The adsorption properties

including the adsorption isotherms

thermodynamics and kinetics

of 1-amino-2-naphthol-4-sulfonic acid (1

2

4-acid) onto weakly basic resin ND900 are investigated. Both the Langmuir and Freundlich equations can give a good fit to the adsorption isotherms

which indicates an endothermic and a favorable adsorption in our study range. A high yield in elimination of about 45.21 %-97.28% is obtained for the tested adsorption systems. The capacity and affinity of the adsorption increase with temperature

due to the phenomena of "solvent-motivated" effects. The value of △H is 51.59 kJ/mol

which indicates a chemical adsorption and then expects the poor desorption property of ND900. The negative value of △G indicates the spontaneous nature of the adsorption process

and the positive value of △S shows the increased randomness at the solid/solution interface during the adsorption process. The value of the adsorption rate constant lower than 0.013 min-1 is indicative of a slow adsorption rate. The intra-particle diffusion must be one of the rate limiting steps.