Use of novel organophilic montmorillonites for the removal dyestuff

In this study, removal capacities of raw montmorillonite (MMT) and the organoclays (OMMT-1, OMMT-2 and OMMT-3) prepared by the modification of MMT with the quaternary ammonium salts, which were synthesized previously, acid orange 63, direct yellow 50 and reactive blue 4 dyestuffs from aqueous solution were investigated. It was seen that adsorption process fitted Freundlich model by evaluating adsorption data on different organoclays with Freundlich and Langmuir linear equations for each of dyestuff at 298 and 308 K. Furthermore, it was found that adsorption process on organoclays is endotermic for reactive blue 4 and direct yellow 50. When we applied data optained from the kinetic studies to pseudo first order and pseudo second order models, we concluded that our study fitted pseudo second order model well. We observed that increasaing pH decreases adsorption for acid orange 63 and reactive blue 4, whereas adsorption quantity did not change for direct yellow 50. Thermodynamic parameters such as free enthalpy change (?G0), entalpy change (?H0) and entropy change (?S0) were calculated by using experimental data at different temperatures. In conclusion, we can say that the preparad organoclays are much more effective for removal of acid orange 63, direct yellow 50 and reactive blue 4 dyestuffs from aqueous solution with respect to raw MMT.