Adsorption behavior and mechanism of Hg(II) on highly stable Zn-based metal organic frameworks
(1. State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, China;
2. Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081, China;
3. School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China;
4. College of Chemistry and Chemical Engineering, Henan Polytechnic University, Jiaozuo 454003, China;
5. College of Materials and Chemical Engineering, Tongren University, Tongren 554300, China)
2. Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education, Wuhan University of Science and Technology, Wuhan 430081, China;
3. School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China;
4. College of Chemistry and Chemical Engineering, Henan Polytechnic University, Jiaozuo 454003, China;
5. College of Materials and Chemical Engineering, Tongren University, Tongren 554300, China)
Abstract: 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.
Key words: metal organic frameworks (MOFs); Hg(II); adsorption; selectivity; mechanism