SYNTHESIS AND CHARACTERIZATION OF UiO-66 (Zr-MOF) FOR THE ADSORPTIVE REMOVAL OF MALATHION AND 2, 4-D FROM AQUEOUS SOLUTION

Abstract

UiO-66(Zr) metal organic frame work was successfully synthesized by solvothermal method. The as synthesized UiO-66(Zr) was characterized using FTIR, XRD, TGA and SEM techniques to investigate the functional group, structural crystallinity, thermal stability and morphology of the material, respectively. Adsorptive removal of Malathion and 2, 4-D with UiO-66(Zr) were studied to understand its applicability in the removal of pesticides from contaminated water. According to the outcome of this study, UiO-66(Zr) exhibited fast adsorption capacity (t, one hour) and importantly the adsorption of both pesticides over UiO-66(Zr) were favorable at low concentrations. The high adsorption capacity of UiO-66(Zr) may be attributed to its high porosity, smaller particle sizes and high crystalline nature. The effects of different experimental parameters, namely, pH, adsorbent dose, contact time, speed of agitation and initial pesticides concentration were studied by using batch experiment. The adsorption isotherm experiment showed that the equilibrium data were fitted to the Freundlich model. The kinetic study demonstrated that pseudo-second-order model gave a best fitting to the adsorption of Malathion and 2, 4-D on the (UiO-66) adsorbent. The thermodynamic parameters were calculated and the results show that the adsorption of Malathion and 2,4-D on the adsorbent is a spontaneous and exothermic process. To evaluate the matrix effect on adsorption performance of UiO66(Zr), real sample, (tap water) were spiked and its recovery were evaluated. The results revealed that the recovery values were satisfactory (found to be in the range of (70-120%), and it can be said that the matrix effect from the water samples on the adsorption of Malathion and 2, 4-D on to UiO-66(Zr) was not affect their adsorption. Therefore, UiO-66(Zr) is the promising adsorbent for the removal of pesticides in waste water.