Structure Optimization Of Novel Potassium Ionic Sieve And Research On K~+ /Na~+ Ion-exchange Process

The novel potassium ionic sieve was synthesized by the way of hydrothermal growth using Al₂(SO₄)₃, soluble glass and KOH as the raw materials. In the size of synthesized potassium ionic sieve, the influencing factors of crystal seeds, synthesis time and frequency, as well as templates were investigated respectively. The prepared crystals were characterized by means of XRD and SEM. The results show that inputting seeds was helpful to the synthesis of large crystal of potassium ionic sieve. Synthesis time and frequency also influence the size of crystals, and the best factors were three times and every time last for 24 hours. Different templates,different influence on the novel potassium ionic sieve. The study show Dual-template, consist of n-Butylamine (n-TBA) and Diethanolamine (DEA), was the most suitable template. In the conditions above, the novel potassium ionic sieve crystals of 32.9μm were synthesized.Rebuilding and optimization of the structure of phillipsite are performed using materials studio 5.0 software package. The results show that with the progress of optimization, the energy tends to a stable value, which changes from -15517.6639eV to -15520.0855eV, and the configuration becomes stable more and more. The diffusion trajectory of Na⁺,and K⁺/Na⁺ ion-exchange process in phillipsite cage were investigated in this paper. The simulation result of the diffusion trajectory of Na⁺ shows that Na⁺ absorbed on the Al-site first. And it further proved that the distribution of the Al-site determines the distribution of cation in phillipsite. The simulation of K⁺-Na⁺ ion-exchange process in the channel of phillipsite show that the interaction between particles in the channel and the zeolite framework causes the K⁺-Na⁺ ion-exchange process to take place, which means that clinoptilolite possesses better selectivity to K⁺ than to Na⁺.