| Nuclear energy is a valuable contributor to economic growth,environmental protection,and national security since it is a safe and dependable energy source.Nuclear safety concerns and the treatment of radioactive wastewater are two obstacles that the quick expansion of nuclear energy also faces.Numerous highly radioactive fission products,including 137Cs,90Sr,and 133Ba,as well as neutron activation products,including 60Co and 63Ni,are present in nuclear effluent.These elements,including groundwater,soil,and air,can enter the ecosystem in a number of different ways.They can inflict significant internal radiation damage once swallowed into the human body,as well as high-fatality illnesses like cancer,blood disorders,and organ failure.For example,137Cs and 90Sr are two extremely harmful fission products,which can cause damage to the human nervous system,immune system,bones,etc.Therefore,it is of great significance to develop new adsorbents to enrich radionuclides such as 137Cs,90Sr,133Ba,60Co and 63Ni quickly and efficiently.Tin-based chalcogenide ion exchange materials have gained increasing attention in recent years.Numerous coordination modes exist for the group 14 element tin(Sn),which is typically coordinated with S2-and Se2-to form a geometric polyhedron with a coordination number of 4-6.It has a higher affinity for soft alkali metal ions,alkaline earth metal ions,and heavy metal ions and a wider range of chemical bonding flexibility and framework flexibility.These properties are favourable to the creation of a channel environment for ion shuttle.The adsorption rate and exchange capacity of the described tin-based chalcogenide ion exchange materials are still inadequate.Preparing tin-based chalcogenides with quick adsorption rates and large exchange capacities as a result by optimizing the composition and structure is one of the key research objectives.In this thesis,two examples of tin-based sulfur compounds were prepared by low eutectic method using small molecule amines as structural guides and templating agents,and their crystal structures and adsorption properties were investigated respectively.The details are as follows.1.A layered tin-based sulfide material[CH3CH2NH3]1.2[NH2CH2CH2NH3]0.8Sn3S7·0.1C3H6N2O(SnS-1)have been synthesized with a honeycomb structure characterized by a low eutectic solvothermal method using DES composed of 2-imidazolidinone and ethylamine hydrochloride as the reaction medium.The[Sn3S7]n2n-anion lamellae are formed by {Sn3S10} clusters connected by co-edges and have a hexagonal window with a size of about 11.02 × 13.12 A2 and a unique layered structure.It has a fast kinetic response to Sr2+,Ba2+,Co2+,and Ni2+ions with maximum adsorption capacities of 80.24±41.03,276.01±148.05,71.23± 28.30,and 82.51±7.79 mg·g-1,respectively,and exhibits good adsorption performance in the pH range of 4-11,while being able to adsorb from higher concentrations of Na+,K+,Mg2+,Ca2+ ions in solution and selectively adsorbed Sr2+,Ba2+,Co2+,Ni2+.2.Using DES composed of N,N’-dimethylurea and diethylamine hydrochloride as the reaction medium,A Three-dimensional(CH3NH3)3NH4Cd2Sn3Se10(CdSnSe-2)materials have been synthesized.To improve the kinetic response and adsorption capacity,K3.4(CH3NH3)0.45(NH4)0.15Cd2Sn3Se10·3.4H2O(CdSnSe-2K).CdSnSe-2K have a fast kinetic response for Cs+,Co2+,and Ni2+,and the removal rate of Cs+reached 98.5%within 2 min.The maximum adsorption capacities are 218.08 ± 80.08,43.95 ±16.57,and 42.53±16.50 mg g-1,respectively.In the ion-exchange column experiment,the removal rate still reach more than 99%by 5000 times the bed volume of the mixed solution of Cs+,Co2+,and Ni2+.The CdSnSe-2K/PTFE composite membrane is prepared to realize the removal of Cs+,Co2+,and Ni2+rapidly and continuously,and the removal rate of Cs+remained in the range of 98%-100%during the treatment of 350 mL of the solution with mixed ions. |
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