Doped CaFe2O4@alpha-Fe2O3 heterojunction composite photocatalyst, and preparation method and applications thereof

Abstract

The invention discloses a doped CaFe2O4@alpha-Fe2O3 heterojunction composite photocatalyst, and a preparation method and applications thereof. According to the preparation method, converter sludge is subjected to hydrochloric acid acidolysis so as to transfer metal ions such as Fe, Ca, Al, Mg, and Mn in converter sludge into an obtained acidolysis liquid, insoluble substances are removed via filtering so as to obtain an acidolysis solution, a certain amount of sodium oxalate is added so as to obtain a mixed solution, and the mixed solution is subjected to hydrothermal reaction, room temperature secondary precipitation, and short time heat treatment so as to obtain a finished product. The component elements of the doped CaFe2O4@alpha-Fe2O3 heterojunction composite photocatalyst all come from converter sludge, no chemical reagent raw material is added, a problem in the prior art that raw materials all come from a plurality of chemical reagents is solved, preparation cost is reduced, a novel method used for high additional value utilization of iron containing metallurgical dust is provided, the obtained doped CaFe2O4@alpha-Fe2O3 heterojunction composite photocatalyst possesses excellent photocatalytic activity and recycling performance, and can be used for photocatalytic degradation of organic dye pollutants in waste water.

Description

technical field

[0001] The invention belongs to the technical field of photocatalyst preparation, and in particular relates to a preparation of doped CaFe from converter sludge. 2 o 4 @α-Fe 2 o 3 Methods and applications of heterojunction composite photocatalysts. Background technique

[0002] The solid waste generated in the iron and steel metallurgy process contains more Fe, Ca and various valuable metal elements, and is a secondary resource with high resource endowment. However, the current disposal methods are mostly disposal or low value-added utilization, resulting in It is a great waste of resources, so the development of high value-added utilization new technologies for such secondary resources is an urgent need for technological upgrading of the metallurgical industry, realization of mineral resource recycling, and sustainable development. Steelmaking converter sludge is the iron-containing dust collected through the wet dust removal process in the converter ste...

Examples

Embodiment 1

[0031] (1) Take 20 g of dried and ground converter sludge (wherein the mass percentage of TFe is 56.5%, and the mass percentage of CaO is 12.5%), add it to 200 mL of HCl solution with a concentration of 3 mol / L, and stir the acid in a water bath at 70 ° C. Decompose for 1 hour, stirring at a speed of 500 rpm, let the reacted solid-liquid mixture stand at room temperature for 10 hours, filter out insoluble matter to obtain a clear acid solution, and detect the concentration of Fe ions and Ca ions in the acid solution.

[0032] (2) Pour the acid solution obtained in step (1) into a beaker, add 5 mL of 30% hydrogen peroxide dropwise, stir for 1 h in a water bath at 70° C., add 40 g of sodium oxalate and continue stirring for 1 h to obtain a clear mixed solution.

[0033] (3) In the mixed solution of step (2), dropwise add NaOH solution with a concentration of 1mol / L to adjust the pH to 5, stir for 0.5h and then move it into the reaction kettle, heat water at 150°C for 8h, and cool...

Embodiment 2

[0038] (1) Take 20 g of dried and ground converter sludge (the mass percentage of Tfe is 56.5%, and the mass percentage of CaO is 12.5%), add it to 170 mL of HCl solution with a concentration of 3.5 mol / L, and stir in a water bath at 80 °C Acid hydrolysis for 2 hours, with a stirring speed of 400 rpm. The reacted solid-liquid mixture was allowed to stand at room temperature for 15 hours, and the insoluble matter was filtered off to obtain a clear acid solution. The concentrations of Fe ions and Ca ions in the acid solution were detected.

[0039] (2) Pour the acid solution prepared in step (1) into a beaker, add 5 mL of 30% hydrogen peroxide dropwise, stir for 0.5 h in a water bath at 80°C, add 40 g of sodium oxalate and continue stirring for 2 h to obtain a clear mixed solution .

[0040] (3) Add KOH solution with a concentration of 0.5mol / L dropwise to the mixed solution in step (2) to adjust the pH to 4.5, stir for 1 hour, then move it into the reaction kettle, heat it in w...

technical field

[0001] The invention belongs to the technical field of photocatalyst preparation, and in particular relates to a preparation of doped CaFe from converter sludge. 2 o 4 @α-Fe 2 o 3 Methods and applications of heterojunction composite photocatalysts. Background technique

[0002] The solid waste generated in the iron and steel metallurgy process contains more Fe, Ca and various valuable metal elements, and is a secondary resource with high resource endowment. However, the current disposal methods are mostly disposal or low value-added utilization, resulting in It is a great waste of resources, so the development of high value-added utilization new technologies for such secondary resources is an urgent need for technological upgrading of the metallurgical industry, realization of mineral resource recycling, and sustainable development. Steelmaking converter sludge is the iron-containing dust collected through the wet dust removal process in the converter ste...

Examples

Embodiment 1

[0031] (1) Take 20 g of dried and ground converter sludge (wherein the mass percentage of TFe is 56.5%, and the mass percentage of CaO is 12.5%), add it to 200 mL of HCl solution with a concentration of 3 mol / L, and stir the acid in a water bath at 70 ° C. Decompose for 1 hour, stirring at a speed of 500 rpm, let the reacted solid-liquid mixture stand at room temperature for 10 hours, filter out insoluble matter to obtain a clear acid solution, and detect the concentration of Fe ions and Ca ions in the acid solution.

[0032] (2) Pour the acid solution obtained in step (1) into a beaker, add 5 mL of 30% hydrogen peroxide dropwise, stir for 1 h in a water bath at 70° C., add 40 g of sodium oxalate and continue stirring for 1 h to obtain a clear mixed solution.

[0033] (3) In the mixed solution of step (2), dropwise add NaOH solution with a concentration of 1mol / L to adjust the pH to 5, stir for 0.5h and then move it into the reaction kettle, heat water at 150°C for 8h, and cool...

Embodiment 2

[0038] (1) Take 20 g of dried and ground converter sludge (the mass percentage of Tfe is 56.5%, and the mass percentage of CaO is 12.5%), add it to 170 mL of HCl solution with a concentration of 3.5 mol / L, and stir in a water bath at 80 °C Acid hydrolysis for 2 hours, with a stirring speed of 400 rpm. The reacted solid-liquid mixture was allowed to stand at room temperature for 15 hours, and the insoluble matter was filtered off to obtain a clear acid solution. The concentrations of Fe ions and Ca ions in the acid solution were detected.

[0039] (2) Pour the acid solution prepared in step (1) into a beaker, add 5 mL of 30% hydrogen peroxide dropwise, stir for 0.5 h in a water bath at 80°C, add 40 g of sodium oxalate and continue stirring for 2 h to obtain a clear mixed solution .

[0040] (3) Add KOH solution with a concentration of 0.5mol / L dropwise to the mixed solution in step (2) to adjust the pH to 4.5, stir for 1 hour, then move it into the reaction kettle, heat it in w...

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