电气石吸附直接红23吸附性能研究

发布时间：2018-07-04 14:57

本文选题：电气石 + 直接红23　；参考：《吉林大学》2017年硕士论文

【摘要】：偶氮染料因其具有易着色,牢度好等特点在印染、纺织等行业被广泛应用。其生产废水具有色度高,组成成分复杂,可生化性差,毒性强等特点,因此当此类生产废水未经适当的处理排入受纳水体时,会通过增加受纳水体的色度而影响水生植物的光合作用从而使该水生环境生态遭到破坏。此外由于染料的生产废水毒性强会抑制水生生物的生长,其毒性也会通过生物链的逐级富集作用对人类的安全构成威胁。因此,目前如何处理染料废水成为了研究热点。吸附作用既可以起到去除水中污染物的作用,又可以起到富集污染物的作用,因此本研究旨在选择廉价的吸附剂,通过研究其吸附性能,探讨其吸附机理。电气石因其分布广,价格低的特点,在污染物的去除方面有良好的应用前景。本文以直接红23偶氮染料为例,利用电气石作为吸附剂对其进行吸附去除。首先对电气石进行理化性质的研究(表面形态结构,表面官能团分析,元素组成,等电位点,平均粒径等),其次通过条件实验得到电气石在不同条件下吸附直接红23的吸附性能(电气石的浓度,pH,温度,离子强度),然后通过利用不同吸附动力学模型和吸附平衡学模型对实验数据进行拟合并对拟合结果进行分析。通过比较吸附剂(电气石)在不同条件下所表现出的不同吸附性能,研究吸附剂(电气石)对直接红23的吸附机理。此外,本研究还对已达到吸附饱和的电气石进行回收,并将其进行解吸附处理,将解吸附的电气石进行重复利用实验后,研究其吸附性能。得出结论如下:(1)通过对电气石进行表征得知电气石表面含有羟基官能团并且当溶液中的pH值小于pHzpc时电气石表面带有正电,因此对于低pH溶液,电气石与染料分子之间靠静电作用以及氢键作用结合在一起,从而起到富集作用。(2)通过将此实验数据分别用假一级反应动力学模型和假二级反应动力学模型来拟合。结果显示此实验更适合用假二级反应动力学模型拟合,其限速步骤为内部颗粒扩散的快慢。此外,温度对该反应的影响较大,计算得出反应的活化能为4.54 kcal/mol,属于物理吸附。通过对其进行平衡学的分析,发现此实验结果相比于用Freundlich模型拟合,更适合用Langmuir模型进行拟合。而且当溶液中离子强度增加时,电气石的吸附容量下降。因为离子可以通过影响电气石表面双电层的厚度,导致了其吸附容量的下降,此外,阴离子的竞争吸附也是使其吸附性能下降的一个原因。通过对电气石进行重复利用实验发现电气石的重复利用率良好,当重复利用至第五次是其吸附能力下降了51%,而且电气石的最大吸附容量可以达到153 mg/g。因此,电气石可以作为廉价高效的吸附剂对直接红23染料进行吸附去除,同时为偶氮染料的吸附去除提供了理论分析以及技术支持,还为电气石提供了一个新的应用方向。
[Abstract]:Azo dyes are widely used in printing, dyeing, textile and other industries because of their characteristics of easy coloring and good fastness. The wastewater is characterized by high chromaticity, complex composition, poor biodegradability and strong toxicity. Therefore, when the wastewater is discharged into the receiving water without proper treatment, The photosynthesis of aquatic plants will be affected by increasing the chroma of the receiving water, and the aquatic environment and ecology will be destroyed. In addition, the toxicity of dyestuff wastewater will inhibit the growth of aquatic organisms, and its toxicity will threaten the safety of human beings through the enrichment of biological chain step by step. Therefore, how to treat dye wastewater has become a research hotspot. Adsorption can not only remove pollutants in water, but also enrich pollutants. Therefore, the purpose of this study is to select cheap adsorbents and to study their adsorption properties and adsorption mechanism. Tourmaline has a good prospect in pollutant removal because of its wide distribution and low price. In this paper, direct red 23 azo dyes are used as adsorbent to remove direct red 23 azo dyes. Firstly, the physical and chemical properties of tourmaline were studied (surface morphology, surface functional group analysis, element composition, equipotential point, etc. Secondly, the adsorption properties of tourmaline adsorbed direct red 23 under different conditions (the concentration of tourmaline, pH value, temperature, etc.) were obtained by conditional experiments. Ion strength), and then by using different adsorption kinetic models and adsorption equilibrium models to analyze the fitting results of the experimental data. The adsorption mechanism of direct red 23 by tourmaline adsorbent (tourmaline) was studied by comparing the adsorption properties of adsorbent (tourmaline) under different conditions. In addition, the adsorbed tourmaline was recovered and desorbed, and the adsorbed tourmaline was reused to study its adsorption performance. The conclusions are as follows: (1) by characterizing tourmaline, we know that there are hydroxyl functional groups on tourmaline surface and there is positive charge on tourmaline surface when pH value in solution is lower than pHzpc, so for low pH solution, The interaction between tourmaline and dyestuff is combined by electrostatic interaction and hydrogen bond interaction, so it can be enriched. (2) the experimental data are fitted by pseudo-first-order reaction kinetic model and pseudo-second-order reaction kinetic model, respectively. The results show that this experiment is more suitable for fitting with pseudo-second-order reaction kinetic model, and the speed limiting step is the speed of particle diffusion inside. In addition, the temperature has a great effect on the reaction. The calculated activation energy of the reaction is 4.54 kcal / mol, which belongs to physical adsorption. It is found that the experimental results are more suitable to be fitted by Langmuir model than by Freundlich model. Moreover, the adsorption capacity of tourmaline decreases with the increase of ionic strength in the solution. The adsorption capacity of tourmaline can be decreased by affecting the thickness of double layer on tourmaline surface. In addition, the competitive adsorption of anions is also one of the reasons for the degradation of adsorption performance of tourmaline. The repeated utilization of tourmaline was found to be good through the experiment of repeated utilization of tourmaline. The adsorption capacity of tourmaline decreased 51g / g when it was reused to the fifth time, and the maximum adsorption capacity of tourmaline could reach 153 mg / g. Therefore, tourmaline can be used as a cheap and efficient adsorbent to remove direct red 23 dye, which provides theoretical analysis and technical support for the adsorption removal of azo dyes. It also provides a new application direction for tourmaline.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X791

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