Preparation Of Pyrolyzed Cobalt Phthalocyanine For Degradation Of Dyes

Recently, the water pollution has become more and more serious with the rapiddevelopment of industrialization and urbanization. China, as a big textile country, discharges theprinting and dyeing wastewater reach to millions of tons per day. Therefore, it is a big problem toefficiently address such a large number of printing and dyeing wastewater with high chromic andhigh COD. Compared with conventional treatment technology such as physical method(adsorption, membrane separation, etc.) and biological method, the evolving chemical method inrecent years on dyeing wastewater treatment has attracted more and more attention for itsthoroughness and strong oxidizing. Among them, advanced oxidation process has become a hotresearch by producing strong oxidizing species, which were efficient for substrates degradationand even mineralization. However, in actual printing and dyeing wastewater, the dye additivessuch as surfactants, metal salts, swelling agent, etc., are often the hundreds of times higher thanthe concentration of the dye. So it can be a great challenge to catalytic oxidization of lowconcentrations of dye molecules in a complex environment such large amounts of organic/inorganic compounds in actual printing and dyeing wastewater. Therefore, designing a kind ofcatalysts with selective catalytic oxidization of target pollutants efficiently can be of greatsignificance.In this thesis, pyrolysis cobalt phthalocyanine catalysts were prepared by calcination of thecobalt tetraaminophthalocyanine(CoTAPc) under atmospheric conditions, and via characterizingtests found that the composition of the heterogeneous catalysts were organic and inorganiccompound. Then selected CoTAPc calcined by410°C (CoTAPc-410) as catalyst, Acid Red G(AR1) as the target pollutant, H2O2as oxidant for catalytic degradation experiments. The resultsshow that CoTAPc-410exhbits strong catalytic oxidation ability for AR1, and in alkalineconditions shows good catalytic activity; CoTAPc-410/H2O2system degrades AR1with loweractivation energy (Ea=22.67kJ/mol), which demonstrates that temperature has a smallinfluence on catalytic oxidation; CoTAPc-410has good stability and recyclability; comparedwith the Fenton reaction, CoTAPc-410/H2O2system on the catalytic oxidation of AR1showsgood selectivity under high concentrations of NaCl, polyethylene glycol and urea; CoTAPc-410/H2O2system also shows efficient catalytic degradation ability on the other dyeswith different structures; the add of isopropanol shows promotion on AR1degradation,combined with Electron paramagnetic resonance (EPR) results, suggesting that the possiblemechanism of the catalytic oxidation was due to the generation of high-valent cobalt (Co(IV)=O)active species. Finally, the oxidation pathway of AR1was presented according to the productsdetected by ultra-performance liquid chromatography high-definition mass spectrometry and gasmass spectrometry.In order to further improve the catalytic activity, we use silica gel (SG) as carrier, loadingthe pyrolysis of CoTAPc. By characterizing tests obtain that the surface and internal pores of SGhave carried out the load, thus greatly improving the dispersibility of the catalyst. Then selectedSG loaded with CoTAPc-410(CoTAPc-410@SG) as catalyst, AR1as the target pollutant, H2O2as oxidant for catalytic oxidation experiments, the results show that the catalytic activity ofCoTAPc-410@SG has been significantly improved compared with CoTAPc-410under the samecontents of cobalt. In addition, CoTAPc-410@SG exhbits better stability and recyclabilitycompared with CoTAPc-410.