Preparation of ZIF-8-DMTD@ALG aerogels and their adsorption properties towards Pb(Ⅱ)and Cd(Ⅱ)
In this paper,2,5-dimercapto-1,3,4-thiadiazole(DMTD)was introduced into zeolitic imid-azolate framework material(ZIF-8)by post-synthesis modification method,and then combined with sodium alginate(ALG)by blending method to prepare ZIF-8-DMTD@ALG aerogels.ZIF-8-DMTD@ALG aerogels solve the problems that powder adsorbents are easy to agglomerate and difficult to recov-er.The introduction of DMTD brings abundant functional groups to ZIF-8-DMTD@ALG aerogels and improves their adsorption performance.The static batch adsorption experiments showed that the ad-sorption of Pb(Ⅱ)and Cd(Ⅱ)by ZIF-8-DMTD@ALG aerogels followed the quasi-second-order ki-netic model and Langmuir adsorption isothermal model.The maximum adsorption capacities of ZIF-8-DMTD@ALG for Pb(Ⅱ)and Cd(Ⅱ)obtained by Langmuir model reached 352.101 mg/g and 170.592 mg/g,respectively.Ionic strength experiments and cyclic adsorption experiments showed that ZIF-8-DMTD@ALG aerogels had good salt resistance and regeneration ability.Characterization techniques and batch adsorption experiments revealed that ZIF-8-DMTD@ALG aerogels mainly ad-sorbed Pb(Ⅱ)and Cd(Ⅱ)through complexation,and a small amount of ion exchange and electro-static interaction also contributed to the adsorption.The results show that ZIF-8-DMTD@ALG aero-gels have the advantages of simple preparation,easy recovery and strong adsorption capacity,and have a good application prospect in the field of sewage treatment.