空心莲子草活性炭对抗生素、染料吸附性能的研究

发布时间：2018-06-24 19:17

本文选题：空心莲子草活性炭 + 头孢氨苄　；参考：《山东师范大学》2017年硕士论文

【摘要】：本文以廉价易得,来源广泛的多年生草本水生植物空心莲子草为原料,采用磷酸活化法制得比表面积高、孔径结构发达的活性炭。运用BET比表面积分析仪、SEM扫描电镜、孔径分析仪和FTIR傅里叶红外光谱等分析方法对其物化性质进行表征,分析得出空心莲子草活性炭对头孢氨苄、日落黄和罗丹明B的吸附性能。同时,探究了吸附时间、吸附剂投加量、溶液pH、温度对吸附效果的影响,并结合伪动力学模型、吸附等温模型和热力学模型对吸附机理进行了深入探讨。并设计正交实验,利用极差分析法,综合考虑去除率和平衡吸附量两个指标,得出最佳组合条件和各因素影响大小的顺序。其主要结论如下:(1)磷酸活化法制备的活性炭具有表面凹凸不平,孔结构丰富等特点。BET法测得的活性炭的比表面积为736.3 m2/g,孔径容量的平均值为4.05 nm;孔径结构为典型的微孔-中孔混合结构,这种孔径结构能够较大幅度的提高活性炭对大分子和小分子微粒的吸附特性。活性炭表面的官能团主要为磷酸基团、C=C、C-O和C-H基团等,有利于和吸附质水解分子结合或发生反应,提高吸附性能。(2)空心莲子草活性炭对水体中的这三种污染物有较好的吸附效果。在头孢氨苄溶液浓度为35 mg/L时,去除率达93%,在温度为308K下,最大平衡吸附量可达45 mg/g;在日落黄溶液浓度为150 mg/L时,去除率达96%,在温度为308K下,最大平衡吸附量可达271 mg/g;在罗丹明B溶液浓度为100 mg/L时,去除率可达96%,最大平衡吸附量可达286 mg/g。(3)空心莲子草活性炭对头孢氨苄、日落黄和罗丹明B溶液的吸附与伪二级吸附模型模拟的机理相符合,表明化学吸附机制是限制活性炭吸附速率的主要原因,而颗粒内传质阻力对吸附过程的阻止作用并不明显。吸附等温模型均符合Langmuir等温模型,表明吸附过程属于SX分子层吸附。吸附热力学模型表明空心莲子草活性炭对这三种物质的吸附是一个自发的(ΔG0),无序性增加的吸热(ΔH0)的过程,这与Langmuir等温模型模拟的结果是一致的。
[Abstract]:In this paper, activated carbon with high specific surface area and well-developed pore size structure was prepared by phosphoric acid activation method with cheap and widely available perennial herbaceous aquatic plant lotus seed as raw material. The physicochemical properties of Cefalexin were characterized by BET specific surface area analyzer (BET), SEM scanning electron microscope (SEM), aperture analyzer and FTIR Fourier transform infrared spectroscopy (FTIR). Adsorption properties of sunset yellow and rhodamine B. At the same time, the effects of adsorption time, dosage of adsorbent, pH of solution and temperature on the adsorption effect were investigated. The adsorption mechanism was also discussed in combination with pseudo-kinetic model, adsorption isothermal model and thermodynamic model. The orthogonal experiment was designed and the optimal combination conditions and the order of the influence of each factor were obtained by using the range analysis method and considering the removal rate and the equilibrium adsorption capacity. The main conclusions are as follows: (1) activated carbon prepared by phosphoric acid activation method has uneven surface. The specific surface area of activated carbon measured by BET method is 736.3 m2 / g, and the average pore size is 4.05 nm. This pore structure can greatly improve the adsorption characteristics of activated carbon to macromolecular and small molecular particles. The functional groups on the surface of activated carbon are mainly phosphoric acid groups, such as Con C-O and C-H groups, which are beneficial to the reaction with adsorbent hydrolysate molecules and improve the adsorption performance. (2) the activated carbon of lotus seed grass has a good adsorption effect on these three pollutants in water. When the concentration of cefalexin solution is 35 mg / L, the removal rate is 933%, and the maximum equilibrium adsorption capacity can reach 45 mg / g at 308 K, and at 150 mg / L of sunset yellow solution, the removal rate reaches 96%, and at 308K, When the concentration of Rhodamine B solution is 100 mg / L, the removal rate can reach 96, and the maximum equilibrium adsorption capacity can reach 286 mg / g 路g. (3) the active carbon of lotus seed grass can treat cefalexin, The adsorption mechanism of sunset yellow and Rhodamine B solution is consistent with the pseudo-second-order adsorption model, which indicates that the chemisorption mechanism is the main reason for limiting the adsorption rate of activated carbon, but the resistance of mass transfer in particles has no obvious effect on the adsorption process. The adsorption isotherm models all accord with Langmuir isotherm model, which indicates that the adsorption process belongs to SX molecular layer adsorption. The adsorption thermodynamic model showed that the adsorption of these three substances was a spontaneous (螖 G _ 0) process and a disordered endothermic (螖 H _ 0) process, which was consistent with the results of Langmuir isothermal model.
【学位授予单位】：山东师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703;O647.3

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