| Dye is a typical pollutant in the field of textile industry,food industry and cosmetics production and so on, azo dyes are widely used in fiber, silk, nylon, wool and leather dyeing, which is characterized by complex composition, color and high biodegradability poor, difficult to degrade. Physico-chemical and biochemical methods are usually used in dye wastewater treatment, but these methods can mainly make the pollutant separate, concentrate, or transfer to another phase, which is difficult to really achieve the purpose of the destruction of pollutants, also easy to cause secondary pollution, operating costs are relatively high.Photocatalytic oxidation degrades the organic matter by generated strong oxidizing free radicals, eventually producing CO2 and water, inorganic small molecule, the reaction is complete, the device is simple and without secondary pollution. In this paper, azo dye Acid Red B was used as the research object, using modified diatomite- Photocatalytic Oxidation was used to process dye, including the following five areas:(1) When modified diatomite was used to degrade Acid Red B simulated dye wastewater, the diatomite modified through 4mmol/L sulfuric acid and 10% CTMAB had the best dye adsorption effect. The optimal reaction conditions were: initial concentration of dye wastewater was 100mg/L, the dosage of compound modified diatomite was 10g/L,the reaction time was 4.5h, the reaction temperature was 20℃, chroma and COD removal rate reached respectively 73.6% and 64.4%.(2) Prepared the TiO2 supported catalyst by sol-gel method,determined the optimum load condition through the study of sol pH,calcination temperature, load times and other main factors, and supported catalyst prepared in the best conditions was characterized through XRD,EDS and SEM analytical methods.(3) Load type catalyst was used for photocatalytic oxidation experiment, the optimal reaction conditions were determined through the orthogonal experiment: Acid Red B dye wastewater simulated concentration was 100mg/L, dosage of supported diatomite was 1g/L, p H was 3, the reaction time was 2h, this time chroma and COD removalreached respectively 90.1% and 81.1%.(4) It was known through the study of photocatalytic reaction kinetics, the reaction of TiO2/Diatomite photocatalytic degrading of acid red B simulated dye wastewater was consistent with Langmuir-Hinshelwood kinetic model. At lower concentrations of acid red B analog dye solution, photocatalytic degradation experiments were consistent with first order reaction kinetics equation, along with simulated dye Acid Red B initial concentration increased, the reaction rate constant declined. At higher concentrations of acid red B analog dye solution,photocatalytic degradation experiments were consistent with zero order kinetics equation.(5) Together used Fenton-like reagent and TiO2/diatomite supported catalyst to degrade simulated Acid Red B dye wastewater, the optimal reaction conditions: dosage of supported catalyst was 0.8g/L, the initial concentration of the dye was 100mg/L, dosage of H2O2 was 6mmol/L,dosage of Fe3+ was 0.15mmol/L, p H was 4, illumination time was 1h,chroma and COD removal reached respectively 98.8% and 92.5%. It was known through comparing the results of different experimental systems for degradation of dyes, the degradation effect of acid red B dye wastewater simulation of UV-Fenton-like-TiO2/diatomite system was better than UV-Fenton-like and UV-TiO2/diatomite system. The innovations in this paper cover the following: investigated the feasibility of using sulfuric acid and CTMAB to modify diatomite, and explored the optimal conditions of using sulfuric acid and CTMAB to modify diatomite, deeply studied the effect and influencing factors of compound modified diatomite degrading Acid Red B. Used composite modified diatomite as carrier, prepared the TiO2/ composite modified diatomite supported photocatalyst, and studied the treatment effect of union between Fenton-like reagent and supported catalyst to degrade dye wastewater. |
PDF Full Text Request