Bismuth Vanadate-Carbon Nitride Preparation And Photocatalytic Degradation Of Composite Mechanism Nitro Phenol

When this thesis, BiVO4 and graphite phase g-C3N4 photocatalytic degradation of pollutants things, the utilization of visible light is relatively weak, by this paper experiments will BiVO4 with C3N4 proportional composite, preparation of new photocatalytic materials BiVO4 / g-C3N4. By UV- visible diffuse reflectance(UV-Vis / DRS), X- ray powder diffraction(XRD), scanning electron microscopy(SEM), infrared spectroscopy(FT-IR), Xray photoelectron spectroscopy(XPS), transmission electron microscope(TEM) and other means of a series of tests, respectively BiVO4, g-C3N4 and BiVO4 / g-C3N4 structure,elemental composition, morphology and absorption of visible light range were characterized.Also studied in detail the system in the visible(400nm <λ <780nm) treated with BiVO4 /g-C3N4 photocatalyst organic pollutants nitro phenol photocatalytic degradation, through experimental results to determine the best catalyst synthesis conditions, the load ratio,investment amount, the pH of the reaction system, the initial concentration and other conditions.BiVO4 / g-C3N4 materials in visible light(400nm <λ <780nm) under the catalytic activity of a relatively high C3N4 and BiVO4 compound synthesized by one-step method(milder hydrothermal method) were prepared. Its characterization results confirmed: in the product, there is a form of block structure BiVO4 monoclinic scheelite crystals, C3N4 lamellar structure to exist and BiVO4 nanoparticles distributed on lamellar C3N4, and the gC3N4 sheet closely. Photocatalyst BiVO4 / g-C3N4 at 200-800 nm(visible region) showed a strong absorption peak,, obviously visible response. By the experimental conditions, to determine the best experimental synthesis BiVO4 conditions: at pH 6, hydrothermal temperature of 150 ℃ conditions of preparation BiVO4. Synthesis BiVO4 / g-C3N4, put into a beaker ultrasound 1 hour, then stirred one hour, and finally into the oven 80 ℃ dried for 12 hours. Degradation by the experiments, the optimal load ratio BiVO4 and g-C3N4 of: 10%BiVO4 / 90% g-C3N4 nitrophenol degradation rate has reached 91%, while 20% BiVO4 /80% g-C3N4 and 30% BiVO4 / 70% g-C3N4, BiVO4 and g-C3N4 degradation rate of PNP were: 85.84%, 71.29%, 47.46%, 51.79%. This means that only a certain percentage of the load in order to improve the catalytic activity in the visible region. Degradation by the best experimental conditions: catalyst dosage administered 1g / L, the initial concentration of nitrophenol solution is 10 mg / L, pH = 5.The main active species yielded in the g-C3N4-and BiVO4 / g-C3N4-catalyzed PNP degradation systems were also investigated by the freeradical and hole scavenging experiments. Accordingly, the photodegradation mechanism was given. And 10% BiVO4 / 90% g-C3N4 was chosen to evaluate the recyclability of the BiVO4/ g-C3N4 photocatalysts by five times’ RhB degradation reaction.