated. The effects of alkyl chain length and amount of quaternary ammonium salt on the adsorption of phthalates in aqueous solution by CnTA / montmorillonite and vermiculite nanocomposites were investigated. The adsorption reaction mechanism was revealed by fitting the adsorption thermodynamic and kinetic equations. The results showed that the interlayer spacing of CnTA / montmorillonite prepared with the same amount of quaternary ammonium salt increased with the increase of chain length of quaternary ammonium salt. For CnTA / montmorillonite prepared by quaternary ammonium salt with the same chain length, the interlayer spacing of vermiculite nanocomposite increased with the increase of dosage. Quaternary ammonium salt cations in montmorillonite and vermiculite layers have different distribution patterns due to different dosage and length of alkyl carbon chain. After organic intercalation of CnTA / montmorillonite, the adsorption ability of vermiculite nanocomposites to PAEs was higher than that of original montmorillonite and vermiculite. With the increase of quaternary ammonium salt content and alkyl chain length of quaternary ammonium salt, the removal of PAEs by CnTA / montmorillonite nanocomposites and CnTA / vermiculite nanocomposites increased first and then decreased. The adsorption of PAEs on CnTA / montmorillonite nanocomposites and CnTA / vermiculite nanocomposites was related to the molecular size and hydrophobicity of PAEs. The adsorption capacity increased with the increase of adsorption time. The adsorption of PAEs by CnTA / montmorillonite nanocomposites and Cn TA / vermiculite nanocomposites was not affected by the initial pH. Temperature has a certain effect on adsorption, but it has little effect. The adsorption removal rate decreases with the increase of temperature. Langmuir adsorption isotherm model and Freundlich adsorption isotherm model were used to fit the adsorption results. The adsorption process was fitted by two isothermal adsorption models. The adsorption of PAEs on sodium montmorillonite and vermiculite samples was mainly surface adsorption. It also includes chemical adsorption such as ion exchange adsorption. In CnTA / montmorillonite, the adsorption on vermiculite nanocomposites is mainly due to the distribution of organic matter, and surface adsorption is one of the mechanisms of adsorption. The adsorption process can not be fitted by the pseudo-first-order kinetic adsorption model, but it accords with the pseudo-second-order kinetic adsorption model.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X592;O647.3
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