Study On The Treatment Process Of Fluorine Wastewater In Thermal Power Plant

Fluoride produced in the process of industrial production will be discharged into the atmosphere,water and soil to produce secondary pollution.The treatment of fluorine-containing waste has always been the focus of people’s research.Hwever,the fluorine-containing waste water from thermal power plants has not been widely concerned,which has the characteristics of large emission and interference.In this paper,the discharge standard of fluorine-containing wastewater in thermal power plant is taken as the research goal,and the process technology route of chemical precipitation and adsorption is established by using simulated wastewater experiment.The process conditions of chemical precipitation process and adsorption process are optimized respectively with fluorine ion removal rate as the inspection index,and the suitable process conditions are preliminarily established,and the thermodynamics and kinetics of adsorption process are fitted.The results are as follows:1.The suitable technological conditions of chemical precipitation method were established:Calcium chloride was selected as precipitant,p H was 10,molar ratio of Ca²⁺/F^-was 1.5,stirring speed was 400 r/min,reaction time was 40 min,and reaction temperature was 30℃.After treatment,the fluoride concentration decreased from 600 mg/L to 8.92 mg/L,and the removal rate was 98.51%.2.The optimum technological conditions of adsorption process were established:Through the comparison of fly ash,cellulose,alumina and their modified materials and two kinds of adsorbents,2^#rare earth materials were selected as adsorbents.The optimal dosage was 1 g/L,p H was 5,adsorption temperature was 25℃,and adsorption equilibrium was basically reached after 24 h.After treatment,the fluoride concentration decreased from 20 mg/L to 1.27 mg/L,the adsorption capacity was 18.73 mg/g,and the removal rate was 93.66%.3.The adsorption isotherm equation and kinetics of 2^#rare earth materials were studied.The results show that the adsorption process conforms to the Langmuir adsorption isotherm model,and the separation factors R_Lare less than 1,indicating that the adsorption reaction is easy to occur.The adsorption process was fitted by the intra particle diffusion model,pseudo first-order and pseudo second-order kinetic models,respectively.The results showed that the adsorption process was in line with the pseudo second-order kinetic model,and R²was greater than 0.9876.