Study On Modification And Properties Of Visible Light Degradation Materials

In recent years,with the rapid development of industrial production,water pollution has become more and more serious,and it has become an urgent problem to be solved.Compared with traditional sewage treatment methods,advanced oxidation technology has the advantages of low energy consumption and no secondary pollution.photocatalytic oxidation method and Fenton catalytic oxidation method have been widely studied due to the advantages of cheap and easy availability of catalytic materials and low safety toxicity.Amongmanysemiconductorphotocatalyticmaterials,semiconductor TiO₂ is regarded as one of the ideal photocatalytic materials due to its non-toxicity,strong oxidizing ability,high catalytic activity and good stability.However,TiO₂ has some disadvantages such as wider band gap and the higher recombination rate of the photogenerated electrons and holes.In the Fenton catalytic oxidation method,the homogeneous Fenton oxidation method has a narrow pH range and is easy to generate sludge to cause secondary pollution.In order to overcome the shortcomings of the homogeneous Fenton oxidation method,heterogeneous Fenton oxidation method catalyzed by solid iron-based catalysts such as FeS₂ have received increasing attention.Based on the problems of photocatalytic materials,TiO₂ and FeS₂,we mainly have done following research:?1?Preparation of Ti³⁺self-doped TiO₂ by carbothermal reduction.The effects of calcination temperature and the relative content of titanium dioxide and carbon powder on the photocatalytic degradation activity of modified titanium dioxide were investigated using RhB as a simulated degradation product.The modified TiO₂ photodegradation catalyst was characterized by XRD,Raman,TEM,SEM,UV-vis,BET,XPS and EPR.The results show that the Ti³⁺self-doped TiO₂ catalyst has the best degradation activity for RhB when the molar ratio of TiO₂ to carbon powder is 1:0.5 and the calcination temperature is 600°C,the degradation efficiency is as high as 97.6%in 120 min.?2?Pyrite FeS₂ was synthesized by hydrothermal method using sodium thiosulfate pentahydrate,ferrous sulfate heptahydrate and sulfur powder as raw materials.The photocatalytic degradation of RhB by FeS₂under visible light and the effects of different reaction conditions such as H₂O₂ dosage,pH and inorganic compounds on the degradation of RhB were also studied.The main active oxygen species and the amount of iron ions leached in the heterogeneous Fenton reaction catalyzed by FeS₂ were systematically studied.The results show that when the amount of H₂O₂ is0.5mL,and under acidic conditions,it is more favorable for the FeS₂/H₂O₂ Fenton reaction system to degrade RhB.?3?The SiO₂ base sphere was selected as the carrier and modified by3-mercaptopropyl trimethoxysilane.The modified SiO₂ basal sphere was added during the hydrothermal synthesis of FeS₂ to prepare the supported FeS₂ catalyst.The effects of different concentrations of mercaptosilane on FeS₂ loading were also investigated,and the stability of supported FeS₂catalysts was evaluated.The results show that supported FeS₂ can effectively reduce the leaching of Fe²⁺and Fe³⁺and accelerate the effective circulation of Fe²⁺/Fe³⁺,thus increasing the repeatability of supported FeS₂.