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以稻壳为原料采用煅烧-水热合成法制备了合成沸石,运用XRD和SEM表征了合成沸石的特性,通过静态实验,研究了合成沸石对磷酸盐的吸附和脱附机理。结果表明:12 h后产物发现了Na P沸石的特征峰和亚晶结构,延长水热合成晶化的时间有利于沸石晶核的形成。沸石对磷酸盐的吸附机理符合伪二级模型,实测值与伪二级吸附动力学模型的拟合值相差在1.1%以内。颗粒内扩散速率是由膜扩散和内扩散共同控制,颗粒内扩散速率常数kp随初始浓度的增加而减小。升温有利于磷酸盐的脱附,MNa OH/P>8.0时(MNa OH/P为Na OH物质的量与吸附的磷酸盐物质的量之比),磷酸盐的脱附率可达82.9%。伪二级脱附动力学模型的拟合结果优于伪一级,拟合值与实测值相差在1.7%以内。
Synthesized zeolites were prepared by calcination - hydrothermal synthesis method using rice husk as raw material. The characteristics of synthesized zeolites were characterized by XRD and SEM. The adsorption and desorption mechanism of synthetic zeolites on phosphates were studied by static experiments. The results showed that the characteristic peak and subgrain structure of Na P zeolite were found after 12 h, and the prolonged hydrothermal synthesis crystallization time was beneficial to the formation of zeolite nucleus. The adsorption mechanism of zeolite to phosphate is in accordance with the pseudo-second-order model, and the difference between the measured value and the fitted value of the pseudo-second-order kinetic model is less than 1.1%. The rate of intraparticle diffusion is controlled by both diffusion and diffusion, and the intraparticle diffusion rate constant, kp, decreases with increasing initial concentration. When MNaOH / P> 8.0 (MNa OH / P is the ratio of Na OH species to the amount of phosphate species adsorbed), the desorption rate of phosphate can reach 82.9%. The fitting results of pseudo-second-order desorption kinetics model are better than pseudo-first-order, the difference between fitting value and measured value is less than 1.7%.