Study On The Synthesis, Modification Of MCM-22 Zeolite And Its Application In Dye Wastewater Treatment

Owing to its unique structure comprising both 10 member-ring (MR) and 12MR channel system and special physiochemical properties, MCM-22 zeolite has shown many promising applications. This paper aims to reduce the synthesis of MCM-22 molecular sieve time, and low-cost synthesis, and optimize its absorption performance by doped.In this paper, silica sol was used as silicon source, hexamethylene imine (HMI) as template agent, with the molar ratio of SiO2: 0.3HMI: 0.035Al₂O₃: 0.2NaOH: 20H₂O, and compared the method of conventional synthesis of MCM-22 and the temperature change static hydrothermal method, The results showed that the static temperature change hydrothermal method reduce the synthesis time, reducing the synthesis temperature, and MCM-22 molecular sieve with MWW of layer structure was synthesized. Molecular sieve of MCM-22 was characterizated by power X-ray diffraction(XRD), scanning electron microscope(SEM),transmission electron microscopy (TEM),fourier transform infrared spectroscopy (FT-IR), TG-DTA,N2 adsorption and desorption and so on. The results showed that the synthesis of MCM-22 molecular sieve pore size was very uniformity, specific surface area was reached 388 m2/g, and it is a good adsorption and catalytic materials.Due to the introduction of heteroatoms can effectively regulate the nature of zeolite, but also the introduction of other active center, so zeolite has a special catalytic property. In this paper, synthesized Ce-MCM-22 zeolite with the molar ratio of 0.0025Ce:SiO2∶0.3HMI∶0.035Al₂O₃∶0.2NaOH∶20H₂O,and characterizated it by XRD, TEM. The results show it maintains crystalline layered structure, the ordered zeolite structure has not been destroyed, it is a new type of adsorbent material. In the study of Ce-MCM-22 molecular sieve adsorption methylene blue, the results showed that Ce-MCM-22 zeolite dosage was 0.6g / L, methylene blue concentration was 2.0mg / L, pH was 7, the shock absorption time xas 60 minutes, the adsorption effect was best, and decolorization rate reached 90.5%. Ce-MCM-22 adsorption dynamic second equation was y = 0.4657x + 1.2005, R² = 0.9995, relative to be a equation model, the results related to be better, more truly reflect the response of molecular sieve adsorption of methylene blue solution mechanism.Then synthesized N-Ti-MCM-22 molecular sieves by doped titanium (Ti) and non-metallic nitrogen (N), synthesized N-Ti-MCM-22 zeolite with the molar ratio of 0.008N:SiO2∶0.03TiO2∶0.3HMI∶0.035Al₂O₃∶0.2NaOH∶20H₂O and study of its photocatalytic degradation of methylene blue solution effects, and study of the solution pH, methylene blue concentration, zeolite dosage factors that influence their effect. The results showed that the nitrogen content was 0.008 mol of Ti-MCM-22 zeolite , and zeolite dosage was 1g / L, the concentration of methylene blue solution was 4.0mg / L, pH was neutral, the photocatalytic time was 40 minutes, the methylene blue decoloration rate and the degradation rate reached 95.9% and 97.8%, was a good composite catalytic materials.