Cluster-built Microporous Sulfides Ion Exchange Materials

The strategic requirement to drive the green and efficient development of nuclear energy and continuously strengthen the level of nuclear safety is to achieve the goal of becoming a strong nuclear power,promote the transformation and upgrading of industrial structure,pursue low-carbon energy and build a beautiful China.On the one hand,the fission isotopes ⁸⁷Rb,¹³⁷Cs,and neutron activation product ⁶³Ni generated during reactor operation have strong radioactivity and toxicity,pose a long-term potential threat to the body and environment.If ⁸⁷Rb,¹³⁷Cs,and ⁶³Ni in wastewater can be captured in a timely and rapid manner to block their diffusion,the effectiveness of nuclear pollution control will be greatly enhanced.On the other hand,the extracted⁸⁷Rb,¹³⁷Cs,and ⁶³Ni can be purified and used to prepare nuclear batteries andβ/γradiation sources,realizing the comprehensive utilization value of fission isotopes.Therefore,proper disposal of nuclear waste and utilization fission isotopes ⁸⁷Rb,¹³⁷Cs and ⁶³Ni are of practical significance.Metal sulfide ion exchangers,as an emerging material in which the S atom has a larger radius than the O atom,are soft bases that exhibit exceptional selectivity and fast adsorption kinetics for Lewis acidic softer metal ions.However,most of the currently reported sulfide ion exchangers are layer-stacking structures,whose limited interlamellar space makes the actual exchange capacity low,thus restricting the performance enhancement.Moreover,materials can lead to interlayer distance expansion when exposed to hydrated ions with large radii during ion exchange,rendering phenomena such as powdering and layer peeling during the adsorption process,which shortens the service life of the exchange column.This thesis aims to meet the national nuclear security strategic and focuses on the efficient adsorption and separation of radioactive ions in nuclear waste streams.Therefore,a novel cluster metal sulfide ion exchanges with excellent functionality and unique structure is prepared by a soft chemical synthesis technique using Deep Eutectic Solvents（DESs）as the reaction medium in order to achieve a more excellent adsorption and separation effect.The research concentrated on the adsorption and separation of Rb⁺,Cs⁺and Ni²⁺by metal sulfide ion exchangers constructed based on T2supertetrahedral clusters,to investigate the adsorption/separation of ions by the materials,and to provide new ideas for the adsorption and purification of radioactive fission isotopes;to study the influence law of material structure on adsorption rate,adsorption capacity and selectivity,and the total structure-efficiency relationship.Details are as follows:1.Using template-directed technique,[Ge₄S₁₀]^4-clusters and tetracoordinate Cd²⁺nodes were selectively assembled in a reaction medium consisting of guanidine hydrochloride and N,N’-dimethylurea（DES）,resulting in the formation of a 3D open-framework material K_1.35[CH₃NH₃]_0.65CdGe₄S₁₀·2H₂O（CdGeS-1K）with suitable pore structures upon K⁺activation.The material exhibited exchangeable K⁺ions and showed high selectivity for sorption and separation of single/mixed Rb⁺and Cs⁺ions.2.An example of microporous framework compound[NH₄][NH₃CH₃]₃Ga₄Sb S₉SH（Ga Sb S-2）constructed by the assembly of T2 super tetrahedral clusters and tri-ligated Sb³⁺nodes was synthesized in DES composed of methylamine hydrochloride and N,N’-dimethylthiourea.The[NH₄]⁺and[NH₃CH₃]⁺ions in the material were substituted with harder K⁺to obtain K salt analogues with the same framework structure,K_3.6[NH₄]_0.1[CH₃NH₃]_0.3 Ga₄Sb S₉SH·H₂O_0.9（Ga Sb S-2K）.It can capture Ni²⁺quickly and efficiently with high selectivity.3.2D layered antimony sulfide materials[NH₄][CH₃NH₃]₂Sb₉S₁₅（Sb S-2）constructed on the basis of trinuclear{Sb₃S₆}clusters were synthesized in DES composed of methylamine hydrochloride and N,N’-dimethylurea,with[CH₃NH₃]⁺and NH₄⁺cations as anti-balance cations and structural guides filled in between the layers.Substitution of NH₄⁺or[CH₃NH₃]⁺in the framework with the harder Na⁺ions yielded the isomeric Na⁺salt analogue Na_1.6[NH₄]_0.8[CH₃NH₃]_0.6Sb₉S₁₅·3H₂O（Sb S-2Na）,which exhibited fast adsorption kinetics.4.The structures and characteristics of two compounds{[Zn（en）（H₂O）][Zn（dien）]}₂[Zn（en）₂]₂[Ge₆V₁₅O₄₈（1）and[Na₃（H₂O）₄][B₁₈V₁₂O₅₄（OH）₆]·13H₂O（2）constructed from boronate or germanate substituted octadecanoate clusters were investigated to provide material and ideas for the synthesis of cluster-based.To provide ideas and accumulate materials for synthesis of sulfides based on cluster construction.