Preparation And Degradation For Organic Pollutants Of Lanthanum Hydroxycarbonate/Indium Based Heterojunction Photocatalyst

Photocatalytic oxidation technology is widely used in the field of water pollution control due to its high efficiency and no secondary pollution.It is one of the important ways to achieve complete degradation of toxic pollutants and plays an important role in solving energy crisis and environmental pollution problems.For the better application of technology in water treatment systems,the key is to synthesize visible-light-driven photocatalysts with high-activity and stable,and the construction of heterojunction photocatalysts is one of the best effective method to achieve this effect.In this paper,based on the special electronic structures of lanthanide compounds,a series of LaCO3OH/based-In heterojunction photocatalysts were constructed.The obtained catalysts were characterized by various techniques and applied to the degradation of organic pollutants in water.The mechanism of degradation was preliminary explored.The main research work of this article is as follows:1.LaCO3OH/In(OH)3/In2S3 heterojunction photocatalyst was synthesized by two-step hydrothermal method.The composition,structure and morphology of the obtained catalyst was investigated by XRD,SEM,XPS,BET,TG and other characterization techniques.The activity of samples with different LaCO3OH content was evaluated by the degradation of Rhodamine B(RhB)under visible light(??420 nm).The results show that when the molar ratio of La/In is 15%,the sample has the highest degradation activity,and two times as high as that of In(OH)3/In2S3.This may be due to its higher surface area,suitable energy band structure and better adsorption performance.Taking terephthalic acid as a probe molecule,photocatalysis experiments was carried out and hydroxyl radical(·OH)was proved to be an important active species in the catalytic process,and the possible degradation mechanism was proposed.2.The LaCO3OH/ZnIn2S4 heterojunction photocatalyst was synthesized in two steps by the mixed solvent method.The influence of synthetic experimental parameters on the photocatalytic activity was investigated.The prepared heterojunctions were analysis by various characterization methods.The results show the prepared sample has the best catalytic activity when the amount of ethylene glycol,the compounding amount of LaCO3OH and the reaction time is 60 ml,0.5 mmol and 4 hours,respectively.And the degradation rate of methyl orange reaches 94.5%during 60 minutes.This could be attributed to its proper energy band structure,special microstructure,and interaction between components.3.The photodegradation of other water-pollutants(malachite green MG,tetracycline TC)with the LaCO3OH/ZnIn2S4 catalytic was studied.The results show that the MG and TC could be completely degraded within 100 minutes,which is related with the active radicals generated during the degradation process.And the intermediate products of MG degradation were analyzed by mass spectrometry.Combined with mass spectrometry data and activity species experiments,the degradation process and related mechanisms of MG degradation with catalysts were discussed.