Summary of the invention
For solving the problems of the technologies described above, the object of this invention is to provide a kind of method that magnetic active carbon works in coordination with activator restoration of soil polluted by heavy metal, the method can remove the heavy metal in heavy-metal contaminated soil efficiently, can heavy metal reclaim again.
For achieving the above object, the technical solution used in the present invention is:
Magnetic active carbon works in coordination with a method for activator restoration of soil polluted by heavy metal, comprises the following steps:
(1) in heavy-metal contaminated soil, add activator, turn over evenly, activation 20 ~ 30d;
(2) in the heavy-metal contaminated soil after activation, add magnetic active carbon, turn over evenly, absorption 20 ~ 30d;
(3) magnetic active carbon in the mode recycling step (2) of magnetic separation is utilized;
(4) by the acid soak 1 ~ 2h of the magnetic active carbon of recovery in step (3) with 0.1mol/L ~ 0.5mol/L, then neutrality is washed till by deionized water;
(5) heavy metal in the acid solution that uses of recycling step (4);
(6) circulation step (1) ~ (5), until heavy metal in soil content is up to standard;
In described step (1), activator comprises the raw material of following weight portion: fruit/vegetable waste 30 ~ 50 parts, weathered coal 30 ~ 50 parts and fertilizer 20 ~ 30 parts.
Preferably, in described step (1), the addition of activator is 15 ~ 20g/m
2.
Preferably, in described step (2), the addition of magnetic active carbon is 8 ~ 10g/m
2.
Preferably, the acid solution in described step (4) is HCl, H
2sO
4and HNO
3in one.
Preferably, in described step (1), the preparation of activator comprises the following steps:
Taking fruit/vegetable waste and weathered coal, is 20 ~ 30 DEG C in temperature, and moisture is that under the condition of 50 ~ 60% after retting 20 ~ 30d, being dried to water content is 10% ~ 15%, crosses 30 ~ 50 mesh sieves, mix, namely prepare activator with fertilizer after pulverizing.
Preferably, described fertilizer is the fertilizer that feces of livestock and poultry is made through retting.
Preferably, in described step (2), the preparation method of magnetic active carbon is:
By 10 ~ 15 weight portion FeSO
47H
2o and 10 ~ 25 weight portion FeCl
36H
2o is dissolved in deionized water, then adds 30 ~ 60 parts by weight of activated carbon, is heated to 40 ~ 60 DEG C, stirs 40min ~ 60min; Drip alkaline solution while stirring to solution alkaline, then slaking 3h ~ 4h in 100 DEG C of water-baths, is cooled to 20 ~ 30 DEG C, after spending deionized water to neutrality, isolate the magnetisable material of generation with magnet, at 100 ~ 110 DEG C, dry 4h ~ 5h, namely prepares magnetic active carbon.
Preferably, described alkaline solution is NaOH, KOH and NH
3h
2one in O.
The invention has the beneficial effects as follows:
The present invention's adopt magnetic active carbon to work in coordination with soil that activator carrys out repairing heavy metal pollution, first use activator by the heavy metallic activation in soil, then the heavy metal in magnetic active carbon absorption soil is utilized, finally magnetic active carbon is reclaimed, recycling after wash-out, the heavy metal in eluent then can be recovered.
Activator mixes with fertilizer after adopting fruit/vegetable waste and weathered coal retting, fruit/vegetable waste is the discarded object of the fruits and vegetables used in daily life, as the pericarp of apple, lemon, grape and orange etc. and the discarded object of vegetables, containing a large amount of organic matters in these fruit/vegetable waste, the element such as cellulose and N, P, K, and be nontoxic; Then containing a large amount of humic acids in weathered coal; After fruit/vegetable waste and the fermentation of weathered coal retting, the humic acid in weathered coal will be activated, and humic acid is the conditioner of soil, can improve the physicochemical property of soil, increases soil and fats up, the metallic element in activating soil; And containing a large amount of organic acid in fruit/vegetable waste after fermentation, and organic acid can be dissociated into proton and low molecular organic acid in soil, proton can cause the change of pH value in environment and oxidation-reduction potential, promotes the weathering course of dissolution of heavy metal in soil host mineral.And the fertilizer used in activator is the fertilizer that feces of livestock and poultry is made through retting, containing multiple organic acid, peptide class and the abundant nutrient comprising nitrogen, phosphorus, potassium in this fertilizer, full nutrition can not only be provided for crops, and fertilizer efficiency is long, can increase and upgrade the soil organism, promote microbial reproduction, improve physicochemical property and the biologically active of soil.
The magnetic active carbon used in the present invention adopts infusion process ferrite load to be prepared on the activated carbon, containing a large amount of micropores on active carbon, have very large specific area, have very strong adsorption capacity to the heavy metal in soil, the active carbon after load iron oxysome is magnetic.When magnetic active carbon is in soil after Adsorption of Heavy Metals, the mode of magnetic separation is utilized to be reclaimed by magnetic active carbon, acid solution is used to be eluted by the heavy metal on magnetic active carbon after recovery, magnetic active carbon after wash-out can also recycle after utilizing deionized water to be washed till neutrality, environmental protection.
Therefore, employing magnetic active carbon of the present invention is worked in coordination with the beneficial effect that activator carrys out the method for restoration of soil polluted by heavy metal and is mainly reflected in:
(1) in activator containing a large amount of organic acid, humic acid, and abundant nutrient, can heavy metal in activating soil, increases and upgrades the soil organism, promoting microbial reproduction, improve physicochemical property and the soil activation of soil;
(2) heavy metal of magnetic active carbon absorption in the soil of overactivation is used, the high adsorption capacity of magnetic active carbon heavy metal, and the magnetic active carbon of Adsorption of Heavy Metals can be reclaimed by the mode of magnetic separation, after magnetic active carbon after recovery uses acid soak wash-out, the heavy metal of magnetic active carbon absorption is entered in acid solution by wash-out, then that magnetic active carbon washing is extremely neutral, after dry, magnetic active carbon recycles, and the heavy metal in acid solution is reclaimed, environmental protection is efficient.
Detailed description of the invention
Below in conjunction with specific embodiment, the invention will be further described.
Experiment soil is selected from one piece of arable land contaminated by heavy metals near mining area, Henan, and pollutant comprises zinc, plumbous, cadmium, copper, mercury, arsenic.This arable land is divided into 7 pieces of regions, each region is label 1#, 2#, 3#, 4#, 5#, 6# and 7# respectively, every block region 40 × 50m, every block region arranges 5 sampled points, gather total 35 of the soil sample of 0 ~ 20cm in heavy-metal contaminated soil, after mixing, according to the method listed in GB5085.3-2007 " hazardous waste judging standard leaching characteristic identification ", the content of beary metal in soil is measured.After testing, the heavy metal Zn in the soil of this heavy metal pollution, Pb, Cd, Cu, Hg, As, Cr concentration is respectively: 380.6mg/kg, 150.3mg/kg, 25.87mg/kg, 300.1mg/kg, 19.43mg/kg, 68.5mg/kg, 389.2mg/kg, and pH value is 6.6.
According to the environment second level standard value of soil inorganic pollutant in GB15618-2008 " national Soil-environmental standard ", Zn, Pb during agriculture pH6.5 ~ 7.5, nonirrigated farmland, Cd, Cu, Hg, the secondary standard value of As, Cr is respectively 250,80,0.45,100,0.7,30,200mg/kg, therefore, this block is ploughed and be there is more serious heavy metal pollution.
Embodiment 1
Magnetic active carbon works in coordination with a method for activator restoration of soil polluted by heavy metal, comprises the following steps:
(1) in 1# heavy-metal contaminated soil, add activator, the addition of activator is 15g/m
2, the soil on top layer of turning over, turns over evenly, makes soil activating 20d;
(2) in the soil of the heavy metal pollution after activation, add magnetic active carbon, the addition of magnetic active carbon is 8g/m
2, the soil on top layer of turning over, turns over evenly, and keep soil moisture 15% ~ 20%, magnetic adsorbent acts on 20d in soil, makes the heavy metal in soil be attracted on magnetic active carbon;
(3) Soil tillage of magnetic active carbon effect is even, utilize magnetic separator to isolate magnetic active carbon;
(4) magnetic active carbon reclaimed in step (3) is used 0.5mol/LHCl immersion bubble 1h, then be washed till neutrality by deionized water, magnetic active carbon reusable edible;
(5) heavy metal in recycling step (4) in acid solution;
(6) if through detecting, the content of beary metal in soil exceeds standard, circulation above-mentioned steps (1) ~ (5), until the content of beary metal in soil meets standard.
Wherein activator comprises the raw material of following weight portion: fruit/vegetable waste 30 parts, weathered coal 50 parts and fertilizer 20 parts.
The preparation method of activator is: the fruit/vegetable waste and the 50 weight portion weathered coals that take 30 weight portions, it is 20 DEG C in temperature, moisture is retting after 20 days under the condition of 50%, being dried to water content is 10%, 30 mesh sieves are crossed after pulverizing, mix with 20 weight portion fertilizers, namely prepare activator.
Wherein the preparation method of fertilizer is: by chicken manure, pig manure and cow dung, and at the temperature of 20 DEG C ~ 30 DEG C, moisture is retting 30d under 30% condition, and being dried to water content is 10%, crosses 30 mesh sieves, namely prepare fertilizer after pulverizing.
Wherein the preparation method of magnetic active carbon is: by 10 weight portion FeSO
47H
2o and 25 weight portion FeCl
36H
2o is dissolved in deionized water, then adds 30 parts by weight of activated carbon, is heated to 40 DEG C, stirs 60min; Drip 0.5mol/LNaOH while stirring to solution alkaline, then slaking 3h in 100 DEG C of water-baths, is cooled to 20 ~ 30 DEG C, after spending deionized water to neutrality, isolate the magnetisable material of generation with magnet, be placed in dry 5h at 100 DEG C, baking oven, namely prepare magnetic active carbon.
Circulate after repairing for three times, the pH value in detection soil and the content of heavy metal, Zn in soil, Pb, Cd, Cu, the content of Hg, As, Cr is respectively 180.8mg/kg, 75.9mg/kg, 0.4mg/kg, 89.6mg/kg, 0.7mg/kg, 24.5mg/kg, 180.6mg/kg, pH value is 6.8, and heavy metal in soil content reaches soil safety standard.
Embodiment 2
Magnetic active carbon works in coordination with a method for activator restoration of soil polluted by heavy metal, comprises the following steps:
(1) in 2# heavy-metal contaminated soil, add activator, the addition of activator is 16g/m
2, the soil on top layer of turning over, turns over evenly, makes soil activating 22d;
(2) in the soil of the heavy metal pollution after activation, add magnetic active carbon, the addition of magnetic active carbon is 9g/m
2, the soil on top layer of turning over, turns over evenly, and keep soil moisture 15% ~ 20%, magnetic active carbon acts on 23d in soil, makes the heavy metal in soil be attracted on magnetic active carbon;
(3) Soil tillage of magnetic active carbon effect is even, utilize magnetic separator to isolate magnetic active carbon;
(4) magnetic active carbon reclaimed in step (3) is used 0.1mol/LHNO
3immersion bubble 2h, then be washed till neutrality by deionized water, magnetic active carbon reusable edible;
(5) heavy metal in recycling step (4) in acid solution;
(6) if through detecting, the content of beary metal in soil exceeds standard, circulation above-mentioned steps (1) ~ (5), until the content of beary metal in soil meets standard.
Wherein activator comprises the raw material of following weight portion: fruit/vegetable waste 35 parts, weathered coal 45 parts and fertilizer 30 parts.
The preparation method of activator is: the fruit/vegetable waste and the 45 weight portion weathered coals that take 35 weight portions are 30 DEG C in temperature, and moisture is that under the condition of 53%, retting is after 24 days, and being dried to water content is 15%, crosses 50 mesh sieves after pulverizing; Mix with 30 weight portion fertilizers, namely prepare activator.
Wherein the preparation method of fertilizer is: by chicken manure, pig manure and cow dung, and at 20 DEG C ~ 30 DEG C, moisture is retting 20d under 50% condition, and being dried to water content is 15%, crosses 50 mesh sieves, namely prepare fertilizer after pulverizing.
Wherein the preparation method of magnetic active carbon is:
By 12 weight portion FeSO
47H
2o and 10 weight portion FeCl
36H
2o is dissolved in deionized water, then adds 40 parts by weight of activated carbon, is heated to 50 DEG C, stirs 55min; Drip the KOH of 0.5mol/L while stirring to solution alkaline, then slaking 4h in 100 DEG C of water-baths, be cooled to 20 DEG C ~ 30 DEG C, after spending deionized water to neutrality, isolate the magnetisable material of generation with magnet, be placed in dry 4h at 105 DEG C, baking oven, namely prepare magnetic active carbon.
Circulate after repairing for three times, the pH value in detection soil and the content of heavy metal, Zn in soil, Pb, Cd, Cu, the content of Hg, As, Cr is respectively 170.9mg/kg, 68.3mg/kg, 0.36mg/kg, 89.2mg/kg, 0.64mg/kg, 22.6mg/kg, 160.7mg/kg, pH value is 6.8, and heavy metal in soil content reaches soil safety standard.
Embodiment 3
Magnetic active carbon works in coordination with a method for activator restoration of soil polluted by heavy metal, comprises the following steps:
(1) in 3# heavy-metal contaminated soil, add activator, the addition of activator is 17g/m
2, the soil on top layer of turning over, turns over evenly, makes soil activating 25d;
(2) in the soil of the heavy metal pollution after activation, add magnetic active carbon, the addition of magnetic active carbon is 10g/m
2, the soil on top layer of turning over, turns over evenly, and keep soil moisture 15% ~ 20%, magnetic active carbon acts on 26d in soil, makes the heavy metal in soil be attracted on magnetic active carbon;
(3) Soil tillage of magnetic active carbon effect is even, utilize magnetic separator to isolate magnetic active carbon;
(4) magnetic active carbon reclaimed in step (3) is used 0.1mol/LH
2sO
4immersion bubble 1.5h, then be washed till neutrality by deionized water, magnetic active carbon reusable edible;
(5) heavy metal in recycling step (4) in acid solution;
(6) if through detecting, the content of beary metal in soil exceeds standard, circulation above-mentioned steps (1) ~ (5), until the content of beary metal in soil meets standard.
Wherein activator comprises the raw material of following weight portion: fruit/vegetable waste 40 parts, weathered coal 40 parts and fertilizer 25 parts.
The preparation method of activator is: the fruit/vegetable waste and the 40 weight portion weathered coals that take 40 weight portions are 25 DEG C in temperature, and moisture is that under the condition of 56%, retting is after 26 days, and being dried to water content is 12%, crosses 40 mesh sieves after pulverizing; Mix with 25 weight portion fertilizers, namely prepare activator.
Wherein the preparation method of fertilizer is: by chicken manure, pig manure and cow dung, and at 20 DEG C ~ 30 DEG C, moisture is retting 26d under 40% condition, and being dried to water content is 12%, crosses 40 mesh sieves, namely prepare fertilizer after pulverizing.
Wherein the preparation method of magnetic active carbon is:
By 13 weight portion FeSO
47H
2o and 15 weight portion FeCl
36H
2o is dissolved in deionized water, then adds 50 parts by weight of activated carbon, is heated to 45 DEG C, stirs 45min; Drip the NH of 0.5mol/L while stirring
3h
2o is to solution alkaline, and then slaking 3.5h in 100 DEG C of water-baths, is cooled to 20 DEG C ~ 30 DEG C, after spending deionized water to neutrality, isolates the magnetisable material of generation with magnet, is placed in dry 4.5h at 110 DEG C, baking oven, namely prepares magnetic active carbon.
Circulate after repairing for three times, detect Zn, Pb in the content soil of pH value in soil and heavy metal, Cd, Cu, Hg, the content of As, Cr is respectively 100.5mg/kg, 60.5mg/kg, 0.29mg/kg, 85.0mg/kg, 0.59mg/kg, 20.8mg/kg, 130.1mg/kg, pH value is 7.0, and heavy metal in soil content reaches soil safety standard.
Embodiment 4
Magnetic active carbon works in coordination with a method for activator restoration of soil polluted by heavy metal, comprises the following steps:
(1) in 4# heavy-metal contaminated soil, add activator, the addition of activator is 18g/m
2, the soil on top layer of turning over, turns over evenly, makes soil activating 28d;
(2) in the soil of the heavy metal pollution after activation, add magnetic active carbon, the addition of magnetic active carbon is 8.5g/m
2, the soil on top layer of turning over, turns over evenly, and keep soil moisture 15% ~ 20%, magnetic active carbon acts on 28d in soil, makes the heavy metal in soil be attracted on magnetic active carbon;
(3) Soil tillage of magnetic active carbon effect is even, utilize magnetic separator to isolate magnetic activity;
(4) magnetic active carbon reclaimed in step (3) is used 0.2mol/LH
2sO
4immersion bubble 2h, then be washed till neutrality by deionized water, magnetic active carbon reusable edible;
(5) heavy metal in recycling step (4) in acid solution;
(6) if through detecting, the content of beary metal in soil exceeds standard, circulation above-mentioned steps (1) ~ (5), until the content of beary metal in soil meets standard.
Wherein activator comprises the raw material of following weight portion: fruit/vegetable waste 45 parts, weathered coal 35 parts and fertilizer 22 parts.
The preparation method of activator is: the fruit/vegetable waste and the 35 weight portion weathered coals that take 45 weight portions are 28 DEG C in temperature, and moisture is that under the condition of 58% after retting 28d, being dried to water content is 13%, crosses 35 mesh sieves after pulverizing; Mix with 22 weight portion fertilizers, namely prepare activator.
The preparation method of fertilizer is: by chicken manure, pig manure and cow dung, and at 20 DEG C ~ 30 DEG C, moisture is retting 28d under 45% condition, and being dried to water content is 12%, crosses 35 mesh sieves, namely prepare fertilizer after pulverizing.
Wherein the preparation method of magnetic active carbon is:
By 14 weight portion FeSO
47H
2o and 20 weight portion FeCl
36H
2o is dissolved in deionized water, then adds 60 parts by weight of activated carbon, is heated to 55 DEG C, stirs 50min; Drip the NH of 0.5mol/L while stirring
3h
2o is to solution alkaline, and then slaking 3.5h in 100 DEG C of water-baths, is cooled to 20 DEG C ~ 30 DEG C, after spending deionized water to neutrality, isolates the magnetisable material of generation with magnet, is placed in dry 4.5h at 110 DEG C, baking oven, namely prepares magnetic active carbon.
Circulate after repairing for three times, the pH value in detection soil and the content of heavy metal, Zn in soil, Pb, Cd, Cu, the content of Hg, As, Cr is respectively 145.8mg/kg, 74.2mg/kg, 0.32mg/kg, 83.2mg/kg, 0.52mg/kg, 25.8mg/kg, 150.9mg/kg, pH value is 7.2, and heavy metal in soil content reaches soil safety standard.
Embodiment 5
Magnetic active carbon works in coordination with a method for activator restoration of soil polluted by heavy metal, comprises the following steps:
(1) in 5# heavy-metal contaminated soil, add activator, the addition of activator is 20g/m
2, the soil on top layer of turning over, turns over evenly, makes soil activating 30d;
(2) in the soil of the heavy metal pollution after activation, add magnetic active carbon, the addition of magnetic active carbon is 9.5g/m
2, the soil on top layer of turning over, turns over evenly, and keep soil moisture 15% ~ 20%, magnetic active carbon acts on 30d in soil, makes the heavy metal in soil be attracted on magnetic active carbon;
(3) Soil tillage of magnetic active carbon effect is even, utilize magnetic separator to isolate magnetic active carbon;
(4) magnetic active carbon reclaimed in step (3) is used 0.3mol/LH
2sO
4immersion bubble 2h, then be washed till neutrality by deionized water, magnetic active carbon reusable edible;
(5) heavy metal in recycling step (4) in acid solution.
(6) if through detecting, the content of beary metal in soil exceeds standard, circulation above-mentioned steps (1) ~ (5), until the content of beary metal in soil meets standard.
Wherein activator comprises the raw material of following weight portion: fruit/vegetable waste 50 parts, weathered coal 30 parts and fertilizer 28 parts.
The preparation method of activator is: the fruit/vegetable waste and the 30 weight portion weathered coals that take 50 weight portions are 22 DEG C in temperature, and moisture is that under the condition of 60%, retting is after 30 days, and being dried to water content is 15%, crosses 45 mesh sieves after pulverizing; Mix with 28 weight portion fertilizers, namely prepare activator.
Wherein the preparation method of fertilizer is: by chicken manure, pig manure and cow dung, and at 20 DEG C ~ 30 DEG C, moisture is retting 30d under 40% condition, and being dried to water content is 15%, crosses 45 mesh sieves, namely prepare fertilizer after pulverizing.
Wherein the preparation method of magnetic active carbon is:
By 15 weight portion FeSO
47H
2o and 23 weight portion FeCl
36H
2o is dissolved in deionized water, then adds 45 parts by weight of activated carbon, is heated to 60 DEG C, stirs 40min; Drip the NaOH of 0.5mol/L while stirring to solution alkaline, then slaking 4h in 100 DEG C of water-baths, be cooled to 20 DEG C ~ 30 DEG C, after spending deionized water to neutrality, isolate the magnetisable material of generation with magnet, be placed in dry 4.5h at 105 DEG C, baking oven, namely prepare magnetic active carbon.
Circulate after repairing for three times, the pH value in detection soil and the content of heavy metal, Zn in soil, Pb, Cd, Cu, the content of Hg, As, Cr is respectively 120.8mg/kg, 76.8mg/kg, 0.42mg/kg, 86.7mg/kg, 0.61mg/kg, 27.6mg/kg, 154.8mg/kg, pH value is 7.1, and heavy metal in soil content reaches soil safety standard.
Comparative example 1
Comparative example 1 adopts the condition identical with embodiment 3 to repair the soil of 6# heavy metal pollution, and difference is not use activator.
Circulate after repairing for three times, the pH value in detection soil and the content of heavy metal, in earth, content of beary metal declines to some extent, but do not reach soil safety standard completely, Zn, Pb in soil, Cd, Cu, Hg, the content of As, Cr is respectively 256.3mg/kg, 78.0mg/kg, 1.96mg/kg, 94.3mg/kg, 5.81mg/kg, 27.9mg/kg, 250.7mg/kg, pH value is 6.6.
Comparative example 2
Comparative example 1 adopts the condition identical with embodiment 3 to repair the soil of 7# heavy metal pollution, and difference is that the fertilizer using preparation in embodiment 3 replaces activator.
Circulate after repairing for three times, the pH value in detection soil and the content of heavy metal, in earth, content of beary metal declines to some extent, but do not reach soil safety standard completely, Zn, Pb in soil, Cd, Cu, Hg, the content of As, Cr is respectively 200.4mg/kg, 70.6mg/kg, 1.02mg/kg, 90.4mg/kg, 3.28mg/kg, 49.7mg/kg, 210.3mg/kg, pH value is 6.7.
The repairing effect of heavy-metal contaminated soil
The arable land of the heavy metal pollution of 7 pieces of 40 × 50m is repaired by above-described embodiment 1 ~ 5 and these 7 kinds of methods of comparative example 1 and 2, after the initial content (mg/kg) and reparation of the pH value of repairing front heavy-metal contaminated soil, heavy metal, test to restorative procedure in content (mg/kg) three aspects of heavy metal, as shown in table 1.
Table 1 heavy-metal contaminated soil repairs testing result
Adopt after the soil of method to 1# ~ 5# heavy metal pollution of embodiment 1 ~ 5 repairs, in soil, pH value is in the scope of 6.8 ~ 7.1, according to the environment second level standard value of soil inorganic pollutant in GB15618-2008 " national Soil-environmental standard ", Zn during agricultural pH6.5 ~ 7.5, nonirrigated farmland, Pb, Cd, Cu, Hg, As, the secondary standard value of Cr is respectively 250, 80, 0.45, 100, 0.7, 30, 200mg/kg, as can be seen from Table 1, the content of the heavy metal in the soil of this block heavy metal pollution before repairing all exceeds secondary standard value, testing result shows that the content of beary metal in soil can be reduced to secondary standard value through three circulations by the restorative procedure of embodiment 1 ~ 5, and in comparative example 1, do not use activator, after the circulations of three times are repaired, the content of beary metal in this 6# region does not then reach the standard value of secondary, in comparative example 2, manure use replaces activator, content of beary metal after three circulations in 7# regional soil does not also reach secondary standard, but the clearance of comparative example 2 heavy metal is better than comparative example 1, show thus, if soil is without activation, heavy metal in soil exists mainly with in conjunction with state greatly, the heavy metal existed in conjunction with state is not easy to be adsorbed by magnetic active carbon, heavy metal in Organic Manure on Soil has certain activation, and in soil, add activator, can heavy metal in activating soil, promote that heavy metal changes to ionic condition, adsorbed by magnetic active carbon.