A method for preparing coated nano zero-valent iron loaded zinc-manganese-nickel composite material from phosphating slag and co-producing ammonium dihydrogen phosphate

Abstract

The present invention provides a method for preparing a coated nano-zero-valent iron-loaded zinc-manganese-nickel composite material from phosphating slag and co-producing ammonium dihydrogen phosphate. The solid waste phosphating slag is dissolved with formic acid, diluted with deionized water, and the formic acid is evaporated. The slag is transferred to an autoclave, and ammonium formate and a dispersant are added under a nitrogen atmosphere. The mixture is heated to undergo a reduction reaction. The nano-zero-valent iron-loaded zinc-manganese-nickel particles and the supernatant are separated by magnetic separation. The nano-zero-valent iron-loaded zinc-manganese-nickel particles are dispersed in ethanol, and a deionized water solution of a polymer material is added and stirred to obtain a coated nano-zero-valent iron-loaded zinc-manganese-nickel composite material. Phosphoric acid is added to the supernatant, heated for a reaction, and the formic acid is evaporated. The pH is adjusted and the mixture is concentrated to obtain ammonium dihydrogen phosphate. The coated nano-zero-valent iron-loaded zinc-manganese-nickel composite material of the present invention has good dispersibility, stability, and reactivity. The resources of the solid waste phosphating slag are rationally utilized, eliminating environmental pollution and resource waste.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical industry and environmental protection, and particularly relates to a method for preparing a coated nano zero-valent iron-loaded zinc-manganese-nickel composite material from phosphating slag and co-producing ammonium dihydrogen phosphate. Background Art

[0002] Global environmental pollution and resource shortages are becoming increasingly severe, threatening human survival. Phosphating slag is waste residue generated during the phosphating treatment of metal surfaces in the automotive, shipbuilding, military, and machinery manufacturing industries. Phosphating metal materials is an essential step in metal processing, and phosphating slag production is substantial, reaching millions of tons annually nationwide. Phosphating slag contains 15-20% iron, approximately 50% phosphate (phosphate), and 5-8% zinc. Depending on the phosphating solution used, it also contains small amounts of Mn and Ni ions and other insoluble matter. Its complex composition makes it difficult to handle, and most companies resort to dumping or landfilling it, resulting in a waste of resources, particularly non-renewable phosphorus, and severe environmental pollution. Extracting resources from phosphating slag and converting it into valuable chemical products while reducing pollution is of great significance.

[0003] Nano-zero-valent iron has shown excellent performance in solving organic pollution, heavy metal pollution and environmental pollution remediation. However, due to its magnetic attraction, nano-zero-valent iron particles are prone to agglomeration. Due to its extremely strong reducibility, it is easily oxidized, resulting in reduced activity and limited application. Most existing technologies use iron salts and NaBH4 to react to prepare nano-zero-valent iron, which is relatively expensive. Due to the combined effect of nano-iron and other metals and the interaction between the components, adding other metals to nano-zero-valent iron metal materials can enhance its reactivity, dispersibility and stability. There are no reports on the use of metals such as iron, zinc, manganese and nickel in solid waste phosphating slag to prepare zero-valent nano-iron-loaded zinc-manganese-nickel composite materials with good dispersibility, high activity and stability through reduction reaction, and converting the phosphate therein into ammonium dihydrogen phosphate, turning waste into treasure and eliminating pollution. At the same time, coating and modifying the surface of the nano-iron-loaded zinc-manganese-nickel metal composite material can further improve its stability and enhance the use effect. Summary of the Invention

[0004] The present invention addresses the shortcomings of existing technologies by providing a method for preparing a coated nano-zero-valent iron-loaded zinc-manganese-nickel composite material from phosphating slag and co-producing ammonium dihydrogen phosphate. The method is simple to operate, fully utilizes phosphating slag resources, and eliminates secondary pollution. The coated nano-zero-valent iron-loaded zinc-manganese-nickel composite material is well-suited for sewage treatment, and ammonium dihydrogen phosphate, as a chemical product, has a wide range of applications.

[0005] The technical solution of the present invention is:

[0006] A method for preparing a coated nano-zero-valent iron-loaded zinc-manganese-nickel composite material from phosphating slag and co-producing ammonium dihydrogen phosphate comprises the following steps:

[0007] The solid waste phosphating slag is dissolved by heating with formic acid, filtered to remove insoluble matter, the filtrate is diluted with deionized water, formic acid is recovered by distillation, the residual liquid is transferred to an autoclave, ammonium formate and a dispersant are added under a nitrogen atmosphere, heated to 180-190°C, reacted for 15-24 hours, cooled to room temperature, and magnetically separated from the supernatant. The nano-zero-valent iron-loaded zinc-manganese-nickel particles are washed with deionized water and ethanol respectively, dispersed in ethanol, and a deionized water solution of a polymer material is added. The mixture is stirred for 1-2 hours, magnetically separated, washed, and vacuum dried to obtain a coated nano-zero-valent iron-loaded zinc-manganese-nickel composite material; an appropriate amount of phosphoric acid is added to the supernatant, heated for reaction and distilled until no formic acid is distilled out, the pH is adjusted to 4-5 with concentrated ammonia water, and concentrated to obtain ammonium dihydrogen phosphate.

[0008] The solid waste phosphating slag, depending on the phosphating solution used, mainly contains 15-20% iron, about 50% phosphoric acid (root), 5-8% zinc, and also contains a small amount of manganese, nickel, and other insoluble substances;

[0009] The dispersant is one or more of polyethylene glycol, sodium carboxymethyl cellulose, β-cyclodextrin, water-soluble starch, and plant extract containing polyphenol active substances;

[0010] The polymer material is one or more of sodium carboxymethyl cellulose, β-cyclodextrin, water-soluble starch, polyvinyl alcohol, chitosan, and sodium polyacrylate;

[0011] The mass ratio of the solid waste phosphating slag to ammonium formate is 100:45-70;

[0012] The mass ratio of the solid waste phosphating slag to deionized water is 1:15-20;

[0013] The amount of the dispersant used is 0.5%-1.0% of the total mass of the system.

[0014] Application of the coated nano zero-valent iron loaded zinc-manganese-nickel composite material in sewage treatment.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. Comprehensively recycle and utilize solid waste phosphating slag resources to eliminate their pollution; the metal ions in the solid waste phosphating slag are reduced with ammonium formate to prepare nano-zero-valent iron composite materials loaded with zero-valent zinc, manganese, and nickel. The presence of small amounts of zinc, manganese, and nickel in the nano-zero-valent iron-loaded zinc-manganese-nickel composite materials can enhance the reactivity, dispersibility, and stability of the nano-zero-valent iron; the phosphate ions in the solid waste phosphating slag are converted into valuable ammonium dihydrogen phosphate, efficiently recovering the scarce phosphorus element; the method is simple and easy to implement, with low preparation cost, turning waste into treasure, and achieving multiple benefits in one fell swoop.

[0017] 2. The nano-ZVI-loaded Zn-Mn-Ni composite material is coated with an environmentally friendly polymer, further enhancing its reactivity, dispersibility, and stability, while also facilitating the recovery of the ZVI. The nano-ZVI-loaded Zn-Mn-Ni composite material can be stored in air for several months, facilitating storage, transportation, and practical applications.

[0018] 3. Nano-zero-valent iron loaded zinc-manganese-nickel composite materials can efficiently remove organic matter and heavy metals in sewage. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail with reference to specific embodiments, but the protection scope of the present invention is not limited to the following embodiments. Example 1

[0020] Take 100g of phosphating slag (15.7% iron, 51.5% phosphate (root), 5.2% zinc, 0.97% manganese, 1.6% nickel), add 200g formic acid, heat to dissolve, filter, remove insoluble matter, dilute the filtrate with 1.5kg deionized water, distill to recover formic acid, transfer the residual liquid to an autoclave, add 45g ammonium formate and 0.7g polyethylene glycol 3000, heat to 180-185℃ under nitrogen atmosphere, react for 24h, cool to room temperature, and separate nano zero-valent iron charges by magnetic separation. The zinc-manganese-nickel particles and supernatant, and the nano-zero-valent iron-loaded zinc-manganese-nickel particles were washed with deionized water and ethanol respectively, dispersed in ethanol, added with 10 mL of sodium carboxymethyl cellulose deionized water solution, stirred for 1 hour, magnetically separated, washed, and vacuum dried to obtain a coated nano-zero-valent iron-loaded zinc-manganese-nickel composite material, recorded as material 1; 35 g of phosphoric acid was added to the supernatant, heated to react and distilled until no formic acid was distilled out, the pH was adjusted to 4.5 with concentrated ammonia water, and concentrated to obtain ammonium dihydrogen phosphate with a purity of 98.9%. Example 2

[0021] Take 100g of phosphating slag (20% iron, 50.3% phosphate (root), 7.4% zinc, 1.3% manganese, 1.59% nickel), add 210g formic acid, heat to dissolve, filter, remove insoluble matter, dilute the filtrate with 2kg deionized water, distill and recover formic acid, transfer the residual liquid to an autoclave, add 70g ammonium formate and 1.4g sodium carboxymethyl cellulose, heat to 185-190℃ under nitrogen atmosphere, react for 20h, cool to room temperature, and magnetically separate the nano-zero-valent iron-loaded zinc-manganese-nickel particles and the supernatant. The nano-zero-valent iron-loaded zinc-manganese-nickel particles are washed with deionized water and ethanol respectively, dispersed in ethanol, and added with 10mL β -cyclodextrin deionized water solution, stirred for 2 hours, magnetically separated, washed, and vacuum dried to obtain a coated nano-zero-valent iron loaded zinc-manganese-nickel composite material, recorded as material 2; 54 g of phosphoric acid was added to the supernatant, heated for reaction and distilled until no formic acid was distilled out, concentrated ammonia water was used to adjust the pH to 4.6, and concentrated to obtain ammonium dihydrogen phosphate with a purity of 99.0%. Example 3

[0022] Take 100g of phosphating slag (17.9% iron, 51.0% phosphate (root), 6.1% zinc, 1.21% manganese, 1.66% nickel), add 210g formic acid, heat to dissolve, filter, remove insoluble matter, dilute the filtrate with 2kg deionized water, distill and recover formic acid, transfer the residual liquid to an autoclave, add 55g ammonium formate and 1.1g water-soluble starch, heat to 185-190℃ under nitrogen atmosphere, react for 15h, cool to room temperature, and separate nano-zero-valent iron loaded zinc by magnetic separation. The manganese-nickel particles and supernatant, and the nano-zero-valent iron-loaded zinc-manganese-nickel particles were washed with deionized water and ethanol, respectively, dispersed in ethanol, and 15 mL of a water-soluble starch deionized water solution was added. The mixture was stirred for 2 h, magnetically separated, washed, and vacuum-dried to obtain a coated nano-zero-valent iron-loaded zinc-manganese-nickel composite material, recorded as material 3. 42.5 g of phosphoric acid was added to the supernatant, heated to react, and distilled until no formic acid was distilled out. The pH was adjusted to 4.8 with concentrated ammonia water, and the mixture was concentrated to obtain ammonium dihydrogen phosphate with a purity of 99.4%. Example 4

[0023] Take 100g of phosphating slag (15.7% iron, 51.5% phosphate (root), 5.2% zinc, 0.97% manganese, 1.6% nickel), add 210g formic acid, heat to dissolve, filter, remove insoluble matter, dilute the filtrate with 1.8kg deionized water, distill to recover formic acid, transfer the residual liquid to an autoclave, add 60g ammonium formate and 9g green tea extract, heat to 180-185℃ under nitrogen atmosphere, react for 24h, cool to room temperature, and separate nano-zero-valent iron loaded zinc by magnetic separation. The manganese-nickel particles and supernatant, and the nano-zero-valent iron-loaded zinc-manganese-nickel particles were washed with deionized water and ethanol, respectively, dispersed in ethanol, and 10 mL of polyvinyl alcohol deionized water solution was added. The mixture was stirred for 1.5 h, magnetically separated, washed, and vacuum dried to obtain a coated nano-zero-valent iron-loaded zinc-manganese-nickel composite material, recorded as material 4; 40 g of phosphoric acid was added to the supernatant, heated to react and distilled until no formic acid was distilled out, the pH was adjusted to 4.7 with concentrated ammonia water, and the mixture was concentrated to obtain ammonium dihydrogen phosphate with a purity of 99.1%. Example 5

[0024] Take 100g of phosphating slag (20% iron, 50.3% phosphate (root), 7.4% zinc, 1.3% manganese, 1.59% nickel), add 205g formic acid, heat to dissolve, filter, remove insoluble matter, dilute the filtrate with 1.8kg deionized water, distill to recover formic acid, transfer the residual liquid to an autoclave, add 60g ammonium formate and 1g β -cyclodextrin, heated to 180-185°C under a nitrogen atmosphere, reacted for 24 hours, cooled to room temperature, and magnetically separated the nano-zero-valent iron-loaded zinc-manganese-nickel particles and the supernatant. The nano-zero-valent iron-loaded zinc-manganese-nickel particles were washed with deionized water and ethanol, respectively, dispersed in ethanol, and 10 mL of sodium polyacrylate deionized water solution was added. The mixture was stirred for 1.5 hours, magnetically separated, washed, and vacuum dried to obtain a coated nano-zero-valent iron-loaded zinc-manganese-nickel composite material, recorded as material 5; 43 g of phosphoric acid was added to the supernatant, heated to react and distilled until no formic acid was distilled out, concentrated ammonia water was used to adjust the pH to 4.6, and concentrated to obtain ammonium dihydrogen phosphate with a purity of 99.2%. Example 6

[0025] Take 100g of phosphating slag (17.9% iron, 51.0% phosphate (root), 6.1% zinc, 1.21% manganese, 1.66% nickel), add 205g formic acid, heat to dissolve, filter, remove insoluble matter, dilute the filtrate with 2kg deionized water, distill to recover formic acid, transfer the residual liquid to an autoclave, add 60g ammonium formate and 0.8g sodium carboxymethyl cellulose, heat to 185-190℃ under nitrogen atmosphere, react for 24h, cool to room temperature, and separate nano zero-valent iron by magnetic separation. The loaded zinc-manganese-nickel particles and supernatant, the nano-zero-valent iron loaded zinc-manganese-nickel particles were washed with deionized water and ethanol respectively, dispersed in ethanol, added with 10 mL of chitosan deionized water solution, stirred for 2 h, magnetically separated, washed, and vacuum dried to obtain a coated nano-zero-valent iron loaded zinc-manganese-nickel composite material, recorded as material 6; 43 g of phosphoric acid was added to the supernatant, heated to react and distilled until no formic acid was distilled out, the pH was adjusted to 4.6 with concentrated ammonia water, and concentrated to obtain ammonium dihydrogen phosphate with a purity of 99.1%.

[0026] Comparative Example

[0027] The operation is the same as that of Example 1, except that the prepared nano zero-valent iron loaded zinc-manganese-nickel composite material is not coated with a polymer material.

[0028] Application Example 1

[0029] Adsorption and degradation effect of reactive brilliant blue in wastewater by coated nano-zero-valent iron loaded zinc-manganese-nickel composites

[0030] 5g of each of the coated nano-zero-valent iron-loaded zinc-manganese-nickel composites 1-6, the comparative composite, and commercially available nano-zero-valent iron were added to simulated reactive brilliant blue (RBB) wastewater at an initial concentration of 100mg / L. The pH was adjusted to 5, the reaction was stirred for 30 minutes, and the supernatant was centrifuged at 2500 rpm. The absorbance of the supernatant was measured at 590nm, and the RBB removal efficiency was calculated (Table 1). The results showed that the coated nano-zero-valent iron-loaded zinc-manganese-nickel composites of the present invention significantly removed RBB from wastewater, outperforming the comparative nano-zero-valent iron-zinc composites and significantly outperforming commercially available nano-zero-valent iron materials.

[0031]

[0032] Application Example 2

[0033] Removal effect of chromium from wastewater by coated nano-zero-valent iron loaded zinc-manganese-nickel composite material

[0034] Simulated wastewater containing an initial 20 mg / L Cr(VI) ion concentration was adjusted to pH 5. 0.5 mg / L of the coated nano-zero-valent iron-loaded zinc-manganese-nickel composite materials 1-6, a comparative composite material, and commercially available nano-zero-valent iron were added. The mixture was shaken in a thermostatic oscillator at 220 rpm for 60 minutes. The mixture was centrifuged and 10 mL of the supernatant was collected. The concentration of residual Cr(VI) in the solution was measured, and the removal efficiency was calculated (Table 2). The results showed that the coated nano-zero-valent iron-loaded zinc-manganese-nickel composite materials 1-6 exhibited significant Cr(VI) ion removal efficiency in wastewater.

[0035]

[0036] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any equivalent modifications or substitutions made by persons skilled in the art without departing from the spirit and technical concepts disclosed herein shall be covered by the claims of the present invention.

Claims

1. A method for preparing a coated nano-zero-valent iron loaded zinc-manganese-nickel composite material from phosphating slag and co-producing ammonium dihydrogen phosphate, characterized in that: The following steps are involved: The solid waste phosphating slag is dissolved by heating with formic acid, filtered to remove insoluble matter, the filtrate is diluted with deionized water, and the formic acid is recovered by distillation. The residual liquid is transferred to an autoclave, and ammonium formate and a dispersant are added under a nitrogen atmosphere. The mixture is heated to 180-190° C., reacted for 15-24 hours, cooled to room temperature, and the nano-zero-valent iron-loaded zinc-manganese-nickel particles and the supernatant are separated by magnetic separation. The nano-zero-valent iron-loaded zinc-manganese-nickel particles are washed with deionized water and ethanol, respectively, dispersed in ethanol, and a deionized water solution of a polymer material is added. The mixture is stirred for 1-2 hours, separated by magnetic separation, washed, and vacuum dried to obtain a coated nano-zero-valent iron-loaded zinc-manganese-nickel composite material. An appropriate amount of phosphoric acid is added to the supernatant, heated for reaction, and distilled until no formic acid is distilled out. Concentrated ammonia water is used to adjust the pH to 4-5, and the mixture is concentrated to obtain ammonium dihydrogen phosphate. The solid waste phosphating slag, depending on the phosphating solution used, mainly contains 15-20% iron, about 50% phosphoric acid (root), 5-8% zinc, and also contains a small amount of manganese, nickel, and other insoluble substances; The dispersant is one or more of polyethylene glycol, sodium carboxymethyl cellulose, β-cyclodextrin, water-soluble starch, and plant extract containing polyphenol active substances; The polymer material is one or more of sodium carboxymethyl cellulose, beta-cyclodextrin, water-soluble starch, polyvinyl alcohol, chitosan, and sodium polyacrylate.

2. The method for preparing a coated nano-zero-valent iron loaded zinc-manganese-nickel composite material from phosphating slag and co-producing ammonium dihydrogen phosphate according to claim 1, characterized in that: The mass ratio of the solid waste phosphating slag to ammonium formate is 100:45-70; the mass ratio of the solid waste phosphating slag to deionized water is 1:15-20; and the amount of the dispersant used is 0.5%-1.0% of the total mass of the system.

3. A method for preparing a coated nano-zero-valent iron-loaded zinc-manganese-nickel composite material from phosphating slag and co-producing ammonium dihydrogen phosphate according to claim 1, and use of the coated nano-zero-valent iron-loaded zinc-manganese-nickel composite material prepared by the method in sewage treatment.

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