Adsorption of water-soluble dye onto functionalized resin

The adsorption of water-soluble dye reactive brilliant blue KN-R onto the functionalized resin NKY has been dynamically and thermodynamically investigated. The adsorption rate constant is obtained from the first-order expression log(Q(e) - Q) = log Q(e) - k(ad)t/2.303. The adsorption is complex since the equilibrium data are well described by the Langmuir equation, the Freundlich equation, and the three-parameter equation. The first layer adsorption of KN-R onto NKY is physical, enhanced by a chemical effect, but multilayer adsorption is typically physical adsorption at normal temperature. The adsorption process is endothermic. The obtained standard free energy change and the inferred standard entropy change show that the adsorption of the dye onto NKY can occur spontaneously. Moreover, the effect of pH and temperature on the adsorption has been explored. The apparent activation energy E-a of the adsorption process has been calculated as well. (C) 2001 Academic Press.