WO2021031516A1 - Passivation method for heavy metal contaminated farmland soil - Google Patents
Passivation method for heavy metal contaminated farmland soil Download PDFInfo
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- WO2021031516A1 WO2021031516A1 PCT/CN2020/070832 CN2020070832W WO2021031516A1 WO 2021031516 A1 WO2021031516 A1 WO 2021031516A1 CN 2020070832 W CN2020070832 W CN 2020070832W WO 2021031516 A1 WO2021031516 A1 WO 2021031516A1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09C—RECLAMATION OF CONTAMINATED SOIL
- B09C1/00—Reclamation of contaminated soil
- B09C1/08—Reclamation of contaminated soil chemically
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- the invention belongs to the field of soil restoration in the technical field of environmental engineering, and specifically relates to a passivation method for heavy metal polluted farmland soil.
- Soil heavy metal pollution has now become one of the major environmental pollution problems in my country. With the continuous and rapid development of heavy metal industries such as mining, metal smelting, chemical industry, battery manufacturing, etc., heavy metal pollutant emissions have also increased year by year. In addition, some illegal and illegal enterprises have outstanding pollution problems, making my country's heavy metal pollution present a high incidence. situation. Of arable land suffering from varying degrees of heavy metal pollution has been close to 010 million hm 2, every year because of pollution caused by heavy metals in food production over 10 million t, the food was contaminated with heavy metals up to 12 million t.
- the harm of soil heavy metals to crop production is mainly reflected in two aspects: one is to make the heavy metal content of agricultural products exceed the standard; the other is to have a toxic effect on crops and cause crop production to decrease or even to no harvest. Even when the heavy metal arsenic is at a low concentration, the seedlings of more sensitive crops such as rice, pepper, red cowpea, etc. are already very poisoned, and the biomass can be reduced by more than 10%. Heavy metals can pass through the soil-plant system and finally enter the human body through the food chain, affecting human health.
- the main domestic treatment methods for heavy metal contaminated farmland soil include soil passivation, agronomic regulation, phytoremediation, soil leaching, and planting structure adjustment.
- phytoremediation is the main technology used, but this technology has a long processing cycle.
- Chinese invention patents CN201711464010, CN201610596960, CN201710178365, CN201810365538, CN201610079842 and many other prior arts disclose methods of soil passivation and passivating agents used in the methods, which are mainly achieved by mixing different types of passivating agents with soil. It acts with heavy metals to passivate them, but each type of passivator has a different principle for removing heavy metals. It is difficult to distinguish the actual effect and interaction of each passivator, and it is difficult to further improve the removal of heavy metals. In addition, many effects such as adsorption and chemical effects in the prior art are carried out simultaneously, which may have restrictive effects between different effects.
- the invention combines ferric oxide, calcium carbonate, calcium hydroxyphosphate, plant ash, and bentonite and uses them step by step, and fully utilizes the advantages of chemical complexation, precipitation and physical adsorption of heavy metal pollutants of different passivation materials, and combines the advantages of all parties Together, an economic, efficient, green and environmentally friendly heavy metal passivation agent and its repair method have been established, which effectively realizes the effective repair of heavy metal polluted farmland.
- the present invention provides a passivation method for heavy metal polluted farmland soil, which is specifically as follows:
- step 2) Add a passivating agent, which is mainly used for adsorption, to the mixture obtained in step 1), stir it evenly, and leave it for curing;
- step 3 Add water to the mixture obtained in step 2), adjust the weight moisture content to 20%-40%, and leave it for curing.
- the weight ratio of ferric oxide, calcium carbonate, and calcium hydroxyphosphate is 0.5:0.25:0.25; the weight ratio of plant ash and bentonite is 0.5:1.
- the bentonite is calcium-based bentonite, and its main component is montmorillonite.
- the weight of the passivation agent that mainly plays a chemical reaction is 0.6%-1% of the heavy metal contaminated soil; the weight of the passivation agent that mainly plays the role of adsorption is 0.75%-% of the heavy metal contaminated soil. 3%.
- the curing time of step 1) is 10-30 min; the curing time of step 2) is 10-30 min; the curing time of step 3) is 2-5 days.
- the heavy metal contaminated soil contains arsenic, copper, lead, nickel, and zinc.
- the heavy metal contaminated soil is farmland soil contaminated by heavy metals around the mining area.
- the present invention Compared with the existing farmland soil remediation technology, the present invention has the following advantages:
- This application first uses a passivator that mainly plays a role of chemical reaction to mix with heavy metal contaminated soil. While realizing the chemical reaction, the passivator and heavy metal pollutants can be distributed more uniformly in the soil, which can fully make The passivator is in contact with heavy metal pollutants in the soil mass. Then add a passivator that mainly plays a role of adsorption, which can adsorb heavy metal pollutants and also the adsorption part mainly plays a role of chemical reaction, so that the chemical reaction reagent is distributed around the adsorbent or adsorbed on the adsorbent In this way, it is possible to better realize the unified chemical treatment of the physically concentrated heavy metals, thereby more effectively realizing the soil passivation effect.
- This application uses ferric oxide, calcium carbonate, and calcium hydroxyphosphate to remove heavy metals to achieve synergy among the three substances.
- Iron trioxide can generate iron ions that react with heavy metal oxyacid radicals (such as arsenate) in the presence of water, which can passivate such heavy metal pollutants through chemical reactions.
- Calcium carbonate is slightly dissolved in water, and calcium ions are also It can react with heavy metal oxyacid radicals (such as arsenate) to passivate such heavy metal pollutants.
- Carbonate and more heavy metal ions can form carbonates, and the hydroxide radicals produced by hydrolysis can also interact with more heavy metal ions.
- the heavy metal ions of the ions generate hydroxides, thereby removing more kinds of heavy metal pollutants.
- the calcium ions and hydroxides produced by the part of calcium hydroxyphosphate dissolved in water can play a similar role to the hydrolysis of calcium ions and carbonates in calcium carbonate to produce hydroxides, but the produced phosphate can react with some heavy metal ions at the same time , Can also play a role in adjusting and buffering the pH value.
- iron ions usually combine with heavy metal oxyacid radicals to cause the pH of the soil to drop, while calcium ions combine with heavy metal oxyacid radicals more stably under neutral and alkaline pH conditions.
- the removal of the heavy metal oxyacid radical can be maintained under high efficient pH reaction conditions.
- hydroxide, carbonate and phosphate can also efficiently interact with heavy metal ions under the pH buffering effect of phosphate and carbonate, thereby realizing three types of iron trioxide, calcium carbonate and calcium hydroxyphosphate.
- the mutual support of the components of the material makes the reaction always proceed under suitable conditions, which can better passivate the soil.
- Ferric oxide, calcium carbonate, and calcium hydroxyphosphate mainly play a chemical reaction, but as solid substances, they have a certain specific surface area and also have an adsorption effect, but the adsorption effect is much smaller than that of an adsorbent.
- Plant ash is the residue of agricultural herbs and woody plants after incineration. It has weak alkalinity, large specific surface area and pore volume, and has strong adsorption capacity and surface complexing capacity for heavy metals. Its weak alkalinity is beneficial to increase
- the pH of the soil promotes the precipitation of heavy metals to form hydroxides; bentonite is a natural clay mineral with abundant reserves in nature and low price. Its main component is montmorillonite, with fine particles, large specific surface area and high
- the interlayer structure contains exchangeable inorganic cations. Part of the oxygen atom electrons are exposed on the crystal surface.
- Heavy metal elements can be fixed by ion exchange and coprecipitation with specific adsorbents.
- the special structure of clay minerals helps To form a soil aggregate structure and increase the soil's ability to retain fertilizer and water.
- Plant ash and bentonite mainly play the role of adsorption due to their large specific surface area. They also have the role of pH adjustment and ion exchange. In addition to the role of adsorption, they can interact with the evenly distributed ferric oxide, calcium carbonate, and calcium hydroxyphosphate. In addition to the synergistic effect, it can further interact with ferric oxide, calcium carbonate, and calcium hydroxyphosphate by exerting pH adjustment and ion exchange effects, making the soil passivation effect better.
- the samples of heavy metal contaminated soil in the following embodiments of the present invention come from farmland soil around a certain mining area in Jingmen, Hubei.
- the samples are mainly contaminated by arsenic, copper, lead, nickel, zinc, etc. See Table 1 for specific parameters.
- step 2) Add 5 g of plant ash and 10 g of calcium bentonite to the mixture obtained in step 1), stir it evenly, and leave it for 20 minutes for curing;
- step 3 Sprinkle tap water into the mixture obtained in step 2), adjust the weight water content to 30%, stir evenly and leave it for 3 days for curing.
- step 2) Add 2 g of plant ash and 13 g of calcium bentonite to the mixture obtained in step 1), stir evenly, and leave it for 10 minutes for curing;
- step 3 Sprinkle tap water into the mixture obtained in step 2), adjust the weight water content to 30%, stir evenly and leave it for 3 days for curing.
- step 2) Add 9 g of plant ash and 6 g of calcium bentonite to the mixture obtained in step 1), stir evenly, and leave for 30 min for curing;
- step 2) Sprinkle tap water into the mixture obtained in step 1), adjust the weight moisture content to 30%, stir evenly, and then stand for 3 days for curing.
- step 2) Add 4g of ferric oxide, 2g of calcium carbonate and 2g of hydroxycalcium phosphate to the mixture obtained in step 1), stir it evenly, and leave it to stand for 20 minutes;
- step 3 Sprinkle tap water into the mixture obtained in step 2), adjust the weight water content to 30%, stir evenly and leave it for 3 days for curing.
- step 2) Add 5 g of plant ash and 10 g of calcium bentonite to the mixture obtained in step 1), stir it evenly, and leave it for 20 minutes for curing;
- step 3 Sprinkle tap water into the mixture obtained in step 2), adjust the weight water content to 30%, stir evenly and leave it for 3 days for curing.
- step 2) Add 5 g of plant ash and 10 g of calcium bentonite to the mixture obtained in step 1), stir it evenly, and leave it for 20 minutes for curing;
- step 3 Sprinkle tap water into the mixture obtained in step 2), adjust the weight water content to 30%, stir evenly and leave it for 3 days for curing.
- step 2) Add 5 g of plant ash and 10 g of calcium bentonite to the mixture obtained in step 1), stir it evenly, and leave it for 20 minutes for curing;
- step 2) Add 15g of activated carbon to the mixture obtained in step 1), stir it evenly, and leave it for 20 minutes for curing;
- step 3 Sprinkle tap water into the mixture obtained in step 2), adjust the weight water content to 30%, stir evenly and leave it for 3 days for curing.
- the passivation method of the present application has a good passivation effect, can passivate the effective state of heavy metals in the contaminated farmland soil, and has a good passivation effect.
- the passivation agent which mainly plays a role of chemical reaction, is uniformly distributed in the soil body phase contaminated by heavy metals, and then the passivation agent, which mainly plays a role of adsorption, is uniformly distributed.
- the chemical agent is uniformly distributed in the above mixture, which can make the chemical reaction passivator and heavy metals mix uniformly in the soil, and then concentrate on the surface or around the adsorbent together, which can make the chemical reaction proceed under uniform and effective conditions.
- a more optimized passivation effect can be achieved. It can be seen from Comparative Example 1 that if the passivation agent, which mainly plays the role of chemical reaction and adsorption, is added to the soil at the same time, each reagent will act at the same time.
- the conditions for chemical reaction are uncertain, chemical reaction and physical adsorption
- the different reagents may cause part of the adsorbent to adsorb excessive pollutants and insufficient passivation agent, while another part of the adsorbent adsorbs excessive passivation agent without contacting the appropriate amount of pollutants.
- Comparative Example 2 if the passivation agent that mainly plays the role of adsorption is added first, the uneven distribution of heavy metal pollutants and the passivation agent that mainly plays the role of chemical reaction will increase, and the chemical reaction in the soil body will increase.
- the environment is not uniform, although most heavy metals can be passivated, but the passivation effect cannot reach the level of Example 1.
- Example 1 By comparing Example 1 with Comparative Examples 3-5, it can be seen that the combined use of ferric oxide, calcium carbonate, and calcium hydroxyphosphate has a mutually supporting effect in function, thereby producing a synergistic effect to passivate heavy metals through chemical reactions .
- Iron ions and calcium ions can react with heavy metal oxyacids under neutral partial acid or neutral alkaline environmental conditions, and can make them react together under the buffer conditions of phosphate and carbonate, making heavy metal oxyacids It can be effectively passivated under stable chemical environmental conditions from weak acid to weak base.
- the carbonate ion, hydroxide ion, and phosphate ion also achieve stable passivation of heavy metal ions under the buffering effect of phosphate and carbonate.
- Example 1 Comparative Example 6
- plant ash and bentonite which also have pH adjustment and ion exchange effects, can better achieve the adjustment and supplementation of the chemical effects of ferric oxide, calcium carbonate and calcium hydroxyphosphate, so as to better achieve the effect of Passivation effect of substances.
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Abstract
A passivation method for heavy metal contaminated farmland soil, comprising: 1) adding a passivating agent mainly achieving a chemical reaction function into heavy metal contaminated soil, uniformly stirring, and standing for maintenance; 2) adding a passivating agent mainly achieving an adsorption function into the mixture obtained in the step 1), uniformly stirring, and standing for maintenance; and 3) adding water into the mixture obtained in the step 2), adjusting the weight moisture content to 20-40%, and standing for maintenance. The method achieves effective remediation of heavy metal contaminated farmland.
Description
本发明属于环境工程技术领域中的土壤修复领域，具体涉及一种重金属污染农田土壤的钝化方法。The invention belongs to the field of soil restoration in the technical field of environmental engineering, and specifically relates to a passivation method for heavy metal polluted farmland soil.
土壤重金属污染现已成为我国主要的环境污染问题之一。随着矿山开采、金属冶炼、化工、电池制造等涉及重金属行业的不断快速发展，重金属的污染物排放量也逐年增加，加之一些违规违法企业超标排污等问题突出，使得我国重金属污染呈现一个高发的态势。我国遭受不同程度重金属污染的耕地面积已接近0.1亿hm
2，每年因重金属污染导致的粮食减产超过1000万t，被重金属污染的粮食多达1200万t。
Soil heavy metal pollution has now become one of the major environmental pollution problems in my country. With the continuous and rapid development of heavy metal industries such as mining, metal smelting, chemical industry, battery manufacturing, etc., heavy metal pollutant emissions have also increased year by year. In addition, some illegal and illegal enterprises have outstanding pollution problems, making my country's heavy metal pollution present a high incidence. situation. Of arable land suffering from varying degrees of heavy metal pollution has been close to 010 million hm 2, every year because of pollution caused by heavy metals in food production over 10 million t, the food was contaminated with heavy metals up to 12 million t.
土壤重金属对作物生产的危害主要体现在两个方面：一是使农产品重金属含量超标；二是对作物产生毒害作用致使作物减产，甚至绝收。即使重金属砷在低浓度时，水稻、辣椒、红豇豆等较敏感的作物幼苗受毒害已非常明显，生物量减少就可达10％以上。重金属可以通过土壤-植物***，经由食物链最终进入人体，影响人体健康。且可以危害人的皮肤、呼吸、消化、泌尿、心血管、神经、造血等***，可以诱发细胞染色体畸变、姐妹染色单体互换和微核的增加等DNA结构损伤的细胞学后果。The harm of soil heavy metals to crop production is mainly reflected in two aspects: one is to make the heavy metal content of agricultural products exceed the standard; the other is to have a toxic effect on crops and cause crop production to decrease or even to no harvest. Even when the heavy metal arsenic is at a low concentration, the seedlings of more sensitive crops such as rice, pepper, red cowpea, etc. are already very poisoned, and the biomass can be reduced by more than 10%. Heavy metals can pass through the soil-plant system and finally enter the human body through the food chain, affecting human health. And it can harm the human skin, breathing, digestion, urinary, cardiovascular, neurological, hematopoietic and other systems, and can induce cellular chromosomal aberrations, sister chromatid exchange, and increase in micronuclei and other cytological consequences of DNA structural damage.
目前，国内主要使用的重金属污染农田土壤处理方法包括土壤钝化法、农艺调控、植物修复、土壤淋洗、种植结构调整等。其中，植物修复是主要的使用技术，但该技术处理周期较长。At present, the main domestic treatment methods for heavy metal contaminated farmland soil include soil passivation, agronomic regulation, phytoremediation, soil leaching, and planting structure adjustment. Among them, phytoremediation is the main technology used, but this technology has a long processing cycle.
土壤钝化，是指在土壤中添加化学调理剂或钝化剂，通过吸附或共沉淀作用来降低重金属的可移动性，以降低土壤中重金属有效态的含量，减少作物对重金属的吸收量，从而最大限度地降低重金属的毒性。这是一种简便、快速、效果好、经济实用的方法，是对污染农田土壤修复行之有效的方法。Soil passivation refers to adding chemical conditioning agents or passivators to the soil to reduce the mobility of heavy metals through adsorption or co-precipitation, so as to reduce the effective content of heavy metals in the soil and reduce the absorption of heavy metals by crops. So as to minimize the toxicity of heavy metals. This is a simple, fast, effective, economical and practical method, and an effective method for remediation of contaminated farmland soil.
中国发明专利CN201711464010、CN201610596960、CN201710178365、CN201810365538、CN201610079842等众多现有技术公开了土壤钝化的方法以及用于该方法的钝化剂，其主要是通过将不同种类的钝化剂与土壤进行混合以与重金属发生作用而将其钝化，但每种种类的钝化剂去除重金属的原理不同，难以区分每种钝化剂的实际作用与相互作用，难以进一步提升重金属去除效果。而且现有技术中的吸附作用和化学作用等众多作用同时进行，其可能存在不同作用之间限制性的影响。中国发明专利CN201710902422公开了先加入吸附剂再加入化学反应试剂的技术方案以去除土壤中的重金属，但将重金属先进行吸附可能造成其在土壤中局部过量，对进一步提高土壤钝化可能产生不利影响。因 此，对于如何提高土壤钝化的技术效果仍然需要进行更深入的研究。Chinese invention patents CN201711464010, CN201610596960, CN201710178365, CN201810365538, CN201610079842 and many other prior arts disclose methods of soil passivation and passivating agents used in the methods, which are mainly achieved by mixing different types of passivating agents with soil. It acts with heavy metals to passivate them, but each type of passivator has a different principle for removing heavy metals. It is difficult to distinguish the actual effect and interaction of each passivator, and it is difficult to further improve the removal of heavy metals. In addition, many effects such as adsorption and chemical effects in the prior art are carried out simultaneously, which may have restrictive effects between different effects. Chinese invention patent CN201710902422 discloses a technical solution of adding adsorbents and then chemical reaction reagents to remove heavy metals in the soil. However, first adsorbing heavy metals may cause local excess in the soil, which may have an adverse effect on further improving soil passivation . Therefore, how to improve the technical effect of soil passivation still needs more in-depth research.
发明内容Summary of the invention
本发明将三氧化二铁、碳酸钙、羟基磷酸钙、草木灰、膨润土结合并分步使用，充分发挥不同钝化材料的化学络合、沉淀和物理吸附重金属污染物的优势，将各方的优点结合在一起，建立了一种经济、高效、绿色、环保的重金属钝化药剂及其修复方法，有效实现了重金属污染农田的有效修复。The invention combines ferric oxide, calcium carbonate, calcium hydroxyphosphate, plant ash, and bentonite and uses them step by step, and fully utilizes the advantages of chemical complexation, precipitation and physical adsorption of heavy metal pollutants of different passivation materials, and combines the advantages of all parties Together, an economic, efficient, green and environmentally friendly heavy metal passivation agent and its repair method have been established, which effectively realizes the effective repair of heavy metal polluted farmland.
为实现上述目的，本发明提供了一种重金属污染农田土壤的钝化方法，具体如下：To achieve the above objective, the present invention provides a passivation method for heavy metal polluted farmland soil, which is specifically as follows:
1)将主要起到化学反应作用的钝化剂加入重金属污染土壤中，搅拌均匀，静置养护；1) Add the passivation agent that mainly plays a role of chemical reaction to heavy metal contaminated soil, stir it evenly, and leave it for curing;
2)向步骤1)得到的混合物中加入主要起到吸附作用的钝化剂，搅拌均匀，静置养护；2) Add a passivating agent, which is mainly used for adsorption, to the mixture obtained in step 1), stir it evenly, and leave it for curing;
3)向步骤2)得到的混合物中加入水，调节重量含水率至20％-40％，静置养护。3) Add water to the mixture obtained in step 2), adjust the weight moisture content to 20%-40%, and leave it for curing.
优选的，主要起到化学反应作用的钝化剂为三氧化二铁、碳酸钙、羟基磷酸钙，其重量比为0.3-0.7：0.15-0.35：0.15-0.35。Preferably, the passivating agent that mainly plays the role of chemical reaction is ferric oxide, calcium carbonate, calcium hydroxyphosphate, and the weight ratio is 0.3-0.7:0.15-0.35:0.15-0.35.
优选的，主要起到吸附作用的钝化剂为草木灰、膨润土，其重量比为0.25-0.75：0.5-1.5。Preferably, the deactivator that mainly plays the role of adsorption is plant ash and bentonite, and the weight ratio is 0.25-0.75:0.5-1.5.
优选的，三氧化二铁、碳酸钙、羟基磷酸钙的重量比为0.5：0.25：0.25；草木灰、膨润土的重量比为0.5：1。Preferably, the weight ratio of ferric oxide, calcium carbonate, and calcium hydroxyphosphate is 0.5:0.25:0.25; the weight ratio of plant ash and bentonite is 0.5:1.
优选的，所述膨润土为钙基膨润土，其主要成分为蒙脱石。Preferably, the bentonite is calcium-based bentonite, and its main component is montmorillonite.
优选的，所述的主要起到化学反应作用的钝化剂的重量为重金属污染土壤的0.6％-1％；所述主要起到吸附作用的钝化剂的重量为重金属污染土壤的0.75％-3％。Preferably, the weight of the passivation agent that mainly plays a chemical reaction is 0.6%-1% of the heavy metal contaminated soil; the weight of the passivation agent that mainly plays the role of adsorption is 0.75%-% of the heavy metal contaminated soil. 3%.
优选的，步骤1)的养护时间为10-30min；步骤2)的养护时间为10-30min；步骤3)的养护时间为2-5天。Preferably, the curing time of step 1) is 10-30 min; the curing time of step 2) is 10-30 min; the curing time of step 3) is 2-5 days.
优选的，所述重金属污染土壤中含有砷、铜、铅、镍、锌。Preferably, the heavy metal contaminated soil contains arsenic, copper, lead, nickel, and zinc.
优选的，所述重金属污染土壤为矿区周边的受重金属污染的农田土壤。Preferably, the heavy metal contaminated soil is farmland soil contaminated by heavy metals around the mining area.
与现有的农田土壤修复技术相比，本发明具有如下优势：Compared with the existing farmland soil remediation technology, the present invention has the following advantages:
(1)本申请先采用主要起到化学反应作用的钝化剂与重金属污染土壤混合，实现化学反应的同时，使得钝化剂与重金属污染物能够在土壤中实现更均匀的分布，能够充分使得钝化剂与重金属污染物在土壤体相中接触。然后再加入主要起到吸附作用钝化剂，能够将重金属污染物吸附的同时也将吸附部分主要起到化学反应作用的钝化剂，使得在化学反应试剂分布在吸附剂周围或被吸附于吸附剂中，从而能够更好的实现将物理集中的重金属统一进行化学处理，从而更有效地实现了土壤钝化效果。如现有技术中先进行物理吸附则导致重金属污染物在吸附剂中的浓度较高，而土壤中的浓度较低，再分布化学反应试剂时，虽然化学反应试剂均匀分布在土壤中，但其以均一浓度去除土壤中的低浓度和吸附剂中高 浓度的重金属污染物时，存在局部化学反应试剂过剩或不足的情况，虽然能够实现土壤钝化，但钝化效果是难以达到本申请的程度的。(1) This application first uses a passivator that mainly plays a role of chemical reaction to mix with heavy metal contaminated soil. While realizing the chemical reaction, the passivator and heavy metal pollutants can be distributed more uniformly in the soil, which can fully make The passivator is in contact with heavy metal pollutants in the soil mass. Then add a passivator that mainly plays a role of adsorption, which can adsorb heavy metal pollutants and also the adsorption part mainly plays a role of chemical reaction, so that the chemical reaction reagent is distributed around the adsorbent or adsorbed on the adsorbent In this way, it is possible to better realize the unified chemical treatment of the physically concentrated heavy metals, thereby more effectively realizing the soil passivation effect. For example, the first physical adsorption in the prior art results in a higher concentration of heavy metal pollutants in the adsorbent, but a lower concentration in the soil. When the chemical reaction reagent is redistributed, although the chemical reaction reagent is evenly distributed in the soil, its When removing low-concentration heavy metal pollutants in the soil and high-concentration heavy metal pollutants in the adsorbent at a uniform concentration, there is a situation of excessive or insufficient local chemical reaction reagents. Although the soil passivation can be achieved, the passivation effect is difficult to reach the level of this application. .
(2)本申请采用三氧化二铁、碳酸钙、羟基磷酸钙去除重金属时实现了三种物质之间的协同作用。三氧化二铁能够在水存在作用下生成与重金属含氧酸根(例如砷酸根)反应的铁离子，从而能够通过化学反应使该类重金属污染物钝化，碳酸钙在水中微量溶解，钙离子也能够与重金属含氧酸根(例如砷酸根)反应，从而使该类重金属污染物钝化，而碳酸根与较多的重金属离子能够生成碳酸盐，其水解生成的氢氧根也能够与较多的重金属离子生成氢氧化物，从而去除较多种类的重金属污染物。羟基磷酸钙在水中溶解的部分产生的钙离子和氢氧根能够起到碳酸钙中钙离子和碳酸根水解产生氢氧根相似的作用，但产生的磷酸根在能够与部分重金属离子反应的同时，还能够起到调节以及缓冲pH值的作用。对于重金属含氧酸根的去除，铁离子通常在与重金属含氧酸根结合导致土壤的pH下降，而钙离子在pH值中性偏碱性条件下与重金属含氧酸根结合更稳定，因此在磷酸根以及碳酸根的多元酸根的pH缓冲作用下，能够使得重金属含氧酸根的去除保持在高效的pH反应条件下。而对于重金属离子，氢氧根、碳酸根和磷酸根在磷酸根和碳酸根的pH缓冲作用下也能够高效地与重金属离子作用，从而实现了三氧化二铁、碳酸钙、羟基磷酸钙三种组分的物质在作用上的相互支持，使得反应一直在适合的条件下进行，从而能够更好的将土壤钝化。三氧化二铁、碳酸钙、羟基磷酸钙主要起到化学反应作用，但作为固体物质其具有一定的比表面积，也具有吸附作用，但该吸附作用相对于吸附剂的吸附作用要小很多。上述三种试剂施加时，均匀的混合于土壤的体相中形成复合钝化剂起到协同作用。(2) This application uses ferric oxide, calcium carbonate, and calcium hydroxyphosphate to remove heavy metals to achieve synergy among the three substances. Iron trioxide can generate iron ions that react with heavy metal oxyacid radicals (such as arsenate) in the presence of water, which can passivate such heavy metal pollutants through chemical reactions. Calcium carbonate is slightly dissolved in water, and calcium ions are also It can react with heavy metal oxyacid radicals (such as arsenate) to passivate such heavy metal pollutants. Carbonate and more heavy metal ions can form carbonates, and the hydroxide radicals produced by hydrolysis can also interact with more heavy metal ions. The heavy metal ions of the ions generate hydroxides, thereby removing more kinds of heavy metal pollutants. The calcium ions and hydroxides produced by the part of calcium hydroxyphosphate dissolved in water can play a similar role to the hydrolysis of calcium ions and carbonates in calcium carbonate to produce hydroxides, but the produced phosphate can react with some heavy metal ions at the same time , Can also play a role in adjusting and buffering the pH value. For the removal of heavy metal oxyacid radicals, iron ions usually combine with heavy metal oxyacid radicals to cause the pH of the soil to drop, while calcium ions combine with heavy metal oxyacid radicals more stably under neutral and alkaline pH conditions. As well as the pH buffering effect of the polybasic acid radical of the carbonate radical, the removal of the heavy metal oxyacid radical can be maintained under high efficient pH reaction conditions. For heavy metal ions, hydroxide, carbonate and phosphate can also efficiently interact with heavy metal ions under the pH buffering effect of phosphate and carbonate, thereby realizing three types of iron trioxide, calcium carbonate and calcium hydroxyphosphate. The mutual support of the components of the material makes the reaction always proceed under suitable conditions, which can better passivate the soil. Ferric oxide, calcium carbonate, and calcium hydroxyphosphate mainly play a chemical reaction, but as solid substances, they have a certain specific surface area and also have an adsorption effect, but the adsorption effect is much smaller than that of an adsorbent. When the above three reagents are applied, they are uniformly mixed in the body phase of the soil to form a composite passivating agent to play a synergistic effect.
(3)本申请采用草木灰、膨润土作为主要起到吸附作用的钝化剂。草木灰是农业草本和木本植物焚烧后的残余物，具有弱碱性、较大的比表面积和孔容，对重金属具有较强的吸附能力和表面络合能力，其弱若碱性有利于提高土壤的pH，促进重金属形成氢氧化物沉淀；膨润土是一种天然黏土矿物，在自然界中储量丰富，且价格低廉，其主要成分为蒙脱石，颗粒细小，具有较大的比表面积和较高的孔隙度，层间结构包含可交换的无机阳离子，部分氧原子电子暴露在晶体表面，可通过离子交换、专性吸附剂共沉淀等作用将重金属元素固定下来，此外黏土矿物的特殊结构有助于形成土壤团粒结构，增加土壤的保肥持水能力。草木灰、膨润土由于其具有较大的比表面积，主要起到吸附作用，其还具有pH调节和离子交换作用，除发挥吸附作用能够与已经均匀分布的三氧化二铁、碳酸钙、羟基磷酸钙进行协同作用外，还能够通过发挥pH调节和离子交换作用进一步与三氧化二铁、碳酸钙、羟基磷酸钙发生相互作用，使得土壤钝化效果更佳。(3) This application uses plant ash and bentonite as the passivating agent that mainly plays the role of adsorption. Plant ash is the residue of agricultural herbs and woody plants after incineration. It has weak alkalinity, large specific surface area and pore volume, and has strong adsorption capacity and surface complexing capacity for heavy metals. Its weak alkalinity is beneficial to increase The pH of the soil promotes the precipitation of heavy metals to form hydroxides; bentonite is a natural clay mineral with abundant reserves in nature and low price. Its main component is montmorillonite, with fine particles, large specific surface area and high The interlayer structure contains exchangeable inorganic cations. Part of the oxygen atom electrons are exposed on the crystal surface. Heavy metal elements can be fixed by ion exchange and coprecipitation with specific adsorbents. In addition, the special structure of clay minerals helps To form a soil aggregate structure and increase the soil's ability to retain fertilizer and water. Plant ash and bentonite mainly play the role of adsorption due to their large specific surface area. They also have the role of pH adjustment and ion exchange. In addition to the role of adsorption, they can interact with the evenly distributed ferric oxide, calcium carbonate, and calcium hydroxyphosphate. In addition to the synergistic effect, it can further interact with ferric oxide, calcium carbonate, and calcium hydroxyphosphate by exerting pH adjustment and ion exchange effects, making the soil passivation effect better.
下面结合具体实施例对本发明作进一步说明，以使本领域的技术人员可以更好的理解本发明并能予以实施，但所举实施例不作为对本发明的限定。The present invention will be further described below in conjunction with specific examples, so that those skilled in the art can better understand and implement the present invention, but the examples cited are not intended to limit the present invention.
本发明的以下实施例中重金属污染土壤的样品来自湖北荆门某矿区周边农田土壤。样品主要受砷、铜、铅、镍、锌等污染，具体参数参见表1所示。The samples of heavy metal contaminated soil in the following embodiments of the present invention come from farmland soil around a certain mining area in Jingmen, Hubei. The samples are mainly contaminated by arsenic, copper, lead, nickel, zinc, etc. See Table 1 for specific parameters.
表1土壤样品参数Table 1 Soil sample parameters
实施例1Example 1
1)将4g三氧化二铁、2g碳酸钙和2g羟基磷酸钙加入1kg重金属污染土壤中，搅拌均匀，静置养护20min；1) Add 4g of ferric oxide, 2g of calcium carbonate and 2g of calcium hydroxyphosphate to 1kg of heavy metal contaminated soil, mix well, and leave for 20min for curing;
2)向步骤1)得到的混合物中加入5g草木灰和10g钙基膨润土，搅拌均匀，静置养护20min；2) Add 5 g of plant ash and 10 g of calcium bentonite to the mixture obtained in step 1), stir it evenly, and leave it for 20 minutes for curing;
3)向步骤2)得到的混合物中喷洒自来水，调节重量含水率至30％，搅拌均匀后静置养护3天。3) Sprinkle tap water into the mixture obtained in step 2), adjust the weight water content to 30%, stir evenly and leave it for 3 days for curing.
实施例2Example 2
1)将3g三氧化二铁、3.5g碳酸钙和1.5g羟基磷酸钙加入1kg重金属污染土壤中，搅 拌均匀，静置养护30min；1) Add 3g of ferric oxide, 3.5g of calcium carbonate and 1.5g of calcium hydroxyphosphate to 1kg of heavy metal contaminated soil, mix well, and leave for 30min for curing;
2)向步骤1)得到的混合物中加入2g草木灰和13g钙基膨润土，搅拌均匀，静置养护10min；2) Add 2 g of plant ash and 13 g of calcium bentonite to the mixture obtained in step 1), stir evenly, and leave it for 10 minutes for curing;
3)向步骤2)得到的混合物中喷洒自来水，调节重量含水率至30％，搅拌均匀后静置养护3天。3) Sprinkle tap water into the mixture obtained in step 2), adjust the weight water content to 30%, stir evenly and leave it for 3 days for curing.
实施例3Example 3
1)将4.5g三氧化二铁、1g碳酸钙和2.5g羟基磷酸钙加入1kg重金属污染土壤中，搅拌均匀，静置养护10min；1) Add 4.5g of ferric oxide, 1g of calcium carbonate and 2.5g of calcium hydroxyphosphate to 1kg of heavy metal contaminated soil, stir it evenly, and leave it to stand for 10 minutes;
2)向步骤1)得到的混合物中加入9g草木灰和6g钙基膨润土，搅拌均匀，静置养护30min；2) Add 9 g of plant ash and 6 g of calcium bentonite to the mixture obtained in step 1), stir evenly, and leave for 30 min for curing;
3)向步骤2)得到的混合物中喷洒自来水，调节重量含水率至30％，搅拌均匀后静置养护3天。3) Sprinkle tap water into the mixture obtained in step 2), adjust the weight water content to 30%, stir evenly and leave it for 3 days for curing.
对比例1Comparative example 1
1)将4g三氧化二铁、2g碳酸钙、2g羟基磷酸钙、5g草木灰和10g钙基膨润土加入1kg重金属污染土壤中，搅拌均匀，静置养护40min；1) Add 4g of ferric oxide, 2g of calcium carbonate, 2g of hydroxycalcium phosphate, 5g of plant ash and 10g of calcium bentonite to 1kg of heavy metal contaminated soil, stir evenly, and leave for 40min;
2)向步骤1)得到的混合物中喷洒自来水，调节重量含水率至30％，搅拌均匀后静置养护3天。2) Sprinkle tap water into the mixture obtained in step 1), adjust the weight moisture content to 30%, stir evenly, and then stand for 3 days for curing.
对比例2Comparative example 2
1)将5g草木灰和10g钙基膨润土加入1kg重金属污染土壤中，搅拌均匀，静置养护20min；1) Add 5g of plant ash and 10g of calcium bentonite to 1kg of heavy metal contaminated soil, stir evenly, and leave for 20min for curing;
2)向步骤1)得到的混合物中加入4g三氧化二铁、2g碳酸钙和2g羟基磷酸钙，搅拌均匀，静置养护20min；2) Add 4g of ferric oxide, 2g of calcium carbonate and 2g of hydroxycalcium phosphate to the mixture obtained in step 1), stir it evenly, and leave it to stand for 20 minutes;
3)向步骤2)得到的混合物中喷洒自来水，调节重量含水率至30％，搅拌均匀后静置养护3天。3) Sprinkle tap water into the mixture obtained in step 2), adjust the weight water content to 30%, stir evenly and leave it for 3 days for curing.
对比例3Comparative example 3
1)将5g三氧化二铁和3g碳酸钙加入1kg重金属污染土壤中，搅拌均匀，静置养护20min；1) Add 5g of ferric oxide and 3g of calcium carbonate to 1kg of heavy metal contaminated soil, mix well, and let stand for 20min;
2)向步骤1)得到的混合物中加入5g草木灰和10g钙基膨润土，搅拌均匀，静置养护20min；2) Add 5 g of plant ash and 10 g of calcium bentonite to the mixture obtained in step 1), stir it evenly, and leave it for 20 minutes for curing;
3)向步骤2)得到的混合物中喷洒自来水，调节重量含水率至30％，搅拌均匀后静置养护3天。3) Sprinkle tap water into the mixture obtained in step 2), adjust the weight water content to 30%, stir evenly and leave it for 3 days for curing.
对比例4Comparative example 4
1)将5g三氧化二铁和3g羟基磷酸钙加入1kg重金属污染土壤中，搅拌均匀，静置养护20min；1) Add 5g of ferric oxide and 3g of calcium hydroxyphosphate to 1kg of heavy metal contaminated soil, stir evenly, and let stand for 20min;
2)向步骤1)得到的混合物中加入5g草木灰和10g钙基膨润土，搅拌均匀，静置养护20min；2) Add 5 g of plant ash and 10 g of calcium bentonite to the mixture obtained in step 1), stir it evenly, and leave it for 20 minutes for curing;
3)向步骤2)得到的混合物中喷洒自来水，调节重量含水率至30％，搅拌均匀后静置养护3天。3) Sprinkle tap water into the mixture obtained in step 2), adjust the weight water content to 30%, stir evenly and leave it for 3 days for curing.
对比例5Comparative example 5
1)将4g碳酸钙和4g羟基磷酸钙加入1kg重金属污染土壤中，搅拌均匀，静置养护20min；1) Add 4g of calcium carbonate and 4g of calcium hydroxyphosphate to 1kg of heavy metal contaminated soil, stir evenly, and let stand for 20min;
2)向步骤1)得到的混合物中加入5g草木灰和10g钙基膨润土，搅拌均匀，静置养护20min；2) Add 5 g of plant ash and 10 g of calcium bentonite to the mixture obtained in step 1), stir it evenly, and leave it for 20 minutes for curing;
3)向步骤2)得到的混合物中喷洒自来水，调节重量含水率至30％，搅拌均匀后静置养护3天。3) Sprinkle tap water into the mixture obtained in step 2), adjust the weight water content to 30%, stir evenly and leave it for 3 days for curing.
对比例6Comparative example 6
1)将4g三氧化二铁、2g碳酸钙和2g羟基磷酸钙加入1kg重金属污染土壤中，搅拌均匀，静置养护20min；1) Add 4g of ferric oxide, 2g of calcium carbonate and 2g of calcium hydroxyphosphate to 1kg of heavy metal contaminated soil, mix well, and leave for 20min for curing;
2)向步骤1)得到的混合物中加入15g活性炭，搅拌均匀，静置养护20min；2) Add 15g of activated carbon to the mixture obtained in step 1), stir it evenly, and leave it for 20 minutes for curing;
3)向步骤2)得到的混合物中喷洒自来水，调节重量含水率至30％，搅拌均匀后静置养护3天。3) Sprinkle tap water into the mixture obtained in step 2), adjust the weight water content to 30%, stir evenly and leave it for 3 days for curing.
实施例1-3与对比例1-6通过取样检测获得的钝化土壤研究结果参见表2。See Table 2 for the study results of passivated soil obtained by sampling and testing in Examples 1-3 and Comparative Examples 1-6.
表2钝化检测结果Table 2 Passivation test results
通过实施例1-3的结果可以看出，本申请的钝化方法具有良好的钝化效果，能够将污染的农田土壤中的有效态的重金属钝化，具有良好的钝化效果。通过对比实施例1与对比例1,2的结果可以看出，先将主要起到化学反应作用的钝化剂均匀分布于受到重金属污染的土壤体相中，再将主要起到吸附作用的钝化剂均匀分布于上述混合物中，能够使得发生化学反应的钝化剂和重金属在土壤中混合均匀，然后再一起集中于吸附剂表面或周围，能够使得化学反应在统一的有效的条件下进行，从而能够实现更优化的钝化效果。通过对比例1可以看出，如果将主要起化学反应作用和起吸附作用的钝化剂同时加入土壤中，则每种试剂都同时发生作用，发生化学反应的条件不确定，化学反应和物理吸附的试剂不同可能导致部分吸附剂吸附了过量的污染物而接触的钝化剂不足，而另一部分吸附剂吸附了过量的钝化剂而没有接触到适量的污染物。通过对比例2可以看出，如果先加入主要起到吸附作用的钝化剂，则使得重金属污染物和主要起到化学反应作用的钝化剂的分布不均加剧，土壤体相中的化学反应环境不统一，虽然也能够使得大部分重金属钝化，但钝化效果无法达到实施例1的程度。通过对比实施例1与对比例3-5可以看出，三氧化二铁、碳酸钙和羟基磷酸钙的联合使用在功能上具有相互支持的作用，从而产生协同作用而将重金属通过化学反应钝化。铁离子和钙离子能够在中性偏酸或中性偏碱的环境条件下与重金属含氧酸根反应，在磷酸根和碳酸根的缓冲条件下能够使其共同发挥反应作用，使得重金属含氧酸根在弱酸至弱碱的稳定的化学环境条件下都能够有效的被钝化。而碳酸根离子、氢氧根离子、磷酸根离子也在磷酸根和碳酸根的缓冲作用下对重金属离子实现稳定的钝化。从而仅采用上述三种物质，即可以能够去除广泛的重金属，而且仅采用上述物质中的两种在效果上是无法达到采用三种物质的效果，其也说明上述三种物质之间产生了协同作用。通过对比实施例1与对比例6可以发现，当将主要起到吸附作用的钝化剂替换为活性碳时，其相对于现有技术也能够取得较好的钝化效果，但如果采用除吸附作用外还具有pH调节和离子交换作用的草木灰和膨润土，则能够更好的实现与三氧化二铁、碳酸钙和羟基磷酸钙在化学作用上的调节与补充，从而能够更好的实现对重金属物质的钝化效果。From the results of Examples 1-3, it can be seen that the passivation method of the present application has a good passivation effect, can passivate the effective state of heavy metals in the contaminated farmland soil, and has a good passivation effect. By comparing the results of Example 1 and Comparative Examples 1,2, it can be seen that the passivation agent, which mainly plays a role of chemical reaction, is uniformly distributed in the soil body phase contaminated by heavy metals, and then the passivation agent, which mainly plays a role of adsorption, is uniformly distributed. The chemical agent is uniformly distributed in the above mixture, which can make the chemical reaction passivator and heavy metals mix uniformly in the soil, and then concentrate on the surface or around the adsorbent together, which can make the chemical reaction proceed under uniform and effective conditions. Thus, a more optimized passivation effect can be achieved. It can be seen from Comparative Example 1 that if the passivation agent, which mainly plays the role of chemical reaction and adsorption, is added to the soil at the same time, each reagent will act at the same time. The conditions for chemical reaction are uncertain, chemical reaction and physical adsorption The different reagents may cause part of the adsorbent to adsorb excessive pollutants and insufficient passivation agent, while another part of the adsorbent adsorbs excessive passivation agent without contacting the appropriate amount of pollutants. It can be seen from Comparative Example 2 that if the passivation agent that mainly plays the role of adsorption is added first, the uneven distribution of heavy metal pollutants and the passivation agent that mainly plays the role of chemical reaction will increase, and the chemical reaction in the soil body will increase. The environment is not uniform, although most heavy metals can be passivated, but the passivation effect cannot reach the level of Example 1. By comparing Example 1 with Comparative Examples 3-5, it can be seen that the combined use of ferric oxide, calcium carbonate, and calcium hydroxyphosphate has a mutually supporting effect in function, thereby producing a synergistic effect to passivate heavy metals through chemical reactions . Iron ions and calcium ions can react with heavy metal oxyacids under neutral partial acid or neutral alkaline environmental conditions, and can make them react together under the buffer conditions of phosphate and carbonate, making heavy metal oxyacids It can be effectively passivated under stable chemical environmental conditions from weak acid to weak base. The carbonate ion, hydroxide ion, and phosphate ion also achieve stable passivation of heavy metal ions under the buffering effect of phosphate and carbonate. Therefore, only the above three substances can be used to remove a wide range of heavy metals, and the effect of using only two of the above substances cannot achieve the effect of using three substances, which also shows that there is a synergy between the above three substances. effect. By comparing Example 1 and Comparative Example 6, it can be found that when the passivation agent that mainly plays the role of adsorption is replaced with activated carbon, it can also achieve better passivation effect compared to the prior art, but if desorption is used In addition to its functions, plant ash and bentonite, which also have pH adjustment and ion exchange effects, can better achieve the adjustment and supplementation of the chemical effects of ferric oxide, calcium carbonate and calcium hydroxyphosphate, so as to better achieve the effect of Passivation effect of substances.
本申请通过先加入主要起到化学反应作用的钝化剂，再加入主要起到吸附作用的钝化剂，实现了化学作用与物理作用的有机结合，为重金属的去除提供了统一的反应环境，实现了更好的钝化效果。本申请进一步研究开发了三氧化二铁、碳酸钙、羟基磷酸钙、草木灰、膨润土结合并分步使用，三氧化二铁、碳酸钙、羟基磷酸钙的联合使用具有协同作用，而进一步添加草木灰、膨润土能够进一步促进协同作用，得到了良好的钝化效果。In this application, by first adding the passivating agent that mainly plays the role of chemical reaction, and then adding the passivation agent that mainly plays the role of adsorption, the organic combination of chemical and physical effects is realized, and a unified reaction environment is provided for the removal of heavy metals. A better passivation effect is achieved. This application further researched and developed the combination of ferric oxide, calcium carbonate, calcium hydroxyphosphate, plant ash, and bentonite and used them step by step. The combined use of ferric oxide, calcium carbonate, and calcium hydroxyphosphate has a synergistic effect, and further addition of plant ash, Bentonite can further promote the synergy and obtain a good passivation effect.
以上所述实施例仅是为充分说明本发明而所举的较佳的实施例，本发明的保护范围不限于此。本技术领域的技术人员在本发明基础上所作的等同替代或变换，均在本发明的保护范围之内。本发明的保护范围以权利要求书为准。The above-mentioned embodiments are only preferred embodiments for fully explaining the present invention, and the protection scope of the present invention is not limited thereto. The equivalent substitutions or changes made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the present invention is subject to the claims.
Claims (9)
- 一种重金属污染农田土壤的钝化方法，包括如下步骤：A passivation method for heavy metal polluted farmland soil includes the following steps:1)将主要起到化学反应作用的钝化剂加入重金属污染土壤中，搅拌均匀，静置养护；1) Add the passivation agent that mainly plays a role of chemical reaction to heavy metal contaminated soil, stir it evenly, and leave it for curing;2)向步骤1)得到的混合物中加入主要起到吸附作用的钝化剂，搅拌均匀，静置养护；2) Add a passivating agent, which is mainly used for adsorption, to the mixture obtained in step 1), stir it evenly, and leave it for curing;3)向步骤2)得到的混合物中加入水，调节重量含水率至20％-40％，静置养护。3) Add water to the mixture obtained in step 2), adjust the weight moisture content to 20%-40%, and leave it for curing.
- 根据权利要求1所述的方法，其特征在于，主要起到化学反应作用的钝化剂为三氧化二铁、碳酸钙、羟基磷酸钙，其重量比为0.3-0.7：0.15-0.35：0.15-0.35。The method according to claim 1, characterized in that the passivating agent mainly playing a chemical reaction is ferric oxide, calcium carbonate, calcium hydroxyphosphate, and the weight ratio is 0.3-0.7:0.15-0.35:0.15- 0.35.
- 根据权利要求2所述的方法，其特征在于，主要起到吸附作用的钝化剂为草木灰、膨润土，其重量比为0.25-0.75：0.5-1.5。The method according to claim 2, characterized in that the deactivator which mainly plays a role of adsorption is plant ash and bentonite, and the weight ratio is 0.25-0.75:0.5-1.5.
- 根据权利要求3所述的方法，其特征在于，三氧化二铁、碳酸钙、羟基磷酸钙的重量比为0.5：0.25：0.25；草木灰、膨润土的重量比为0.5：1。The method according to claim 3, wherein the weight ratio of ferric oxide, calcium carbonate, and calcium hydroxyphosphate is 0.5:0.25:0.25; the weight ratio of plant ash and bentonite is 0.5:1.
- 根据权利要求3所述的方法，其特征在于，所述膨润土为钙基膨润土，其主要成分为蒙脱石。The method according to claim 3, wherein the bentonite is calcium-based bentonite, and its main component is montmorillonite.
- 根据权利要求1所述的方法，其特征在于，所述的主要起到化学反应作用的钝化剂的重量为重金属污染土壤的0.6％-1％；所述主要起到吸附作用的钝化剂的重量为重金属污染土壤的0.75％-3％。The method according to claim 1, characterized in that the weight of the passivation agent mainly playing a chemical reaction is 0.6%-1% of the heavy metal contaminated soil; the passivating agent mainly playing a role of adsorption The weight of heavy metal contaminated soil is 0.75%-3%.
- 根据权利要求6所述的方法，其特征在于，步骤1)的养护时间为10-30min；步骤2)的养护时间为10-30min；步骤3)的养护时间为2-5天。The method according to claim 6, wherein the curing time in step 1) is 10-30 min; the curing time in step 2) is 10-30 min; and the curing time in step 3) is 2-5 days.
- 根据权利要求1所述的方法，其特征在于，所述重金属污染土壤中含有砷、铜、铅、镍、锌。The method of claim 1, wherein the heavy metal contaminated soil contains arsenic, copper, lead, nickel, and zinc.
- 根据权利要求8所述的方法，其特征在于，所述重金属污染土壤为矿区周边的受重金属污染的农田土壤。The method according to claim 8, wherein the heavy metal contaminated soil is farmland soil contaminated by heavy metals around the mining area.
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