Method for remedying heavy metal contaminated soil through passivation

A technology of polluted soil and heavy metals, which is applied in the restoration of polluted soil and the removal of solid waste, etc., can solve the problems of complicated process, fertilizer efficiency, safety and durability to be observed, heavy metal passivation repair without data support, etc., to achieve broad The effect of applying the foreground

Inactive Publication Date: 2017-05-10
CHINESE RES ACAD OF ENVIRONMENTAL SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This patent discloses the material ratio and preparation method of red mud composite materials, but there are many types of materials and complicated processes, which are not suitable for the implementation of passivation restoration of heavy metal-contaminated soils in large areas in my country
Chinese patent application number 201510733378.7, application publication number CN105330476A, application publication date: February 17, 2016, discloses a red mud assisted soil repair fertilizer, but mainly uses biochar as a substrate to improve soil nutrients and is insensitive to heavy metals in the soil. There is no data support for chemical restoration, and the components contain microbial agents, the safety and durability of fertilizer effects remain to be seen

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  • Method for remedying heavy metal contaminated soil through passivation
  • Method for remedying heavy metal contaminated soil through passivation
  • Method for remedying heavy metal contaminated soil through passivation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0053] Passivation treatment experiment: Weigh 100g of heavy metal-contaminated soil through a 2mm sieve, numbered ①, ②, ③, ④, ⑤, ⑥, add 0.5g of iron-modified red mud dry powder in sequence, and correspondingly improve The treatment is as follows: ① Desalted red mud pH = 8, ferrous sulfate addition is 1% (recorded as CRM ~ 8 ~ 1%); ② desalted red mud pH = 8, ferrous sulfate addition is 3% (recorded as CRM ~8~3%); ③Desalted red mud pH=10, ferrous sulfate addition is 1% (denoted as CRM~10~1%); ④Desalted red mud pH=10, ferrous sulfate addition is 3% (Recorded as CRM~10~3%); ⑤Desalted red mud pH=11, ferrous sulfate addition is 1% (recorded as CRM~11~1%); ⑥Desalted red mud pH=11, ferrous sulfate added The amount is 3% (recorded as CRM ~ 11 ~ 3%); then add 60.3mL of deionized water, stir well to form a uniform slurry, and maintain it at a temperature of 25°C ± 0.5°C and a humidity of 95%. After curing for 25-35 days, samples were taken, dried, ground, passed through a 0.125mm sieve...

Embodiment 2

[0057] Passivation treatment experiment: Weigh 100g of heavy metal-contaminated soil passed through a 2mm sieve, numbered as ①, ②, ③, ④, ⑤, ⑥, and add 1g of iron-modified red mud dry powder in turn with different improvement treatments. It is: ①The desalted red mud pH=8, the ferrous sulfate addition is 1% (recorded as CRM~8~1%); ②The desalted red mud is pH=8, the ferrous sulfate addition is 3% (recorded as CRM~ 8~3%); ③Desalted red mud pH=10, ferrous sulfate addition is 1% (recorded as CRM~10~1%); ④Desalted red mud pH=10, ferrous sulfate addition is 3% ( Recorded as CRM ~ 10 ~ 3%); ⑤ desalted red mud pH = 11, the amount of ferrous sulfate added is 1% (recorded as CRM ~ 11 ~ 1%); ⑥ desalted red mud pH = 11, the amount of ferrous sulfate added 3% (recorded as CRM ~ 11 ~ 3%); then add 60.6mL of deionized water, stir well to form a uniform slurry, and maintain under the conditions of temperature 25°C ± 0.5°C and humidity 95%. After curing for 25-35 days, samples were taken, dried...

Embodiment 3

[0061] Passivation treatment experiment: Weigh 100g of heavy metal-contaminated soil that passed through a 2mm sieve, numbered ①, ②, ③, ④, ⑤, ⑥, add 2g of iron-modified red mud dry powder with different improvement treatments in turn, and the corresponding improvement treatment It is: ①The desalted red mud pH=8, the ferrous sulfate addition is 1% (recorded as CRM~8~1%); ②The desalted red mud is pH=8, the ferrous sulfate addition is 3% (recorded as CRM~ 8~3%); ③Desalted red mud pH=10, ferrous sulfate addition is 1% (recorded as CRM~10~1%); ④Desalted red mud pH=10, ferrous sulfate addition is 3% ( Recorded as CRM ~ 10 ~ 3%); ⑤ desalted red mud pH = 11, the amount of ferrous sulfate added is 1% (recorded as CRM ~ 11 ~ 1%); ⑥ desalted red mud pH = 11, the amount of ferrous sulfate added 3% (denoted as CRM ~ 11 ~ 3%); then add 61.2mL of deionized water, stir well to form a uniform slurry, and maintain at a temperature of 25°C ± 0.5°C and a humidity of 95%. After curing for 25-35 d...

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Abstract

The invention provides a method for remedying heavy metal contaminated soil through passivation. The method comprises the following steps: collecting heavy metal contaminated top soil, removing large impurity granules, performing air drying, uniformly mixing, grinding, and sieving by using a 2mm sieve; grinding dried red mud, sieving by using a 100-mesh sieve, adding deionized water for washing red mud powder, measuring the pH value of a mixed solution system by using a pH meter, and repeatedly washing till the pH value of desalinated red mud is 8, 10 or 11 to obtain the desalinated red mud; adding ferrous sulfate into the desalinated red mud obtained in the former step, adding deionized water to ensure that the water content is 40-70%, and maintaining for 7-10 days under the conditions that the temperature is 25 DEG C plus or minus 0.5 DEG C and the humidity is 95% to obtain improved red mud; adding the improved red mud obtained in the former step into the heavy metal contaminated soil according to an addition ratio that the weight of the improved red mud is 0.5-2% of the dry weight of the contaminated soil, sufficiently mixing uniformly under the condition that the water content in terms of the dry weight of the solid is 40-70%, maintaining for 25-35 days under the conditions that the temperature is 25 DEG C plus or minus 0.5 DEG C and the humidity is 95%, drying and grinding for standby application.

Description

technical field [0001] The invention relates to a passivation method for repairing heavy metal-contaminated soil, and belongs to the technical field of methods for repairing heavy metal-contaminated soil. Background technique [0002] Relevant data from the 2014 "National Soil Pollution Survey Bulletin" shows that about 300 million mu of cultivated land in my country is polluted by heavy metals, and the rate of soil points exceeding the standard is as high as 19.4%, and the main types of heavy metal pollutants are cadmium, arsenic, and lead. Among them, soil Cd The point exceeding standard rate reached 7%, and the annual output of Cd exceeding standard agricultural products reached 1.5 million tons, resulting in economic losses of more than 20 billion. my country's soil is seriously polluted by heavy metals, and heavy metal pollutants are highly toxic, easy to accumulate, and non-degradable, posing a serious threat to the ecological environment, food security, and human healt...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/08B09B3/00B09B5/00
CPCB09C1/08B09B3/00B09B5/00
Inventor 杜平陈娟任杰韩雷刘继东刘小莲
Owner CHINESE RES ACAD OF ENVIRONMENTAL SCI
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