酰腙类化合物修饰MCM-41吸附Cr(Ⅵ)性能

Adsorption Properties of Two Hydrazone Compounds Modified MCM-41 towards Cr(Ⅵ)

合成了2-羰基丙酸-4-甲基苯甲酰腙(简称酰腙1)和2-羰基丙酸-4-硝基苯甲酰腙(简称酰腙2)两种酰腙化合物,采用红外光谱法和X射线单晶衍射法对其进行了表征,并将其应用于修饰MCM-41分子筛中。用两种酰腙修饰后的MCM-41分子筛吸附废水中的铬(Ⅵ),考察了吸附时间、溶液pH值、吸附剂用量和温度对吸附效果的影响,同时对吸附过程进行了热力学和动力学拟合。测试结果表明,在吸附时间为40 min,分子筛加入量为0.3 g,溶液pH值为6,溶液温度为20℃时,吸附效果最好,MCM-41-酰腙1和MCM-41-酰腙2对铬(Ⅵ)的去除率分别可以达到97.6%和98.2%。吸附过程是熵减小的放热过程,反应过程分别遵循准一级反应和准二级反应动力学。

Two kinds of novel hydrazone compounds,2-oxo propionic acid-4-methyl benzoyl hydrazone synthesis（hydrazone1） and 2-oxo propionic acid-4-nitrobenzene hydrazone（hydrazone 2）,were synthesized and characterized by infrared spectroscopy and X-ray diffraction methods. Then they were used to modify MCM-41 molecular sieve by physical impregnation method. Adsorption properties of two hydrazone compounds modified MCM-41 towards Cr（Ⅵ） were tested and the influencing factors were studied such as adsorption time,pH,mass of adsorbent and temperature. In addition,thermodynamic and kinetic fitting of adsorption process were also carried out. The results showed that the proper conditions for modified MCM-41 to adsorb Cr（Ⅵ） were when the adsorption time was 40 min,the dosage of modified MCM-41 was 0. 3 g,solution pH was 6,and the solution temperature 20 ℃. Removal rates of MCM-41-hydrazone 1 and MCM-41-hydrazone 2 towards Cr（Ⅵ） could reach to97. 6% and 98. 2%,respectively. The adsorption process was an exothermic and entropy decreasing non spontaneous reaction.The adsorption processes satisfied simple pseudo-first-order kinetics and quasi secondary-order kinetics.