Adsorption of Congo-red onto Carbon Mesoporous Material

In the present study, adsorption of Congo red dye on carbon mesoporous surface has been investigated. Mesoporous carbon CMK-3 adsorbent with high surface area and large pore volume was prepared and itstextual and structural properties were characterized by powder X-ray diffraction patterns (XRD) and nitrogen physisorption isotherms. Adsorption experiments were carried out as batch studies at different contact time, pH, initial dye concentration and salt concentration. The maximum adsorption capacity was rapidly attained after 60 min of contact time. Adsorption was improved when dye solution adjusted to acidic condition. The adsorption of dye increased with increasing initial dye concentration and salt concentration. The equilibrium data were analyzed by the Langmuir and Freundlich models, which revealed that Langmuir model was more suitable to describe the Congo red adsorption than Freundlich model. Experimental data were analyzed using pseudo-first order and pseudo-second order kineticmodels. It was found that kinetics followed a pseudo-second order equation. Thermodynamic study showed that the adsorption was a spontaneous and exothermic process.