Search

CN-121972136-A - Ferrous sulfide particles with shell and preparation method and application thereof

CN121972136ACN 121972136 ACN121972136 ACN 121972136ACN-121972136-A

Abstract

The invention relates to the technical field of soil pollution treatment, solves the problems that in the prior art, when a large-area hexavalent chromium-polluted medium is treated, the dosage of ferrous sulfide is inaccurate, and the repairing effect is not ideal, and provides ferrous sulfide particles with shells, a preparation method and application thereof, wherein the prepared ferrous sulfide particles with shells can also keep high-efficiency chromium removal within the pH value range of 5-9, and the problem that the adsorption behavior of a traditional model in a low chromium concentration area is difficult to predict is effectively solved by means of a corrected adsorption model with higher fitting precision, so that the actual demand of target repairing liquid can be accurately predicted, the injection of the target repairing liquid is more accurate, and excessive or insufficient is avoided. After the hexavalent chromium is reduced to trivalent chromium by ferrous sulfide, the trivalent chromium can form a stable chelate with carboxymethyl cellulose, and zero-valent sulfur can also form a compact passivation layer on the surface of a polluted medium to inhibit reoxidation of the trivalent chromium, so that long-term stable repair of the hexavalent chromium is realized.

Inventors

  • JI HAODONG
  • ZHANG KUO
  • ZHU LIMIN
  • YU KAI
  • MA HAORAN
  • ZHU MINGYE

Assignees

  • 南燕生态环境研究实验室(深圳)有限公司
  • 中交一公局集团有限公司
  • 北京大学深圳研究生院

Dates

Publication Date
20260505
Application Date
20260205

Claims (10)

  1. 1. The ferrous sulfide particle with the shell is characterized by comprising ferrous sulfide particles and a stabilizer shell coating the surfaces of the ferrous sulfide particles, wherein the molar ratio of the stabilizer shell to the ferrous sulfide particles is in the range of 0.0006-0.002, and the stabilizer shell comprises carboxymethyl cellulose.
  2. 2. The coated ferrous sulfide particle of claim 1, wherein the Zeta potential of the coated ferrous sulfide particle ranges from-35 mV to-42 mV, the particle size of the coated ferrous sulfide particle ranges from 130nm to 200nm, and the thickness of the stabilizer coating ranges from 0.8 nm to 2nm.
  3. 3. A method of preparing ferrous sulfide particles with a shell as claimed in claim 1 or 2, comprising: mixing a ferrous salt solution with a sulfide solution based on a first molar ratio to prepare a suspension containing ferrous sulfide particles; Adding a stabilizer solution to the suspension based on a second molar ratio to obtain a target reaction solution, wherein the target reaction solution contains the ferrous sulfide particles with the shell, and the stabilizer solution comprises a carboxymethyl cellulose water solution; Concentrating the ferrous sulfide particles with the shell in the target reaction liquid to obtain solid ferrous sulfide particles with the shell.
  4. 4. A method of preparing ferrous sulfide particles having a shell as claimed in claim 3 wherein the mixing of the ferrous salt solution with the sulfide solution based on the first molar ratio to form a suspension of ferrous sulfide particles comprises: preparing a ferrous salt solution with the concentration range of 0.05 mol-0.2 mol/L and a sulfide solution with the concentration range of 0.05 mol-0.2 mol/L in an environment filled with inert gas; Taking the molar ratio of ferrous sulfide ions to sulfide ions as the first molar ratio, dropwise adding the sulfide solution into the ferrite solution based on the first molar ratio to prepare the suspension, controlling the stirring rotation speed to be 250-550 r/min, controlling the dropwise adding rate of the sulfide solution to be 0.8-2.5 ml/min, and controlling the first molar ratio to be 1-1.1.
  5. 5. A method of preparing ferrous sulfide particles with a shell as claimed in claim 3, wherein the adding a stabilizer solution to the suspension based on a second molar ratio to obtain a target reaction solution includes: Taking the molar ratio of the carboxymethyl cellulose to the ferrous sulfide particles as the second molar ratio, adding the stabilizer solution into the suspension based on the second molar ratio, and controlling the stirring time to be 25-45 min, wherein the second molar ratio is 0.0006-0.002.
  6. 6. The method for producing a coated ferrous sulfide particle according to claim 3, wherein the concentrating the coated ferrous sulfide particle in the target reaction liquid to obtain a solid coated ferrous sulfide particle comprises: Centrifuging the target reaction liquid to obtain concentrated liquid, controlling the duration range of the centrifuging to be 8-20 min, and controlling the rotating speed range of the centrifuging to be 7000-12000 r/min; and performing vacuum freeze drying on the concentrated solution to obtain solid ferrous sulfide particles with shells, controlling the temperature range of vacuum freezing to be minus 60 ℃ to minus 30 ℃, and controlling the vacuum degree of vacuum freezing to be less than or equal to 20Pa.
  7. 7. Use of ferrous sulphide particles with a casing according to claim 1 or 2, comprising: Mixing the ferrous sulfide particles with the shell with a buffer solution to obtain a target repairing solution; injecting the target repair liquid into the medium to be treated based on the initial repair parameters, and continuously monitoring real-time repair index parameters in the medium to be treated; And determining dynamic repair parameters based on a preset corrected adsorption model and the real-time repair index parameters, and repairing the medium to be treated by using the dynamic repair parameters.
  8. 8. The use of the coated ferrous sulfide particles of claim 7, wherein the mixing of the coated ferrous sulfide particles with a buffer solution to obtain a target repair solution comprises: mixing the ferrous sulfide particles with the shells and the mass concentration range of 0.08-0.12 g/L with the buffer solution with the molar concentration range of 8-12 mM/L to obtain the target repair liquid with the pH value range of 6.5-7.8.
  9. 9. The ferrous sulfide granule application with a casing of claim 7, wherein the injecting the target remediation liquid into the medium to be remediated based on initial remediation parameters and continuously monitoring real-time remediation index parameters in the medium to be remediated, comprises: determining an injection mode of the target repair liquid according to the type of the medium to be treated, and injecting the target repair liquid into the medium to be treated based on the initial repair parameters, wherein the initial repair parameters comprise initial injection pressure, single pulse injection quantity and initial pulse period; monitoring at least one point position of the medium to be treated to obtain the real-time repair index parameters, wherein the real-time repair index parameters comprise hexavalent chromium concentration and pH value.
  10. 10. The ferrous sulfide granule application with a casing of claim 9, wherein the determining a dynamic repair parameter based on a preset modified adsorption model and the real-time repair index parameter, and repairing the medium to be treated with the dynamic repair parameter includes: Establishing a modified adsorption model based on a linear distribution coefficient, a cadmium concentration reciprocal and a Langmuir equation, and determining a dynamic repair parameter of the target repair liquid by utilizing the modified adsorption model and the real-time repair index parameter; Repairing the medium to be treated by using the dynamic repairing parameters, wherein the dynamic repairing parameters comprise the supplementing amount of the buffer solution, the injection flow rate of the target repairing solution and the injection concentration.

Description

Ferrous sulfide particles with shell and preparation method and application thereof Technical Field The invention relates to the field of chromium pollution treatment, in particular to ferrous sulfide particles with shells, and a preparation method and application thereof. Background Hexavalent chromium is used as heavy metal pollutant with high toxicity and high mobility, is widely derived from industrial activities such as metallurgy, electroplating, tanning and the like, exists in the form of anions such as CrO 42-、HCrO4- and the like in the environment, has strong water solubility and biological permeability, can cause carcinogenic and teratogenic risks through food chain accumulation, and forms serious threat to ecological environment and human health. The traditional hexavalent chromium restoration technology mainly comprises a chemical reduction method, an electrochemical method and the like, but has a plurality of limitations that the chemical reduction method adopts reducing agents such as sulfite, ferrous sulfate and the like, is difficult to uniformly diffuse in soil and cannot be restored uniformly, the dissolution rate of iron under an acidic condition is as high as 44.3mg/L, secondary pollution is easy to cause, and the electrochemical method has high cost, can damage the soil structure and is not suitable for large-area pollution restoration. Since ferrous sulfide has Fe 2+/S2- double reduction active sites, the prior art has the problem of adopting ferrous sulfide to repair hexavalent chromium, for example, chinese patent CN105460979A discloses a preparation and use method of FeS particles for repairing hexavalent chromium polluted soil, and the actual dosage is still calculated based on theory when the FeS particles are used for repairing the hexavalent chromium in the soil. However, in the prior art, iron reduction is considered to lead to a hexavalent chromium removal process, but a density functional theory calculation support is lacked, and an atomic level mechanism of sulfur sites in electron transfer is not yet elucidated, so that the deviation of theoretical calculation dosage and actual required dosage is more than 20%, feS particles are easy to be too little or too much, pollution repair of hexavalent chromium is not facilitated, pores are easy to be blocked by FeS particle repair liquid due to a filter cake effect, and the prior art cannot be suitable for repairing a large-area hexavalent chromium polluted medium. Disclosure of Invention In view of the above, the embodiment of the invention provides ferrous sulfide particles with a shell, and a preparation method and application thereof, which are used for solving the problems that in the prior art, when a large-area medium polluted by hexavalent chromium is treated, the dosage of ferrous sulfide is inaccurate, and the repairing effect is not ideal. In a first aspect, the embodiment of the invention provides ferrous sulfide particles with a shell, which comprise ferrous sulfide particles and a stabilizer shell coating the surface of the ferrous sulfide particles, wherein the molar ratio of the stabilizer shell to the ferrous sulfide particles is in the range of 0.0006-0.002, and the stabilizer shell comprises carboxymethyl cellulose. As an alternative implementation mode, the Zeta potential range of the ferrous sulfide particles with the shells is minus 35mV to minus 42mV, the particle size range of the ferrous sulfide particles with the shells is 130 nm-200 nm, and the thickness range of the stabilizer shells is 0.8-2 nm. In a second aspect, the embodiment of the invention provides a preparation method of ferrous sulfide particles with a shell, which comprises the steps of mixing ferrous salt solution and sulfide solution according to a first molar ratio to prepare a suspension containing ferrous sulfide particles, adding stabilizer solution to the suspension according to a second molar ratio to obtain a target reaction solution, wherein the target reaction solution contains the ferrous sulfide particles with the shell, the stabilizer solution comprises carboxymethyl cellulose water solution, and concentrating the ferrous sulfide particles with the shell in the target reaction solution to obtain solid ferrous sulfide particles with the shell. In an alternative embodiment, the preparation method comprises the steps of mixing a ferrous salt solution and a sulfide solution based on a first molar ratio to prepare a suspension containing ferrous sulfide particles, wherein the preparation method comprises the steps of preparing the ferrous salt solution with the concentration range of 0.05 mol-0.2 mol/L and the sulfide solution with the concentration range of 0.05 mol-0.2 mol/L in an environment filled with inert gas, taking the molar ratio of ferrous sulfide ions to sulfide ions as the first molar ratio, dripping the sulfide solution into the ferrous salt solution based on the first molar ratio, preparing the suspension, controlling t