The Modification Of Attapulgite Clay And The Application In Dyeing And Printing Wastewater Decoloring

Attapulgite clay is crystal hydrated magnesium aluminum silicate with a unique layer-chain structure. It has unique advantages and attractive in the treatment of dyeing and printing wastewater because of its larger size and specific surface area.Dyeing and printing wastewater contains a certain amount of toxic organism that includes residual dyestuffs, dyeing auxiliaries, acid and alkali and some heavy metals. Residual dyestuffs and dyeing auxiliaries are the main ingredients of organic pollutants in wastewater and make the wastewater have the special color. Therefore, the study of the method of decoloring and how to make the dyeing and printing wastewater decolor become an important issue of printing and dyeing wastewater.The surface area morphology,crystal structure,surface area,functional groups and weightlessness situation of attapulgite clay was analyzed by field emission sweep electron,basal spacing(XRD),specific surface area(BET method),FT-IR spectroscopy and thermal properties (TGA). The adsorption properties and mechanisms of different types of dyes onto thermal-modified and cationic modified attapulgite clay on basis of adsorption thermodynamics and kinetics were investigated. It was compared adsorption performance of the different modification attapulgite clay for different types of dye and used in the treatment of dyeing and printing wastewater.The results showed that the surface area of attapulgite clay of 350℃was bigger and it had better dispersion. In the test conditions range, the adsorption data of Methylene Blue onto thermal-modified attapulgite clay was fitted well to the Langmuir isotherms and the equilibrium adsorption is 73.05mg.g-1. The adsorption enthalpy changes and the values of adsorption entropy changes were positive, the adsorption Gibbs free energy changes was negative. The prosess of the adsorption of the Methylene Blue onto thermal-modified attapulgite clay was endothermic and spontaneous. The adsorptive kinetics data were in good agreement with the pseudo-second rate equation.It can be sure that cation modifier was connected in attapulgite clay by the X-ray diffraction (XRD) and FT-IR spectroscopy. The adsorption data of reactive bluel9 onto cationic modified attapulgite clay was fitted well to the Langmuir isotherms and the equilibrium adsorption is 167.8mg.g-1. The adsorption enthalpy changes and the values of adsorption entropy changes were positive, the adsorption Gibbs free energy changes was negative. The prosess of the adsorption of the reactive blue 19 onto cationic modified attapulgite clay was endothermic and spontaneous. The adsorptive kinetics data were in good agreement with the pseudo-second rate equation.The adsorption capacity of thermal-modified and cationic modified attapulgite clay was increased with different degree to the different structures of cationic dye and anion dye. And it was increased with the reducing of electric charges in the dye.