Preparation And Adsorption Properties Of Gelatin/Montmorillonite Composites

Applied gelatin?GEL?and montmorillonite?MMT?as raw materials and glutaraldehyde as the cross-linking agent,the gelatin/montmorillonite?GEL/MMT?composites were prepared to solve the increasing pollution problem of printing and dyeing wastewater.Cationic dye crystal violet,anionic dye acid red 18 and nonionic dye disperse red 3B were to simulated dye wastewater.The adsorption properties of GEL/MMT composites on three dyes under different conditions?adsorption time,temperature,pH and ionic strength etc?were investigated.Meanwhile,the adsorption kinetics,thermodynamics,adsorption isotherm model and diffusion model were also studied.The adsorption mechanism of three dyes adsorbed by GEL/MMT composites was discussed.The results showed that when the ratio of GEL to MMT was 3:1 and the amount of glutaraldehyde was 1.4 mL,the adsorption capacities of GEL/MMT composites on crystal violet,acid red 18 and disperse red 3B were the highest.At 303 K,the adsorption capacities of GEL/MMT for crystal violet,acid red 18 and disperse red 3B were 354.90 mg?g^-1,557.21 mg?g^-11 and 90.14 mg?g^-1,respectively.With the increasing of adsorption time and initial concentration of dyes,the adsorption capacity of GEL/MMT on the three dyes gradually increased,and finally reached equilibrium.With the increasing of pH value and ionic strength,the adsorption capacity of GEL/MMT on crystal violet increased continously,while the adsorption capacity of acid red 18 decreased,and the effect on the adsorption capacity of dispersed red 3B was slight.The adsorption process of crystal violet,acid red 18 and disperse red 3B by GEL/MMT was spontaneous,and both correlated to the quasi-secondary kinetic model and the Langmuir model.The adsorption of crystal violet and acid red 18 by GEL/MMT was an endothermic process,and the adsorption of disperse red 3B was an exothermic process.The adsorption of crystal violet and acid red 18 by GEL/MMT was mainly based on intragranular diffusion model,and the adsorption of disperse red 3B was mainly based on liquid membrane diffusion.The adsorption mechanism of GEL/MMT composites to crystal violet,acid red 18 and disperse red 3B mainly included hydrogen bonding,electrostatic interaction,hydrophobic interaction,van der Waals force and ion exchange.53 Figures,22 tables,105 references.