| Montmorillonite(MMT)is one kind of 2:1 clay minerals containing the aqueous aluminosilicate.Due to the particular layered structure,montmorillonite has a lot of special properties,such as huge area,high cation exchange capacity and the ability of the interlayer to swell easily.Make use of MMT to resolve the environment problem with high adsorption and low cost will have the huge economic efficiency and the good environment effect.The preparation of organic-modified clay complexes has led to the development of a new class of adsorbents,which provides a new way to remove the pollutant in the environment.Organic montmorillonite(OMMT)was produced by the exchange of cetyltrimethyl ammonium bromide(CTAB)for Na+ ions that occur on the internal and external mineral surfaces of montmorillonite.The Cellulose acetate/Organic montmorillonite(CA/OMMT)nanocomposites were prepared by cellulose acetate(CA)and OMMT by the method of polymer solution intercalation.The characterization of nanocomposites by XRD,SEM,and TG-DTA indicated that exfoliated nanocomposites were obtained when the proportion of OMMT was lower than 20 wt%.The adsorption of Acid Scarlet G(ASG)anionic dye from aqueous solution onto CA/OMMT nanocomposites was carried out.The effect of mass rate of CA and OMMT for the adsorption of ASG on CA/OMMT nanocomposites was studied.The optimal proportion was concluded.The effects of pH value of the dye solution,adsorption temperature,adsorption time and the initial dye concentration on the adsorption capacity of ASG on CA/OMMT have been investigated.The results showed that the adsorption kinetic of ASG on CA/OMMT could be best described by the pseudo-second-order model and that the adsorption isotherm of ASG was in good agreement with the Langmuir equation.Up to now,the most commonly used method to modify clay surface is the cation exchange reaction with alkylammonium.Another modification approach involving direct grafting reaction to form covalent bonds on the clay surfaces has attracted much attention.Montmorillonite particles were cross-linked by tetraethylorthosilicate(TEOS)and bis(trimethoxysilyl)hexane during a well-controlled sol-gel procedure.In the acid-catalyzed case,TEOS and bis(trimethoxysilyl)hexane were covalently bonded to the clay surfaces via condensation reaction with the surface silanol groups(Si-OH),resulting in more tight interactions between organic components and clay than ion interaction and physical adsorption.It was proposed that the hydrolyzed bis(trimethoxysilyl)hexane reacted with edge hydroxyl groups and connected the neighboring clay platelets to form a network. |
