亚临界水处理模拟有机—矿质复合体形成机制探讨

发布时间：2018-02-03 02:05

本文关键词： 腐殖酸高岭土有机-矿质复合体亚临界水处理方法吸附　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：为模拟地质吸附剂中的有机质矿化腐殖化及有机-矿质复合体的形成过程,探讨其作用机制,采用亚临界水处理技术,通过控制压力反应釜的温度、压力和反应时间对商用腐殖酸、高岭土及有机-矿质复合体进行处理,并通过比表面积全分析、傅里叶红外光谱(FTIR)、特定波长可见吸光度比值(E4/E6)、X射线衍射(XRD)和13C核磁共振(13C-NMR)等表征手段及对典型疏水性有机污染物卡马西平(CBZ)的吸附批实验,探讨了不同处理条件下有机质、粘土矿物及二者复合体的各自变化特征及吸附机制,并建立了概念模型。本研究主要得到以下结论:(1)比表面积全分析和E4/E6测定表明升温增压导致腐殖酸从“软碳”向“硬碳”转化。表现为比表面积显著增加、分子量增大、以及芳化度增加;红外光谱代表性基团的含量差异分析表明,其主要原因是游离羧基和链烃在升温增压条件下实现了成环、聚合过程,使其结构更加复杂,化学稳定性提高。吸附批实验显示腐殖酸的吸附等温线从非线性到线性,再到非线性转变,是由于腐殖酸升温增压过程中,产生了从小球状到链状,再到团聚状的结构改变,同时受水分子的竞争吸附作用和芳环的大π键之间的范德华力共同影响。基于比表面积变化的吸附位点计算进一步证实,腐殖酸处于小球状和链状时,吸附位点的多少控制吸附过程,当腐殖酸变为聚集态时,π键相互平衡使CBZ协同吸附在HA芳环结构上,进而控制吸附行为。(2) XRD衍射图和四种高岭土的红外光谱代表性基团差异表明,高岭土在升温增压的过程中脱水,架构起结晶更完整的有序结构。高岭土吸附CBZ前后的红外光谱的差异表明,常温常压下CBZ分子在KL表面填充空隙达到饱和后进入层间;升温增压前期高岭土层间距减小,层状结构被压缩导致CBZ分子进入困难,引起了升温增压初期Kd锐减;后期高温高压的处理加剧了 Al-OH消耗,其释放的OH-与CBZ分子C=O中O孤对电子的排斥作用削减,使得高温高压的后期KL对CBZ的吸附能力在保持平稳态势的前提下略有增强。(3)复合体实际吸附量和理论叠加吸附量的差值△Q表明,有机-矿质复合体的宏观吸附并非腐殖酸和高岭土吸附的简单叠加。XRD图谱显示,升温增压初期,复合体相对于腐殖酸的芳香度变化存在滞后,表明腐殖酸的部分芳香组分插入高岭土层间而免受高温高压的影响;同时复合体的芳化度与其非线性程度对应性表明,芳香化诱导力使靠近高岭土表面的腐殖酸排列紧密;后期逐步升温增压的处理使得未被保护的腐殖酸成链成环,致密的交界面上的变化共同导致有机-矿质复合体吸附介质的非均质性,也控制了吸附曲线的走向。此外,吸附量差值△Q与其脂肪度的变化具有一致性,表明复合体外空间可能存在依靠分子间作用力连接的脂肪性腐殖酸,且对CBZ分子的吸附有贡献。
[Abstract]:In order to simulate the process of organic matter mineralization humification and the formation of organic-mineral complex in geological adsorbent, the mechanism of its action was discussed. The subcritical water treatment technology was used to control the temperature of pressure reactor. The commercial humic acid, kaolin and organo-mineral complex were treated by pressure and reaction time. Specific wavelength visible absorbance ratio E4 / E6). X-ray diffraction (XRD) and 13C NMR (13C-NMRs) and adsorption batch experiments on typical hydrophobic organic pollutant carbamazepine (CBZ). The characteristics and adsorption mechanism of organic matter, clay minerals and their complexes under different treatment conditions were discussed. The main conclusions of this study are as follows: 1). The total surface area analysis and E4 / E6 measurement showed that heating and pressurization resulted in the transformation of humic acid from "soft carbon" to "hard carbon", which was characterized by a marked increase in specific surface area. The molecular weight increased and the degree of aromatization increased; The analysis of the content difference of representative groups in infrared spectrum shows that the main reason is that the free carboxyl group and the chain hydrocarbon can be formed and polymerized under the condition of temperature and pressure, which makes the structure more complex. The adsorption batch experiment showed that the adsorption isotherm of humic acid changed from nonlinear to linear and then to nonlinear because of the small globular to chain shape in the process of heating and pressurizing humic acid. At the same time, it is affected by the competitive adsorption of water molecules and the van der Waals force between the large 蟺 bonds of aromatic rings. The calculation of adsorption sites based on the change of specific surface area further proves that. When humic acid is in small globular and chain shape, the number of adsorption sites controls the adsorption process. When humic acid becomes aggregated, 蟺 -bond equilibrium makes CBZ synergistically adsorbed on HA aromatic ring structure. The difference of IR groups between the XRD diffraction pattern and the four kaolinites shows that the kaolin dehydrates in the process of heating and increasing pressure. The IR spectra of kaolin before and after adsorption of CBZ indicate that the CBZ molecules enter the interlayer after filling the pores on the KL surface at room temperature and atmospheric pressure. In the early stage of heating and pressurizing, the interlayer spacing of kaolin decreases, and the lamellar structure is compressed, which makes it difficult for CBZ molecules to enter, which results in a sharp decrease of KD in the early stage of heating and pressurizing. The high temperature and high pressure treatment increased the consumption of Al-OH, which reduced the repulsion of OH- and O solitary electrons in CBZ molecule Con O. The difference Q between the actual adsorption capacity of KL and the theoretical superposition adsorption capacity of KL on CBZ at the later stage of high temperature and high pressure is slightly enhanced on the premise of maintaining a steady state. The macroscopical adsorption of organic-mineral complex is not a simple superposition of humic acid and kaolin adsorption. XRD spectra show that the aromaticity of the complex relative to humic acid lags at the initial stage of heating and pressurization. It is shown that some aromatic components of humic acid are inserted into the interlayer of kaolin to avoid the influence of high temperature and high pressure. At the same time, the degree of aromatization of the complex corresponds to its nonlinear degree, which indicates that aromatization induces the arrangement of humic acids near the surface of kaolin. In the later stage, the unprotected humic acid was chained into a ring, and the change of the dense interface resulted in the heterogeneity of the adsorptive medium of the organic-mineral complex. In addition, the difference of adsorption quantity Q is consistent with the change of fat degree, which indicates that there may be fatty humic acid connected by intermolecular force in the complex space in vitro. In addition, the adsorption of CBZ molecules has a contribution.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X52;O647.3

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