Preparation Of New MOFs-Based Sup-Ramolecular Recognition Material And Its Adsorption Property

Some radionuclides such as Am,Cm,Tc,I,Cs and Sr might have potential risks to environment and human health.This problem has attracted increasing attention with the development of nuclear energy.For example,Cs-135 with a half-life of 2×106 yr and Cs-137 with a half-life of 30-yr are fission products of uranium.Cs-135 would have long-termed harmful to environment and human health.While Cs-137 is one of the heat generators,it might be harmful to the vitrified-HLLW in final geological disposal.Cs is also one of the main sources of radioactivity in the accident at the Fukushima nuclear power plant in 2011.Consideration of environmental protection and human health,the effective removal of Cs is of great valueable.But this global problem has not yet been solved.For this purpose,a new MOFs-based supramolecular recognition material for the adsorption of Cs and Rb was prepared.The main results are as follows:(1)Four 1,3-alternate derivatives of calix[4]crown-5 and calix[4]crown-6,iPCC5,nOCC5,iPCC6 and nOCC6,were synthesized.While a nano metal-organic framework material,UiO-66,was preaped.Their compositions and structures were characterized by elemental analysis,1H NMR?ESI-MS?TG-DSC?SEM and XRD,respectively.(2)Four new MOFs-based supramolecular recognition materials,UiO-66@iPCC5,UiO-66@nOCC5,UiO-66@iPCC6 and UiO-66@nOCC6,were prepared by UiO-66 as a nano carrier.The internal and external morphology,structural characteristics,thermal stability of the materials were studied by SEM?XRD?TG-DSCand N2 adsorption and desorption isotherms.The elements composition of supramolecular recognition materials was studied by EDS and XPS.(3)The influence of HNO3 concentration,pH,contact time and temperature on the adsorption of Rb,Cs and some typical coexistent metals were investigated.The results show that the materials have excellent adsorption ability and selectivity for Cs and Rb over others.The adsorption mechabism was evaluated by EDS and XPS.The separation factor of Rb with Cs onto UiO-66@iPCC5 in 3.0 M HNO3 was 126.7.This provides a new ideal for effective removal of Rb and Cs.