Study on Lanthanum Modification of Fly Ash and the Performance of Phosphorus Adsorption in Water
Lanthanum-modified fly ash(La-FA)was prepared by mixing fly ash with potassium carbonate and impregnating lanthanum nitrate.It was characterized by various means and used in the adsorption of phosphorous-containing wastewater.The surface of La-FA has many pores and more adsorption sites and hydroxyl functional groups,and the content of silicon and aluminum was increased to facilitate the adsorption of phosphorus.The increase in pH caused the potential of the La-FA surface to gradually decrease,and its zero potential has a pH of 5.8.The adsorption results showed that when the initial phosphorus mass concentration was 30 mg/L,the temperature was 20℃ ,the solution pH was 4.1,the La-FA dosage was 2 g/L,and the adsorption time was 20 min,the phosphorus removal rate reached 98% ,and the adsorption capacity was 24.13 mg/g.The adsorption process of La-FA on phosphorus can be divided into three stages,which conform to the Langmuir isothermal adsorption model and quasi-secondary kinetic model,the adsorption can be carried out spontaneously,the reaction process is endothermic,and the adsorption mechanism is ion exchange.
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