论文部分内容阅读
采用巨正则统计系综蒙特卡罗模拟方法研究了不同温度、不同吸附方式下,ZSM-5型分子筛上氯乙酸和二氯乙酸分子的吸附行为。由分子筛内吸附质粒子云分布可知,氯乙酸和二氯乙酸分子主要吸附在12元环超笼内,仅有少数氯乙酸可以吸附在十元环孔道内。相同条件下,氯乙酸吸附量大于二氯乙酸吸附量。另外,由吸附相互作用能分布来看,氯乙酸与分子筛之间相互作用能要高于二氯乙酸与分子筛之间的相互作用能,这就使二氯乙酸分子吸附相对氯乙酸分子更为稳定。在350 k Pa时,温度变化对两种分子吸附数量无明显影响,温度升高,其粒子云密度变大。ZSM-5分子筛上存在氯乙酸和二氯乙酸分子的竞争吸附,两种分子由于尺寸相差较小,在吸附过程中相互挤压,相互排斥,造成一部分分子进入到十元环孔道,改变了能量的最可几分布。氯乙酸与二氯乙酸在分子筛内吸附等温线的模拟结果表明,在压力大于40 k Pa和300 k Pa时,氯乙酸和二氯乙酸吸附量分别达到饱和。
Adsorption behavior of chloroacetic acid and dichloroacetic acid on ZSM-5 molecular sieve under different temperatures and different adsorption modes was studied by the Monte-Carlo Monte Carlo method with giant regularity ensemble. According to the molecular cloud distribution of the adsorbed particles in the molecular sieve, the molecules of chloroacetic acid and dichloroacetic acid are mainly adsorbed in the 12-membered ring supercages, and only a few chloroacetic acids can be adsorbed in the ten-membered ring channel. Under the same conditions, the adsorption capacity of chloroacetic acid is greater than that of dichloroacetic acid. In addition, the interaction energy between the chloroacetic acid and the molecular sieve is higher than that between the dichloroacetic acid and the molecular sieve due to the distribution of the adsorption interaction, which makes the dichloroacetic acid molecule adsorb more stable to the chloroacetic acid molecule . At 350 k Pa, the change of temperature has no obvious effect on the adsorption quantity of the two molecules. As the temperature rises, the particle cloud density becomes larger. ZSM-5 zeolite competitive adsorption of chloroacetic acid and dichloroacetic acid molecules, the two molecules due to smaller size differences in the adsorption process of mutual squeeze, mutual exclusion, resulting in part of the molecule into the ten-membered ring channel, changing the energy The most probable distribution. The simulation results of the adsorption isotherms of chloroacetic acid and dichloroacetic acid in the molecular sieve show that the adsorption capacities of chloroacetic acid and dichloroacetic acid are saturated respectively when the pressure is higher than 40 kPa and 300 kPa.