CN105675360A

CN105675360A - Method of high-effectively leaching heavy metal cadmium ions from soil

Info

Publication number: CN105675360A
Application number: CN201410673772.1A
Authority: CN
Inventors: 贾志军; 王毅; 刘晨明; 曹宏斌; 齐涛
Original assignee: Institute of Process Engineering of CAS
Current assignee: Institute of Process Engineering of CAS
Priority date: 2014-11-21
Filing date: 2014-11-21
Publication date: 2016-06-15

Abstract

The invention discloses a method of high-effectively leaching heavy metal cadmium ions from soil. The method includes: a) soil pretreatment: placing a soil sample in a heating furnace, increasing the temperature to 450 DEG C, maintaining the temperature for 3 h, and cooling the soil sample in the furnace to room temperature; b) with a proper acetic acid/acetate solution, leaching the pre-treated soil sample to extract the heavy metal cadmium ions from soil into the leaching solution; and c) separating the leaching solution from soil residue, and filtering the leaching solution for awaiting later detection.

Description

A kind of method of efficient leaching heavy metal in soil cadmium ion

Technical field

The invention belongs to technical field of environmental detection, a kind of method being specifically related to efficient leaching heavy metal in soil cadmium ion.

Background technology

Development along with industry, metallurgical and mining industry creates substantial amounts of heavy metal ion, such as: hydrargyrum, cadmium, chromium, zinc, lead, copper, nickel etc., these heavy metal ion can be diffused by soil, water, air, and it is enriched with by food chain, the health of the mankind is constituted irreversible harm.

Cadmium is that health is threatened one of maximum harmful element, and it has carcinogenic, teratogenesis, mutagenic action, and human health is produced many-sided impact. Therefore the efficient detection of cadmium ion is realized, significant for protection health.

The Comparison between detecting methods of cadmium ion is many, these methods based on principle different, technically also differ from one another, for instance, 1) ultraviolet spectrophotometry: the method is different to the absorption spectrum wavelength of ultraviolet light from other elements based on cadmium ion, it is achieved qualitative and quantitative analysis; 2) atomic absorption method: the ground state atom more the gasified degree of absorption to its characteristic spectrum, it is achieved the quantitative analysis to measured matter; 3) inductively coupled plasma mass spectrometry: utilize inductively coupled plasma technology to make sample enterprise planning, then utilize mass-spectrometric technique to measure, it is possible to analyze detection device for multi metallic elements simultaneously; 4) anodic stripping voltammetry: being enriched on electrode by measured object under the current potential set in advance, then make the current potential of microelectrode be scanned by negative sense positive direction, the material of enrichment reversely removes, and carries out quantitative analysis by volt-ampere curve; 5) fluorescence polarization immunoassay method: utilize polyclonal antibody technology to detect, excessive chelating agen is added testing sample, it is made to form metal-chelant complex with metal ion to be measured, this complex and concentration known and with the meeting point on fluorescently-labeled metal-chelant-fluorescent composition Nintaus multi-resistance, then utilize fluorescence polarization assay instrument to be analyzed; And competitiveness enzyme-linked immunodetection and immune colloid gold flash chromatography method etc. In the detection process of Cadmium in Soil ion, which kind of method no matter is adopted to detect, being required for being transferred in liquid phase by the cadmium ion in soil and can complete measuring, therefore realizing that Cadmium in Soil ion is efficiently transferred in liquid phase is the key that accurately detects of Cadmium in Soil ion.

The present invention accurately detects as starting point and standpoint to realize Cadmium in Soil ion, sets up a kind of efficiently leaching heavy metal in soil Cd²⁺The method of ion, it is achieved the leaching efficiency of Cadmium in Soil ion reaches about 90%.

Summary of the invention

A kind of method that it is an object of the invention to provide efficient leaching heavy metal in soil cadmium ion, the method is capable of the accurate detection of Cadmium in Soil ion.

First technical problem that this invention address that there is provided the pretreating process of a kind of samples-soil, the present invention adopts heat treated mode that sample soil is carried out pretreatment, heat treated purpose has two, one is dry sample, remove the moisture impact on result in sample, two is the mode by high-temperature heating, it is achieved cadmium element fully oxidized, it is simple to the leaching of cadmium ion.

Second this invention address that technical problem is that and propose a kind of cadmium ion leachate, the compound system that the leaching liquid that the present invention adopts is acetic acid and acetate (ammonium and sodium) forms, the pH of this buffer solution is 3.5～6, when external condition changes, the pH change of solution itself is less, it is possible to overcome the soil pH impact on cadmium ion leaching effect. Acetic acid in leaching liquid provides hydrion, it is possible to increase leaching efficiency, effectively shortens extraction time, adopts the compound leachate that the present invention adopts to be typically in 20 minutes namely up to leaching balance.

The 3rd this invention address that technical problem is that the leaching method proposing Cadmium in Soil ion, the method is to provide suitable turnover condition for the present invention, wherein, in leaching process, the ratio of the volume (milliliter) of the quality (gram) of soil and leaching liquid is 1:10 or 1:20; The alr mode selected in leaching process can be mechanical agitation, mechanical oscillation and sonic oscillation; Leaching time is 20 minutes.

Then through ion isolation residue, and by supernatant liquid filtering, only use in order to subsequent detection.

Accompanying drawing explanation

Fig. 1 is Technology for Heating Processing schematic diagram;

Fig. 2 is the concentration of cadmium ions change with leaching time

Detailed description of the invention

Following will come that the invention will be further described in conjunction with the accompanying drawings and embodiments, but it will be not to the restriction invented.

Embodiment 1

Sample soil is cleared up experiment, utilizes inductively coupled plasma method detection heavy metal in soil ion concentration.

Methods of Soil Digestion: weigh soil sample 2 grams, be placed in politef crucible, adds a small amount of water and moistens. Add 8 milliliters of nitric acid-hydrochloric acid (3+1) mixed acid, shake up soaked overnight. It is placed on electric hot plate heating next day to clear up. Electric plate temperature should be adjusted to about 100 DEG C lower temperatures, to residual acid amount less time, add 2 milliliters of Fluohydric acid .s, slightly heighten temperature and continue to clear up. To residual acid amount less time, count 3 milliliters of perchloric acid, heighten temperature and continue to clear up. Residual acid approach exhaustion to crucible, clears up soil sample when being semi-solid rolling condition, and digestion process is basically completed. Filtering filtrate, be transferred in 100 milliliters of volumetric flasks, constant volume shakes up.

Result (ppm) is analyzed in clearing up of table 1 samples-soil

Element

Chromium

Cadmium

Arsenic

Copper

Plumbous

Nickel

Content

～10.2

～0.3

ND

～30.7

～5.15

～43.3

Embodiment 2

Refer to Fig. 1. First with Technology for Heating Processing as shown in Figure 1, samples-soil is carried out heat treatment, then weighing samples-soil 2 grams, measure Acetic acid-sodium acetate solution 20 milliliters, wherein the concentration of acetic acid and sodium acetate is 0.5 mole every liter, it is concurrently placed in beaker, put into rotor, magnetic agitation 20 minutes, be then centrifuged for separating solid phase, supernatant liquid filtering, in order to detection. Utilize inductively coupled plasma method detection Cadmium in Soil ion concentration.

Table 2 cadmium ion leaches result (ppm)

Element	Leaching concentration	Clear up result	Dissolution ratio
				Cd	～0.27	～0.3	～90%

Embodiment 3

Refer to Fig. 1.First with Technology for Heating Processing as shown in Figure 1, samples-soil is carried out heat treatment, then weigh samples-soil 2 grams, measure Acetic acid-sodium acetate solution 20 milliliters, wherein the concentration of acetic acid and sodium acetate is 0.5 mole every liter, is concurrently placed in beaker, puts into rotor, magnetic agitation 10 minutes, 20 minutes, 60 minutes and 360 minutes, it is then centrifuged for separating solid phase, supernatant liquid filtering, in order to detection. Utilizing inductively coupled plasma method detection Cadmium in Soil ion concentration, result is as shown in table 3, and the broken line graph of leaching efficiency is as shown in Figure 2, it has been found that namely up to leaching balance in 20 minutes.

Table 3 different time cadmium ion leaches result (ppm)

Leaching time (minute)	Leaching concentration	Clear up result	Dissolution ratio
				10	～0.2	～0.3	～67%
20	～0.27	～0.3	～90%
				60	～0.26	～0.3	～87%
360	～0.28	～0.3	～93%

Embodiment 4

Refer to Fig. 1. First with Technology for Heating Processing as shown in Figure 1, samples-soil is carried out heat treatment, then weighing samples-soil 2 grams, measure Acetic acid-sodium acetate solution 20 milliliters, wherein the concentration of acetic acid and sodium acetate is 0.5 mole every liter, it is concurrently placed in beaker, adopt mechanical agitation, sonic oscillation and three kinds of modes of mechanical oscillation to process, process 20 minutes respectively, be then centrifuged for separating solid phase, supernatant liquid filtering, in order to detection. Utilizing inductively coupled plasma method detection Cadmium in Soil ion concentration, result is as shown in table 4, it was shown that the effect of mechanical agitation and sonic oscillation is better than mechanical oscillation.

Table 4 cadmium ion leaches result (ppm)

Hybrid mode	Leaching concentration	Clear up result	Dissolution ratio
				Mechanical agitation	～0.26	～0.3	～87%
Sonic oscillation	～0.27	～0.3	～90%
				Mechanical oscillation	～0.24	～0.3	～80%

Claims

1. a method for efficient leaching heavy metal in soil cadmium ion, described method includes:

A) soil pretreatment, is positioned in heating furnace by samples-soil, is warming up to 450 DEG C, is incubated 3 hours, then cools to room temperature with the furnace;

B) select the suitable Acetic acid-sodium acetate solution that utilizes that pretreated samples-soil is leached, by the heavy metal cadmium the ion extraction in soil to leaching liquid;

C) this leaching liquid is separated with soil residue, filter, wait to be detected.

2. method according to claim 1, in soil pretreatment process, sintering temperature lower than 325 DEG C, must not be incubated no less than 2 hours.

3. method according to claim 1, the acetate in acetic acid-acetate composite solution is sodium acetate or ammonium acetate, constitutes hac buffer, and its pH is 3.5～6.

4. method according to claim 1, in leaching process, the quality (gram) of soil is 1:10 or 1:20 with the ratio of the volume (milliliter) of leaching liquid.

5. method according to claim 1, the alr mode selected in leaching process can be mechanical agitation, mechanical oscillation and sonic oscillation.

6. method according to claim 1, leaching time is 20 minutes.