磁性MCM-41分离回收RT培司废水中四甲基氢氧化铵的研究

硝基苯法合成RT培司(4-氨基二苯胺)的废水色度高、组分复杂、催化剂四甲基氢氧化铵(TMAOH)难以分离回收。提出采用磁性MCM-41对RT培司废水中有机副产物进行选择性吸附分离。制备的磁性MCM-41样品采用X射线衍射仪(XRD)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)、N₂吸附-脱附和振动样品磁场计(VSM) 等手段进行表征。结果表明, 磁性MCM-41颗粒的粒径范围为200~300 nm, BET比表面积约为655.2 m²/g, 孔径分布为0.5~4 nm, 内核铁酸镍的存在使磁性MCM-41具有超顺磁性。吸附研究表明磁性MCM-41对RT培司废水中吩嗪、偶氮苯和苯胺等有机物具有良好吸附作用, 经5次吸附磁分离后, RT培司废水中四甲基氢氧化铵能够达到回用要求, 吸附后的磁性MCM-41在外加磁场下极易分离。

Magnetic MCM-41 for TMAOH Recovery from RT Base Wastewater

RT base wastewater has high colority, complex components and troubles to recover the TMAOH catalyst in the process of RT base production by nitrobenzene method. Selectively adsorption and separation of by-product from RT base wastewater with magnetic MCM-41 adsorbent was proposed to recover the TMAOH. The magnetic MCM-41 samples prepared were characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD), N₂ adsorption-desorption vibrating sample magnetometer (VSM). The results showed that the samples had an obvious core-shell structure with an average size of about 200~300 nm in diameter. The N₂ adsorption-desorption results showed that the magnetic MCM-41 exhibited micro-mesoporous structure with specific area of 655 m²/g and pore size distribution of 0.5-4 nm. The as-prepared magnetic MCM-41 displayed typical super paramagnetic property due to the inside component of NiFe₂O₄. The adsorption experiments showed that magnetic MCM-41 selectively adsorbed phenazine, azobenzene and aniline from RT base wastewater. TMAOH aqueous solution could be reused after 5 times adsorptive separation. The synthesized magnetic MCM-41 exhibits high adsorption efficiency and potential applications for the recover for TMAOH catalyst from RT base wastewater with the help of magnetic separation.