adsorption of anionic dye from aqueous solution using activated montmorillonite/graphene oxide/ gelatin composites

The present work describes the adsorption of the anionic dye congo red (cr) by materials based on activated montmorillonite (am), graphene oxide (go), and gelatin (g). the materials were prepared and characterized by x-ray diffraction (xrd), infrared spectroscopy (ft-ir), and thermal analysis (atg/dtg) in the previous study. adsorption experiments of cr dye on go/am at different ratios of go were performed to evaluate the adsorption efficiencies. the maximum adsorption capacity of anionic dye (cr) onto (go / am10%) composite was insufficient. to improve the adsorption capacity, a cationic-charged component such as gelatin was added to obtain a new composite (go/am/g). therefore, the effects of several factors on the adsorption capacity of (go/am/g) composite, such as the ph of dye solution, adsorbent dosage, contact time, initial dye concentrations, temperature, and regeneration, were investigated. in addition, the kinetics of dye adsorption followed the pseudo-second-order model, and the adsorption isotherm was very well described by the freundlich model. afterward, the study of the temperature’s effect on the adsorption rate indicated that the reaction was exothermic with the medium disorder. the values of the free energy showed that the nature of the adsorption was physisorption. the reusability of the composites using 0.1n hcl for over six cycles indicated the economic significance of these materials as adsorbents. the fast removal rate in a wider range of ph and the easy reusability and regeneration make the composite (go/am/g) a prospective material for dye adsorption from aquatic environments.