Application of Carbonized Metal-Organic Framework as Efficient Adsorbent of Cationic Dye

Herein, we report study about adsorption kinetics of rhodamine B onto metal organic framework containing cobalt (CoOF). The CoOF can be successfully produced from the reused waste-organic ligands and solvents. The as-prepared material was carbonized and purified prior to testing. The adsorbent was characterized with scanning electron microscopy, Fourier transform infrared spectrophotometer, X-ray diffractometer, thermogravimetric analysis, Raman spectroscope, and N-2 adsorption/desorption isotherms. The kinetics of dye adsorption onto structure was examined with the UV-Vis spectrophotometer. Various physiochemical parameters such as initial dye concentration, pH of dye solution, and temperature were investigated in an adsorption technique. The adsorption uptake was found to increase with increase in initial dye concentration. An increase in adsorption capacity was noticed when the solution was changed to basic, optimum conditions obtained at pH 7. The results indicate that along with an increase in the temperature the adsorption capacities decrease. The maximum monolayer adsorption capacity of RhB onto CoOF was 72.150 mg/g. Kinetic adsorption data were analyzed using the pseudo-first-order kinetic model, the pseudo- second-order kinetic model, and the intraparticle diffusion model. The adsorption kinetics well fit using a pseudo-second-order kinetic model. The experimental data were analyzed by the Langmuir and Freundlich adsorption isotherms. Equilibrium data fit well with the Freundlich isotherm. Thermodynamic parameters such as Gibbs free energy, enthalpy and entropy were determined. It was found that the adsorptions of RhB onto CoOF was a spontaneous and exothermic physisorption.