Zeolitic imidazolate frameworks: Experimental and molecular simulation studies for efficient capture of pesticides from wastewater

Abstract

The agricultural drainage water represents the largest part of the contaminated water with pesticide, it was necessary to remove all pesticide from it. In this paper, two different zeolite imidazole frameworks (ZIF-67 and ZIF-8) based in two different metal ions (cobalt and zinc) was investigated. The preceding two nanoparticles adsorbents were used for the elimination of two common pesticides, prothiofos and ethion. Surprising results lie in the selectivity of pesticide toward different metal ions. The maximum adsorption capacities of prothiofos onto ZIF-8 and ZIF-67 were 366.7 and 261.1 mg g−1, respectively. Whereas in ethion; the maximum adsorption capacities were 279.3 and 210.8 mg g-1 for ZIF-8 and ZIF-67, respectively. Both pesticide adsorption followed pseudo-second-order kinetics and best fit the Langmuir adsorption model. The adsorption of ethion and prothiofos insecticides on to the surface of ZIFs were confirmed by using Fourier transform infrared (FTIR) spectroscopy and energy-dispersive X-ray spectroscopy (EDS). The adsorption of the pesticide molecules onto the ZIF surfaces was investigated in dry system using Grand canonical Monte Carlo (GCMC) simulation. The GCMC simulation provides information on the adsorption energies and maximum adsorption capacities. Molecular dynamics simulation was also revealed the effect of water solvent on the adsorption mechanism. This combination of simulations provides a complete picture of the adsorption mechanism which is needed for understanding the adsorption process of ZIF materials and the practical applications uses.