Sorption of acid dyes from effluents using activated carbon

The sorption of three acid dyes, namely, Acid Red 114, Polar Yellow and Pol ar Blue RAWL, onto activated carbon, has been studied. Equilibrium isotherm s have been measured for three single component systems (AB, AR, AY) and on e binary component system (AB + AY). The isotherms were determined by shaki ng 0.05 g activated carbon, particle size range 500-710 mu m, with 0.05 dm( 3) dye solution of initial concentrations from 10 to 250 mg/dm(3). A consta nt temperature agitating 400-rpm shaking water bath was used and the temper ature maintained at 20 +/- 2 degrees C. A contact time of 21 days was requi red to achieve equilibrium Analysis of data has been carried out in two sta ges. (a) In single component analysis, the experimental isotherm data were analysed using Langmuir, Freundlich, Redlich-Peterson, Temkin and Dubinin-R adushkevich equations for each individual dye. The monolayer adsorption cap acities are 101.0 mg Acid Red per g carbon, 100.9 mg Acid Blue per g carbon and 128.8 mg Acid Yellow per g carbon. (b) In multicomponent analysis, one binary system has been analysed using an extended form of the Langmuir equ ation. The correlation between theoretical data and experimental data only had limited success due to competitive and interactive effects between the dyes and dye-surface interactions. (C) 1999 Elsevier Science B.V. All right s reserved.