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CN-122012115-A - PH heavy metal ion double-response biological nano-selenium soil restoration agent and preparation method thereof

CN122012115ACN 122012115 ACN122012115 ACN 122012115ACN-122012115-A

Abstract

The invention discloses a pH heavy metal ion double-response biological nano-selenium soil restoration agent and a preparation method thereof, and belongs to the technical field of soil restoration. The invention discloses a preparation method of a biological nano selenium soil restoration agent, which comprises the steps of slowly stirring biological nano selenium, a sodium citrate buffer solution and succinic anhydride for reaction, centrifugally washing to obtain carboxylated modified biological nano selenium, mixing sodium alginate solution, carboxymethyl chitosan solution and ethylenediamine tetraacetic anhydride for reaction to obtain a mixed solution A, mixing carboxylated modified biological nano selenium and the mixed solution, performing ultrasonic dispersion under ice bath to obtain a mixed solution B, dripping the mixed solution B into a calcium chloride solution, and filtering and drying to obtain the biological nano selenium soil restoration agent. The pH/heavy metal ion double-response type core-shell structure biological nano-selenium restoration agent developed successfully by the invention can intelligently target release and effectively passivate soil heavy metals, so that the cadmium content of rice seeds is reduced by more than 65 percent and lower than national standard, and the agent is long-acting and stable, thereby realizing accurate intelligent treatment of heavy metal pollution of farmlands.

Inventors

  • YU XIANGHAI
  • LUO MINGHUA
  • YOU ZHENHAI
  • GUO XIAOHUA

Assignees

  • 硒游记(深圳)合成生物科技有限公司

Dates

Publication Date
20260512
Application Date
20260205

Claims (10)

  1. 1. The preparation method of the pH heavy metal ion double-response biological nano-selenium soil restoration agent is characterized by comprising the following steps of: s1, slowly stirring biological nano-selenium, sodium citrate buffer solution and succinic anhydride for reaction, and centrifugally washing to obtain carboxylated modified biological nano-selenium; s2, mixing and reacting a sodium alginate solution, a carboxymethyl chitosan solution and ethylenediamine tetraacetic acid dianhydride to obtain a mixed solution A; s3, mixing carboxylated modified biological nano selenium and the mixed solution, and performing ultrasonic dispersion under ice bath to obtain a mixed solution B; S4, dripping the mixed solution B into a calcium chloride solution, filtering and drying to obtain the biological nano-selenium soil restoration agent.
  2. 2. The preparation method of claim 1, wherein the mass ratio of biological nano-selenium, sodium citrate buffer solution and succinic anhydride in S1 is (0.02-0.05) 1 (0.02-0.05).
  3. 3. The process according to claim 1, wherein the temperature of the stirring reaction in S1 is 20 to 25 ℃ for 4 hours.
  4. 4. The preparation method of claim 1, wherein the volume to mass ratio of the sodium alginate solution, the carboxymethyl chitosan solution and the ethylenediamine tetraacetic acid dianhydride in the S2 is (30-40) mL (10-15) mL (0.01-0.03) g.
  5. 5. The preparation method of claim 4, wherein the concentration of the sodium alginate solution is 2-4% w/v, and the concentration of the carboxymethyl chitosan solution is 1-3% w/v.
  6. 6. The preparation method according to claim 1, wherein the temperature of the S2 mixing reaction is 40-50 ℃ and the time is 1-3h.
  7. 7. The preparation method of claim 1, wherein the ratio of the volume to the mass of the biological nano selenium modified by carboxylation in S3 to the mixed solution is (0.1-3:1).
  8. 8. The method according to claim 1, wherein the concentration of the calcium chloride solution in S4 is 4% wt.
  9. 9. The preparation method of claim 1, wherein the particle size of the biological nano-selenium soil restoration agent is 0.8-1.5mm.
  10. 10. A pH heavy metal ion double-response biological nano-selenium soil restoration agent, which is characterized by being prepared by the preparation method of any one of claims 1-9.

Description

PH heavy metal ion double-response biological nano-selenium soil restoration agent and preparation method thereof Technical Field The invention belongs to the technical field of building decoration materials, and particularly relates to a pH heavy metal ion double-response biological nano-selenium soil restoration agent and a preparation method thereof. Background Soil heavy metal pollution has become a global environmental problem, and seriously threatens the safety of agricultural products and the health of an ecological system. Common repair techniques include physical soil-blocking, chemical leaching, and biological repair. In recent years, the passivation repairing technology has been attracting attention because of low cost and simple operation, and the core is that effective heavy metals are converted into stable forms by adding passivation materials into soil, so that the bioavailability of the heavy metals is reduced. Among the many passivation materials, nano-selenium, especially nano-selenium synthesized by biological methods, has application potential due to environmental friendliness, high specific surface area and strong reactivity. The prior art mainly relates to 1) directly applying biological nano-selenium suspension and 2) simply loading biological nano-selenium on a porous carrier and then applying the biological nano-selenium. However, the methods have obvious limitations that firstly, the nano selenium particles are easy to agglomerate and oxidize in a complex soil medium to lead to rapid reduction of an active surface, secondly, the release and action processes of the nano selenium particles are completely and passively diffused, intelligent response cannot be carried out according to space-time difference of pollution degree, material waste is caused in a low pollution area, and the nano selenium particles are possibly not completely repaired in a high pollution core area due to insufficient local dosage, and furthermore, the stability and passivation efficiency of the nano selenium are obviously influenced by the fluctuation of key environmental factors such as soil pH and the like, especially under an acidic condition, the long-term stability of a fixed product is doubtful. In addition, the prior art focuses on a single chemical fixing mechanism, and the interaction effect and ecological compatibility of materials and soil microenvironment are not enough. Therefore, developing a novel biological nano selenium material which can adapt to the soil environment change, realize heavy metal targeted passivation and has long-term stability becomes a technical bottleneck to be broken through in the current field. Disclosure of Invention In view of the above, the invention aims to provide the pH heavy metal ion double-response biological nano-selenium soil restoration agent and the preparation method thereof, and the biological nano-selenium restoration agent can intelligently release in a targeted manner and effectively passivate soil heavy metals, thereby realizing accurate intelligent treatment of farmland heavy metal pollution. In order to achieve the above object, the present invention provides the following technical solutions: the invention provides a preparation method of a pH heavy metal ion double-response biological nano-selenium soil restoration agent, which comprises the following steps: s1, slowly stirring biological nano-selenium, sodium citrate buffer solution and succinic anhydride for reaction, and centrifugally washing to obtain carboxylated modified biological nano-selenium; s2, mixing and reacting a sodium alginate solution, a carboxymethyl chitosan solution and ethylenediamine tetraacetic acid dianhydride to obtain a mixed solution A; s3, mixing carboxylated modified biological nano selenium and the mixed solution, and performing ultrasonic dispersion under ice bath to obtain a mixed solution B; S4, dripping the mixed solution B into a calcium chloride solution, filtering and drying to obtain the biological nano-selenium soil restoration agent. Preferably, the mass ratio of the biological nano selenium, the sodium citrate buffer solution and the succinic anhydride in the S1 is (0.02-0.05) 1 (0.02-0.05). Preferably, the temperature of the stirring reaction in the step S1 is 20-25 ℃ and the time is 4h. Preferably, the volume mass ratio of the sodium alginate solution, the carboxymethyl chitosan solution and the ethylenediamine tetraacetic acid dianhydride in the S2 is (30-40) mL (10-15) mL (0.01-0.03) g. Preferably, the concentration of the sodium alginate solution is 2-4% w/v, and the concentration of the carboxymethyl chitosan solution is 1-3% w/v. Preferably, the temperature of the S2 mixing reaction is 40-50 ℃ and the time is 1-3h. Preferably, the ratio of the volume to the mass of the biological nano selenium modified by carboxylation in the S3 to the mixed solution is (0.1-3:1). Preferably, the concentration of the calcium chloride solution in S4 is 4% wt. Preferabl