Adsorption of Two Cationic Dyes from Aqueous Solution onto Natural Attapulgite

The adsorption of two dyes, namely, cationic red X-GRL and cationic brilliant blue RL onto natural attapulgite were studied, and adsorption mechanism was focused on from the view point of kinetics. Kinetic analysis showed that the adsorption processes of two cationic dyes on natural attapulgite obey the pseudo second-order model. The adsorption capacity of dyes was raised with temperature, but the equilibrium adsorption capacity of cationic brilliant blue RI was more than cationic red X-GRL. The activation energies of adsorption had also been evaluated with the pseudo-second-order. The result showed that the low activation energies indicate physical adsorption control process. Adsorption equilibrium data were well fitted by the Langmuir. From the results it can be concluded that the natural attapulgite could be a good adsorbent for treating cationic dyes-contaminated waters.