Optimal Design Of Pt/SDB Hydrophobic Catalyst

Hydrogen isotope separation technology has an important use in the field of heavy water tritium removal,fusion fuel recycle and high level radioactive liquid waste removal of tritium and other nuclear fields.The liquid phase catalytic exchange(LPCE)method using hydrophobic catalyst is one of the most useful separation methods by virtue of the advantages of low energy efficiency and high efficiency.The practical catalysts for liquid phase catalytic exchange are mainly composed of a series of catalysts and carriers that have hydrophobic properties of polytetrafluoroethylene(PTFE)and a hydrophobic platinum/styrene two ethylene benzene copolymer(Pt/SDB)catalyst.The Pt/SDB catalyst has a larger specific surface area than the polytetrafluoroethylene catalyst and can make full use of the catalytic ability of platinum.However,there is still no clear and effective method to control the performance of the SDB carrier,such as the pore size,the specific surface,the hydrophobicity and the hardness.In actual use,which factor is the most significant impression of catalytic effect.According to what kind of indicators,the preparation of carrier is the most conducive to the actual use of Pt/SDB catalyst,which needs further investigation.In this paper,the controllable preparation of large size SDB carrier is realized through the experiments of the speed,the size of the blade and the stirring time.In the experimental results,the blade width of 1.5 cm was selected and the particle size distribution of the 1mm carrier was the narrowest when the speed was 200 rotation.It is shown that the delay stirring time of small blade area and high stirring speed is beneficial to the SDB carrier with uniform particle size.By combining the orthogonal experiment with the linear test,the control of the aperture and the specific surface of the SDB carrier is realized in a certain range.When the non good solvent is a pore forming agent,the pore size of the SDB carrier is positively related to the molecular weight of the non good solvent,and there is a negative correlation between the surface and the hardness of the carrier and the molecular weight of the pore agent.And thus get the maximum pore radius of 10nm,than the maximum surface for a series of samples of 470 m~2/g.Compared with the amount of crosslinking agent,the type and dosage of pore forming agent had more significant effect on the hydrophobicity of SDB,indicating that the microstructure had a more direct effect on the hydrophobicity of the carrier.The analysis of the morphology of hysteresis loop and scanning electron microscope revealed that the pore size of the similar pore size was different from that of the surface carrier.This indicates that there are limitations in evaluating SDB performance only by pore structure data.There is a bottleneck in some of the carriers,which is caused by the low strength of the polymer particles when the amount of low crosslinker is used.It is feasible to prepare Pt/SDB catalyst by reduction of platinum at normal temperature of sodium borohydride at normal temperature on SDB carrier,but the agglomeration of platinum particles prepared by this method is serious.In the range of the selected carrier,the influence of the pore size on the catalytic efficiency is greater than the specific surface area.The large pore size carrier is beneficial to the load of the platinum shell structure,and can improve the catalytic efficiency.