Removal of Ametryn From Aqueous Solutions With Zeolite Nanoparticles Optimized Using the Box-Behnken Design

Nowadays, adsorption techniques are widely used to remove certain classes of pollutants from water..
The aim of this study was to remove ametryn from water solutions by natural zeolite nanoparticles from the Semnan region of Iran..
For this purpose zeolite nanoparticles were synthesized from natural zeolite using planetary ball-mill. The zeolite nanoparticles properties were verified by a particle size analyzer, XRD, XRF and TEM. To remove ametryn from water, the box-behnken design (BBD) of response surface methodology (RSM) was employed for simultaneous optimization of all parameters affecting the adsorption process. In this research, the studied parameters were pH (6 - 8), the amount of adsorbent (0.5 - 2 g) and temperature (25 - 45°C). Fifteen experimental runs were calculated using BBD for these three-levels three-factorial. To determine the effect of contact time (10 - 120 minutes) on the adsorption of ametryn under optimal conditions, seven runs were carried out. Reversed-phase HPLC-UV was used for ametryn determination, using an isocratic solvent delivery system (methanol: H2O, 60:40, pH = 4.6), flow-rate of 1.2 mL.min-1 and a UV wavelength of 228 nm..
The optimal conditions predicted by the model were pH 6, 2 g of adsorbent and 43.3°C temperature. Kinetic studies of the adsorption process specified the efficiency of the pseudo second-order kinetic model and showed that the equilibrium time was 45 minutes. The maximum percentage of ametryn removed was found to be 64.12% after 120 minutes. Regression analysis showed good fit of the experimental data and the correlation coefficient with determination (R) value of 0.9568. The adsorption isotherm fitted well with the Freundlich model..
The zeolite from Semnan, with low cost and abundant availability has a good potential to be used as an adsorbent for removal of ametryn from polluted water resources..