Method for removing heavy metal from sludge

A heavy metal and sludge technology, applied in the field of environmental treatment, can solve the problems of high acid consumption, high cost and long time, and achieve the effect of less acid consumption, low cost and short time.

Inactive Publication Date: 2012-07-18
HUBEI DINGXIN ENVIRONMENTAL PROTECTION TECHCO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the current chemical method has the disadvantages of high acid consumption, long time and high cost

Method used

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  • Method for removing heavy metal from sludge
  • Method for removing heavy metal from sludge

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] The sludge was taken from a sewage treatment plant in Xingsha, Hunan. After the wet sludge was dried, the heavy metal components of the dried sludge samples were analyzed, as shown in Table 1.

[0025] Table 1 Heavy metal composition analysis (mg / Kg) of sludge samples from a sewage treatment plant in Wuhan, Hubei

[0026] Element

Cu

Pb

Zn

Hg

Ni

Cr

CD

As

content

480

190

841

104

8

73

4

19

[0027] Take 1 kilogram of the original sludge and place it in a beaker, add 2L of 2mol / L citric acid solution, stir while adding the liquid, then adjust the pH to 5 with nitric acid and sodium hydroxide, and then add 0.5L of 27.5% citric acid Hydrogen peroxide, similarly, stir while adding liquid, and continue to stir for 20 minutes after adding liquid.

[0028] The above-mentioned sludge solid-liquid mixture is heated by microwave, and after being heated to 50°C, it is kept for 1...

Embodiment 2

[0034] The sludge was taken from the wastewater treatment plant of a printing and dyeing enterprise in Zhijiang, Hubei. After the wet sludge was dried, the heavy metal components of the dried sludge samples were analyzed, as shown in Table 3.

[0035] Table 3 Heavy metal composition analysis (mg / Kg) of sludge samples from a wastewater treatment plant of a printing and dyeing enterprise in Zhijiang, Hubei

[0036] Element

Cu

Pb

Zn

Hg

Ni

Cr

CD

As

content

535

210

923

86

15

64

12

5

[0037] Take 1 kg of the original sludge and place it in a beaker, add 2L of 3mol / L citric acid solution, stir while adding the liquid, then adjust the pH to 5 with nitric acid and sodium hydroxide, and then add 0.5L of 33% citric acid solution Hydrogen peroxide, similarly, stir while adding liquid, and continue to stir for 20 minutes after adding liquid.

[0038] The above-mentioned sludge solid-...

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PUM

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Abstract

The invention relates to a method for removing heavy metal from sludge. The method comprises the following steps of: extracting the heavy metal by using citric acid and hydrogen peroxide, performing microwave heating and solid-liquid separation, and adding sodium hydroxide to precipitate the heavy metal. The method is simple in process, the removal rate of the heavy metal is high, and consumption of acid is low; the citric acid solution can be recycled; the method is low in cost and does not harm the environment; and by adding the hydrogen peroxide into the extract, the extraction rate is improved, the reaction is quickened, and loss of available chemical elements such as N and P is reduced.

Description

technical field [0001] The invention relates to the technical field of environmental treatment, in particular to a method for removing heavy metals in sludge. Background technique [0002] Sludge is the solid sedimentation material produced by water and wastewater treatment processes. With the growth of population and the acceleration of urbanization, the output of municipal sludge is increasing day by day, forming new environmental problems. The traditional methods of sludge disposal are landfill, incineration, and throwing into the sea. These disposal methods have not fundamentally eliminated its impact on the environment. On the other hand, sludge contains a large amount of nutrients such as humus, nitrogen and phosphorus, and has huge resource utilization value. These treatment methods are obviously a waste of resources. However, since the sludge contains heavy metals, it greatly affects the resource utilization of sludge and aggravates the risk of sludge polluting the...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F11/00C02F11/06C05F7/00
CPCY02A40/20
Inventor 李少华
Owner HUBEI DINGXIN ENVIRONMENTAL PROTECTION TECHCO
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