Preparation Of Hydrophobic Catalysts Pt/SDB And Its Catalytic Performance For Isotope Exchange Of Hydrogen

The application of hydrogen isotope exchange technology has a high value on extracting tritium from deuterium oxide,producing deuterium oxide and the wastewater detritiation.However,due to the slow study of hydrophobic catalyst,the hydrogen isotope exchange technology is dominated by vapor phase catalytic exchange reaction(VPCE).But vapor phase catalytic exchange reaction(VPCE)has many problems such as high operating temperature(>200?),high operating pressure(0.2 MPa)and large energy consumption.The liquid phase catalytic exchange reaction(LPCE)under atmospheric pressure and 50-80 ? can be carried out.The potential application of the liquid phase catalytic exchange technology accelerates the study of hydrophobic catalysts.Large porous styrene-divinylbenzene(SDB)microballoon with a particle size(the diameter is 0.8-1 mm)were synthesized by suspension polymerization method used styrene(St)as monomer,divinylbenzene(DVB)as cross-linking agent,benzoperoxide(BPO)as the initiator,And the pore forming agent is made up of pore forming agent A and pore forming agent B with a volume ratio of 1:1.The structures and properties of samples were characterized by FT-IR,BET,XRD,SEM,and TG-DTA.The results showed that the diameter,aperture,specific surface area and contact angle of the prepared SDB was 0.8-1 mm,1.02 nm,244 m2/g and 132°,respectively the SDB microballoon has a good stability below 350 ?.And the number of suspended double bonds on the surface of carrier is 0.96?1.02 mmol/g.The Pt-SDB hydrophobic catalyst was prepared by impregnation reduction method used SDB particles as the carrier and i-POL as the solvent.The influence of adding dispersing agent,soaking time,soaking temperature and immersion condition and hydrogen reduction temperature on the catalyst preparation were investigated.And Pt-SDB hydrophobic catalyst with good dispersity and uniform distribution were obtained.The optimum conditions for the preparation of the catalyst were as follows:the impregnation temperature was at 30-60 ?,the soaking time was above 12h,and the dosage of the dispersant was 0.8wt%,and the reduction temperature of hydrogen was at 200?-300 ?,5 and the reduction time was 8-12.The structures and properties of samples were characterized by TPD and XPS.The results show that the contact angle of Pt-SDB catalyst is 125° and the surface area is 40 m2/g,stable temperatures is below 350 ?;The active component platinum element is double layer load,The degree of dispersion is about 50%,Pure platinum accounted for more than 60%of platinum elementsThe catalytic activity of the catalyst was tested by liquid phase catalytic exchange(LPCE).The catalytic performance of the catalyst in this paper is simulated by H,D isotope exchange on the surface of the catalyst.The effects of temperature and vapor/liquid ratio on the catalytic performance of the catalysts were investigated,respectively,at 50 ?,60 ?,70 ?,80 ?,and four ratios 1:1-1:4.The results show that when the temperature is at 80 oC and the gas liquid ratio is up to 1:2,the catalytic performance of the catalyst for hydrogen isotope exchange is the best,and the concentration of deuterium in the gas phase is up to 9851 ppm.The catalytic activity of the catalyst was tested at 55?,65 ? and 75?,respectively.The results showed that the activity of the catalyst was decreased slightly,and the activity of 60 h was almost unchanged.In addition,the adsorption of CO on the catalyst poisoning properties were investigated.CO gas is adsorbed on the catalyst surface active site,which prevents the reaction gas from contacting the catalyst,leading to the deactivation of the catalyst.