Safe utilization method for heavy metal polluted farmland

Abstract

The invention relates to the technical field of electromagnetic heating rollers, and discloses a safe utilization method of a heavy metal polluted farmland, which comprises composite passivation repair, and the composite passivation repair comprises preparation and application of a composite nano porous passivator, an intelligent dynamic moisture regulation and control system, CRISPR / Cas9 gene editing low accumulation crop and an Internet of Things multi-source perception and risk early warning platform. According to the safe utilization method for the heavy metal polluted farmland, by using a multi-target passivation technology, through nanometer material compounding and biological protein coupling, physical-chemical-biological triple fixation of heavy metal is achieved, and the passivation efficiency is improved by 2-3 times compared with that of a traditional method.

Description

Technical Field

[0001] The present invention relates to the technical field of soil remediation, and specifically to a method for the safe utilization of heavy metal-polluted farmland. Background Art

[0002] In China, approximately 20 million hectares of cultivated land are polluted by heavy metals such as cadmium, arsenic, and lead, and 19.4% of soil sites exceed the standard. The cadmium exceeding rate of rice in industrial areas such as Hunan and Yunnan reaches 10%-30%‌15. The main pollution causes include industrial emissions (accounting for 70%), agricultural inputs (chemical fertilizers, pesticides), and natural high background values. Cadmium and arsenic can cause health risks such as Itai-itai disease and cancer through the food chain, and also damage the activity of soil microorganisms. The use of passivation technology can achieve soil remediation‌.

[0003] In the prior art during use, the existing traditional passivators (such as lime, biochar) have a single action target, making it difficult to passivate multiple heavy metals simultaneously, and long-term use is likely to cause soil compaction or secondary pollution. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for the safe utilization of heavy metal-polluted farmland to solve the problem in the above background art that the existing traditional passivators (such as lime, biochar) have a single action target, making it difficult to passivate multiple heavy metals simultaneously, and long-term use is likely to cause soil compaction or secondary pollution.

[0005] To solve the above technical problems, the present invention provides the following technical solution: A method for the safe utilization of heavy metal-polluted farmland, including composite passivation remediation, and the composite passivation remediation includes the preparation and application of a composite nanoporous passivator, an intelligent dynamic water regulation system, CRISPR / Cas9 gene-edited low-accumulation crops, and an Internet of Things multi-source perception and risk warning platform; The preparation and application of the composite nanoporous passivator include material composition, preparation method, and action mechanism; The intelligent dynamic water regulation system includes a hardware architecture and a control logic‌; The CRISPR / Cas9 gene-edited low-accumulation crops include target gene design and field configuration‌; The Internet of Things multi-source perception and risk warning platform includes data fusion and a warning mechanism.

[0006] Preferably, the material composition uses modified biochar as a carrier (pore size 5-20nm), and loads hydroxyapatite nanoparticles (particle size 20-50nm), iron sulfide compounds (FeS / FeS2), and cadmium-specific adsorption proteins.

[0007] Preferably, the preparation method is to pyrolyze rice husks under oxygen-limited conditions (600 °C, 2 h), and then activate them with KOH to obtain porous biochar; in-situ synthesize hydroxyapatite in the pores of the biochar by the sol-gel method; load the FeS / FeS2 nanolayer by chemical vapor deposition; and finally immobilize cadmium-adsorbing protein (adsorption capacity ≥ 800 mg / g) by covalent coupling.

[0008] Preferably, the mechanism of action is multi-stage adsorption, including physical adsorption by nano-pores, chemical precipitation by hydroxyapatite, and reductive immobilization by FeS2 (converting Cd²⁺ to CdS), targeted chelation, where the adsorbing protein specifically binds to free cadmium, blocking its migration (selectivity coefficient K_Cd / Pb > 100), and pH self-regulation: the carboxylic acid groups on the biochar surface release H⁺ / OH⁻ with changes in pH, maintaining the optimal soil pH range of 6.5 - 7.5.

[0009] Preferably, the hardware architecture includes deploying a wireless soil sensor network (Eh, pH, conductivity, temperature), a drip irrigation / drainage device equipped with an electric valve control, and an edge computing gateway (embedded with a heavy metal migration model).

[0010] Preferably, the control logic is as follows: when Eh > -50 mV, initiate the flooding mode, with the water depth maintained between 5 cm and 10 cm to promote the conversion of Cd²⁺ to CdS; when Eh < -150 mV and the As concentration > 2 mg / kg, switch to intermittent wetting and drying, with 72 hours of flooding and 24 hours of drainage to inhibit the reduction and release of arsenic. Combine with real-time pH data and automatically inject citric acid or sodium bicarbonate solution to regulate the proportion of dissolved heavy metals.

[0011] Preferably, the targeted gene design includes knocking out the rice OsNramp5 (manganese / cadmium absorption channel) to reduce the root cadmium absorption rate by 70% - 90%; overexpressing OsHMA3 (vacuolar cadmium sequestration protein) to enrich cadmium in the root cell vacuoles (reducing the translocation to stems and leaves by more than 50%); and introducing the exogenous yeast MT-II metallothionein gene to enhance the cadmium-binding ability of the cell wall.

[0012] Preferably, the field configuration is to be used in conjunction with the passivator, adopting "double-row dense planting" (row spacing 15 cm × plant spacing 10 cm), and activating the passivator activity through the secretion of organic acids by high-density roots.

[0013] Preferably, the data fusion is to integrate satellite remote sensing (NDVI index inversion of crop stress), unmanned aerial vehicle multispectral (identification of heavy metal pollution patches), and ground sensor network (real-time soil data) to construct a three-dimensional model of heavy metal migration; When the predicted cadmium content in rice exceeds 0.2 mg / kg, the early warning mechanism automatically triggers an emergency response (such as applying additional passivator, draining water in advance).

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: First, by using the multi-target passivation technology and through the combination of nanomaterial composite and bioprotein conjugation, the present invention realizes the triple fixation of heavy metals in terms of physics, chemistry, and biology, and the passivation efficiency is increased by 2-3 times compared with the traditional method; Second, by using dynamic and precise regulation and an intelligent irrigation system based on real-time feedback of soil parameters, the present invention breaks through the blind area of traditional static water management; Third, by using the coordination of crops and soil and the collaborative design of gene-edited crops and passivators, the present invention blocks the migration of heavy metals from both the "absorption source" and the "soil reservoir".

[0015] Fourth, by using full-chain digitization and through integrated space-air-ground monitoring, the present invention realizes closed-loop management from pollution identification to risk warning BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the main body of the soil remediation method of the present invention; Figure 2 It is a schematic diagram of the hardware architecture of the intelligent regulation system of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0018] Please refer to Figure 1-2 , a method for the safe utilization of heavy metal-contaminated farmland, including composite passivation repair, and the composite passivation repair includes the preparation and application of a composite nanoporous passivator, an intelligent dynamic water regulation system, CRISPR / Cas9 gene-edited low-accumulation crops, and an Internet of Things multi-source perception and risk warning platform; The preparation and application of the composite nanoporous passivator include material composition, preparation method, and action mechanism; The intelligent dynamic water regulation system includes a hardware architecture and a control logic; The CRISPR / Cas9 gene-edited low-accumulation crops include target gene design and field configuration; The Internet of Things multi-source perception and risk warning platform includes data fusion and a warning mechanism.

[0019] Furthermore, the material composition uses modified biochar as a carrier (pore size 5-20nm), loaded with hydroxyapatite nanoparticles (particle size 20-50nm), iron sulfide compounds (FeS / FeS2) and cadmium-specific adsorption proteins.

[0020] Furthermore, the preparation method comprises pyrolyzing rice husks under oxygen-limited conditions (600°C, 2h) and then activating them with KOH to obtain porous biochar; in situ synthesizing hydroxyapatite within the pores of the biochar by a sol-gel method; loading FeS / FeS2 nanolayers by vapor deposition; and finally immobilizing cadmium adsorption proteins (adsorption capacity ≥800 mg / g) by covalent coupling.

[0021] Furthermore, the mechanism of action is multi-stage adsorption nanopore physical adsorption + hydroxyapatite chemical precipitation + FeS2 reduction fixation (converting Cd²+ into CdS), targeted chelation adsorption protein specifically binds to free cadmium, blocking its migration (selectivity coefficient K_Cd / Pb>100), pH self-regulation: the carboxylic acid groups on the biochar surface release H⁺ / OH⁻ with pH, maintaining the optimal soil pH range of 6.5-7.5.

[0022] The composite passivator was prepared by the above technical scheme: (1) 1 kg of rice husk was taken, heated to 600℃ at 10℃ / min in N2 atmosphere for 2 hours, immersed in 2 mol / L KOH solution and shaken for 24 hours after cooling, and washed and dried to obtain porous biochar; (2) the biochar was immersed in a solution containing Ca(NO3)2 (0.5 mol / L) and NH4H2PO4 (0.3 mol / L), the pH was adjusted to 9, and a hydroxyapatite coating was generated by hydrothermal reaction (120℃, 6h); (3) FeS / FeS2 nanolayer was deposited at 300℃ in H2S atmosphere for 1 hour; (4) the fermentation liquid of the engineered bacteria expressing cadmium adsorption protein (OD600=5) was mixed with the biochar, coupled at 37℃ for 12 hours, and centrifuged to obtain the finished product.

[0023] Furthermore, the hardware architecture includes the deployment of a wireless soil sensor network (Eh, pH, conductivity, temperature), a drip irrigation / drainage device equipped with electric valve control, and an edge computing gateway (with a built-in heavy metal migration model).

[0024] Furthermore, the control logic is that when Eh>-50mV, the flooding mode is activated, in which the water depth is maintained between 5cm and 10cm to promote the conversion of Cd²+→CdS; when Eh<-150mV and the As concentration is>2mg / kg, the intermittent dry-wet alternation is switched, maintaining flooding for 72 hours and drainage for 24 hours to inhibit arsenic reduction and release, and combined with real-time pH data, citric acid or sodium bicarbonate solution is automatically injected to regulate the proportion of dissolved heavy metals.

[0025] Through the above technical solutions, sensor nodes are deployed in cadmium-polluted paddy fields (initial concentration 2.5 mg / kg) during intelligent water regulation (one per 10 m²), and control strategies are set; when Eh > -50 mV and pH < 6.0, irrigation is started and pH adjustment liquid (sodium bicarbonate, concentration 0.1%) is injected. When the As concentration suddenly increases, the drainage pump is started and a warning is sent to the management terminal.

[0026] Furthermore, the targeted gene design includes knocking out the rice OsNramp5 (manganese / cadmium absorption channel) to reduce the cadmium absorption rate of the roots by 70% - 90%; overexpressing OsHMA3 (vacuolar cadmium isolation protein) to enrich cadmium in the root cell vacuoles (reducing the translocation to stems and leaves by more than 50%); and introducing the exogenous yeast MT-II metallothionein gene to enhance the cadmium-binding ability of the cell wall.

[0027] Furthermore, the field configuration is used in cooperation with the passivator, adopting "double-row dense planting" (row spacing 15 cm × plant spacing 10 cm), and activating the activity of the passivator through the secretion of organic acids by high-density roots.

[0028] Through the above technical solutions, the OsNramp5 knockout strain is planted, in combination with a composite passivator (application rate 3 tons / ha), and the cadmium content in the rice at the harvest stage is 0.05 mg / kg (the control group is 0.38 mg / kg), and the yield does not decrease significantly.

[0029] Furthermore, the data fusion integrates satellite remote sensing (inversion of crop stress by NDVI index), UAV multispectral (recognition of heavy metal pollution patches), and ground sensor networks (real-time soil data) to construct a three-dimensional model of heavy metal migration; When the predicted cadmium content in the rice exceeds 0.2 mg / kg, the warning mechanism automatically triggers an emergency response (such as applying additional passivator, draining water in advance).

[0030] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for the safe utilization of heavy metal contaminated farmland, including composite passivation repair, characterized in that, The composite passivation and remediation includes the preparation and application of a composite nanoporous passivator, an intelligent dynamic water regulation system, CRISPR / Cas9 gene-edited low-accumulation crops, and an Internet of Things multi-source perception and risk warning platform; The preparation and application of the composite nanoporous passivator includes material composition, preparation method, and mechanism of action; The intelligent dynamic water regulation system includes a hardware architecture and control logic; The CRISPR / Cas9 gene-edited low-accumulation crops include target gene design and field configuration; The Internet of Things multi-source perception and risk warning platform includes data fusion and warning mechanism.

2. The method for safe utilization of heavy metal contaminated farmland according to claim 1, wherein: The material composition uses modified biochar as a carrier (pore size 5-20 nm), loaded with hydroxyapatite nanoparticles (particle size 20-50 nm), iron sulfide compounds (FeS / FeS2), and cadmium-specific adsorption proteins.

3. A method for the safe utilization of heavy metal contaminated farmland according to claim 1, characterized in that: The preparation method is to pyrolyze rice husks under oxygen-limited conditions (600 °C, 2 h), and then activate them with KOH to obtain porous biochar; in-situ synthesize hydroxyapatite in the pores of the biochar by the sol-gel method; load the FeS / FeS2 nanolayer by chemical vapor deposition; finally, immobilize the cadmium adsorption protein by covalent coupling (adsorption capacity ≥ 800 mg / g).

4. A method for the safe utilization of heavy metal contaminated farmland according to claim 1, characterized in that: The mechanism of action is multi-level adsorption, physical adsorption in nanopores + chemical precipitation of hydroxyapatite + reduction fixation of FeS2 (converting Cd²⁺ to CdS), targeted chelation, specific binding of the adsorption protein to free cadmium, blocking its migration (selectivity coefficient K_Cd / Pb > 100), pH self-regulation: carboxylic acid groups on the biochar surface release H⁺ / OH⁻ with pH, maintaining the optimal soil pH range of 6.5-7.

5.

5. A method for the safe utilization of heavy metal contaminated farmland according to claim 1, characterized in that: The hardware architecture includes deploying a wireless soil sensor network (Eh, pH, conductivity, temperature), equipped with a drip irrigation / drainage device controlled by an electric valve, and an edge computing gateway (built-in heavy metal migration model).

6. The method for safe utilization of heavy metal contaminated farmland according to claim 1, characterized in that: The control logic is that when Eh > -50 mV, start the flooding mode, where the water depth is maintained between 5 cm and 10 cm, promoting the conversion of Cd²⁺ → CdS; when Eh < -150 mV and the As concentration > 2 mg / kg, switch to intermittent wet-dry alternation, maintaining flooding for 72 hours and drainage for 24 hours, inhibiting the reduction and release of arsenic, and combining real-time pH data to automatically inject citric acid or sodium bicarbonate solution to regulate the proportion of dissolved heavy metals.

7. A method for the safe utilization of heavy metal contaminated farmland according to claim 1, characterized in that: The target gene design includes knocking out the rice OsNramp5 (manganese / cadmium absorption channel), reducing the root cadmium absorption rate by 70%-90%; overexpressing OsHMA3 (vacuolar cadmium isolation protein), enriching cadmium in the root cell vacuoles (reducing the translocation to stems and leaves by more than 50%); introducing the exogenous yeast MT-II metallothionein gene to enhance the cadmium-binding ability of the cell wall.

8. A method for the safe utilization of heavy metal-polluted farmland according to claim 1, characterized in that: The field configuration is to use it in coordination with the passivator, adopting "double-row dense planting" (row spacing 15 cm × plant spacing 10 cm), activating the passivator activity through high-density root secretion of organic acids.

9. A method for safe utilization of heavy metal contaminated farmland according to claim 1, characterized in that: The data fusion integrates satellite remote sensing (inversion of crop stress by NDVI index), UAV multispectral (recognition of heavy metal pollution patches), and ground sensor networks (real-time soil data) to construct a three-dimensional model of heavy metal migration; when the predicted cadmium content in rice exceeds 0.2 mg / kg, the warning mechanism automatically triggers an emergency response (such as applying a passivator and draining water in advance).

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