In-situ decrement remediation method for cadmium-polluted farmland

A remediation method and technology for cadmium pollution, applied in the field of soil pollution remediation of environmental protection, can solve problems such as high cost, low Cd reduction efficiency, complicated operation, etc., achieve long plant growth cycle, increase treatment steps and costs, and remediation efficiency. low effect

Active Publication Date: 2020-08-11
POWERCHINA ZHONGNAN ENG +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The above patents have low mass transfer efficiency, low Cd reduction efficiency, complicated operation and high cost

Method used

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  • In-situ decrement remediation method for cadmium-polluted farmland
  • In-situ decrement remediation method for cadmium-polluted farmland
  • In-situ decrement remediation method for cadmium-polluted farmland

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] Take 1000 g of farmland Cd-contaminated soil, in which the Cd content is 1.64 mg / kg, and the available Cd content is 0.63 mg / kg. 8 mMFeCl respectively 3 , 8 mM citric acid, compound eluent (FeCl 3 (5 mM) + citric acid (3 mM)) as the eluent, deionized water as the blank sample, rinse the contaminated soil, put the contaminated soil in a beaker, the eluent coverage height is 5 cm, rinse for 12 hours, See Table 1 for the leaching rate of Cd (1.64mg / kg) in the soil.

[0052] Table 1 The leaching effect of different leaching agents on available Cd and total Cd in soil

[0053]

[0054] It can be seen from Table 1 that the leaching agent mainly acts on the available Cd in the soil, and the compound leaching agent FeCl 3 + A rinse with citric acid works best. Use FeCl 3 (5 mM) + citric acid (3 mM) leached soil to achieve a leaching rate of total Cd of 13.1%, which was much higher than the expected value, while the leaching rate of the compound leaching agent to effecti...

Embodiment 2

[0056] Configure eluent solution (FeCl 3 (5 mM) + citric acid (3 mM)), while plowing and crushing the farmland soil to be repaired, introduce the eluent solution through the water inlet 6 to the field and continue plowing, so that the heavy metal Cd in the soil can be leached and dissolved and transferred to the eluent; stand still for 24 hours, so that the field leaching wastewater is allowed to stand and stratify, and the water coverage depth in the farmland is 10cm; the ecological floating board is put into the leaching wastewater (the input density is 3 / m 2 ), use the floating plate to make it float on the rinsing wastewater, place it for 30 days and take it out, and the rinsing wastewater can be discharged through the outlet pipe 7. The leaching rate of Cd in soil, the removal rate of Cd in leaching water, and the enrichment rate of Cd in Cd-enriched plants were measured.

[0057] Measured by the atomic absorption spectrometer, the content of Cd in the leaching water is ...

Embodiment 3

[0061] Repeat Example 2, the only difference is that in this example, the volume ratio of sesame straw biochar to attapulgite in the planting tank is controlled to be 1:5.

[0062] Such as Figure 8 It was shown that with the increase of the proportion of clay in the planting tank matrix, a large amount of clay was adsorbed on the surface of biochar, which hindered the adsorption effect of biochar in the mixed matrix, so the adsorption efficiency of planting tank matrix for Cd became worse.

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Abstract

The invention relates to an in-situ decrement remediation method for a cadmium-polluted farmland, which comprises the following steps: turning over a farmland to be repaired, meanwhile, introducing aneluting agent solution into the farmland to enable the turned-over soil and the eluting agent solution to be uniformly mixed, then standing for layering, putting an ecological floating plate into thefarmland, and taking out the ecological floating plate after 15-30 days, so as to realize in-situ removal of cadmium in the cadmium-polluted farmland. According to the method, efficient decrement remediation of the Cd-polluted farmland is carried out in situ, the technological process is simple, the cost is low, and the method is environmentally friendly.

Description

technical field [0001] The invention relates to an in-situ reduction and restoration method for cadmium-contaminated farmland, and belongs to the technical field of soil pollution restoration for environmental protection. Background technique [0002] At present, the overall situation of my country's farmland soil environment is worrying. According to the results of the "Soil Pollution Survey Bulletin" issued by the Ministry of Environmental Protection and the Ministry of Land and Resources in 2014, more than 12% of the country's 1.826 billion mu of cultivated land has been polluted by heavy metals. The standard-exceeding rate was 16.1%, among which the rate of cadmium (Cd) pollution points exceeding the standard reached 7%. Cd pollution is mainly caused by industrial sewage discharge, mineral development, and unreasonable use of chemical fertilizers and pesticides. Cd pollution not only reduces the yield of farmland grain, but long-term consumption of grain with excessive C...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/02B09C1/00B09C1/08
CPCB09C1/02B09C1/105B09C1/00B09C1/08Y02A40/22
Inventor 肖劲光刘喜王薇肖武王琳玲张永涛杜成琼
Owner POWERCHINA ZHONGNAN ENG
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