Degradation Of DEP, P-nitroaniline And 4-nitrophenol By Photocatalysis And Associated With Fenton Method

The application of photo catalysis coupling with many other advanced oxidation processes attract many environmentalist' interesting in wastewater treatment in recent years. Because of its long reaction time, low efficiency and some other problems, the studies are still focused on the lab's field and the real application is just start. With the advantages of high speed of reaction, easy process and without second pollution of Fenton techniques, it's applying a lot but not alone because of its insufficiency degradation, high dose of oxidant and high cost.In this dissertation, Fenton system and like-Fenton system using zero valent metallic iron facilitated by photo catalysis had been developed for the degradation of bio-refractory organic contaminations in wastewater.(1) The degradation of DEP in a synergetic system of photo catalysis coupled with like-Fenton reagent was studied. The influences of operation conditions on the degradation of DEP was investigated, such as pH value, the concentration of DEP, the additional amount of Fe0 and H2O2 catalytic agent,temperature and the UV radiation power. Structures of intermediate products and final products were detected by gas chromatography-mass spectrometry (GC/MS). The results showed that the degradation rate reached 86% after treated for 1 hour with photo catalysis/Fenton technique, Moreover,80% of DEP were still degraded after reused the iron and TiO2 for 3 times, and the phenyl was decomposed to the bio-degradable substances.(2) The degradation of p-nitroaniline using zero iron metal of Fenton process facilitated by photo catalysis was studied. The influences of UV irradiation, pH value, the concentration of p-nitroaniline, the additional amount of Fe0 and TiO2, H2O2 and temperature, CH3OH were investigated. GC/MS was applied to study the degradation pathways. The results showed that pH play an important role in the degradation. P-nitroaniline can not be reacted under the basic condition. The results showed that the degradation rate reached 80% after treated for 14min with photo catalysis/Fenton technique. Moreover,80% of p-nitroaniline were still degraded after reused the iron and TiO2 for 3 times.(3) The degradation of 4-nitrophenol using Fenton process assisted by photo catalysis was studied. The influences of different impact factors such as pH value, the concentration of 4-nitrophenol, the additional amount of TiO2 and H2O2 were studied in detail. Further more, hydroquinone,4-nitrocatechol, p-Benzoquinone and other intermediate products were found by GC/MS and a probable degradation mechanism was proposed.