Novel Zn metal-organic framework with the thiazole sites for fast and efficient removal of heavy metal ions from water

Abstract

Pollution of water by heavy metal ions such as Pb²⁺ and Hg²⁺ is considered as an important issue, because of the potential toxic effects these ions impose on environmental ecosystems and human health. A new Zn-based metal-organic framework, [Zn₂(DPTTZ) (OBA)₂] (IUST-2), was synthesized through a solvothermal method by the reaction of 2, 5-di (4- pyridyl) thiazolo [5, 4-d] thiazole ligand (DPTTZ), the "V-shape" 4,4'-oxybis (benzoic acid) ligand (OBA) and zinc nitrate (Zn(NO₃)₂·6H₂O). This novel MOF has been characterized by several analysis techniques such as fourier transform infrared spectroscopy (FT-IR), elemental analysis (EA), powder x-ray diffraction (PXRD), thermogravimetry analysis (TGA), differential thermal analysis (DTA), field emission scanning electron microscopy (FE-SEM), Brunauer-Emmett-Teller (BET) surface area analysis and single-crystal X-ray diffraction (SXRD). This 3D MOF was tested for removing Pb²⁺ and Hg²⁺ ions from water. The factors that were investigated on the elimination of Pb²⁺ and Hg²⁺ ions were of pH, adsorption time, and the effect of initial ions concentration. According to the results, this particular Zn-MOF had significant performance in eliminating Pb²⁺ and Hg²⁺ ions from water with a removal efficiency of more than 97% and 87% within 3 min, respectively.