Novel synthesis of Chrysanthemum indicum flower as an adsorbent for the removal of direct Congo red from aqueous solution

The present study focused on preparation of thermally activated carbon from Chrysanthemum indi- cum flower and investigated its effectiveness on removal of direct congo red (DCR) dye from aqueous solution by batch mode. The Chrysanthemum indicum flower carbon (CIFC) was prepared and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The batch adsorption study showed that the amount of adsorption depends on various physicochemical parameters, such as solution pH, adsorbent dose, contact time, dye concentration and temperature. Further, pseudo-second-order model was fitted to examine the adsorption kinetics and mechanism of adsorption. Equilibrium data was fitted with Langmuir and Freundlich adsorption isotherm models and thermodynamic parameters were calculated such as ΔG°, ΔH°, and ΔS°. The maximum adsorption capacity of 43.47 mg g -1 was obtained for direct congo red. Through this study it was found out that the CIFC is a good and a cheap precursor to produce an effective adsorbent and alternative to commercial-activated carbon.