硝基苯在渭河沉积物中吸附特征及双模式阻滞因子的研究

发布时间：2018-05-01 08:32

本文选题：渭河沉积物砂样 + 硝基苯　；参考：《长安大学》2015年硕士论文

【摘要】：硝基苯在工业中是一种重要的有机中间体,它属于优先被控制的有机污染物,对人体及其环境有很大的危害。本论文以三种不同岩性的渭河沉积物砂样为研究对象,考察渭河沉积物对硝基苯的吸附解吸特征和淋溶实验迁移规律,分别求出其静态阻滞因子和动态阻滞因子。1、对渭河沉积物的吸附特性研究表明:渭河沉积物中的三种砂样:粉砂、细砂、中砂对硝基苯的动力学吸附达到平衡的时间分别为:12h,12h,8h;平衡后的吸附量分别为:8.1mg/kg,7.6mg/kg,5.8mg/kg。对渭河沉积物中的三种砂样的动力学曲线拟合后显示Elovich方程拟合的效果理想,粉砂的拟合度R2=0.959细砂的拟合度R2=0.968中砂的拟合度R2=0.955。对三种渭河砂样进行等温平衡实验后,对获得数据拟合后表明:用线性与Freundlich耦合模型能够很好的描述砂样的等温平衡过程。其中粉砂的拟合度R2=0.993,细砂的拟合度R2=0.994,中砂的拟合度R2=0.991。通过阻滞因子的求解公式求得:粉砂的静态阻滞因子Rd=24.28,细砂的静态阻滞因子Rd=15.78,中砂的静态阻滞因子Rd=8.63。本文考察了不同因素:腐殖酸、盐度、pH、温度、初始浓度对沉积物砂样的吸附影响。腐殖酸可加大沉积物的吸附量,盐度也可加大沉积物的吸附量,温度的增大会减少沉积物的吸附量,沉积物的吸附量会随着初始浓度的增加而增加。pH的加入会减少沉积物的吸附量。2、渭河沉积物的解吸特性研究表明:三种砂样的对硝基苯的动力学解吸在12小时的时候达到平衡。对渭河沉积物中的三种砂样的动力学曲线拟合后显示Elovich方程拟合的效果理想,粉砂的拟合度R2=0.954,细砂的拟合度R2=0.963,中砂的拟合度R2=0.952。对硝基苯的等温平衡解吸引入滞后系数,求得数据显示:粉砂的滞后系数HI大于细砂的滞后系数,中砂的滞后系数小于细砂。所以粉砂在解吸过程总的滞后现象最为明显。吸附过程中的阻滞因子和解吸过程中的滞后系数呈正相关关系。对硝基苯解吸的影响因素和吸附一样。实验表明腐殖酸和盐度(NaCl)的加入会使硝基苯的解吸率下降,温度的升高、初始浓度的增加以及pH的上升会使硝基苯的解吸率上升。3、硝基苯的动态实验研究表明:通过对硝基苯的土柱实验中迁移规律的研究,得出其相关迁移参数,求得动态阻滞因子Rd=71.12,远远大于静态阻滞因子和双模式阻滞因子。这是因为动态实验过程中有机污染物的迁移机理更复杂但更接近自然条件下有机污染物的迁移过程而静态试验是在比较理想的条件下求得的。
[Abstract]:Nitrobenzene is an important organic intermediate in industry. It is a priority organic pollutant and has great harm to human body and its environment. In this paper, three kinds of sand samples of Weihe River sediment with different lithology were studied to investigate the characteristics of adsorption and desorption of nitrobenzene in the sediment of Weihe River and the law of experimental migration of leaching. The adsorption characteristics of Weihe River sediment were studied. The results showed that three kinds of sand samples in Weihe River sediment: silt, fine sand, fine sand, fine sand, fine sand, fine sand, fine sand, fine sand, fine sand, fine sand, fine sand, fine sand, fine sand, fine sand. The kinetic adsorption time of nitrobenzene reached equilibrium at 1: 12 h ~ (12) h ~ (-1), and the adsorption capacity after equilibrium was 7. 6 mg 路kg ~ (-1) 路kg ~ (-1) mg 路kg ~ (-1) and 5.8 mg / kg ~ (-1) 路min ~ (-1) 路kg ~ (-1) 路kg ~ (-1) respectively. After fitting the dynamic curves of three kinds of sand samples in Weihe River sediment, the Elovich equation is proved to be effective. The fitting degree of silt is R2O0.959. The fit degree of fine sand R2O0.968 is R20.9555. After isothermal equilibrium experiments on three kinds of Weihe sand samples, the fitting results show that the linear and Freundlich coupling model can well describe the isothermal equilibrium process of sand samples. The fitting degree of silty sand is 0.993, that of fine sand is 0.994, and that of medium sand is 0.991. According to the formula of block factor, the static block factor of silt is 24.28, the static block factor of fine sand is 15.78, and the static block factor of middle sand is 8.63. The effects of different factors such as humic acid salinity pH temperature and initial concentration on the adsorption of sediment sand samples were investigated. Humic acid can increase the amount of sediment adsorption, salinity can also increase the amount of sediment adsorption, the increase of temperature will reduce the amount of sediment adsorption, The adsorption capacity of sediment increased with the increase of initial concentration. The addition of pH decreased the adsorption capacity of sediment. The desorption characteristics of Weihe River sediment showed that the kinetic desorption of nitrobenzene from three kinds of sand samples reached equilibrium at 12 hours. After fitting the dynamic curves of three kinds of sand samples in Weihe River sediment, the results show that the Elovich equation is effective, the fitting degree of silt is 0.954, the fit degree of fine sand is 0.963, the fitting degree of medium sand is R20.9052. The hysteresis coefficient is introduced into the isothermal equilibrium desorption of nitrobenzene. The results show that the hysteresis coefficient of silt is larger than that of fine sand, and the lag coefficient of medium sand is smaller than that of fine sand. Therefore, the total lag of silt in desorption process is the most obvious. There was a positive correlation between the retardation factor in the adsorption process and the hysteresis coefficient in the desorption process. The factors affecting desorption of p-nitrobenzene are the same as those of adsorption. The results showed that the desorption rate of nitrobenzene decreased and the temperature increased with the addition of humic acid and sodium chloride. With the increase of initial concentration and pH, the desorption rate of nitrobenzene will increase by .3.The dynamic experimental study of nitrobenzene shows that the migration parameters of nitrobenzene are obtained through the study of migration law in soil column experiment of nitrobenzene. The dynamic block factor RdN is 71.12, which is much larger than that of static block factor and double mode block factor. This is due to the fact that the transport mechanism of organic pollutants in dynamic experiments is more complex but closer to that of organic pollutants under natural conditions while the static experiments are obtained under more ideal conditions.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X52

【参考文献】