SYNTHESIS AND CHARACTERIZATION OF UIO-66 METAL ORGANIC FRAMEWORKS FOR SORPTION OF LEAD, CADMIUM AND ZINC FROM AQUEOUS SOLUTION

Abstract

Various industries like galvanizing, metallurgical, electroplating, mining, pharmaceuticals, agrochemicals and leather industry produce metal-containing waste waters that have harmful effects on the environment as well as human health. For this purpose, UiO-66 (Zr-MOF) adsorbent was prepared to evaluate the removal capacity of selected metals Lead Pb(II), Cadmium Cd(II) and Zinc (Zn(II) from aqueous solution. The adsorbent UiO-66(Zr-MOF) was synthesized by solvothermal method and was characterized using XRD, TGA, SEM-EDX, AAS, BET and FTIR. The results indicated that UiO-66(Zr-MOF) demonstrated a high adsorption capacity which may possibly arise from its high porosity and smaller particle size. Adsorption study was carried out by batch experiment. The effects of different experimental parameters, namely, solution pH, adsorbent dose, contact time, and initial metal concentrations were determined. The isotherm experiment showed that equilibrium data were well fitted to the Freundlich model. From kinetic study, pseudo-second order model gave a best fit to the adsorption of metals on the adsorbent. The thermodynamic parameters were calculated and the results showed that the adsorption of metals on the adsorbent was spontaneous and endothermic process. The regeneration of metals saturated UiO-66(Zr-MOF) was investigated by using NaOH 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 themetals adsorption from wastewater.