Study On Adsorption Thermodynamics And Kinetics Of Dyestuff Onto Modified Bentonite

Bentonite, a kind of layered aluminosilicate clay, possesses of many special physical and chemical properties resulting from its structure characteristic. It has been widely used as adsorbent in all walks of lives.Dye wasterwater has been one of the most difficult environment problems for it gets high content of organism, heavy color and large quantity let, complex component. At present, the physichical adsorption is the simplest and most efficient means dealing with decolorization by chemical, biological and physical method. So far, active carbon is the most excellent adsorbent. However, its application is limited for its expensive production and high regeneration cost. To develop effeicient and low-cost adsorbent has been the focus of scholars.This thesis studied the adsorption thermdynamics and kinetics of two kinds of dyestuff onto bentonite modified by sodium, acid and iron hydroxyl from Ningming, Guangxi. The adsorption properties of different modified bentonite were compared. The result illustrates that the adsorption of Acid Blue 74 from aqueous solution onto modified bentonite is correlated with the Langmuir type isotherm equation. At 298K, the maxmum adsorption of sodium bentonite, acid bentonite and iron hydroxyl pillared bentonite is 14.45 mg g^-1, 205.2 mg g^-1, 41.43 mg g^-1 respectively. The adsorption kinetics result illustrates it fit the pseudo-second order equation. The adsorption of Basic Yellow 13 from aqueous solutions by modified bentonite is also correlated with the Langmuir type isotherm equation and the adsorption kinetics result illustrates it fit the pseudo-second order equation. At 298K, the maxmum adsorption of sodium bentonite, acid bentonite and iron hydroxyl pillared bentonite is 118.1 mg g^-1, 17.62 mg g^-1, 28.17 mg g^-1 respectively. The adsorption kinetics result illustrates it fit the pseudo-second order equation.