| The separation of H2-D2mixture by porous materials is a hotspot in the field of hydrogen isotope separation in recent years.This article chose the two-dimensional layered MOFs[M-bpydc（M=Ni/Co/Zn）]and three-dimensional MOF[Ni（nic）（4,4’-bpy）]as porous materials to separate H2-D2mixture.After 150℃activation,M-bpydc（M=Ni/Co/Zn）and Ni（nic）（4,4’-bpy）both have open metal sites.The distance between the adjacent layers of M-bpydc（M=Ni/Co/Zn）is 3.67?and Ni（nic）（4,4’-bpy）pore size is about3.9×4.2?2,so these two kinds of MOFs have potentially chemical affinity quantum sieving（CAQS）effect and kinetics quantum sieving（KQS）effect.This article adopts the method of molecular simulation combined with experiments,comprehensive inspected the M-bpydc（M=Ni/Co/Zn）and Ni（nic）（4,4’-bpy）of H2-D2mixed gas separation performance,and the results are as follows:（1）The molecular simulation of M-bpydc（M=Ni/Co/Zn）in the temperature range of 20-77 K shows that the adsorption performance of Ni-bpydc about H2-D2mixed gas is better than that of Co-bpydc and Zn-bpydc.The adsorption selectivity of Ni-bpydc for H2-D2mixed gas（H2:D2=1:1）reaches 1.20 at 77 K,and increases gradually with the decrease of D2content.When the D2content is 1%,the adsorption selectivity reaches 5.85,indicating that Ni-bpydc has excellent CAQS effect.At the low temperature of 20 K,the diffusion rate of D2is much higher than that of H2,and the diffusion selectivity is 0.60,showing a significant KQS effect.When the temperature is higher than 20 K,the diffusion rate of H2is gradually higher than that of D2,and the kinetic selectivity reaches 1.57 at 77 K.（2）Load Ni-bpydc onγ-Al2O3to obtainγ-Al2O3@m-Ni-bpydc（m=3.40%、6.65%、9.51%、10.49%）composite as the stationary phase of the column.Factors such as Ni-bpydc loading,gas carrier velocity,H2-D2mixed gas injection amount,Ni,Co and Zn metal centers were investigated successively.The experimental results show that when the load content of Ni-bpydc is 6.65%（γ-Al2O3@6.65%-Ni-bpydc）,the separation effect is the best.When H2-D2mixed gas（1:1）injection volume was 400μL,the resolution R of H2-D2was 1.66 and the separation time was 5.59 min.When the D2content of H2-D2mixture gradually decreased（the total injection volume was 500μL）,the resolution R of H2-D2mixture gradually increased,and when the D2content was reduced to 10%,the resolution R could reach 2.97,and the separation time was 6.11 min.In addition,under the same experimental conditions,the resolution R ofγ-Al2O3@5.69%-Co-bpydc andγ-Al2O3@5.04%-Zn-bpydc as stationary phases of gas chromatography were1.47 and 1.23,respectively,and the separation of H2-D2mixture could not be realized,which was consistent with the trend of molecular simulation research in this paper.（3）The molecular simulation of Ni（nic）（4,4’-bpy）at the temperature range of 20-90 K shows that the adsorption selectivity of Ni（nic）（4,4’-bpy）for H2-D2gas mixture（H2:D2=1:1）reaches 1.30 at 77 K.With the decrease of D2content,the adsorption selectivity increases gradually.When D2content is 1%,the adsorption selectivity reaches 9.52.At 90 K,the adsorption selectivity for H2-D2gas mixture（H2:D2=1:1）is still 1.29,indicating that Ni（nic）（4,4’-bpy）still has excellent CAQS at higher temperature than the temperature of liquid nitrogen.At the same time,through the diffusion performance of H2and D2in Ni（nic）（4,4’-bpy）,it is found that the diffusion rate of H2and D2in Ni（nic）（4,4’-bpy）is significantly different.At 20 K,the diffusion rate of D2is higher than H2,and the diffusion selectivity(SH2/D2)is 0.93,which has the effect of KQS.When the temperature is higher than 20 K,the diffusion rate of H2is gradually higher than that of D2,and the the kinetic selectivity is up to1.53 at 50 K.（4）Ni（nic）（4,4’-bpy）was loaded onγ-Al2O3to obtainγ-Al2O3@m-Ni（nic）（4,4’-bpy）（m=1.12%、1.41%、2.99%、4.56%）composite as the stationary phase of the column.Factors such as Ni（nic）（4,4’-bpy）load,gas chromatographic carrier gas flow rate,H2-D2mixture gas injection volume were explored successively.The experimental results show that when the load content of Ni（nic）（4,4’-bpy）is 1.41%,that is,γ-Al2O3@Ni（nic）（4,4’-bpy）,the separation effect is the best.The H2-D2mixture（H2:D2=1:1）can be separated with the resolution R of 1.59 and a separation time of 5.28 min.In addition,the effects of different D2contents in H2-D2mixture on the separation performance of H2-D2mixture byγ-Al2O3@Ni（nic）（4,4’-bpy）stationary phase were investigated.When the D2content in the H2-D2mixture decreases gradually（the total injection volume is 500μL）,the resolution R increases gradually.When the D2content decreases to 10%,the resolution R reach 2.50and the separation time is 9.25 min.This is consistent with the trend of molecular simulation studies of Ni（nic）（4,4’-bpy）in this paper. |
PDF Full Text Request