Study On The Treatment Of DMF Wastewater By Fly Ash Loaded Metal Doped NanoTiO₂Catalyst

In this paper, based on the characteristics of fly ash and TiO2, fly ash/vanadium-TiO2composite was prepared by sol-gel method with easy recycling and high efficiency. Used some different test technologies, such as XRD, UV-VIS/DRS, TEM, SEM, XPS to research its structure, composition and light absorption. With toxic and difficult to degradation of Dimethyl Formamide (DMF) for pollutants, the catalytic activity and catalytic degradation photoelectric effect of compound material were studied under three dimensional electrode assistance. The preparation and reaction conditions made a detailed analysis, and established the light catalytic reaction, electrochemical catalytic reaction and the photoelectric catalytic reaction dynamics equation and the correlation coefficient. Research shows that:1. Composite material mineral phase was changed with different temperature, from amorphous to anatase to rutile.The TiO2was firmly loaded on fly ash, vanadium in the form of V4+, V5+into the TiO2lattice, composite materials not only in the ultraviolet area at230～360nm have the absorption peak, but also in the visible area at400-800nm also have a strong absorption peak; And due to fly ash good adsorption performance, vanadium ion restrain the role of light born electronic and hole compound so that the photocatalysis has strong effect of degradation.2. Through the researching we got the best photocatalytic reaction conditions:DMF concentration50mg/L, triple loading layers, vanadium doping quantity for1wt%, calcination2hours under500℃, catalyst dosage2.5g/L, pH=3, degradation180minutes reach the removal rate of88.5%.3. Three dimensional particle electrode can increase the electrode surface area, shorten the moving distance of the particle pollution, reduce the concentration polarization, increase effective utilization rate of the electrolysis pool space, and improve the current efficiency, This paper combined the characteristic of three dimension electrode and the photocatalytic degradation, and through the combination achieved photoelectric collaborative catalytic reaction. Its best degradation conditions:the initial concentration of DMF with50mg/L, slot voltage with16V, the distance of plate with6cm, pH=3, particle electrode (the prepared TiO2composite photo catalyst) with2.5g/L, electrolyte Na2SO4with3g/L, and reaction to90minutes removal rate can amount to98.5%.4. According to the removal concentration of DMF, the dynamics equation and related coefficient were confirmed:composite particle photocatalytic degradation of50mg/LDMF kinetics reaction is first-order reaction, equation is y=0.0148x+0.4820, the correlation coefficient for R=-0.9959; three dimensional particle electrode electrochemical catalytic degradation of50mg/LDMF kinetics reaction is zero-order reaction, equation is y=0.0036 x+1.0914, the correlation coefficient for R=-0.9931; three dimensional particle electrode photoelectric collaborative catalytic degradation of50mg/LDMF kinetics reaction is zero-order reaction, equation is y=0.01609x+1.4241, the correlation coefficient for R=-0.9970.