Targeted chelating antagonistic passivator for heavy metal cadmium contaminated soil and application of targeted chelating antagonistic passivator

Abstract

The invention discloses a targeted chelating antagonistic passivator for heavy metal cadmium contaminated soil and application of the targeted chelating antagonistic passivator. The targeted chelating antagonistic passivator for the heavy metal cadmium contaminated soil comprises lime, calcium polysulfide, tricalcium phosphate, sodium metasilicate and zeolite. The compound is applied to heavy metal treatment in soil and cadmium blocking in rice planting. According to the technical scheme, aiming at the problems of effectiveness and economy of an existing conventional soil heavy metal cadmium passivator, heavy metal ion chelation, antagonism, reduction, mineralization factors and the like are introduced on the basis of the conventional soil heavy metal cadmium passivator, so that the form of heavy metal cadmium in soil is more favorable for being converted into a low-biological-activity form; and migration and accumulation of heavy metal cadmium pollutants to cultivated plants are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of pollution remediation, and more specifically to a heavy metal cadmium polluted soil targeted chelating antagonistic passivating agent and application thereof. Background Art

[0002] After heavy metals enter the soil, they form different binding forms through dissolution, precipitation, adsorption exchange, complexation (chelation), etc. The bioavailability of different forms of heavy metals in the soil is as follows: water-soluble state > exchangeable state > carbonate-bound state > iron-manganese oxide-bound state > organic matter and sulfide-bound state > residual state. The acid-base properties, redox properties, colloid composition and content, organic matter composition and content, microbial type and content, external environment, hydrological conditions, etc. of the soil are important factors affecting the existence form of heavy metals in the soil. The type of heavy metal pollution in the soil, the degree of heavy metal pollution, the effectiveness of heavy metals, the type and variety of crops, and agricultural technical measures are also important factors affecting the migration of heavy metals aboveground. Therefore, it is difficult to achieve targeted, economical and effective remediation of heavy metal pollution in the soil based on soil properties, the type of heavy metal pollution in the soil, the degree of heavy metal pollution, the effectiveness of heavy metals, etc. with the current conventional soil heavy metal passivators.

[0003] Cadmium pollution is the most prominent heavy metal pollution in farmland soil, and crops are deeply affected by it. Heavy metal cadmium pollution poses a huge threat to food production, agricultural product safety and human health. The current cadmium-contaminated soil passivators are mainly composed of one or several functional materials that have a series of chemical effects such as exchange, adsorption, and precipitation on heavy metal ions. "An ion mineralization stabilizer and use method for treating heavy metal contaminated soil" (International Protection Technology, Patent No.: C09K17 / 06GK102766465SQ20121026770) is a representative of this type of passivator. This type of passivator is affected by factors such as soil properties, type and degree of heavy metal pollution, and type of crops planted. It is difficult to achieve the expected results in terms of effectiveness and economy in the actual soil remediation process. Summary of the invention

[0004] In view of this, the present invention provides a targeted chelating antagonistic passivating agent for heavy metal cadmium contaminated soil, which introduces heavy metal ion chelating, antagonistic, reducing and mineralizing factors on the basis of conventional soil heavy metal cadmium passivating agents, so that the form of heavy metal cadmium in the soil is more conducive to the transformation into a low biological activity form, thereby reducing the migration and accumulation of heavy metal cadmium pollutants to cultivated crops.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] Firstly, the present invention provides a targeted chelating antagonistic passivating agent for heavy metal cadmium contaminated soil, comprising: lime, calcium polysulfide, tricalcium phosphate, sodium metasilicate and zeolite.

[0007] Preferably, by weight percentage, the lime comprises 8-25%, calcium polysulfide 3-19%, tricalcium phosphate 0-34%, sodium metasilicate 5-29%, and zeolite 33-69%.

[0008] Furthermore, based on weight percentage, it also includes one or more of 5-27% activated carbon, 3-22% coke, and 1-25% biochar.

[0009] The present invention also provides the use of the heavy metal cadmium contaminated soil targeted chelating antagonistic passivating agent in the treatment of heavy metal cadmium contaminated soil.

[0010] Preferably, the heavy metal cadmium contaminated soil is paddy field soil.

[0011] A planting method based on the above application for controlling the effective cadmium content in crops by using the heavy metal cadmium contaminated soil targeted chelating antagonistic passivating agent comprises the following steps:

[0012] (1) Flood the field contaminated by heavy metal cadmium for 5-11 days, apply the soil targeted chelation antagonist passivator contaminated by heavy metal cadmium, and till and mix well. Leave it for 18-36 hours before transplanting rice seedlings.

[0013] (2) During the rice growing season, cadmium inhibitors are sprayed on fields that require cadmium inhibition.

[0014] Preferably, in step (1), the weight ratio of the heavy metal cadmium contaminated soil targeted chelating antagonist passivator to the effective heavy metal content in the heavy metal cadmium contaminated soil is (110-301):1.

[0015] Preferably, the cadmium inhibitor described in step (2) comprises, by mass, 310-440 parts of sodium metasilicate pentahydrate, 28-46 parts of urea, 1-7 parts of potassium humate, 89-113 parts of potassium dihydrogen phosphate, 1-13 parts of zinc sulfate, 3-16 parts of surfactant, 1-11 parts of trace elements and 470-620 parts of water.

[0016] The surfactant is mainly any one or more of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate and sorbitan oleate; the trace elements include any one or more of iron, manganese, copper, boron, molybdenum, chlorine and sodium.

[0017] Preferably, the weight ratio of the amount of the cadmium inhibitor to the effective cadmium content in the soil to be treated for cadmium pollution is (0.01-0.5):1.

[0018] Preferably, the cadmium inhibitor described in step (2) is sprayed at any one or more stages of the rice tillering stage and the jointing-heading stage, and each stage is sprayed 2-3 times, with an interval of 2-6 days between each spraying.

[0019] It can be seen from the above technical solution that, compared with the prior art, the present invention discloses a heavy metal cadmium contaminated soil targeted chelating antagonist passivator and its application, which has the following beneficial effects:

[0020] The zeolite in the targeted chelating antagonistic passivating agent for heavy metal cadmium contaminated soil provided by the present application has interconnected pores in a framework structure, has good heavy metal ion exchange adsorption, and has excellent adsorption and exchange capacity for cadmium in the soil; inorganic metasilicates can solidify effective cadmium in the soil, and at the same time can form antagonistic factors in crops, effectively blocking the entry of cadmium into the grain part of crops; phosphates have a mineralizing effect on heavy metal ions on the one hand, and can also provide the nutrient element phosphorus for crops on the other hand; sulfur-containing compounds can use elemental sulfur to mineralize the effective state of heavy metal cadmium into a stable sulfide state of cadmium that is difficult to be used by crops, thereby reducing the effective concentration, mobility and biological effectiveness of heavy metal cadmium in the soil, thereby reducing its effectiveness against biological invasion, and preventing the migration of heavy metals from the soil through the roots of plants to the upper part of the soil, which can not only effectively reduce the effective cadmium content in cadmium-contaminated soil, but also further block and control the cadmium in crops, thereby reducing the cadmium in crops.

[0021] The application of the targeted chelating antagonist passivator for heavy metal cadmium contaminated soil provided in the present application can not only reduce the effective cadmium content in the soil, but also further control the effective cadmium content in crops. In the field experiment, after the application of the targeted chelating antagonist passivator for heavy metal cadmium contaminated soil, the effective cadmium in the farmland soil was reduced to 0.554 mg / kg, and the effective cadmium decreased by 23.80%; the cadmium in rice roots, stems and leaves and brown rice also decreased, which were reduced by 27.09%, 11.73% and 2.76% respectively compared with the control area. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Example 1

[0024] The components of the targeted chelating antagonistic passivation agent for heavy metal cadmium contaminated soil include, by mass percentage, 12% lime, 7% calcium polysulfide, 12% sodium metasilicate and 69% zeolite.

[0025] Example 2

[0026] The components of the targeted chelating antagonistic passivation agent for heavy metal cadmium contaminated soil include, by mass percentage, 12% lime, 7% calcium polysulfide, 10% tricalcium phosphate, 12% sodium metasilicate and 59% zeolite.

[0027] Example 3

[0028] The components of the targeted chelating antagonistic passivation agent for heavy metal cadmium contaminated soil include, by mass percentage, 12% lime, 7% calcium polysulfide, 15% tricalcium phosphate, 12% sodium metasilicate and 54% zeolite.

[0029] Example 4

[0030] The components of the targeted chelating antagonistic passivation agent for heavy metal cadmium contaminated soil include, by mass percentage, 12% lime, 7% calcium polysulfide, 20% tricalcium phosphate, 12% sodium metasilicate and 49% zeolite.

[0031] Example 5

[0032] The components of the targeted chelating antagonistic passivation agent for heavy metal cadmium contaminated soil include, by mass percentage, 12% lime, 7% calcium polysulfide, 25% tricalcium phosphate, 12% sodium metasilicate and 44% zeolite.

[0033] Example 6

[0034] The components of the targeted chelating antagonistic passivation agent for heavy metal cadmium contaminated soil include, by mass percentage, 12% lime, 7% calcium polysulfide, 30% tricalcium phosphate, 12% sodium metasilicate and 39% zeolite.

[0035] Example 7

[0036] The components of the targeted chelating antagonistic passivation agent for heavy metal cadmium contaminated soil include, by mass percentage, 17% lime, 7% calcium polysulfide, 12% sodium metasilicate and 64% zeolite.

[0037] Example 8

[0038] The components of the targeted chelating antagonistic passivation agent for heavy metal cadmium contaminated soil include, by mass percentage, 17% lime, 7% calcium polysulfide, 10% tricalcium phosphate, 12% sodium metasilicate and 54% zeolite.

[0039] Example 9

[0040] The components of the targeted chelating antagonistic passivation agent for heavy metal cadmium contaminated soil include, by mass percentage, 17% lime, 7% calcium polysulfide, 15% tricalcium phosphate, 12% sodium metasilicate and 49% zeolite.

[0041] Example 10

[0042] The components of the targeted chelating antagonistic passivation agent for heavy metal cadmium contaminated soil include, by mass percentage, 17% lime, 7% calcium polysulfide, 20% tricalcium phosphate, 12% sodium metasilicate and 44% zeolite.

[0043] Embodiment 11

[0044] The components of the targeted chelating antagonistic passivation agent for heavy metal cadmium contaminated soil include, by mass percentage, 17% lime, 7% calcium polysulfide, 25% tricalcium phosphate, 12% sodium metasilicate and 39% zeolite.

[0045] Example 12

[0046] The components of the targeted chelating antagonistic passivation agent for heavy metal cadmium contaminated soil include, by mass percentage, 17% lime, 7% calcium polysulfide, 30% tricalcium phosphate, 12% sodium metasilicate and 34% zeolite.

[0047] Embodiment 13

[0048] The components of the targeted chelating antagonistic passivation agent for heavy metal cadmium contaminated soil include, by mass percentage, 15% lime, 7% calcium polysulfide, 40% tricalcium phosphate, 15% sodium metasilicate, and 23% zeolite.

[0049] Embodiment 14

[0050] The components in the targeted chelating antagonistic passivation agent for heavy metal cadmium contaminated soil include, by mass percentage, 15% lime, 7% calcium polysulfide, 40% tricalcium phosphate, 15% sodium metasilicate, 13% zeolite, and 10% activated carbon.

[0051] Embodiment 15

[0052] The components in the targeted chelating antagonistic passivation agent for heavy metal cadmium contaminated soil include, by mass percentage, 15% lime, 7% calcium polysulfide, 40% tricalcium phosphate, 15% sodium metasilicate, 13% zeolite, and 10% biochar.

[0053] Example 16

[0054] The components of the targeted chelating antagonistic passivation agent for heavy metal cadmium contaminated soil include, by mass percentage, 15% lime, 7% calcium polysulfide, 40% tricalcium phosphate, 15% sodium metasilicate, 13% zeolite, and 10% coke.

[0055] Experimental Example 1

[0056] The heavy metal cadmium contaminated soil targeted chelating antagonistic passivation agent of Examples 1-16 was implemented in the soil from Xinglong Village, Longqiao Town, Mianzhu, Sichuan. The following is the effect of reducing the effective cadmium in the soil 7 days after the use of Examples 1-16.

[0057]

[0058]

[0059] The above results show that the product of the present invention has a good heavy metal reduction effect, and Example 13 has the best effect.

[0060] Embodiment 17

[0061] The product of Example 13 was used for implementation. The field contaminated by heavy metal cadmium was flooded for 7 days, and a heavy metal cadmium-contaminated soil targeted chelating antagonist passivator was applied at a rate of 200 kg / mu, and rotary tillage was performed to mix evenly. After standing for 24 hours, rice seedlings were transplanted, and then the cadmium inhibitor was sprayed during the tillering period of rice growth. The components in the inhibitor were calculated by mass as follows: 320 parts of sodium metasilicate pentahydrate, 32 parts of urea, 3 parts of potassium humate, 100 parts of potassium dihydrogen phosphate, 5 parts of zinc sulfate, 5 parts of sodium dodecyl sulfate, 5 parts of trace element iron and 530 parts of water. The cadmium inhibitor was sprayed at a rate of 30 ml / mu·time (diluted with water to 300 ml before application), and the rice was sprayed twice during the tillering period, with an interval of 3 days each time.

[0062] Embodiment 18

[0063] The product of Example 13 was used for implementation. The field contaminated by heavy metal cadmium was flooded for 7 days, and a heavy metal cadmium-contaminated soil targeted chelating antagonist passivator was applied at a rate of 300 kg / mu, and rotary tillage was performed to mix evenly. After standing for 24 hours, rice seedlings were transplanted, and then the cadmium inhibitor was sprayed during the tillering period of rice growth. The components in the cadmium inhibitor were calculated by mass as follows: 320 parts of sodium metasilicate pentahydrate, 32 parts of urea, 3 parts of potassium humate, 100 parts of potassium dihydrogen phosphate, 5 parts of zinc sulfate, 5 parts of sodium dodecylbenzene sulfonate, 5 parts of trace element manganese and 530 parts of water. The cadmium inhibitor was sprayed at a rate of 30 ml / mu / time (diluted with water to 300 ml before application), and the rice was sprayed twice during the tillering period, with an interval of 3 days each time.

[0064] Embodiment 19

[0065] The product of Example 13 was used for implementation. The field contaminated by heavy metal cadmium was flooded for 7 days, and a heavy metal cadmium-contaminated soil targeted chelating antagonist passivator was applied at a rate of 400 kg / mu, and rotary tillage was performed to mix evenly. After standing for 24 hours, rice seedlings were transplanted, and then the cadmium inhibitor was sprayed during the tillering period of rice growth. The components in the cadmium inhibitor were calculated by mass as follows: 320 parts of sodium metasilicate pentahydrate, 32 parts of urea, 3 parts of potassium humate, 100 parts of potassium dihydrogen phosphate, 5 parts of zinc sulfate, 5 parts of sorbitan oleate, 5 parts of trace element copper and 530 parts of water. The cadmium inhibitor was sprayed at a rate of 30 ml / mu / time (diluted with water to 300 ml before application), and the rice was sprayed twice during the tillering period, with an interval of 3 days each time.

[0066] Embodiment 20

[0067] The product of Example 13 was used for implementation. The fields contaminated by heavy metal cadmium were flooded for 7 days, and a heavy metal cadmium-contaminated soil targeted chelating antagonist passivator was applied at a rate of 500 kg / mu, and rotary tillage was performed to mix evenly. After standing for 24 hours, rice seedlings were transplanted, and then the cadmium inhibitor was sprayed during the tillering period of rice growth. The components in the cadmium inhibitor were calculated by mass as follows: 320 parts of sodium metasilicate pentahydrate, 32 parts of urea, 3 parts of potassium humate, 100 parts of potassium dihydrogen phosphate, 5 parts of zinc sulfate, 5 parts of sodium dodecylbenzene sulfonate, 5 parts of trace element boron and 530 parts of water. The cadmium inhibitor was sprayed at a rate of 30 ml / mu / time (diluted with water to 300 ml before application), and the rice was sprayed twice during the tillering period, with an interval of 3 days each time.

[0068] Embodiment 21

[0069] The product of Example 13 was used for implementation. The fields contaminated by heavy metal cadmium were flooded for 7 days, and a targeted chelating antagonist passivator for heavy metal cadmium-contaminated soil was applied at a rate of 200 kg / mu, and rotary tillage was performed to mix evenly. After standing for 24 hours, rice seedlings were transplanted, and then the cadmium inhibitor was sprayed during the jointing-heading stage of rice growth. The components in the cadmium inhibitor were calculated by mass as follows: 320 parts of sodium metasilicate pentahydrate, 32 parts of urea, 3 parts of potassium humate, 100 parts of potassium dihydrogen phosphate, 5 parts of zinc sulfate, 5 parts of sodium dodecyl sulfate, 5 parts of trace element molybdenum and 530 parts of water. The cadmium inhibitor was sprayed at a rate of 30 ml / mu / time (diluted with water to 300 ml before application), and sprayed twice during the jointing-heading stage of rice growth, with an interval of 3 days each time.

[0070] Embodiment 22

[0071] The product of Example 13 was used for implementation. The fields contaminated by heavy metal cadmium were flooded for 7 days, and a heavy metal cadmium-contaminated soil targeted chelating antagonist passivator was applied at a rate of 300 kg / mu, and rotary tillage was performed to mix evenly. After standing for 24 hours, rice seedlings were transplanted, and then the cadmium inhibitor was sprayed during the jointing-heading stage of rice growth. The components in the cadmium inhibitor were calculated by mass as follows: 320 parts of sodium metasilicate pentahydrate, 32 parts of urea, 3 parts of potassium humate, 100 parts of potassium dihydrogen phosphate, 5 parts of zinc sulfate, 5 parts of sorbitan oleate, 5 parts of trace elements sodium and 530 parts of water. The cadmium inhibitor was sprayed at a rate of 30 ml / mu / time (diluted with water to 300 ml before application), and sprayed twice during the jointing-heading stage of rice growth, with an interval of 3 days each time.

[0072] Embodiment 23

[0073] The product of Example 13 was used for implementation. The fields contaminated by heavy metal cadmium were flooded for 7 days, and a targeted chelating antagonist passivator for heavy metal cadmium-contaminated soil was applied at a rate of 400 kg / mu, and rotary tillage was performed to mix evenly. After standing for 24 hours, rice seedlings were transplanted, and then the cadmium inhibitor was sprayed during the jointing-heading stage of rice growth. The components in the cadmium inhibitor were calculated by mass as follows: 320 parts of sodium metasilicate pentahydrate, 32 parts of urea, 3 parts of potassium humate, 100 parts of potassium dihydrogen phosphate, 5 parts of zinc sulfate, 5 parts of sodium dodecylbenzene sulfonate, 5 parts of trace element chlorine and 530 parts of water. The cadmium inhibitor was sprayed at a rate of 30 ml / mu / time (diluted with water to 300 ml before application), and sprayed twice during the jointing-heading stage of rice growth, with an interval of 3 days each time.

[0074] Embodiment 24

[0075] The product of Example 13 was used for implementation. The fields contaminated by heavy metal cadmium were flooded for 7 days, and a heavy metal cadmium-contaminated soil targeted chelating antagonist passivator was applied at a rate of 500 kg / mu, and rotary tillage was performed to mix evenly. After standing for 24 hours, rice seedlings were transplanted, and then the cadmium inhibitor was sprayed during the jointing-heading stage of rice growth. The components in the cadmium inhibitor were calculated by mass as follows: 320 parts of sodium metasilicate pentahydrate, 32 parts of urea, 3 parts of potassium humate, 100 parts of potassium dihydrogen phosphate, 5 parts of zinc sulfate, 5 parts of sodium dodecylbenzene sulfonate, 5 parts of trace elements iron, manganese and 530 parts of water. The cadmium inhibitor was sprayed at a rate of 30 ml / mu / time (diluted with water to 300 ml before application), and sprayed twice during the jointing-heading stage of rice growth, with an interval of 3 days each time.

[0076] Examples 17-20 show that different amounts of targeted chelating antagonist passivators for heavy metal cadmium contaminated soil were applied when cadmium inhibitors were sprayed during the tillering stage of rice; Examples 21-24 show that different amounts of targeted chelating antagonist passivators for heavy metal cadmium contaminated soil were applied when cadmium inhibitors were sprayed during the jointing-heading stage of rice. The following are the results of soil effective cadmium and rice cadmium reduction in Examples 17-24.

[0077]

[0078] The above results show that compared with the existing soil heavy metal passivators, the chelating antagonist passivator of the present invention has improved the targeted chelating adsorption and ion exchange capabilities of heavy metals due to the use of mineral chelating modification, and at the same time, factors such as precipitation, antagonism and oxidation-reduction are implanted, so that the formed new passivator has the advantages of strong passivation effect on effective heavy metals in the soil, fast effect, small application amount, easy engineering implementation, and no secondary pollution.

[0079] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the embodiments can be referred to each other. The above description of the disclosed embodiments enables professionals and technicians in this field to implement or use the present invention. Various modifications to these embodiments will be obvious to professionals and technicians in this field, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown in this article, but will comply with the widest range consistent with the principles and novel features disclosed herein.

Claims

1. A heavy metal cadmium contaminated soil targeted chelating antagonistic passivation agent, characterized in that: include: Lime, calcium polysulfide, tricalcium phosphate, sodium metasilicate and zeolite.

2. A heavy metal cadmium contaminated soil targeted chelating antagonistic passivator according to claim 1, characterized in that: In terms of weight percentage, the composition includes 8-25% lime, 3-19% calcium polysulfide, 0-34% tricalcium phosphate, 5-29% sodium metasilicate and 33-69% zeolite.

3. A heavy metal cadmium contaminated soil targeted chelating antagonistic passivating agent according to claim 1, characterized in that: In terms of weight percentage, it also includes one or more of 5-27% activated carbon, 3-22% coke, and 1-25% biochar.

4. Use of the heavy metal cadmium contaminated soil targeted chelating antagonistic passivator according to any one of claims 1 to 3 in the treatment of heavy metal cadmium contaminated soil.

5. The use according to claim 4, characterized in that: The heavy metal cadmium contaminated soil is paddy field soil.

6. A planting method for controlling the effective cadmium content in crops by using the heavy metal cadmium contaminated soil targeted chelating antagonistic passivator according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) Flood the field contaminated by heavy metal cadmium for 5-11 days, apply the soil targeted chelation antagonist passivator contaminated by heavy metal cadmium, and till and mix well. Leave it for 18-36 hours before transplanting rice seedlings. (2) During the rice growing season, cadmium inhibitors are sprayed on fields that require cadmium inhibition.

7. The method according to claim 6, characterized in that In step (1), the weight ratio of the targeted chelating antagonistic passivating agent for heavy metal cadmium contaminated soil to the effective heavy metal content in the heavy metal cadmium contaminated soil is (110-301):

1.

8. The method according to claim 6, characterized in that The cadmium blocking agent described in step (2) comprises, by weight, 310-440 parts of sodium metasilicate pentahydrate, 28-46 parts of urea, 1-7 parts of potassium humate, 89-113 parts of potassium dihydrogen phosphate, 1-13 parts of zinc sulfate, 3-16 parts of surfactant, 1-11 parts of trace elements and 470-620 parts of water.

9. The method according to claim 6, characterized in that The weight ratio of the dosage of the cadmium inhibitor to the effective cadmium content in the soil to be treated for cadmium pollution is (0.01-0.5):

1.

10. The method according to claim 6, characterized in that The cadmium inhibitor described in step (2) is sprayed at any one or more stages of the rice tillering stage and the jointing-heading stage, and each stage is sprayed 2-3 times, with an interval of 2-6 days between each spraying.

Images