Study On The Catalytic Oxidation Desulfurization Performance Of Diesel Oil With Framework Heteroatomic Titanate Nanotubes Synthesized By One-step Method

Sulfur oxide（SO_X）from combustion of fuel oil will form acid rain,produce photochemical smog and pollute the environment.In recent years,catalytic oxidation desulfurization has been widely studied due to mild conditions and low equipment requirements.However,there are some problems in oxidative desulfurization such as low selectivity of catalysts,relatively difficult separation and recovery of catalysts,and low utilization rate of oxidants,especially H₂O₂.In the H₂O₂ catalytic oxidation system,titanate nanotubes catalysts not only have excellent catalytic oxidation activity,but also have good catalytic oxidation selectivity due to Ti-η¹-OOH active intermediates.The traditional method for synthesizing titanate nanotubes by organic titanium sources was a two-step method,usually the first step was to generate Ti O₂ as the synthetic intermediate,the second step was similar to the hydrothermal synthesis of titanate nanotubes by inorganic titanium sources.But in this paper,the titanate nanotubes were prepared by one-step hydrothermal method with tetrabutyl titanate after adding crystal seeds.The morphology and structure of the catalysts were characterized by a series of characterizations.Using DBT model oil to investigate the catalytic oxidation desulfurization performance of titanate nanotubes.The results showed that the removal rate of DBT was 100%when 1%Ti O₂-TBOT as crystal seed.The catalyst could still achieve deep desulfurization after being reused for 6 times.The selectivity of catalysts was investigated that the one-step titanate nanotubes had good selectivity compared with Ti O₂and traditional titanate nanotubes.The three samples were characterized and analyzed,and the adsorption energy of the two configurations of Ti-OOH for olefin was calculated.It was found that the good selectivity of one-step titanate nanotubes was related to Ti-η¹-OOH.In order to solve the problem of low H₂O₂ utilization rate,it is necessary to improve the desulfurization rate of titanate nanotubes to achieve rapid reaction.Fe-Ti NTs were prepared by one-step hydrothermal method,which achieved high desulfurization rate and lowest n（O）/n（S）.The morphology and structure of the catalysts were analyzed by a series of characterizations.Using DBT model oil to investigate the catalytic oxidation desulfurization performance of Fe-Ti NTs.The results showed that Fe-Ti NTs-1.5%catalyst still had good catalytic performance at low temperature and low n（O）/n（S）ratio.The selectivity of catalysts was investigated that Fe-Ti NTs showed good catalytic selectivity in the presence of various hydrocarbon compounds in ODS.Characterizations showed that the high activity and selectivity were driven by the mechanism of Ti-η¹-OOH mixed hydroxyl radical（·OH）.