竹炭吸附对硝基苯胺的过程与机理研究

发布时间：2019-01-17 09:29

【摘要】：研究了竹炭吸附对硝基苯胺的过程影响因子以及吸附过程的动力学、等温线和热力学。结果表明,粒径80~100目的竹炭即可实现对对硝基苯胺的高效吸附,吸附效率为95.65%。竹炭对硝基苯胺的吸附效率随溶液pH值的升高而逐渐下降,当溶液pH值超过7.0以后,下降趋势明显加快,实验条件下,溶液pH=2.0可以获得最佳吸附效果,吸附效率为95.85%,静电作用力和氢键作用力在不同溶液pH值下变化的联合作用是造成吸附效率变化的主要原因。吸附动力学研究结果表明:准二级吸附动力学模型可以很好的拟合3种不同温度下的吸附速率数据;吸附等温线研究结果表明,RedlichPeterson吸附等温线模型可以很好的拟合3种不同温度下的吸附等温线数据,说明吸附过程兼有单分子层吸附和吸附表面异质性的特点;吸附热力学计算结果表明,吉布斯自由能ΔG~0小于零,说明竹炭吸附对硝基苯胺的过程可以自发进行,吸附焓变ΔH~0小于零,说明吸附反应为放热过程,并且吸附焓变数值大于单纯由范德华力引起的吸附放热范围,说明吸附过程中存在多种作用力;吸附熵变ΔS~0大于零,说明吸附过程中体系的混乱度显著增大。
[Abstract]:The factors affecting the adsorption of p-nitroaniline by bamboo charcoal and the kinetics, isotherm and thermodynamics of the adsorption process were studied. The results showed that the adsorption efficiency of p-nitroaniline could be achieved by bamboo charcoal with a particle size of 80 ~ 100, and the adsorption efficiency was 95.65. The adsorption efficiency of p-nitroaniline from bamboo charcoal decreased with the increase of the pH value of the solution. When the pH value of the solution exceeded 7.0, the decreasing trend was accelerated obviously. Under the experimental conditions, the solution pH=2.0 could obtain the best adsorption effect. The adsorption efficiency is 95.85. The combined action of electrostatic force and hydrogen bond force under different pH values is the main reason for the change of adsorption efficiency. The results of adsorption kinetics study show that the quasi-second-order adsorption kinetic model can fit the adsorption rate data at three different temperatures. The results of adsorption isotherm study show that the adsorption isotherm model of RedlichPeterson can fit the adsorption isotherm data at three different temperatures, which indicates that the adsorption process has the characteristics of monolayer adsorption and adsorption surface heterogeneity. The calculated results of adsorption thermodynamics show that the Gibbs free energy 螖 G _ (0) is less than zero, which indicates that the adsorption of p-nitroaniline on bamboo charcoal can be carried out spontaneously, and the adsorption enthalpy 螖 H _ (0) is less than zero, indicating that the adsorption reaction is an exothermic process. The adsorption enthalpy variable value is larger than that caused by van der Waals force alone, which indicates that there are many kinds of forces in the adsorption process. The change of adsorption entropy 螖 S0 is greater than zero, which indicates that the degree of confusion in the adsorption process increases significantly.
【作者单位】：南京林业大学生物与环境学院;香港浸会大学研究生院;北卡罗来纳州立大学土木建筑与环境学院;
【基金】：江苏省高校优势学科建设工程重点序列学科项目
【分类号】：X703.1

【相似文献】