|
Mesoporous MCM-48 molecular sieve has two completely independent three-dimensional pore structure and a large specific surface area, pore blockage is greatly reduced, and is more conducive to the transfer and separation of the heavy metal ions. However, the traditional method using a single quaternary ammonium salt type cationic surfactant as the template agent, and requires large number of relatively harsh conditions of the synthesis of MCM-48. Therefore, MCM-48 for the removal of heavy metals rare. We have overcome a series of complex synthesis conditions, the successful preparation of MCM-48, and to characterize its performance. While the surface of the MCM-48 contains a free silicon hydroxy-SiOH and-Si (OH) 2, these silanols can be reacted with a silane coupling agent, the introduction of the organic functional groups of the alkyl group, an amino group, a thiol mesoporous different reactive functional groups may be different functional materials. We will mainly study the modified MCM-48 adsorption of heavy metal ions, expected to have good prospects in the area of ??environmental governance, and to contribute to the sustainable development of the environment. This thesis is divided into four parts. 1, we synthesized with a cationic surfactant (CTAB), Ti-MCM-48. And MCM-48, SH-MCM-48 and the NH2-MCM-48 is a cationic surface-active agent (CTAB) (?) And a non-ionic surface active agent poly (ethylene oxide) - poly (propylene oxide) - poly (ethylene oxide) triblock copolymer (Pluronic 123) as the mixing of the templating agent, tetraethyl orthosilicate (TEOS) as the silicon source synthesis. X-ray diffraction (XRD), N2 adsorption-desorption, scanning electron microscopy (SEM) and infrared (IR) analysis was used to characterize the structure and properties of the material. Ti-MCM-48 adsorbed cadmium, cobalt, nickel, manganese, zinc, copper and lead in seven kinds of ions. The effects of the adsorption effect of factors such as pH, temperature, concentration and time. The optimum pH 8.00, 25 ℃, 40 ℃, 55 ℃ adsorption are the Langmuir model, cadmium, cobalt, nickel, manganese, zinc, copper and lead saturation adsorption at 25 ° C followed by 83.57 mg / g, 9.870 mg / g, 22.94 mg / g, 14.10 mg / g, 21.19 mg / g, 17.76 mg / g, and 50.25 mg / g and Different temperatures and different concentrations adsorption rate equation are in line with the quasi-second-order equation, the linear correlation coefficient r2> 0.999, the SH-MCM-48 can effectively remove lead, cadmium, copper and nickel. 25 ℃ Langmuir model can effectively calculate the saturation adsorption of lead, cadmium, copper, and nickel order 263.16 mg / g, 133.33 mg / g, 108.70 mg / g, and 62.50 mg / g. Adsorption under 25 ° C with different concentrations meet the quasi-second-order equation, linear correlation coefficient over 0.999, competitive adsorption experiments showed that SH-MCM-48 lead good selectivity in the presence of cadmium, copper and nickel, HN03 HCl as eluent can be a good recall of four ion. 4, lead, cadmium, copper and nickel can be removed by NH2-MCM-48. The saturated adsorption amount of lead, cadmium, copper and nickel in the Langmuir model fitting linear equations sequentially to 322.6 mg / g, 158.7 mg / g, 96.15 mg / g and 74.07 mg / g. 25 ° C when different concentrations of metal ions dynamics in line with the quasi-second-order equation, HNO3 and HCl can well recall of four ions.
|