Research On Removal Of Organic Pollutants In Water By Fly Ash

Fly ash is waste discharged from coal-fired power plants.Disorderly management and stacking will pollute the environment.However,since fly ash contains Fe,Si,Al elements and their corresponding oxide components,and the specific area of fly ash is relatively large,these characteristics determine that fly ash can be used for wastewater treatment.Among the water pollutants,there are many kinds of dyes,some of which are difficult to degrade organic matter,so the treatment of dye wastewater has become a hot research topic.In this paper,the original fly ash of four different power plants was selected to adsorb the chrome black T,neutral red and methyl orange dyes in water,and the effects of different experimental conditions on the adsorption of dyes by fly ash were discussed.In addition,in order to further improve the performance of fly ash adsorption dyes,according to the specific adsorption effect of fly ash,the fly ash is modified in a targeted manner,including acid modification,alkali modification and surface modification.The kinetic analysis and adsorption isotherm analysis of the process of dye adsorption of fly ash before and after modification were carried out.Through experimental research,the following conclusions are obtained: the four original fly ash have different adsorption effects on the three dyes,and t he adsorption effect on neutral red is the best,the chrome black T is the second,and the methyl orange effect is the worst;the original powder The adsorption of chrome black T and methyl orange in coal ash is better in acidic environment,and the effect of adsorbing neutral red in alkaline environment is better;the increase of temperature is not conducive to the adsorption of dye by original fly ash.After different modification methods,the adsorption effects of the three dyes were improved;the adsorption effect of the modified fly ash was affected by the temperature,the dosage of fly ash and the initial concentration of the dye.The kinetic analysis of fly ash before and after modification was carried out.The experimental data were fitted by Lagergr en first-order adsorption rate equation,Lagergren second-order adsorption rate equation and Weber-Morris intra-particle diffusion equation,and the original pulverized coal of different power plants was found.The three dyes adsorbed by ash are more consistent with Lagergren’s second-order adsorption kinetics.The TFA adsorption of chrome black T also conforms to the diffusion kinetics of Weber-Morris particles.The modified C/TFA adsorbs methyl orange for three adsorption rate equations.With better correlation,the adsorption process is more complicated but facilitates the adsorption.The linear fitting of the Langmuir isotherm equation and the Freundlich isotherm equation for the dye adsorption process of fly ash before and after modification was carried out.It was found that the experimental data is more consistent with the Langmuir adsorption isotherm equation.The resource utilization and reuse of fly ash have obvious social and environmental significance.In this paper,the adsorption process of fly ash with different dyes from different sources is discussed,and the modification method is studied to save the adsorbent in the actual adsorption process.Improving the adsorption efficiency provides a theoretical basis.