ADSORPTION OF SOME ACID DYES FROM AQUEOUS-SOLUTIONS ONTO NEUTRAL ALUMINA

The kinetics and isotherm studies on the adsorption of five acid dyes, viz., Acid Orange 6, Acid Orange 7, Ethyl Orange, Acid Red 88 and Aci d Blue 113 on neutral alumina have been carried out spectrophotometric ally. In each case the absorption process follows first order kinetics . For all the five dyes the rate of adsorption shows an increase with increase in dye concentration (0.5 - 6.0 x 10(-5)), decrease in pH (4 - 8.5), decrease in temperature (30 -50 degrees C) and amount of adsor bent (0.1 - 0.6g). The adsorption shows the order : Acid Orange 6 > Ac id Orange 7 > Ethyl Orange > Acid Red 88 > Acid Blue 113. The dye adso rption follows the Langmuir and Freundlich isotherms; the various isot herm constants and thermodynamic parameters for the adsorption of dyes have been calculated and discussed.