Study On Performance Of Flyash And Its Modified Treatment Of Quinoline Wastewater

Coal fly ash is mainly solid waste discharged from coal-fired thermal power plants,and it is also a porous spherical fine particle with a certain surface area and activity.In recent years,fly ash has been increasingly used in the field of wastewater treatment.This project uses fly ash from Qingdao Thermal Power Plant to perform adsorption experiments on typical nitrogen-containing heterocyclic organics quinoline in coal chemical wastewater.At the same time,in order to improve the utilization of fly ash,the raw material fly ash is modified to obtain a modified fly ash catalyst.Applying catalyst to wet hydrogen peroxide catalytic oxidation system to explore the kinetics and reaction mechanism of its catalytic degradation of quinoline wastewater,This study describes the investigation into the intrinsic adsorption properties of raw coal fly ash toward quinoline in the aqueous solution.The effects of reaction time,reaction temperature,pH value,and amount of adsorbent on the ability of raw material fly ash to remove quinoline were investigated.The results show that the amounts of adsorbed quinoline increase with the increment of initial quinoline concentration and contact time.The potential adsorption mechanism and rate-determining steps were illustrated by analyzing adsorption equilibrium with Langmuir,Freundlich and RedlichPeterson isotherm models and correlating the experimental results with several kinetic models.It was noticeable that the adsorption process experiences an initial rapid and a subsequent slow uptake stages.Moreover,the adsorption of quinoline on coal fly ash complies with the pseudo-second-order kinetics,and the adsorption isotherm is well described by the Langmuir adsorption model.The raw material fly ash was modified.The raw material fly ash and sodium hydroxide solution are mixed uniformly,and put into a microwave reactor for alkali melting treatment with a certain microwave irradiation power.A metal salt solution was added dropwise to the mixture,and then hydrothermally crystallized,washed,dried,and calcined to obtain a modified fly ash catalyst.The optimum preparation conditions were determined,The load of copper and iron components is 5 wt%each,the hydrothermal crystallization time is 12 h and the calcination temperature of 400?.For a typical degradation experiment,the catalyst with specific amount was added to a 500 mL solution containing quinoline?50 mg/L?with magnetic stirrer,the solution was stirred at 80?.The reaction was initiated at the time of oxidants adding?without pH adjustment,pH 7±0.2?.The typical concentrations of H₂O₂ and catalyst are 30 mM and0.5 g/L,respectively.Total reaction time was fixed at 120 min,the degradation rate of quinoline can reach 96.4%.The modified fly ash catalyst has a good effect in degrading quinoline simulated wastewater in a wet peroxide oxidation system.The kinetic analysis of quinoline degradation was carried out,the degradation kinetics of quinoline were in line with pseudo-first order reaction kinetics.