Adsorption behavior and mechanism of Hg(II) on highly stable Zn-based metal organic frameworks

A novel adsorbent (MTZ-MOFs) was synthesized by a one-step reaction of zinc nitrate hexahydrate and 1-(2-dimethylaminoethyl)-1H-5-mercaptotetrazole to remove mercury from waste water. The results showed that MTZ-MOFs had excellent selectivity and repeatability for Hg(II), the optimum pH was 3.0, the maximum adsorption capacity was 872.8 mg/g, and the process was a spontaneous exothermic reaction. The adsorption behavior was chemisorption, which conformed to the pseudo-second-order kinetic and Freundlich isothermal model. Moreover, the adsorption mechanism showed that the adsorption process mainly depended on ion exchange and chelation, and the synergistic action of S and N atoms played a key role. So, MTZ-MOFs were an efficient adsorbent for mercury ion removal.