Removal of methyl violet dye by adsorption onto N-benzyltriazole derivatized dextran

In this work, N-benzyltriazole derivatized dextran was evaluated for its potential as a novel carbohydrate-based adsorbent for the removal of methyl violet dye from water. The modified dextran was synthesized by a click reaction of pentynyl dextran and benzyl azide, and the structure was characterized by nuclear magnetic resonance spectroscopy, elemental analysis, and scanning electron microscopy.

Dextran was substituted with a triazole-linked benzyl group. For decolorization of the dye effluent, adsorption is a very effective treatment; here, the driving force is based on hydrogen bonding, pi stacking, and electrostatic interaction between the methyl violet dye and the N-benzyltriazole derivatized dextran.

Batch experiments were carried out to investigate the required contact time and the effects of pH, initial dye concentrations, and temperature. The experimental data were analyzed with equilibrium isotherms including the Langmuir, Freundlich, and Temkin models. Based on the Langmuir isotherm, the maximum adsorption capacity was determined to be 95.24 mg of dye per gram of the adsorbent.

The adsorption obeyed pseudo-second order kinetics, and a negative Delta G(0) value indicated adsorption spontaneous in nature.