| In this paper,the dynamic hydrothermal crystallization method was used to synthesize NaP zeolite and the samples were analyzed by XRD,SEM,BET,FTIR,PSD and other characterization methods.The influence of different parameters such as silicon sources aluminum sources,rotational speed,crystallization temperature and time,basicity of synthesis system and ratio of water to silicon on NaP zeolite was investigated by dynamic hydrothermal crystallization method,The samples crystallized by dynamic and static methods were compared,and the adsorption and regeneration performance of NaP zeolite crystallized by dynamic method were studied.The research results were as follows:（1）The effects of five different silicon sources,including sodium silicate fumed silica and so on,and four different aluminum sources,including NaAlO2,aluminum sulfate and so on,on the synthesis of NaP zeolites were investigated.The results showed that when the n（SiO2）/n（Al2O3）was 2.00,the NaP zeolite prepared with sodium silicate as the silicon source and NaAlO2as the aluminum source had higher crystallinity,87.72%.（2）The increasing of the parameters such as silicon-aluminum molar ratio,crystallization temperature,crystallization time,dynamic rotational speed and water-silicon molar ratio of the initial raw material in a certain range was beneficial to improve the purity of NaP zeolite.By optimizing the synthesis parameters,NaP zeolite with a particle size of about1.8μm was synthesized under the conditions of n（SiO2）/n（Al2O3）=2.00,the crystallization temperature of 120℃,the crystallization time of 8 h,the dynamic rotational speed of 70 r/min,alkalinity n（NaOH）/n（SiO2）of 0.220 and the n（H2O）/n（SiO2）of 80,The purity was 90.17%.（3）The dynamic crystallization method can make the reactants fully mixed in the crystallization process,thus shortening the crystallization time,reducing the particle size,increasing the specific surface area of the zeolite and improving the pore structure.The grain size,thermal stability,crystallization process and pore structure parameters of NaP zeolites synthesized by dynamic and static crystallization were compared.The results showed that the induction nucleation period of dynamic crystallizationwas half of the induction nucleation period of static crystallization,and the growth rate of dynamic crystallization was faster.The specific surface area and total pore volume of NaP zeolite synthesized by dynamic method was 25.2 m2g-1and 0.1485 cm3/g,which was about 1.5 times that of NaP zeolite synthesized by static method.（4）The adsorption effect of zeolite on different metal ions is affected by the hydration radius and hydration energy.The order of removal rate of Co2+,Ni2+,Cu2+and Zn2+by NaP zeolite was Co2+>Zn2+>Ni2+>Cu2+.Taking the adsorption Co2+as an example,the adsorption process of Co2+by NaP zeolite was specifically studied.The effects of adsorption temperature and initial concentration on adsorption effect were investigated.（5）The adsorption process of Co2+by NaP zeolite conformed to the second-order kinetic model could describe the adsorption process.the adsorption process was more consistent with the Langmuir adsorption model,indicating that this process belonged to monolayer adsorption.The study of adsorption thermodynamics showed that this process was an endothermic process and can be carried out spontaneously.（6）when the concentration of NaCl was 0.10 mol/L,the regeneration temperature was40℃,the removal rate of Co2+could still reach 97.93%after 1 h of regeneration for the NaP zeolite after adsorption,and the removal rate was 92.33%after three adsorption-regeneration,indicating that the NaP zeolite crystallized by dynamic method had good regeneration performance. |
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