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A high-efficiency passivation repair method for heavy metal cadmium pollution in moderately severe rice fields

A remediation method and cadmium pollution technology, which is applied in chemical instruments and methods, restoration of contaminated soil, and treatment of dyed low-molecular organic compounds, can solve problems such as poor selectivity and limited adsorption capacity of heavy metal ions, and achieve low cost and improved The method is simple and efficient, and the effect of increasing porosity

Active Publication Date: 2021-11-02
湖南仕宏环保科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, it has been found that natural palygorskite has limited adsorption capacity for heavy metal ions, and the selectivity is also poor, so further measures need to be taken to improve its adsorption performance.

Method used

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  • A high-efficiency passivation repair method for heavy metal cadmium pollution in moderately severe rice fields
  • A high-efficiency passivation repair method for heavy metal cadmium pollution in moderately severe rice fields
  • A high-efficiency passivation repair method for heavy metal cadmium pollution in moderately severe rice fields

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Experimental program
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Effect test

preparation example Construction

[0029] 2. Preparation of high-efficiency passivating agent

[0030] According to the mass percentage of the preparation, distilled water: modified palygorskite: silane: sodium hydrosulfide = 15-20:1-2:1-2:0.01-0.05, stirred at high speed for 10-30 minutes, filtered, and dried naturally for later use.

[0031] 3. Soil passivation method

[0032] Apply this high-efficiency passivator to the surface layer (0-20cm) of the heavy metal cadmium-contaminated soil according to 75-300kg / mu of acidic paddy field soil polluted by moderate and severe cadmium, then mix evenly, and the high-efficiency passivator is applied to the soil and then aged for 7 Rice can be transplanted and planted within days.

[0033] Fertilization of rice in the later stage: Ammonium bicarbonate or ammonium nitrate, potassium nitrate, and potassium sulfate fertilizers can make the soil weak and acidic, and urea cannot be used, and potassium chloride should not be applied.

Embodiment 1

[0035] 1. Preparation of modified palygorskite

[0036] (1) Take 2ml of absolute ethanol and add it to 1000ml deionized water to prepare an ethanol solution, and weigh 5g of sodium metaphosphate and add it to the ethanol solution to prepare an ethanol-sodium metaphosphate solution;

[0037] (2) Weigh 60g of palygorskite powder and add it to the ethanol-sodium metaphosphate solution, and place it in an ultrasonic disperser with a set frequency of 4000Hz to disperse for 45 minutes; after ultrasonic dispersion, suction filter to remove water, and dry naturally at room temperature; The dried palygorskite powder was transferred to 1000ml of liquid nitrogen for rapid freezing for 60 minutes; the liquid nitrogen was removed; the water in the palygorskite powder was frozen, the volume expanded, and the pore size became larger.

[0038] (3) Transfer the palygorskite powder to a vacuum drying oven for vacuum drying for 60 minutes, set the temperature at 80°C, and vacuum degree -0.1KPa; ...

Embodiment 2

[0051] Field test of in-situ passivation: In this implementation case, a field plot test was used to study the passivation effect of the present invention on the available state of cadmium in the paddy field soil and the influence of the rice on absorbing and accumulating cadmium. The test site is located in Xiangtan City, Hunan Province. The basic physical and chemical properties of the tested paddy field soil are shown in Table 2 below. The rice variety is Tanzao 215.

[0052] The field test is to set up test plots in cadmium-contaminated acidic paddy fields, each plot is about 30m 2 (5m×6m). The test set 1 group of experiments, using the high-efficiency passivator of palygorskite modified example 1 to restore heavy metal cadmium-contaminated paddy field soil, the addition amount of the acid cadmium-contaminated paddy field passivation repair test was 300kg / mu, and a blank control group was set and passivation test group, each repeated 3 times, and the data results were av...

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Abstract

The invention relates to a high-efficiency passivation repair method for heavy metal cadmium pollution in moderate-to-severe paddy fields. The high-efficiency passivator is applied to the surface layer of the heavy-metal cadmium-contaminated soil according to 75-300 kg / mu of moderate-to-severe cadmium-polluted acidic paddy soil. Then mix evenly, and after the high-efficiency passivating agent is applied to the soil, it will be aged for 7-10 days for rice transplanting and planting. In the modification process of the present invention, low-temperature nitrogen freezing is used to increase the pore size of palygorskite, and the grafting efficiency is higher when it becomes larger, and more silane can be loaded, but the pores are too large and easy to fall off after being loaded, so the present invention adopts The disulfide bond in sodium hydrosulfide improves the binding capacity of silane and palygorskite, ensures the loading effect, and increases the loading rate by about 30%.

Description

technical field [0001] The invention belongs to the technical field of repairing heavy metal cadmium pollution in farmland soil, and specifically relates to a high-efficiency passivation repairing material for heavy metal cadmium pollution in farmland soil and an application method thereof. Background technique [0002] Soil heavy metal cadmium pollution is concealed, long-term and irreversible. Therefore, in the case of farmland polluted by heavy metal cadmium, regulating the transfer and enrichment behavior of the soil-crop system is the key to prevent heavy metal pollution from affecting human health. Among many remediation technologies for heavy metal cadmium pollution in farmland soil, passivation technology has the advantages of fast remediation rate, high effect, moderate price, and simple operation. It is easy to realize the effect of preventing and controlling heavy metal cadmium pollution in farmland. Good choice for farmland soils. However, for moderately and se...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B09C1/08C09K17/04C09C1/28C09C3/08C09C3/06
Inventor 孙国红梁学峰徐应明王林孙约兵秦旭赵立杰黄青青
Owner 湖南仕宏环保科技有限公司
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