The Preparation And Catalytic Degradation Properties Of The Photocatalytically Promoted Heterogeneous Fenton-like Catalysts

The main research work of this paper is to combine photocatalytic oxidation technology and heterogeneous Fenton oxidation technology to degrade the organic dye rhodamine B.This combination not only can improve the efficiency of the degradation of organic dyes but also can recycle the catalyst,widen the pH range of catalyst and reduce the cost.Based on the research status of water treatment technology,this paper has carried out the following three aspects of research work.In the second chapter of this paper,the photocatalyst g-C₃N₄ and reduced graphene oxide?rGO?with strong electron transport capacity were selected to combine with the?-FeOOH.Firstly,g-C₃N₄/rGO was prepared through combined the g-C₃N₄ and GO by ultrasonic and high temperature calcination,then loaded?-FeOOH into the g-C₃N₄/rGO by oil bath method,finally the?-FeOOH/g-C₃N₄/rGO with different mass fraction of?-FeOOH was prepared.The catalytic activities of composite catalyst were evaluated by degrading organic dye rhodamine B?RhB?in the presence of visible light and H₂O₂?photocatalytically promoted Fenton?.It can be found that the photocatalytically promoted Fenton catalytic activity of?-Fe OOH/g-C₃N₄/rGO was significantly higher than pure?-FeOOH and g-C₃N₄.The improvement of catalytic activity can be attributed to the synergistic effect between Fenton-like reaction and photocatalytic reaction.Based on these results,a possible reaction mechanism was proposed for the photocatalytically promoted Fenton-like reaction.Finally,the cyclic experiment was used to verify the stability of the?-FeOOH/g-C₃N₄/rGO.In the third chapter of this paper,Bi₂Fe₄O₉/g-C₃N₄ composite was used to degrade RhB.First,Bi₂Fe₄O₉ which have prepared through hydrothermal method was uniformly ground with melamine and transferred into an alumina crucible for calcination.Then Bi₂Fe₄O₉/g-C₃N₄ composite catalyst with different mass fraction of Bi₂Fe₄O₉ was obtained.The catalytic activities of composite catalyst was evaluated by degrading organic dye rhodamine B?Rh B?in the presence of visible light and H₂O₂.It can be found that the photocatalytically promoted Fenton catalytic activity of Bi₂Fe₄O₉/g-C₃N₄was significantly higher than pure Bi₂Fe₄O₉ and g-C₃N₄.The improvement of catalytic activity can be attributed to the synergistic effect between Fenton-like reaction and photocatalytic reaction.Based on these results,a possible reaction mechanism was proposed for the photocatalytically promoted Fenton-like reaction.Finally,the cyclic experiment was used to verify the stability of the Bi₂Fe₄O₉/g-C₃N₄.In the fourth chapter of this paper,Cu-CNK-OH was prepared by coordinating alkalinized g-C₃N₄ with Cu²⁺.Firstly,the alkaline g-C₃N₄?CNK-OH?was synthesized by calcining of the precursor KCl and NaOH with different quality,and then the Cu²⁺was combined with CNK-OH through an impregnation method to prepare Cu-CNK-OH with different copper mass fraction.The catalytic activities of composite catalyst was evaluated by degrading organic dye rhodamine B?RhB?in the presence of visible light and H₂O₂.It can be found that the photocatalytically promoted Fenton catalytic activity of Cu-CNK-OH was significantly higher than pure g-C₃N₄.The improvement of catalytic activity can be attributed to the synergistic effect between Fenton-like reaction and photocatalytic reaction.Based on these results,a possible reaction mechanism was proposed for the photocatalytically promoted Fenton-like reaction.Finally,the cyclic experiment was used to test the stability of the Cu-CNK-OH.In this thesis,we combined Fenton-like oxidation technology with photocatalytic oxidation technology and make it become a kind of new AOT,and also explored various catalytic degradation reaction under different conditions,which provide a new research idea for AOTs combination.By comparing the catalytic degradation reactions under different conditions,we found that the photocatalytically promoted Fenton-like reaction rate is bigger than the sum of Fenton-like reaction and photocatalytic reaction.It suggests that there should be a synergistic effect between Fenton-like reaction and photocatalytic reaction.Thus,the synergy between photocatalytic and Fenton-like oxidation technology can make up for the defect of single technology,and make them can further make full use of their advantages,then accelerate the catalytic degradation of organic dyes in the waste water,therefore combination of several oxidation technologies plays an important role in the field of wastewater treatment.