Research Of Preparation And Properties Visible-Light Catalyst Bismuth Vanadate

With the development of the social economy, the energy consumption and environmental pollution problems are increasingly serious, the use of a variety of effective means to control environmental pollution was imminent. In more and more governance approach, photocatalytic technology in air purification, wastewater treatment, disinfection sterilization, and other fields of research and application have been paid much attention by people. Use of photocatalyst to degradation of organic pollutants can get effective treatment, at the same time is not easy to bring secondary pollution. Bismuth vanadate as a new type of visible light responding semiconductor photocatalytic materials, because the band gap has a relatively narrow, and the advantages of high visible light catalytic activity and is a major concern. Therefore, bismuth vanadate photocatalytic material has good application prospect.This study Bi (NO3)3·5H2O and NH4VO3 as raw material, using water thermal method under the condition of different temperatures and different pH series BiVO4 was prepared, using SRD, SEM, UV-Vis DRS characterization of its structure performance, with methylene blue as the simulation test the BiVO4 visible light catalytic activity. Discussed the different temperature, different pH of bismuth vanadate crystal structure and catalytic performance of research, finally under the condition of bismuth vanadate catalysis for 2-chloro benzoic acid degradation of visible light has carried on the preliminary study.Results show that hot water temperature, the reaction liquid pH of bismuth vanadate crystal structure has great influence. Temperature is 180 ℃, the reaction of the pH of 5 in preparation of bismuth vanadate in aeration and catalyst dosage is 1.5 g/L its degradation efficiency is best. XRD and SEM analysis showed that pH= 5, the sample of patch pure monoclinic phase BiVO4, pH=2-4 and pH=7-9 preparation is monoclinic phase and phase of mixed phase BiVO4, indicates that under the condition of different pH BiVO4 sample preparation markedly different crystal structure, the overly acidic or basic conditions are not conducive to monoclinic crystal BiVO4 generated. Methylene blue light degradation of the experimental results show that the pH of 5 when preparation of BiVO4 best catalytic effect of methylene blue solution, visible light degradation of 4 hours after the degradation rate is as high as 72%, and the pH value is 2,4 and 9 BiVO4 visible light catalytic degradation of methylene blue rate less than 20.0%, the preparation of solution pH value significantly impact BiVO4 shows visible light catalytic activity. Using the best conditions (aqueous solution, pH=5,T=180 ℃) preparation of bismuth vanadate degradation of refractory material 2-chloro benzoic acid, one of the best degradation effect is about 40%. Ionic liquid preparation bismuth vanadate and doping rare earth elements in the preparation of catalytic properties of bismuth vanadate were common preparation bismuth vanadate catalytic performance is good.