Photocatalytic Oxidation Of Sulfur In Coal By Porphyrin Derivative Sensitized Titanium Dioxide

As a traditional fossil energy source,coal is widely used in the industrial field,but combustion will release SO_x compounds and cause harm to the environment.With the increasingly strict environmental protection regulations,the efficient removal of sulfides from coal has become a research hotspot.TiO₂ has extremely important value in the fields of degrading pollutants and dye-sensitized solar cells,but it can only be excited in the ultraviolet region,which greatly affects its photocatalytic performance.Porphyrins have the advantages of being able to bind to TiO₂,have good absorption characteristics in the visible region and have high charge transport efficiency,and are often used as photosensitizers to improve the photocatalytic performance of TiO₂.In this paper,by synthesizing novel metalloporphyrin derivatives and supporting them on the surface of TiO₂,the mutual bonding and photogenerated electrons are enhanced to obtain photocatalytic materials with better performance.The research contents of this thesis are as follows:?1?The carbazole and pyrrole are reacted to p-fluorobenzaldehyde by a two-step Schiff base reaction to obtain meso-tetrakis?4-carbazole?phenylporphyrin.Synthesis of tetrakis?4-nitro?phenylporphyrin by p-nitrobenzaldehyde and pyrrole,reduction of SnCl₂ to give tetrakis?4-aminophenyl?porphyrin,and reaction with p-oxazolylbenza lde hyde to obtain meso-Tetra[p-?PN-carbazolylbenzylideneimino?]phenylporphyrin..The structure of the precursor porphyrin and the target product was analyzed by infrared spectroscopy and elemental analysis.The performance of the two carbazole porphyrins was analyzed by Uv-Vis and electrochemical properties.?2?Using butyl titanate as raw material,the target product meso-tetrakis[?4-carbazole?phenylporphyrin]?TCPP?supported titanium dioxide,meso-tetra[p-?PN-carbazole?was prepared by sol-hydrothermal method.Two kinds of composite photocatalytic materials of benzylidene imino)]phenylporphyrin?TCIPP?supported titanium dioxide.The results of scanning electron microscopy and XRD showed that the composite photocatalytic material was successfully synthesized.The porphyrin derivative was not decomposed by infrared spectroscopy and solid ultraviolet diffuse reflection,and it was successfully loaded on titanium dioxide.?3?Taking the sulfide in coal as the target catalyst,the content of sulfide in coal is determined by the Ashka method shown in the national standard?GB/T214-2007?.The effect of different photocatalysts,the amount of catalyst,the reaction temperature and time,the amount of oxidant and the pH of the reaction system on the desulfurization rate were determined by using hydrogen peroxide as the oxidant and simulating the illumination under UV light.The results show that TCIPP-TiO₂ has higher desulfurization efficiency under the same conditions;the desulfurization efficiency reaches 76.35%when the catalyst dosage is0.8g;the desulfurization efficiency is 85.90%at 45°C,and the first 30min after the reaction starts The maximum stage of desulfurization rate;when the amount of oxidant H₂O₂ is less than 25ml,the desulfurization efficiency increases with the increase of H₂O₂ dosage.When the dosage exceeds 25ml,the desulfurization rate increases little;the hydrochloric acid is added to adjust the pH of the reaction system,and the catalytic efficiency rises first and then decreases.,reached the highest at pH=3.02.