Lanthanum-doped magnesium ferrite composite material and preparation method and application thereof

Abstract

The invention discloses a lanthanum-doped magnesium ferrite composite material. A preparation method of the lanthanum-doped magnesium ferrite composite material comprises the following steps: (1) adding Fe3O4, magnesium chloride and lanthanum nitrate into water, and uniformly mixing to form a mixed solution, wherein the molar ratio of Fe3O4 to Mg<2+> to La<3+> is 2: 1: 1-8, preferably 2: 1: 7, and(2) adding a NaOH solution to enable the pH value of the solution to be greater than or equal to 10, reacting, and after the reaction is finished, separating out the product to obtain the lanthanum-doped magnesium ferrite composite material which is named as La@MgFe2O4. The invention discloses the lanthanum-doped magnesium ferrite composite material which can be used for adsorbing/removing phosphorus in sewage, has a high adsorption capacity for phosphate, is not influenced by coexisting anions in natural water, has a wide pH application range and a wide temperature application range (when the temperature is reduced to 10 DEG C, the adsorption capacity is almost the same as that at 25 DEG C), is slightly influenced by the temperature, can be recycled for multiple times, and can be separated by using a magnet.

Description

technical field [0001] The present invention relates to lanthanum doped magnesium ferrite composite material and its preparation method and application, Background technique [0002] Phosphorus is an important element in human industrial and agricultural life. However, due to the excessive exploitation of phosphorus and the massive discharge of phosphorus-containing sewage in recent years, the shortage of phosphorus resources and the eutrophication of water bodies and the proliferation of algae have been caused. Therefore, the recovery of phosphorus in water is crucial to reduce water pollution and alleviate the shortage of phosphorus resources. So far, a variety of treatment technologies have been developed to remove or recover phosphate in water, including chemical precipitation, membrane separation, and adsorption, etc. Among them, the adsorption method is an effective method for removing anions in water because of its simple operation, low pollution, and reproducibility....

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Problems solved by technology

Moreover, the existing ferrite-related adsorbents have low adsorption capacity for phosphate, and most of the optimal adsorption capacity occurs in an acidic environment with a pH of 2 to 5, while it is neutral to natural water. Adsorbents with higher adsorption capacity under ambient conditions have been somewhat understudied

In addition, existing research focuses on the temperature range of 15-40°C, while the water temperature of urban sewage plants in northern China is about 10°C in cold seasons, which is impractical for deep phosphorus removal of sewage plant effluent in cold seasons

In addition, the optimal adsorption capacity obtained in the current research takes a long time, that is, the adsorption speed is slow, which is not economical whether it is applied to the low phosphorus concentration effluent at the end of the sewage plant or the pre-process of phosphorus recovery.

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