A kind of heavy-metal contaminated soil renovation agent and applicationTechnical field:
The invention belongs to soil pollution recovery technique field, be specifically related to a kind of heavy-metal contaminated soil renovation agent and application.
Technical background:
" national Soil Pollution Investigation publication " display within 2014, is announced: national edatope situation totally allows of no optimist according to Environmental Protection Department and Ministry of Land and Resources; some areas soil pollution is heavier; arable soil environmental quality causes anxiety, industry and mining discarded ground edatope outstanding problem.The human activity such as industry and mining, agricultural and Environmental Background Values of Soils height are the major causes causing soil pollution or exceed standard.Soil total exceeding standard rate in the whole nation is 16.1%, and wherein slightly, slightly, moderate and serious pollution point position ratio be respectively 11.2%, 2.3%, 1.5% and 1.1%.Pollution type is based on inorganic type, and organic type takes second place, and compound pollution proportion is less, and an inorganic pollutant figure place that exceeds standard accounts for 82.8% of all super punctuation bits.
From pollution distribution situation, soils in south china pollutes and overweights the north; The subregion soil contamination problem such as Yangtze River Delta, the Delta of the Pearl River, Northeastern rust belt are comparatively outstanding, and southwest, variable charge soil heavy metals exceeding standard scope is larger; Cadmium, mercury, arsenic, plumbous 4 kinds of level of inorganic contaminants distribution present the situation raised gradually from northwest to the southeast, from northeast to southwestward.
Principal pollutant are cadmium, nickel, copper, arsenic, mercury, lead, dichlorodiphenyl trichloroethane and polycyclic aromatic hydrocarbons.If be as the criterion with second national land investigation result, China's arable land latest data is 2,030,770,000 mu and calculates, and the cultivated area of middle serious pollution accounts for 2.9%, has reached 5,889 ten thousand mu.
Administering method at present for heavy metal pollution of soil mainly contains immobilization/stabilization, drip-rinsing process, washes local method, electromotion repairing technique method, chemical reduction method, phytoremediation, microorganism remediation, totally there is the problems such as remediation efficiency is low, processing cost is high.Traditional restorative procedure is as large in quantities such as landfill, drip washing, electrochemistry, and cost is high and usually cause Soil structure to destroy and some nutritive element loss.Therefore, develop a kind of low cost, simple, efficient, eco-friendly soil remediation medicament is significant.
Chemical passivation renovation agent is a kind of controlling area-source pollution technology of efficient economy, and this technology also meets the needs of China's Sustainable development.
Summary of the invention
Technical problem to be solved by this invention is to provide a kind of heavy-metal contaminated soil renovation agent, biomass charcoal, alpha-cylodextrin, glucose, iron powder, ferrous sulfate, polyacrylamide, sodium sulphite, thiocarbamide is adopted to be mixed in proportion, make soil-repairing agent, add to by a certain percentage in heavy-metal contaminated soil according to pollution level, reacted by the heavy metal in the synergies such as absorption, ion-exchange, reduction, chelating and soil, heavy metal is made to form stable chemical form, stop its environmental transport and transfer and diffusion, reduce heavy metal murder by poisoning degree in the environment.
For solving the problems of the technologies described above, the invention provides a kind of heavy-metal contaminated soil renovation agent, its raw material is made up of biomass charcoal, alpha-cylodextrin, glucose, iron powder, ferrous sulfate, polyacrylamide, sodium sulphite, thiocarbamide, and the weight percent of each raw material of described soil-repairing agent is:
Biomass charcoal 30-45%;
Alpha-cylodextrin 10-25%;
Glucose 10-15%;
Iron powder 10-15%;
Ferrous sulfate 10-15%;
Polyacrylamide 5-10%;
Sodium sulphite 1-5%;
Thiocarbamide 1-5%;
Described biomass charcoal is for raw material with the mixture of stalk and calcium oxide, the mass ratio of described stalk and calcium oxide is 20:1, system pressure be 20kPa, pyrolysis temperature be the condition of 500 DEG C under vacuum pyrolysis 30min, the particle diameter obtained by milled processed is the pressed powder of below 3mm;
Described alpha-cylodextrin, glucose, iron powder, ferrous sulfate, polyacrylamide, sodium sulphite, thiocarbamide are respectively the pressed powder of below 2mm.
Further, in described renovation agent, the mass percent of each raw material is:
Biomass charcoal 45%;
Alpha-cylodextrin 10%;
Glucose 10%;
Iron powder 10%;
Ferrous sulfate 10%;
Polyacrylamide 5%;
Sodium sulphite 5%;
Thiocarbamide 5%;
A kind of heavy-metal contaminated soil renovation agent of the present invention, by biomass charcoal, alpha-cylodextrin, glucose, iron powder, ferrous sulfate, polyacrylamide, sodium sulphite, thiocarbamide being uniformly mixed according to the above ratio, namely obtains repairing medicament.
A kind of heavy-metal contaminated soil renovation agent of the present invention, after obtaining mixture by said process, add in heavy-metal contaminated soil, the reparation pharmaceutical quantities of adding is the 1-10% of contaminated soil weight, then sprays a small amount of water and make Soil conservation moistening.
This medicament may be used for the improvement of single heavy metal contaminated soil, also the improvement of Compound Heavy Metals is applicable to, be applicable to the reparation of big area heavy-metal contaminated soil, comprise the mine reparation of heavy metal contamination and the reparation of heavy metal use manufacturing enterprise contaminated site.Compared with prior art, reparation medicament of the present invention has the advantage that preparation method is simple, feasible, regulation effect is good.
Relative to prior art, beneficial effect of the present invention is:
Biomass charcoal in renovation agent is obtained by vacuum pyrolysis biomass, and biomass charcoal porosity obtained is under vacuum high, and adsorptive value is high; With biomass such as stalks for raw material, make full use of resource, avoid causing environmental pollution because of its burning.Promote that the output of stalk charcoal in the process of vacuum pyrolysis increases by adding calcium oxide, the biomass charcoal obtained by vacuum pyrolysis, has specific surface area large, and duct is enriched, and easily all kinds of heavy metal ion of absorption, reduces the concentration of transport property heavy metal ion in soil; Calcium oxide self in obtained biomass charcoal can make soil pH value improve soil surface negative charge to be increased, thus the affinity of soil heavy metal increases; On the other hand pH value raises, and is also conducive to the existence of MOH+ and improves the adsorptive capacity of heavy metal ion, impels heavy metal in soil to form oxyhydroxide or combined precipitation or co-precipitation simultaneously.
Alpha-cylodextrin is the cone tubular molecule be made up of glucose ring, is made up of six glucose glycan molecules.Be hydrophobic region in cyclodextrin cylinder, drum diameter is about 0.6nm, has the molecule or group that hold the lyophobic dust that other shapes and size are applicable to and embeds in hole, the characteristic of formation inclusion compound.Cyclodextrin Adsorption of Heavy Metal Ions and organic pollutant, undertaken by tetra-inclusion complex substantially.Alpha-cylodextrin can directly and heavy metal ion coordination generate multi-nuclear metal compound.
Polyacrylamide is high molecular polymer, has good water-soluble, nontoxic, non-corrosiveness, can improve the physicals of soil, increase soil macro aggregate number, improve soil hydraulic and water content, slow down depletion, soil can be allowed fully to contact with passivator; In addition, polyacrylamide has carboxyl and amide group isoreactivity group, by forming coordinate bond with the metal ion on soil particle surface, has the synergy making stable chromium ion;
Glucose is a kind of natural high moleculer eompound, and be the renewable material of one of nature abundance, degradable, can not to environment.The hydroxyl and glycosidic link that can react in a large number is there is, adsorbable a large amount of heavy metal ion in its molecular chain;
Sodium sulphite can react with exchangeable species heavy metal ion and form stable chemical form, stops its environmental transport and transfer and diffusion, reduces heavy metal murder by poisoning degree in the environment.
Thiocarbamide and exchangeable species heavy metal ion are reacted and are formed stable chemical form, form the throw out of stabilization.
The reducing property of iron powder and ferrous sulfate is high, divalence cadmium can be reduced, soluble in water, low price
Except the effects such as said components absorption separately, reduction, precipitation, complexing, adding of biomass charcoal can improve soil physico-chemical property well, greatly strengthens the permeability of soil; Under the effect of polyacrylamide, ammonia has in the edatope of water, promotes that each component is disperseed in soil, to greatest extent with soil contact reacts.
Play synergy by said components, the leaching yield of heavy metal in soil is reduced greatly, reach and be better than the primary standard of country " standard of soil environment quality " (GB15618-1995).
Embodiment:
Embodiment 1
Test soil collecting is from certain heavy metal contamination region, and the heavy metal content in this regional soil top layer is higher than the grade III Standard of " standard of soil environment quality " (GB15618-1995).Practical situation according to polluting are repaired:
(a), sample from soil, detect and adopt turnover oscillator to carry out leaching test to soil according to solid waste " Leaching leaching method sulfonitric method " (HJ/T299-2007), detect preprosthetic heavy metal-polluted soil concentration;
Prepared by (b), soil-repairing agent:
With the mixture of stalk and calcium oxide for raw material, the mass ratio of described stalk and calcium oxide is 20:1, system pressure be 20kPa, pyrolysis temperature be the condition of 500 DEG C under vacuum pyrolysis 30min, the particle diameter obtained by milled processed is the pressed powder of below 3mm;
Obtain pulverous alpha-cylodextrin, glucose, iron powder, ferrous sulfate, polyacrylamide, sodium sulphite, thiocarbamide that particle diameter is less than 2mm.
The mass percent of each raw material is:
Biomass charcoal 45%;
Alpha-cylodextrin 10%;
Glucose 10%;
Iron powder 10%;
Ferrous sulfate 10%;
Polyacrylamide 5%;
Sodium sulphite 5%;
Thiocarbamide 5%;
Carry out Homogeneous phase mixing according to the above ratio, namely complete preparation, obtain repairing medicament.
(c), heavy-metal contaminated soil is dug out, send into crusher in crushing, through Belt Conveying to mixing tank, reparation medicament for soil quality 10% is fully mixed with contaminated soil, in mixing process, spraying a small amount of water makes Soil conservation moistening, leaves standstill 10 days, namely complete reparation after mixing.
(d), effect detection: sample from the soil after reparation, detecting adopts turnover oscillator to carry out leaching test to soil according to solid waste " Leaching leaching method sulfonitric method " (HJ/T299-2007), detect the heavy metal-polluted soil concentration after repairing, result is as shown in table 1:
Table 1
| Embodiment 1 | Cadmium (Cd) | Plumbous (Pb) | Zinc (Zn) | Mercury (Hg) |
| Before process (mg/kg) | 33.3 | 876 | 892 | 5.9 |
| After process (mg/kg) | 0.009 | 0.06 | 0.5 | Do not detect |
Cadmium in Soil after reparation, lead, zinc, mercury content meet the primary standard of " standard of soil environment quality " (GB15618-1995).
Embodiment 2
Test soil collecting is from certain heavy metal contamination region, and the heavy metal content in this regional soil top layer is higher than the grade III Standard of " standard of soil environment quality " (GB15618-1995).Practical situation according to polluting are repaired:
(a), sample from soil, detect and adopt turnover oscillator to carry out leaching test to soil according to solid waste " Leaching leaching method sulfonitric method " (HJ/T299-2007), detect preprosthetic heavy metal-polluted soil concentration;
Prepared by (b), soil-repairing agent:
With the mixture of stalk and calcium oxide for raw material, the mass ratio of described stalk and calcium oxide is 20:1, system pressure be 20kPa, pyrolysis temperature be the condition of 500 DEG C under vacuum pyrolysis 30min, the particle diameter obtained by milled processed is the pressed powder of below 3mm;
Obtain pulverous alpha-cylodextrin, glucose, iron powder, ferrous sulfate, polyacrylamide, sodium sulphite, thiocarbamide that particle diameter is less than 2mm.
The mass percent of each raw material is:
Biomass charcoal 30%;
Alpha-cylodextrin 25%;
Glucose 10%;
Iron powder 15%;
Ferrous sulfate 10%;
Polyacrylamide 8%;
Sodium sulphite 1%;
Thiocarbamide 1%;
Carry out Homogeneous phase mixing according to the above ratio, namely complete preparation, obtain repairing medicament.
(c), heavy-metal contaminated soil is dug out, send into crusher in crushing, through Belt Conveying to mixing tank, reparation medicament for soil quality 1% is fully mixed with contaminated soil, in mixing process, sprays a small amount of water and make Soil conservation moistening, leave standstill 10 days after mixing, namely complete reparation.
(d), effect detection: sample from the soil after reparation, detecting adopts turnover oscillator to carry out leaching test to soil according to solid waste " Leaching leaching method sulfonitric method " (HJ/T299-2007), detect the heavy metal-polluted soil concentration after repairing, result is as shown in table 2:
Table 2
| Embodiment 2 | Cadmium (Cd) | Plumbous (Pb) | Zinc (Zn) | Mercury (Hg) |
| Before process (mg/kg) | 9.1 | 931 | 653 | 4.2 |
| After process (mg/kg) | 0.01 | 0.2 | 0.9 | Do not detect |
Cadmium in Soil after reparation, lead, zinc, mercury content meet the primary standard of " standard of soil environment quality " (GB15618-1995).
Embodiment 3
Test soil collecting is from certain heavy metal contamination region, and the heavy metal content in this regional soil top layer is higher than the grade III Standard of " standard of soil environment quality " (GB15618-1995).Practical situation according to polluting are repaired:
(a), sample from soil, detect and adopt turnover oscillator to carry out leaching test to soil according to solid waste " Leaching leaching method sulfonitric method " (HJ/T299-2007), detect preprosthetic heavy metal-polluted soil concentration;
Prepared by (b), soil-repairing agent:
With the mixture of stalk and calcium oxide for raw material, the mass ratio of described stalk and calcium oxide is 20:1, system pressure be 20kPa, pyrolysis temperature be the condition of 500 DEG C under vacuum pyrolysis 30min, the particle diameter obtained by milled processed is the pressed powder of below 3mm;
Obtain pulverous alpha-cylodextrin, glucose, iron powder, ferrous sulfate, polyacrylamide, sodium sulphite, thiocarbamide that particle diameter is less than 2mm.
The mass percent of each raw material is:
Biomass charcoal 30%;
Alpha-cylodextrin 10%;
Glucose 15%;
Iron powder 10%;
Ferrous sulfate 15%;
Polyacrylamide 10%;
Sodium sulphite 5%;
Thiocarbamide 5%;
Carry out Homogeneous phase mixing according to the above ratio, namely complete preparation, obtain repairing medicament.
(c), heavy-metal contaminated soil is dug out, send into crusher in crushing, through Belt Conveying to mixing tank, reparation medicament for soil quality 5% is fully mixed with contaminated soil, in mixing process, sprays a small amount of water and make Soil conservation moistening, leave standstill 10 days after mixing, namely complete reparation.
(d), effect detection: sample from the soil after reparation, detecting adopts turnover oscillator to carry out leaching test to soil according to solid waste " Leaching leaching method sulfonitric method " (HJ/T299-2007), detect the heavy metal-polluted soil concentration after repairing, result is as shown in table 3:
Table 3
| Embodiment 3 | Cadmium (Cd) | Plumbous (Pb) | Zinc (Zn) | Mercury (Hg) |
| Before process (mg/kg) | 11.1 | 876 | 581 | 4.7 |
| After process (mg/kg) | 0.01 | 0.09 | 0.6 | Do not detect |
Cadmium in Soil after reparation, lead, zinc, mercury content meet the primary standard of " standard of soil environment quality " (GB15618-1995).