Preparation Of Lithium Ion Sieve And Its Adsorption Properties Under Low Lithium Concentration

Lithium is hailed as one of the"important energy elements to promote world progress"in the 21st century and is an important strategic resource.Therefore,it is particularly important to find a method for efficient extraction of Li⁺.The ion sieve materials prepared so far have low Li⁺extraction efficiency and large Ti⁴⁺dissolution loss.Aiming at the current problems of lithium ion sieves,this article uses solid-phase method to prepare titanium-based lithium ion sieve materials.The preparation and elution processes of lithium ion sieves are studied respectively.The research process and research results obtained are as follows:(1)A lithium ion sieve precursor prepared by using C₂H₃LiO₂·2H₂O and Ti O₂as raw materials was eluted with sodium persulfate.Studies have shown that the use of sodium persulfate as the eluent eluent.As the hydrolysis progresses,the intermediate products react with H₂O to form HSO₄^-and H₂O₂.The presence of an oxidant promotes the migration of Li⁺from the precursor and maintains a higher Li⁺.At the same time(83.25%),Ti⁴⁺dissolution loss(0.62‰)can be greatly reduced,and research shows that when the eluent exceeds a certain concentration,it will lead to the production of anatase Ti O₂and affect the adsorption capacity.(2)Lithium acetate and lithium nitrate are mixed at a ratio of 0.25:0.75 as a lithium source,and a lithium-ion sieve precursor is prepared by reacting the solid-state sintering method with Ti O₂.Studies have shown that the mixed lithium source reaction can reduce the temperature of the lithium ion sieve precursor calcination synthesis to 400?,and the prepared lithium ion sieve shows a higher adsorption capacity(41.17 mg/g).Outside the adsorption of Li⁺,only 2.03 mg/g of Mg²⁺was adsorbed,and the cycle stability was good.At the same time,the elution adsorption mechanism was explored,and the results showed that it was difficult for Li⁺to replace H⁺in(HTi₂)during the adsorption process of the layered lithium ion sieve.Instead of H⁺in the H layer,this is also the reason that the adsorption capacity of the layered lithium ion sieve is much lower than the theoretical value.