SYNTHESIS AND CHARACTERIZATION OF UIO-66 METAL ORGANIC FRAMEWORKS FOR SIMULTANEOUS SORPTION OF METHYL ORANGE AND METHYLENE BLUE FROM AQUEOUS SOLUTION

Abstract

Various industries like textile, plastic, pulp, and paper produce dye-containing wastewaters that have harmful effects on the environment as well as human health. For this purpose UiO-66 (ZrMOF), adsorbent was prepared to remove dyes from aqueous solution. The aim of this study was to investigate the capacity of UiO-66(Zr-MOF) in the removal of dyes, methyl orange (MO) and methylene blue (MB), from aqueous solutions. The adsorbent was synthesized by solvothermal method at high temperature condition. The as synthesized UiO-66(Zr-MOF) was characterized using XRD technique thereby ensuring their structural crystallinity. The thermal stabilities of the UiO-66(Zr-MOF) was studied using the TG/DTA technique. The results indicated that UiO66(Zr-MOF) showed a high adsorption capacity which may possibly arise from its high porosity, smaller particle sizes and high crystalline nature. Adsorption study was carried out by batch experiment. The effects of different experimental parameters, namely, solution pH, adsorbent dose, contact time, speed of agitation and initial dyes concentration were determined. The isotherm experiment showed that equilibrium data were well fitted to the Freundlich model. The kinetic study demonstrating the pseudo-second-order model gave a best fitting to the adsorption of dyes on the adsorbent. The thermodynamic parameters were calculated and the results show that the adsorption of dyes on the adsorbent is a spontaneous and endothermic process. The regeneration of dye saturated UiO-66(Zr-MOF) was investigated by using deionized water solution and the result revealed that, UiO-66(Zr-MOF) can be easily regenerated and re-used several times, indicating that this adsorbent could have great potential for the dye adsorption of wastewater.