Preparation Of Bismuth-based Oxide Glass Ceramics And Its Photocatalytic Properties

The problem of water pollution and energy shortage is a major problem that restricts the development of human society in the new century.Bismuth oxide materials can photocatalyze the degradation of organic pollutants.The kind of traditional catalyze materical is nano powder and thin film.However,the nanometer powder is difficult to recycle and easy to cause secondary pollution.Photocatalytic coating is easy to fall off and the photocatalytic efficiency is low.These problems greatly restrict the practical application and development of photocatalytic materials.The glass ceramics can be easily made into various shapes and the use is greatly improved.In this paper,bismuth oxide glass ceramics were prepared by traditional melting method and the properties of photocatalytic degradation of organic pollutants were studied,which provided a new way for the preparation of photocatalytic materials.The glass ceramics with different components were obtained by using the traditional melting quenching method and the main crystal phase was obtained by proper heat treatment.The main crystal phase were Bi₄Ti₃O₁₂,BiVO₄ and Bi₂MoO₆ in glass matrix.Crystallization behavior of the prepared glass material was examined by XRD technique.The structure and morphology of the prepared materials before and after heat-treatment were monitored by Raman spectroscopy and FT-IR spectrum.Specific surface area,average pore diameter,pore volume of glass ceramics were determined by BET.Definite volumes of dye solution were sampled during the reaction and the concentrations of the dye in the samples were analyzed by UV–vis absorbency spectrophotometer.Proper heat-treatment schedule,based on differential thermal analysis（DSC）results,has been applied to improve the crystallinity of the prepared glass–ceramics.The prepared samples were used for the degradation of methylene blue in order to assess their photocatalytic activityThe main contents and conclusions are as follows.（1）The（1-x）Li₂B₄O₇-x Bi₄Ti₃O₁₂（x=0,0.1,0.2,0.3）glass ceramic was prepared by traditional melt quenched method.Proper heat-treatment schedule has been applied to improve the Bi₄Ti₃O₁₂2 crystallinity of the prepared glass–ceramics.The size of the crystals is about 20 nm.With the increase of heat treatment temperature,the content of crystal phase increased.0.7Li₂B₄O₇-0.3Bi₄Ti₃O₁₂2 glass ceramic（500℃-8h）can not remove degradation rhodamine B and methyl orange under the irradiation of simulated sunlight at x=0.3.About 8%removal of methylene blue could be achieved within 180min.（2）The（1-x）Li₂B₄O₇-xBiVO₄（x=0,0.1,0.2,0.3,0.4,0.5）glass ceramic was prepared by traditional melt quenched method.Proper heat-treatment schedule has been applied to improve the BiVO₄ crystallinity of the prepared glass–ceramics.The size of the crystals is about 18nm-25nm.With the increase of heat treatment temperature,the content of crystal phase increase.0.5Li₂B₄O₇-0.5Bi VO₄（475℃-16h）can not remove rhodamine B and methyl orange in neutral and alkaline conditions under the irradiation of simulated sunligh at x=0.5t.About 65%and 63%removal of methylene blue could be achieved within 180min.About 2%removal of methylene blue could be achieved within 180min in acid condition（3）The（1-x）Li₂B₄O₇-xBi₂MoO₆（x=0,0.1,0.2,0.3）glass ceramic was prepared by traditional melt quenched method.Proper heat-treatment schedule has been applied to improve the Bi₂MoO₆ crystallinity of the prepared glass–ceramics.The size of the crystals is about 20 nm.With the increase of heat treatment temperature,the content of crystal phase increased.0.7Li₂B₄O₇-0.3Bi₂MoO₆（475℃-16h）glass ceramic can not remove rhodamine B and methyl orange under simulated sunlight irradiation at x=0.3.About 55%removal of methylene blue could be achieved within 180min in the condition of acidic and neutral.0.7Li₂B₄O₇-0.3Bi₂MoO₆（475-16h）glass ceramic has high photocatalysis degradation activity for methylene blue.About 65%removal of methylene blue could be achieved within 180min in alkaline condition.The photocatalytic activity of 0.7Li₂B₄O₇-0.3Bi₂MoO₆（475℃-16h）glass ceramic after 30min corrosion treatment with nitric acid has obvious improvement of the degradation of the methylene blue.About 73%removal of methylene blue could be achieved within 180min.Bi₂MoO₆ glass ceramic was mixed with H₂O₂（1.67mM/L）,which had a certain degradation effect on rhodamine B（about 54%removal of methylene blue could be achieved within 180min）.