Study On Modification Of Montmorillonite And Its Application

Montmorillonite(MMT) is a low cost silicate mineral with abundant storage which has a unique layered structure with large specific surface area, high cation exchange capacity and gas barrier property. MMT is now playing an increasingly important role in the field of solid catalytic reaction, wastewater treatment and polymer materials and other fields. In this work, the main attempts are focuse on the montmorillonite modification based on its layered structure and cation exchangeable properties, and investigation montmorillonite modification the effect of solid catalysis, organic wastewater treatment and modification of polymer materials. The main conclusions are as follows:First, a series of triphenyl quaternary phosphonium salts were synthesized with with halogenated hydrocarbons and triphenylphosphine as starting materials under assistance of microwave irradiation. The react conditions were studied. The products were characterized by 1H NMR and melting point.Under optimal conditions, the maximum yield was 93.5%.Second, The triphenyl quaternary phosphonium salt can regard as a nucleating agent for causing polyvinylidene fluoride(PVDF) of β crystal transition. The result showed that when added to the 3% octadecyl triphenyl phosphonium bromide of PVDF as a nucleating agent, under the 25℃ temperature, the obtained PVDF polar polymorph highest content.Third, organically modified montmorillonite were synthesized by intercalating the triphenyl quaternary phosphonium salt into the gallery of montmorillonite with interlaminer cations. The synthesized products were characterized by SEM and XRD,and the interlayer space of modified montmorillonite were changed from 1.00 nm to 1.98 nm. The organic modified montmorillonite were used in polypropylene(PP) flame retardant with phosphorus-nitrogen fire retardant. When the 2% modified montmorillonite and 22%phosphorus-nitrogen fire retardant were added to polypropylene, the oxygen index of the modified PP 32.89% and the level of flamerating is V0. Organically modified montmorillonite can a significant reduction in the use of fire retardan, achieving good synergy.Fourth,the hindered phenol structure quaternary phosphonium salt was synthesized and used in the organic modification of montmorillonite, which were used to improve the random copolymer polypropylene(PP-R) and thermal oxidative aging resistance processing performance. The results show that 1% of montmorillonite modifier to PP-R when the modified PP-R hot melt extrusion 5 times, a melt index of PP-R/MMT composite material is from 0.39 to 0.41 g / 10 min, having excellent processing performance.Fifth, the organically modified montmorillonite for dye adsorption of phenol in wastewater were studied. Interlayer spacing, adsorption contact time, montmorillonite concentration, temperature and pH of the solution of phenol adsorption performance were screened to achieve best results. Under optimum conditions,(the modifier is Cetyltrimethylammonium bromide,adsorption contact time of 30 min, montmorillonite amount of 20g/L, the temperature is 30 °C, the pH of 6), the removal efficiency of phenol solution(200mg / L) up to 87.9%.Sixth, the Lewis acid were supported on montmorillonite, changing the surface structure of montmorillonite to prepare a solid acid catalyst. Gramine and natural Gramine benzaldehyde were synthesized by Lewis acid catalytic.The react conditions were studied. It has shown that when the catalyst dosage of ZnCl2 supported on montmorillonite was 15% to indole, the molar ratio of indole, dimethylamine and methanal was 1.3:1.3:1.0, microwave reaction under 50℃for 10 min, the yields up to 93.8%. A synthesis method of natural benzaldehyde was developed with cinnamic aldehyde, when the catalyst dosage of FeCl3 supported on montmorillonite was 10% to cinnamic aldehyde, reaction under 50℃for 24 h,which can yield up to 96.8%.