This study shows that DAH-bentonite is effective adsorbent for
the removal of RB19 dye from aqueous solution. The modification
of adsorbent was confirmed by using FTIR, TGA, BET and elemental
analysis. The amount of dye adsorbed was found to depend on pH,
adsorbent dosage, temperature and contact time. The adsorbent
was the most effective at pH = 1.5 and 20 8C. Adsorption of RB19
onto DAH-bentonite increased with the increase in the adsorbent
dosage and the optimum adsorbent dosage was found to be
0.5 g dm3. The equilibrium between the dye and the adsorbent in
the solution was established within 60 min. The best correlation
was obtained using the pseudo-second-order kinetic model.
Equilibrium data were also fitted well to the Langmuir isotherm
model in the studied concentration range of RB19 at 20 8C.