Removal of Congo red from aqueous solution by anilinepropylsilica xerogel

The hybrid anilinepropylsilica xerogel (SiAn) was synthesized by sol–gel method and it was used as adsorbent for removing Congo red from aqueous solutions. The dye adsorption experiments were carried out by using bath procedure. The pH effects, the contact time and the initial dye concentration were changed to obtain the best experimental conditions. The dye adsorption equilibrium was rapidly attained after 20 min of contact time. The experimental data were best fitted to Sips and Redlich–Peterson isotherm models, attaining a maximum adsorption capacity of 22.62 mg g−1 of Congo red.