Method for remedying cadmium (Cd) and lead (Pb) polluted soil by alum pulp in situ

A lead-contaminated soil, in-situ repair technology, applied in the restoration of contaminated soil, etc., can solve the problems that have not been seen, and achieve the effects of improving passivation ability, reducing absorption, and simple operation

Inactive Publication Date: 2013-03-13
ZHEJIANG ACADEMY OF AGRICULTURE SCIENCES
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

At present, alum slurry has been used in some industries, such as firing cement, ceramic expansion agent and rubber rei

Method used

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  • Method for remedying cadmium (Cd) and lead (Pb) polluted soil by alum pulp in situ
  • Method for remedying cadmium (Cd) and lead (Pb) polluted soil by alum pulp in situ
  • Method for remedying cadmium (Cd) and lead (Pb) polluted soil by alum pulp in situ

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Embodiment 1: (method 1 utilizing alum slurry to remediate Cd, Pb polluted soil in situ)

[0030] Follow these steps:

[0031] (1) Preparation of heat-alkali-modified passivator for heavy metal-contaminated soil: Alum slurry powder obtained by drying, grinding, and passing through a 1mm sieve with 0.5 mol L -1 0.5g: 5 mL of NaOH solution, prepared as a solution, heated in a water bath at 80°C, and continuously stirred at a speed of 10-40 rpm. After activating for 2 hours, wash with water to neutrality. After precipitation, filter the solid part Drying, grinding to obtain hot alkali modified alum slurry passivator, standby;

[0032] (2) Selection of in-situ remediation of Cd and Pb contaminated soil with alum slurry passivator: pH≦5.5, total Cd content 1.2 mg kg -1 and full Pb content 520 mg kg-1 The polluted soil is used as the soil to be repaired and reserved;

[0033] (3) In-situ remediation of soil contaminated by heavy metals Cd and Pb: before planti...

Embodiment 2

[0035] Embodiment 2: (method 2 utilizing alum slurry to remediate Cd, Pb polluted soil in situ)

[0036] In this example, step (1) alum slurry powder and 2.0 mol L -1 The NaOH solution was prepared according to the ratio of 0.65g: 6.5mL by weight and volume, heated in a water bath at 80°C, stirred continuously, and activated for 3.0 hours; in step (2), select pH > 5.5-6.5, and the total Cd content is 2.5 mg kg -1 and full Pb content 650 mg kg -1 The polluted soil was used as the soil to be repaired; step (3) apply the alum slurry passivator to the surface at the rate of 100 kg / mu, and water twice to keep the soil moist for 8 weeks, until the heavy metals Cd and Pb in the polluted soil were Respectively passivate into immobilized forms that cannot be used by plants, lose their bioavailability, realize in-situ remediation of heavy metal-contaminated soil, and reach the second level of China's "Soil Environmental Quality Standards" (GB 15618-2008) according to the pH>5.5-6.5 gro...

Embodiment 3

[0038] Embodiment 3: (the method 3 of utilizing alum slurry to remediate Cd, Pb polluted soil in situ)

[0039] In this example, step (1) alum slurry powder and 3.5 mol L -1 The NaOH solution was prepared according to the ratio of 0.80g:8.0mL by weight and volume, heated in a water bath at 80°C, stirred continuously, and activated for 4.0 hours; in step (2), select pH > 6.5-7.5, and the total Cd content is 3.5 mg kg -1 and full Pb content 800 mg kg -1 The polluted soil was used as the soil to be repaired; step (3) applied the alum slurry passivator to the surface at a rate of 150 kg / mu, watered 3 times to keep the soil moist for 12 weeks, until the heavy metals Cd and Pb in the polluted soil were respectively Passivation into an immobilized form that cannot be used by plants, loses its biological effectiveness, and realizes in-situ remediation of heavy metal-contaminated soil, reaching the second level of China's "Soil Environmental Quality Standards" (GB 15618-2008) accordin...

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Abstract

The invention discloses a method for remedying cadmium (Cd) and lead (Pb) polluted soil by alum pulp in situ and belongs to the technical field of in-situ remediation of heavy metal polluted soil. The method comprises the following steps: (1) preparation of hot-alkali modified passivant of heavy metal polluted soil; (2) selection of Cd and Pb polluted soil suitable to in-situ remediation by alum pulp passivant; and (3) in-situ remediation of heavy metal Cd and Pb polluted soil. In the method, the by-product alum pulp in the production of alum is taken as a raw material which is activated and modified by hot alkali to form an efficient heavy metal passivant, and by the passivant, the contents of the exchangeable Cd and Pb in the soil can be lowered by over 60% and 65% respectively in one to four months; and the method has the characteristics of low raw-material cost, simple production technology, stable passivation effect, operation simpleness and the like. The method can be popularized and used in farmland soil with medium-low Cd and Pb pollution.

Description

technical field [0001] The invention relates to the technical field of soil heavy metal pollution control, in particular to a technology for in-situ restoration of medium and low heavy metal cadmium (Cd) and lead (Pb) polluted soil by using a heavy metal passivator. Background technique [0002] At present, the state of soil pollution in my country has affected the quality of cultivated land, food safety and even human health, and the area of ​​soil pollution is increasing. According to a 2010 research report by the Institute of Ecology, Chinese Academy of Sciences, in the late 1980s, my country’s polluted area was only a few million hectares, but now the area of ​​cultivated land polluted by heavy metals such as cadmium, arsenic, chromium, and lead has reached nearly 20 million hectares, accounting for about 20 million hectares of cultivated land. one-fifth of the total area. Therefore, soil heavy metal pollution remediation technology has attracted much attention. ...

Claims

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Application Information

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IPC IPC(8): B09C1/08
Inventor 李凝玉郭彬傅庆林李华丁能飞林义成刘琛
Owner ZHEJIANG ACADEMY OF AGRICULTURE SCIENCES
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