催化学报

催化学报 ›› 2012, Vol. 33 ›› Issue (11): 1862-1869.DOI: 10.3724/SP.J.1088.2012.20835

• 研究论文 • 上一篇    

A 型分子筛的合成及其对镉离子的吸附性能

王春燕1, 周集体2, 何俊慷1, 郝传松1, 潘玉珍1, 孟长功1,*   

  1. 1大连理工大学化学学院, 辽宁大连116024; 2大连理工大学环境学院, 辽宁大连116024
  • 收稿日期:2012-08-21 修回日期:2012-09-10 出版日期:2012-11-16 发布日期:2012-11-16

Synthesis of Zeolite A and Its Application as a High-Capacity Cadmium Ion Exchanger

WANG Chunyan1, ZHOU Jiti2, HE Junkang1, HAO Chuansong1, PAN Yuzhen1, MENG Changgong1,*   

  1. 1Chemistry College, Dalian University of Technology, Dalian 116024, Liaoning, China; 2Environmental Science College, Dalian University of Technology, Dalian 116024, Liaoning, China
  • Received:2012-08-21 Revised:2012-09-10 Online:2012-11-16 Published:2012-11-16

PDF

655

被引次数

10

摘要： 以廉价的低品位铝矾土为原料, 以偏铝酸钠为补充铝源, 以碳酸钠为活化剂, 采用碱熔融-水热法合成了 A 型分子筛, 考察了水热条件对所制分子筛的影响, 发现 SiO2/Al2O3, Na2O/SiO2 和 H2O/Na2O 摩尔比及反应时间是影响产物晶型的主要因素, 其最佳合成工艺条件是: 反应物配比为 1.5Na2O:0.5Al2O3:1SiO2:128H2O, 于 90 oC 晶化 12 h. 另外, 研究了水溶液中 Cd2+离子在该分子筛上的吸附行为, 考察了吸附时间、Cd2+离子浓度、溶液初始 pH 值以及分子筛用量对吸附行为的影响. 结果表明, A 型分子筛对水中 Cd2+离子吸附 90 min 时达平衡, 吸附过程符合准二级动力学速率方程; 溶液初始 pH = 6 时, Cd2+离子的去除率最高, 吸附等温线可以用 Langmuir 和 Freundlich 模型来描述, 最大吸附容量可达 161.3 mg/g, 最佳吸附剂用量为 1.00 g/L.

关键词: 低品位铝矾土, A 型分子筛, 水热合成, 吸附, 镉离子

Abstract: A facile method comprised of alkali fusion activation and hydrothermal reaction was developed to synthesize high-quality crystallized zeolite A from cost-effective low-grade bauxite. Using sodium aluminate powder as an extra aluminum source and sodium carbonate as an activator, the reactant molar ratios of SiO2/Al2O3, Na2O/SiO2, and H2O/Na2O, the hydrothermal reaction time are optimized in detail. Highly crystallized phase-pure zeolite A is successfully synthesized from low-grade bauxite under the optimized experimental conditions of 1.5 Na2O:0.5 Al2O3:1 SiO2:128 H2O after hydrothermal reaction at 90 oC for 12 h. The cadmium ion removal from aqueous solutions using the as-synthesized zeolite A powders as an adsorbent was studied. The effects of contact time, solution concentration, solution pH value, and adsorbent amount on adsorption was investigated. The adsorption equilibrium could be reached very fast within 90 min. The adsorption followed a pseudo-second-order kinetic adsorption mode well. Both Langmuir and Freundlich models could fit the experimental data well at pH = 6. The maximum adsorption capacity was estimated to be 161.3 mg/g. The optimal adsorbent dosage is about 1.00 g/L.

Key words: low-grade bauxite, zeolite A, hydrothermal synthesis, adsorption, cadmium ion