Method for eluting heavy metals Cu, Zn, Pb and Cd in soil by use of EDTA calcium salt

A technology of EDTA calcium salt and heavy metal, applied in the field of Pb, Cd, heavy metal Cu, Zn, can solve the problems of high repair cost, poor leaching effect, difficult follow-up treatment, etc. Good removal effect

Inactive Publication Date: 2016-04-13
HUNAN AGRICULTURAL UNIV
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Problems solved by technology

[0005] The purpose of the present invention is to provide a method for leaching heavy metals Cu, Zn, Pb, and Cd in soil with EDTA calcium salt to solve the problems of poor leaching effect, high repair cost,

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  • Method for eluting heavy metals Cu, Zn, Pb and Cd in soil by use of EDTA calcium salt

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example 1

[0019] Example 1: The soil used in the test was taken from the farmland downstream of the mining area in Guanxi Town, Chenzhou, Hunan. Its basic physical and chemical properties are shown in Table 1:

[0020] Table 1 Basic physical and chemical properties of soil and background value of heavy metals

[0021] Table2-3Physical-chemicalpropertiesand backgroundvaluesoftheheavymetalsinsoil

[0022]

[0023] The specific method is:

[0024] (1) Determination of the optimal concentration of Ca-EDTA eluent: Take 5.00 g of soil samples passed through a 20-mesh sieve and add 4 different concentration gradients with molar concentrations of 2.5mmol / L, 5mmol / L, 10mmol / L, and 20mmol / L. In the solution, the obtained sample was placed on a shaker at a constant temperature of 150r / min (25°C) for 2h, and the obtained sample was centrifuged at 4000r / min for 15min, and the supernatant was taken to determine the content of heavy metals Pb, Zn, Cu, Cd, As.

[0025] The data show that with the...

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Abstract

The invention discloses a method for eluting heavy metals Cu, Zn, Pb and Cd in soil by use of EDTA calcium salt. Through adoption of the method, the heavy metals in soil can be effectively reduced. The method comprises the following steps: adopting a physical method to enable a heavy metal extracting agent, namely, EDTA to be combined with calcium oxide to form an eluting agent, namely, Ca-EDTA which has an excellent removing effect on the heavy metals in soil; determining an optima eluting condition through a series of experiments bychanging the concentration of the eluting agent, the solid-liquid ratio, the eluting time and the continuous eluting times; finally, realizing the excellent removal effect in a short time (2 h) under the condition that the lower concentration of the eluting agent is 2.5 mmol/l, the solid-liquid ratio is 1: 5 and the continuous eluting times are three. The eluting agent, namely, Ca-EDTA used in the method is lower in turbidity and has better settleability, the follow-up treatment is more convenient, the effect on soil fertility is low, and after treatment, plants can grow normally in the soil, so that convenience is brought to large trials in the future, and a certain treating time and cost can be reduced.

Description

technical field [0001] The invention relates to a method for leaching heavy metals Cu, Zn, Pb and Cd in soil by using an EDTA calcium salt. Background technique [0002] The adsorption mechanism of heavy metal elements in soil is mainly divided into two categories: (1) adsorbed on the solid surface in the soil and exist in the form of ions; (2) exist in the form of compounds to form precipitation of heavy metals. Soil heavy metal chemical leaching repair technology is a technology that reverses these reaction processes, uses leaching fluid to replace heavy metals from the soil, and elutes them out through liquid. At home and abroad, soil chemical leaching repair technology has been widely used in laboratory research and practical engineering applications because of its wide adaptability and relatively fast processing speed. [0003] At present, the main leaching agents for heavy metals in soil remediation by chemical leaching are: (1) Artificial chelating agents: EDTA (ethy...

Claims

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Application Information

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IPC IPC(8): B09C1/08B09C1/02
CPCB09C1/08B09C1/02
Inventor 曾清如胡疆张维宁
Owner HUNAN AGRICULTURAL UNIV
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