技术领域Technical Field
本发明属于重金属土壤污染修复技术领域，尤其涉及一种抑制微塑料活化土壤重金属钝化剂的制备方法及应用。The present invention belongs to the technical field of heavy metal soil pollution remediation, and in particular relates to a preparation method and application of a soil heavy metal passivator for inhibiting microplastic activation.
背景技术Background Art
在工业化快速发展和城市化进程加速的背景下，工业废弃物排放、矿业活动、农业生产以及城市垃圾的不当处理等行为，导致大量重金属富集在土壤中。在重金属污染土壤修复技术中，钝化修复是基于向土壤中添加钝化剂，通过吸附、沉淀、络合等反应，降低重金属的生物有效性和可迁移性，从而达到修复目的的方法，因具有效率高、操作简单和成本低等优势而被广泛使用。然而，钝化修复效率受到与重金属共存污染物的影响显著。其中，微塑料作为一种新兴污染物不仅会对生态和人类健康造成危害，更能与重金属发生复杂的耦合作用，促进土壤中的重金属从生物可利用性和毒性较低的稳定态向酸可溶态、可还原态等生物可利用性和毒性更高的活跃态转换，使得安全稳定形态的重金属被活化，加剧土壤中重金属的安全风险，对生态系统和人类健康构成更大的威胁。Against the backdrop of rapid industrialization and accelerated urbanization, industrial waste discharge, mining activities, agricultural production, and improper disposal of urban garbage have led to the accumulation of a large amount of heavy metals in the soil. In the remediation technology of heavy metal-contaminated soil, passivation remediation is a method based on adding passivators to the soil to reduce the bioavailability and mobility of heavy metals through reactions such as adsorption, precipitation, and complexation, thereby achieving the purpose of remediation. It is widely used due to its advantages of high efficiency, simple operation, and low cost. However, the efficiency of passivation remediation is significantly affected by pollutants coexisting with heavy metals. Among them, microplastics, as an emerging pollutant, not only cause harm to the ecology and human health, but also can have complex coupling effects with heavy metals, promoting the conversion of heavy metals in the soil from a stable state with low bioavailability and toxicity to an active state with higher bioavailability and toxicity such as an acid-soluble state and a reducible state, so that the safe and stable form of heavy metals is activated, aggravating the safety risk of heavy metals in the soil and posing a greater threat to the ecosystem and human health.
专利CN 114751491B公开了水环境中微塑料和重金属污染物同步高效净化方法及系统，该方法仅公开了水环境中微塑料和重金属的同步去除方法，由于土壤环境的复杂性，无法推测将该发明应用于土壤环境中抑制微塑料活化重金属的作用效果。专利CN115213212 A公开了用于缓解土壤微塑料污染的生物炭处理方法，在微塑料和重金属复合污染环境下，所发明的生物炭对重金属的钝化修复效果较差，并且土壤培养周期长达90天，严重降低了土壤修复效率，同时提高了修复的时间成本和运行成本。Patent CN 114751491B discloses a method and system for the simultaneous and efficient purification of microplastics and heavy metal pollutants in water environments. This method only discloses a method for the simultaneous removal of microplastics and heavy metals in water environments. Due to the complexity of the soil environment, it is impossible to speculate on the effect of the invention on inhibiting the activation of heavy metals by microplastics in soil environments. Patent CN115213212 A discloses a biochar treatment method for alleviating soil microplastic pollution. In an environment of combined microplastic and heavy metal pollution, the invented biochar has a poor passivation and repair effect on heavy metals, and the soil cultivation cycle is as long as 90 days, which seriously reduces the soil remediation efficiency and increases the time cost and operating cost of remediation.
因此，亟需开发一种可有效抑制微塑料活化土壤重金属的钝化材料和应用方法。Therefore, there is an urgent need to develop a passivation material and application method that can effectively inhibit the activation of soil heavy metals by microplastics.
发明内容Summary of the invention
本发明的目的是克服上述现有材料和技术存在的不足，提供一种低成本的、环境友好的、能够有效抑制微塑料活化土壤重金属的钝化材料及应用方法，旨在解决常规钝化剂对微塑料和重金属复合污染土壤修复效果差，无法抑制微塑料对重金属的活化作用等问题，还能促进农业废弃物的资源化利用，具有重要的环境保护和社会经济价值，实现高效、稳定、环境友好的钝化修复效果。The purpose of the present invention is to overcome the deficiencies of the above-mentioned existing materials and technologies, and to provide a low-cost, environmentally friendly passivation material and application method that can effectively inhibit the activation of soil heavy metals by microplastics. The invention aims to solve the problems that conventional passivators have poor remediation effects on soil contaminated by microplastics and heavy metals, and cannot inhibit the activation of heavy metals by microplastics. The invention can also promote the resource utilization of agricultural waste, has important environmental protection and socio-economic value, and achieves efficient, stable, and environmentally friendly passivation remediation effects.
为实现上述目的，本发明采用以下技术方案：To achieve the above object, the present invention adopts the following technical solutions:
一种抑制微塑料活化土壤重金属钝化剂的制备方法，包括以下步骤：A method for preparing a soil heavy metal passivator for inhibiting microplastic activation comprises the following steps:
(1)生物炭前驱体制备：按一定重量比(1:2～4:1)，称取干燥的梧桐皮和软木屑，粉碎、混合后加热，所述的，加热温度为50℃～80℃，加热时间为10h～36h，获得生物炭前驱体；(1) Preparation of biochar precursor: Weigh dried tung tree bark and cork chips in a certain weight ratio (1:2-4:1), crush, mix and heat, wherein the heating temperature is 50° C.-80° C. and the heating time is 10 h-36 h to obtain a biochar precursor;
(2)生物炭制备：将步骤(1)中的前驱体进行限氧热解，所述的热解温度300℃～950℃，热解时间1h～3h，然后冷却至室温，经研磨过筛后得到10～400目的生物炭。(2) Preparation of biochar: The precursor in step (1) is subjected to oxygen-limited pyrolysis at a temperature of 300° C. to 950° C. for a pyrolysis time of 1 h to 3 h, and then cooled to room temperature. The biochar is ground and sieved to obtain a biochar with a mesh size of 10 to 400.
(3)生物炭改性：将步骤(2)得到的生物炭与改性溶液按照1：(50～600)的质量比例混合搅拌4h～30h，最后经水洗后在50℃～80℃下烘干，得到抑制微塑料活化土壤重金属钝化剂。(3) Biochar modification: The biochar obtained in step (2) and the modified solution are mixed and stirred at a mass ratio of 1: (50-600) for 4 h to 30 h, and finally washed with water and dried at 50° C. to 80° C. to obtain a soil heavy metal passivator that inhibits microplastic activation.
所述的步骤(1)中，优选的，重量比，梧桐皮:软木屑＝(1:1～3:1)。In the step (1), preferably, the weight ratio of sycamore bark:cork chips is (1:1 to 3:1).
所述的步骤(1)中，优选的，加热温度为60℃～80℃。In the step (1), preferably, the heating temperature is 60°C to 80°C.
所述的步骤(1)中，优选的，加热时间为20h～30h。In the step (1), preferably, the heating time is 20 h to 30 h.
所述的步骤(2)中，限氧热解过程中，氧含量为1％以下。In the step (2), during the oxygen-limited pyrolysis process, the oxygen content is below 1%.
所述的步骤(2)中，优选的，热解温度为400℃～900℃。In the step (2), preferably, the pyrolysis temperature is 400°C to 900°C.
所述的步骤(2)中，优选的，热解时间为2h～3h。In the step (2), preferably, the pyrolysis time is 2h to 3h.
所述的步骤(3)中，改性溶液为1％～10％ H2SO4/HNO3(H2SO4与HNO3摩尔比为1：1)。In the step (3), the modified solution is 1% to 10% H2 SO4 /HNO3 (the molar ratio of H2 SO4 to HNO3 is 1:1).
所述的步骤(3)中，优选的，生物炭与改性溶液的质量比例为1：(200～500)。In the step (3), preferably, the mass ratio of biochar to modified solution is 1:(200-500).
所述的步骤(3)中，优选的，搅拌时间为6h～10h。In the step (3), preferably, the stirring time is 6 h to 10 h.
所述钝化剂在抑制微塑料活化土壤重金属中的应用，即在受微塑料(和重金属复合污染土壤中添加上述方法制备的钝化剂，钝化剂的添加质量与污染土壤干重的比为(1～2)：100。通过翻耕使改性生物炭在土壤中分布均匀；浇水灌溉将土壤水分含量维持在田间最大持水量的60％～75％，维持5～15天完成钝化修复。The use of the passivator in inhibiting microplastics from activating soil heavy metals is to add the passivator prepared by the above method to soil contaminated by microplastics (and heavy metals), and the ratio of the added mass of the passivator to the dry weight of the contaminated soil is (1-2):100. The modified biochar is evenly distributed in the soil by tilling; the soil moisture content is maintained at 60%-75% of the maximum field water holding capacity by watering and irrigation, and the passivation repair is completed for 5-15 days.
所述微塑料浓度为0～10％；重金属为铬和铅中的一种或两种。The concentration of the microplastics is 0-10%; the heavy metals are one or two of chromium and lead.
本发明采用梧桐皮和软木屑制备改性生物炭，与传统的污泥炭和秸秆炭，对微塑料有更强的吸附能力。相比秸秆生物炭，梧桐皮生物炭通常具有更高的碳化程度和更大的比表面积，这提供了更多的吸附位点，有助于增强对微塑料颗粒的吸附能力；同时，梧桐皮的纤维结构较为复杂，碳化后可能形成更多的微孔和中孔，形成复杂的孔隙结构，这些孔隙有助于捕捉更小尺寸的微塑料颗粒；除此之外，梧桐木生物炭通常具有较高的化学稳定性，这使其在复杂环境中具有较长的使用寿命，可以持续吸附微塑料。而相比于秸秆生物炭，软木屑生物炭的灰分含量较低，这意味着它含有较少的矿物质杂质；但软木屑的碳含量通常较高，因此更加稳定，这意味着在土壤中的持续时间更长，能够长期提供其修复能力并改良土壤；软木屑生物炭的孔隙结构通常比秸秆生物炭更发达，这使得它在保持土壤水分、提供生物栖息空间以及改善土壤通气性方面表现更好。The present invention uses sycamore bark and cork chips to prepare modified biochar, which has a stronger adsorption capacity for microplastics than traditional sludge charcoal and straw charcoal. Compared with straw biochar, sycamore bark biochar usually has a higher degree of carbonization and a larger specific surface area, which provides more adsorption sites and helps to enhance the adsorption capacity of microplastic particles; at the same time, the fiber structure of sycamore bark is relatively complex, and more micropores and mesopores may be formed after carbonization, forming a complex pore structure, which helps to capture smaller microplastic particles; in addition, sycamore wood biochar usually has high chemical stability, which makes it have a longer service life in complex environments and can continuously adsorb microplastics. Compared with straw biochar, cork chip biochar has a lower ash content, which means it contains less mineral impurities; but the carbon content of cork chips is usually higher, so it is more stable, which means that it lasts longer in the soil, can provide its repair ability and improve the soil for a long time; the pore structure of cork chip biochar is usually more developed than straw biochar, which makes it perform better in retaining soil moisture, providing biological habitat space and improving soil aeration.
不同热解条件(温度和持续时间)和活化方法对生物炭特性会有不同的影响。温度≥600℃对生物炭形成碳化结构至关重要750℃以上的温度会增加生物炭的多孔结构。更长的热解持续时间(>60分钟)在不影响产率的情况下会提高孔体积。对于潜在的高端新兴应用，酸预处理改性活化可以，有效地从生物炭中去除溶解的有机碳和大多数金属，并表现出更大的孔隙体积。Different pyrolysis conditions (temperature and duration) and activation methods have different effects on the characteristics of biochar. Temperatures ≥ 600 °C are critical for the formation of a carbonized structure of biochar. Temperatures above 750 °C increase the porous structure of biochar. Longer pyrolysis durations (> 60 minutes) increase the pore volume without affecting the yield. For potential high-end emerging applications, acid pretreatment modification activation can effectively remove dissolved organic carbon and most metals from biochar and exhibit a larger pore volume.
将梧桐皮和软木屑按照合适的比例混合制备生物炭，并在一定温度条件下，通过酸改性可以在一定程度上结合两者优点，具有提升吸附性能、稳定性及改善土壤质量的多重优势。这种混合生物炭不仅能够在常规生物炭钝化重金属基础上，还能阻止微塑料活化重金属，提高对微塑料-重金属复合污染土壤钝化的效率和稳定性。The biochar is prepared by mixing sycamore bark and cork chips in a suitable proportion, and under certain temperature conditions, the advantages of both can be combined to a certain extent through acid modification, which has the multiple advantages of improving adsorption performance, stability and improving soil quality. This mixed biochar can not only passivate heavy metals on the basis of conventional biochar, but also prevent microplastics from activating heavy metals, thereby improving the efficiency and stability of passivation of microplastic-heavy metal composite contaminated soil.
本发明制备的改性生物炭可以抑制微塑料对土壤重金属的活化作用，实现对微塑料和重金属复合污染土壤的绿色高效钝化修复。所制备的生物炭创新性的采用复合植物基原料并且经过混合酸氧化改性，不仅充分发挥了两种植物基对重金属的离子交换、络合、沉淀和吸附作用，有效降低了重金属的生物可及性和迁移性，并进一步利用混合酸氧化改性，既增加了生物炭的比表面积，扩增了重金属吸附容量，又丰富了生物炭表面的含氧官能团，通过抢占微塑料表面反应结合位点，从而削弱了微塑料活化重金属的能力。本发明有效解决了传统钝化剂对于微塑料和重金属复合污染土壤钝化修复效率低、修复稳定性差且稳定态重金属容易再活化的问题。且本发明所述生物炭不需要价格昂贵的原料和复杂的制备工艺，仅采用环境友好的、天然的农业废弃物为原料，经过相对简单的制备工艺和钝化操作后能够显著降低污染土壤中铬和铅等多种重金属有效态的浓度，抑制微塑料对重金属的活化作用，具有广阔的应用前景。The modified biochar prepared by the present invention can inhibit the activation of microplastics on soil heavy metals, and realize green and efficient passivation and remediation of soil contaminated by microplastics and heavy metals. The prepared biochar innovatively adopts composite plant-based raw materials and undergoes mixed acid oxidation modification, which not only gives full play to the ion exchange, complexation, precipitation and adsorption of heavy metals by the two plant bases, effectively reduces the bioaccessibility and mobility of heavy metals, and further utilizes mixed acid oxidation modification to increase the specific surface area of biochar, expand the heavy metal adsorption capacity, and enrich the oxygen-containing functional groups on the surface of biochar, thereby occupying the reaction binding sites on the surface of microplastics, thereby weakening the ability of microplastics to activate heavy metals. The present invention effectively solves the problems of low passivation and remediation efficiency of traditional passivators for soil contaminated by microplastics and heavy metals, poor remediation stability, and easy reactivation of stable heavy metals. Moreover, the biochar described in the present invention does not require expensive raw materials and complicated preparation processes, but only uses environmentally friendly, natural agricultural waste as raw materials. After a relatively simple preparation process and passivation operation, it can significantly reduce the concentration of effective states of various heavy metals such as chromium and lead in contaminated soil, inhibit the activation of heavy metals by microplastics, and has broad application prospects.
具体实施方式DETAILED DESCRIPTION
下面结合实施例对本发明作进一步的详细说明。The present invention is further described in detail below in conjunction with embodiments.
实施例1Example 1
1、按照重量比3：1，称取干燥的梧桐皮和软木屑并混合，经过80℃加热20h，制得生物炭前驱体；1. Weigh and mix dried sycamore bark and cork chips at a weight ratio of 3:1, and heat at 80°C for 20 hours to obtain a biochar precursor;
2、生物炭前驱体在600℃、氧气含量为1％以下的条件下进行限氧热解，热解时间2h，冷却至室温。将制备得到的生物炭研磨后用筛网筛分为不同粒径的生物炭颗粒(10～100目、100～200目、200～400目)。2. The biochar precursor was subjected to oxygen-limited pyrolysis at 600°C and an oxygen content of less than 1% for 2 hours, and then cooled to room temperature. The prepared biochar was ground and sieved with a sieve to form biochar particles of different particle sizes (10-100 mesh, 100-200 mesh, 200-400 mesh).
3、将步骤2中得到的生物炭(200～400目)与5％改性溶液(H2SO4与HNO3配比为1：1)混合(质量比1：500)，搅拌6h，然后经水洗后在80℃下烘干，得到改性生物炭钝化剂。3. The biochar (200-400 mesh) obtained in step2 was mixed with 5% modified solution (H2SO4 andHNO3 ratio of 1:1) (mass ratio 1:500), stirred for 6h, then washed with water and dried at 80℃ to obtain a modified biochar passivator.
4、待修复的微塑料和重金属复合污染土壤中微塑料含量在0～10％、污染重金属为1000mg/kg的Pb和200mg/kg的Cr，土壤理化性质如下：砂粒(0.075～2mm)含量61.6％，粉粒(0.005～0.075mm)含量15.6％，黏粒(＜0.005mm)含量22.8％，pH值6.8，有机质含量16.7g/kg；4. The microplastic content of the soil to be repaired is 0-10%, the heavy metal pollution is 1000mg/kg of Pb and 200mg/kg of Cr. The physical and chemical properties of the soil are as follows: sand content (0.075-2mm) is 61.6%, silt content (0.005-0.075mm) is 15.6%, clay content (<0.005mm) is 22.8%, pH value is 6.8, and organic matter content is 16.7g/kg;
5、将制备得到的改性生物炭按照1：100的质量比例添加到上述微塑料和重金属污染土壤中，混合搅拌均匀；5. Add the prepared modified biochar to the microplastics and heavy metal contaminated soil at a mass ratio of 1:100, and mix and stir evenly;
6、定时灌溉以维持土壤水分含量在田间最大持水量的70％，并维持10d。6. Irrigate regularly to maintain soil moisture content at 70% of the maximum field water holding capacity and maintain it for 10 days.
7、修复完成后，利用BCR形态分析污染土壤中重金属的有效态含量。7. After remediation is completed, use BCR morphology to analyze the effective content of heavy metals in the contaminated soil.
表1污染土壤中重金属有效态钝化效果Table 1 Passivation effect of effective heavy metals in contaminated soil
由表1可以看出，添加改性生物炭后，微塑料和重金属复合污染土壤中重金属的有效态含量均出现一定下降，其中2％微塑料污染浓度的土壤中，添加改性生物炭后Cr钝化效率达到了76.9％，Pb钝化效率为30.1％；10％微塑料污染浓度的土壤中，添加改性生物炭后Cr钝化效率达到了74.0％，Pb钝化效率为24.1％。It can be seen from Table 1 that after adding modified biochar, the effective content of heavy metals in the soil contaminated by microplastics and heavy metals decreased to a certain extent. In the soil with a microplastic pollution concentration of 2%, the Cr passivation efficiency reached 76.9% after adding modified biochar, and the Pb passivation efficiency was 30.1%; in the soil with a microplastic pollution concentration of 10%, the Cr passivation efficiency reached 74.0% after adding modified biochar, and the Pb passivation efficiency was 24.1%.
实施例2Example 2
1、按照重量比1：1，称取干燥的梧桐皮和软木屑并混合，经过80℃加热20h，制得生物炭前驱体；1. According to the weight ratio of 1:1, dry sycamore bark and cork chips were weighed and mixed, and heated at 80°C for 20 hours to obtain a biochar precursor;
2、生物炭前驱体在600℃、氧气含量为1％以下的条件下进行限氧热解，热解时间2h，冷却至室温。将制备得到的生物炭研磨后用筛网筛分为不同粒径的生物炭颗粒(10～100目、100～200目、200～400目)。2. The biochar precursor was subjected to oxygen-limited pyrolysis at 600°C and an oxygen content of less than 1% for 2 hours, and then cooled to room temperature. The prepared biochar was ground and sieved with a sieve to form biochar particles of different particle sizes (10-100 mesh, 100-200 mesh, 200-400 mesh).
3、将步骤2中得到的生物炭(200～400目)与5％改性溶液(H2SO4与HNO3配比为1：1)混合(质量比1：500)，搅拌6h，然后经水洗后在80℃下烘干，得到改性生物炭钝化剂。3. The biochar (200-400 mesh) obtained in step2 was mixed with 5% modified solution (H2SO4 andHNO3 ratio of 1:1) (mass ratio 1:500), stirred for 6h, then washed with water and dried at 80℃ to obtain a modified biochar passivator.
4、待修复的微塑料和重金属复合污染土壤中微塑料含量在0～10％、污染重金属为1000mg/kg的Pb和200mg/kg的Cd，土壤理化性质如下：砂粒(0.075～2mm)含量61.6％，粉粒(0.005～0.075mm)含量15.6％，黏粒(＜0.005mm)含量22.8％，pH值6.8，有机质含量16.7g/kg；4. The microplastic content of the soil to be repaired is 0-10%, and the heavy metal pollution is 1000 mg/kg of Pb and 200 mg/kg of Cd. The physical and chemical properties of the soil are as follows: sand content (0.075-2 mm) is 61.6%, silt content (0.005-0.075 mm) is 15.6%, clay content (<0.005 mm) is 22.8%, pH value is 6.8, and organic matter content is 16.7 g/kg;
5、将制备得到的改性生物炭按照1：100的质量比例添加到上述微塑料和重金属污染土壤中，混合搅拌均匀；5. Add the prepared modified biochar to the microplastics and heavy metal contaminated soil at a mass ratio of 1:100, and mix and stir evenly;
6、定时灌溉以维持土壤水分含量在田间最大持水量的70％，并维持10d。6. Irrigate regularly to maintain soil moisture content at 70% of the maximum field water holding capacity and maintain it for 10 days.
7、修复完成后，利用BCR形态分析污染土壤中重金属的有效态含量。7. After remediation is completed, use BCR morphology to analyze the effective content of heavy metals in the contaminated soil.
表2污染土壤中重金属有效态钝化效果Table 2 Passivation effect of effective heavy metals in contaminated soil
由表2可以看出，添改性生物炭后，微塑料和重金属复合污染土壤中重金属的有效态含量均出现一定下降，其中2％微塑料污染浓度的土壤中，添加改性生物炭后Cr钝化效率达到了63.7％，Pb钝化效率为17.3％；10％微塑料污染浓度的土壤中，添加改性生物炭后Cr钝化效率达到了65.9％，Pb钝化效率为17.5％。对比实施例1，本实施例改变梧桐皮和软木屑的配比为1：1，2％微塑料污染浓度土壤中Cr、Pb钝化效率分别下降13.2％、12.8％；10％微塑料污染浓度土壤中Cr、Pb钝化效率分别下8.1％、6.6％。其原因是，改变配比后生成的生物炭的孔隙结构和比表面积有所不同，3：1配比中生物炭的比表面积更大且孔隙结构更发达，并且含有更多的羟基、羧基等含氧官能团，具有更好的钝化性能。As can be seen from Table 2, after adding modified biochar, the effective content of heavy metals in the soil contaminated by microplastics and heavy metals decreased to a certain extent. In the soil with a microplastic pollution concentration of 2%, the Cr passivation efficiency reached 63.7% after adding modified biochar, and the Pb passivation efficiency was 17.3%; in the soil with a microplastic pollution concentration of 10%, the Cr passivation efficiency reached 65.9% after adding modified biochar, and the Pb passivation efficiency was 17.5%. Compared with Example 1, the ratio of sycamore bark and cork chips in this embodiment is changed to 1:1, and the passivation efficiency of Cr and Pb in the soil with a microplastic pollution concentration of 2% decreased by 13.2% and 12.8% respectively; the passivation efficiency of Cr and Pb in the soil with a microplastic pollution concentration of 10% decreased by 8.1% and 6.6% respectively. The reason is that the pore structure and specific surface area of the biochar generated after changing the ratio are different. The biochar in the 3:1 ratio has a larger specific surface area and a more developed pore structure, and contains more oxygen-containing functional groups such as hydroxyl and carboxyl, and has better passivation performance.
实施例3Example 3
1、按照重量比3：1，称取干燥的梧桐皮和软木屑并混合，经过80℃加热20h，制得生物炭前驱体；1. Weigh and mix dried sycamore bark and cork chips at a weight ratio of 3:1, and heat at 80°C for 20 hours to obtain a biochar precursor;
2、生物炭前驱体在300℃、氧气含量为1％以下的条件下进行限氧热解，热解时间2h，冷却至室温。将制备得到的生物炭研磨后用筛网筛分为不同粒径的生物炭颗粒(小于100目、100～200目、200～400目)。2. The biochar precursor was subjected to oxygen-limited pyrolysis at 300°C and an oxygen content of less than 1% for 2 hours, and then cooled to room temperature. The prepared biochar was ground and sieved with a sieve to form biochar particles of different particle sizes (less than 100 mesh, 100-200 mesh, 200-400 mesh).
3、将步骤2中得到的生物炭(200～400目)与5％改性溶液(H2SO4与HNO3配比为1：1)混合(质量比1：500)，搅拌6h，然后经水洗后在80℃下烘干，得到改性生物炭钝化剂。3. The biochar (200-400 mesh) obtained in step2 was mixed with 5% modified solution (H2SO4 andHNO3 ratio of 1:1) (mass ratio 1:500), stirred for 6h, then washed with water and dried at 80℃ to obtain a modified biochar passivator.
4、待修复的微塑料和重金属复合污染土壤中微塑料含量在0～10％、污染重金属为1000mg/kg的Pb和200mg/kg的Cd，土壤理化性质如下：砂粒(0.075～2mm)含量61.6％，粉粒(0.005～0.075mm)含量15.6％，黏粒(＜0.005mm)含量22.8％，pH值6.8，有机质含量16.7g/kg；4. The microplastic content of the soil to be repaired is 0-10%, and the heavy metal pollution is 1000 mg/kg of Pb and 200 mg/kg of Cd. The physical and chemical properties of the soil are as follows: sand content (0.075-2 mm) is 61.6%, silt content (0.005-0.075 mm) is 15.6%, clay content (<0.005 mm) is 22.8%, pH value is 6.8, and organic matter content is 16.7 g/kg;
5、将制备得到的改性生物炭按照1：100的质量比例添加到上述微塑料和重金属污染土壤中，混合搅拌均匀；5. Add the prepared modified biochar to the microplastics and heavy metal contaminated soil at a mass ratio of 1:100, and mix and stir evenly;
6、定时灌溉以维持土壤水分含量在田间最大持水量的70％，并维持10d。6. Irrigate regularly to maintain soil moisture content at 70% of the maximum field water holding capacity and maintain it for 10 days.
7、修复完成后，利用BCR形态分析污染土壤中重金属的有效态含量。7. After remediation is completed, use BCR morphology to analyze the effective content of heavy metals in the contaminated soil.
表3污染土壤中重金属有效态钝化效果Table 3 Passivation effect of effective heavy metals in contaminated soil
由表3可以看出，添加改性生物炭后，微塑料和重金属复合污染土壤中重金属的有效态含量均出现一定下降，其中2％微塑料污染浓度的土壤中，添加改性生物炭后Cr钝化效率达到了73.1％，Pb钝化效率为34.4％；10％微塑料污染浓度土壤中，添加改性生物炭后Cr钝化效率达到了72.0％，Pb钝化效率为21.6％。对比实施例1，本实施例调整了生物炭热解的温度为300℃，2％微塑料污染浓度土壤中Cr钝化效率下降3.8％；10％微塑料污染浓度土壤中Cr、Pb钝化效率分别下降2％、2.5％。降低温度后较低的热解温度通常会导致较高的生物炭产率，因为在较低温度下，生物质中的一些组分尚未完全分解，且其会导致生物炭具有较少的微孔和较低的比表面积。这可能降低生物炭对重金属等污染物的吸附能力。并且较低的热解温度制备的生物炭可能具有较低的热稳定性和耐久性。As can be seen from Table 3, after adding modified biochar, the effective content of heavy metals in the soil contaminated by microplastics and heavy metals decreased to a certain extent. In the soil with a microplastic pollution concentration of 2%, the Cr passivation efficiency reached 73.1% after adding modified biochar, and the Pb passivation efficiency was 34.4%; in the soil with a microplastic pollution concentration of 10%, the Cr passivation efficiency reached 72.0% after adding modified biochar, and the Pb passivation efficiency was 21.6%. Compared with Example 1, the temperature of biochar pyrolysis was adjusted to 300°C in this embodiment, and the Cr passivation efficiency in the soil with a microplastic pollution concentration of 2% decreased by 3.8%; the Cr and Pb passivation efficiencies in the soil with a microplastic pollution concentration of 10% decreased by 2% and 2.5%, respectively. Lower pyrolysis temperatures after lowering the temperature usually result in higher biochar yields, because at lower temperatures, some components in the biomass have not been completely decomposed, and it will cause the biochar to have fewer micropores and a lower specific surface area. This may reduce the adsorption capacity of biochar for pollutants such as heavy metals. And biochar prepared at lower pyrolysis temperatures may have lower thermal stability and durability.
实施例4Example 4
1、按照重量比3：1，称取干燥的梧桐皮和软木屑并混合，经过80℃加热20h，制得生物炭前驱体；1. Weigh and mix dried sycamore bark and cork chips at a weight ratio of 3:1, and heat at 80°C for 20 hours to obtain a biochar precursor;
2、生物炭前驱体在600℃下、氧气含量为1％以下的条件进行限氧热解，热解时间2h，冷却至室温。将制备得到的生物炭研磨后用筛网筛分为不同粒径的生物炭颗粒(10～100目、100～200目、200～400目)。2. The biochar precursor was subjected to oxygen-limited pyrolysis at 600°C and an oxygen content of less than 1% for 2 hours, and then cooled to room temperature. The prepared biochar was ground and sieved with a sieve to form biochar particles of different particle sizes (10-100 mesh, 100-200 mesh, 200-400 mesh).
3、将步骤2中得到的生物炭(200～400目)与5％改性溶液(H2SO4与HNO3配比为1：1)混合(质量比1：500)，搅拌4h，然后经水洗后在80℃下烘干，得到改性生物炭钝化剂。3. The biochar (200-400 mesh) obtained in step2 was mixed with 5% modified solution (H2SO4 andHNO3 ratio of 1:1) (mass ratio 1:500), stirred for 4h, then washed with water and dried at 80℃ to obtain a modified biochar passivator.
4、待修复的微塑料和重金属复合污染土壤中微塑料含量在0～10％、污染重金属为1000mg/kg的Pb和200mg/kg的Cd，土壤理化性质如下：砂粒(0.075～2mm)含量61.6％，粉粒(0.005～0.075mm)含量15.6％，黏粒(＜0.005mm)含量22.8％，pH值6.8，有机质含量16.7g/kg；4. The microplastic content of the soil to be repaired is 0-10%, and the heavy metal pollution is 1000 mg/kg of Pb and 200 mg/kg of Cd. The physical and chemical properties of the soil are as follows: sand content (0.075-2 mm) is 61.6%, silt content (0.005-0.075 mm) is 15.6%, clay content (<0.005 mm) is 22.8%, pH value is 6.8, and organic matter content is 16.7 g/kg;
5、将制备得到的改性生物炭按照2：100的质量比例添加到上述微塑料和重金属污染土壤中，混合搅拌均匀；5. Add the prepared modified biochar to the microplastic and heavy metal contaminated soil at a mass ratio of 2:100, and mix and stir evenly;
6、定时灌溉以维持土壤水分含量在田间最大持水量的70％，并维持10d。6. Irrigate regularly to maintain soil moisture content at 70% of the maximum field water holding capacity and maintain it for 10 days.
7、修复完成后，利用BCR形态分析污染土壤中重金属的有效态含量7. After remediation is completed, use BCR morphology to analyze the effective content of heavy metals in contaminated soil
表4污染土壤中重金属有效态钝化效果Table 4 Passivation effect of effective heavy metals in contaminated soil
由表4可以看出，添加改性生物炭后，微塑料和重金属复合污染土壤中重金属的有效态含量均出现一定下降，其中2％微塑料污染浓度的土壤中，添加改性生物炭后Cr钝化效率达到了79.2％，Pb钝化效率为44.2％；10％微塑料污染浓度土壤中，添加改性生物炭后Cr钝化效率达到了77.2％，Pb钝化效率为31.0％。对比实施例1，本实施例增加生物炭添加量为2％，2％微塑料污染浓度土壤中Cr、Pb钝化效率分别增加2.3％、14.1％；10％微塑料污染浓度土壤中Cr、Pb钝化效率分别增加3.2％、6.9％，是最优处理案例。It can be seen from Table 4 that after adding modified biochar, the effective content of heavy metals in the soil contaminated by microplastics and heavy metals decreased to a certain extent. In the soil with 2% microplastic pollution concentration, the passivation efficiency of Cr reached 79.2% after adding modified biochar, and the passivation efficiency of Pb was 44.2%; in the soil with 10% microplastic pollution concentration, the passivation efficiency of Cr reached 77.2% after adding modified biochar, and the passivation efficiency of Pb was 31.0%. Compared with Example 1, the amount of biochar added in this embodiment is increased by 2%, and the passivation efficiency of Cr and Pb in the soil with 2% microplastic pollution concentration increases by 2.3% and 14.1% respectively; the passivation efficiency of Cr and Pb in the soil with 10% microplastic pollution concentration increases by 3.2% and 6.9% respectively, which is the optimal treatment case.
实施例5Example 5
1、按照重量比3：1，称取干燥的梧桐皮和软木屑并混合，经过80℃加热20h，制得生物炭前驱体；1. Weigh and mix dried sycamore bark and cork chips at a weight ratio of 3:1, and heat at 80°C for 20 hours to obtain a biochar precursor;
2、生物炭前驱体在600℃、氧气含量为1％以下的条件下进行限氧热解，热解时间2h，冷却至室温。将制备得到的生物炭研磨后用筛网筛分为不同粒径的生物炭颗粒(10～100目、100～200目、200～400目)。2. The biochar precursor was subjected to oxygen-limited pyrolysis at 600°C and an oxygen content of less than 1% for 2 hours, and then cooled to room temperature. The prepared biochar was ground and sieved with a sieve to form biochar particles of different particle sizes (10-100 mesh, 100-200 mesh, 200-400 mesh).
3、将步骤2中得到的生物炭(100～200目)与5％改性溶液(H2SO4与HNO3配比为1：1)混合(质量比1：500)，搅拌6h，然后经水洗后在80℃下烘干，得到改性生物炭钝化剂。3. The biochar (100-200 mesh) obtained in step2 was mixed with 5% modified solution (H2SO4 andHNO3 ratio of 1:1) (mass ratio 1:500), stirred for 6h, then washed with water and dried at 80℃ to obtain a modified biochar passivator.
4、待修复的微塑料和重金属复合污染土壤中微塑料含量在0～10％、污染重金属为1000mg/kg的Pb和200mg/kg的Cd，土壤理化性质如下：砂粒(0.075～2mm)含量61.6％，粉粒(0.005～0.075mm)含量15.6％，黏粒(＜0.005mm)含量22.8％，pH值6.8，有机质含量16.7g/kg；4. The microplastic content of the soil to be repaired is 0-10%, and the heavy metal pollution is 1000 mg/kg of Pb and 200 mg/kg of Cd. The physical and chemical properties of the soil are as follows: sand content (0.075-2 mm) is 61.6%, silt content (0.005-0.075 mm) is 15.6%, clay content (<0.005 mm) is 22.8%, pH value is 6.8, and organic matter content is 16.7 g/kg;
5、将制备得到的改性生物炭按照1：100的质量比例添加到上述微塑料和重金属污染土壤中，混合搅拌均匀；5. Add the prepared modified biochar to the microplastics and heavy metal contaminated soil at a mass ratio of 1:100, and mix and stir evenly;
6、定时灌溉以维持土壤水分含量在田间最大持水量的70％，并维持10d。6. Irrigate regularly to maintain soil moisture content at 70% of the maximum field water holding capacity and maintain it for 10 days.
7、修复完成后，利用BCR形态分析污染土壤中重金属的有效态含量。7. After remediation is completed, use BCR morphology to analyze the effective content of heavy metals in the contaminated soil.
表5污染土壤中重金属有效态钝化效果Table 5 Passivation effect of effective heavy metals in contaminated soil
由表5可以看出，添加改性生物炭后，微塑料和重金属复合污染土壤中重金属的有效态含量均出现一定下降，其中2％微塑料污染浓度的土壤中，添加改性生物炭后Cr钝化效率达到了75.9％，Pb钝化效率为29.1％；10％微塑料污染浓度土壤中，添加改性生物炭后Cr钝化效率达到了74.4％，Pb钝化效率为24.8％。It can be seen from Table 5 that after adding modified biochar, the effective content of heavy metals in the soil contaminated by microplastics and heavy metals decreased to a certain extent. In the soil with a microplastic pollution concentration of 2%, the Cr passivation efficiency reached 75.9% after adding modified biochar, and the Pb passivation efficiency was 29.1%; in the soil with a microplastic pollution concentration of 10%, the Cr passivation efficiency reached 74.4% after adding modified biochar, and the Pb passivation efficiency was 24.8%.
实施例6Example 6
1、按照重量比3：1，称取干燥的梧桐皮和软木屑并混合，经过80℃加热20h，制得生物炭前驱体；1. Weigh and mix dried sycamore bark and cork chips at a weight ratio of 3:1, and heat at 80°C for 20 hours to obtain a biochar precursor;
2、生物炭前驱体在600℃、氧气含量为1％以下的条件下进行限氧热解，热解时间2h，冷却至室温。将制备得到的生物炭研磨后用筛网筛分为不同粒径的生物炭颗粒(10～100目、100～200目、200～400目)。2. The biochar precursor was subjected to oxygen-limited pyrolysis at 600°C and an oxygen content of less than 1% for 2 hours, and then cooled to room temperature. The prepared biochar was ground and sieved with a sieve to form biochar particles of different particle sizes (10-100 mesh, 100-200 mesh, 200-400 mesh).
3、将步骤2中得到的生物炭(200～400目)变化与5％改性溶液(H2SO4与HNO3配比为1：1)混合(质量比1：500)，搅拌6h，然后经水洗后在80℃下烘干，得到改性生物炭钝化剂。3. The biochar (200-400 mesh) obtained in step2 was mixed with 5% modified solution (H2SO4 andHNO3 ratio of 1:1) (mass ratio 1:500), stirred for 6h, then washed with water and dried at 80℃ to obtain a modified biochar passivator.
4、待修复的微塑料和重金属复合污染土壤中微塑料含量在0～10％、污染重金属为3000mg/kg的Pb和400mg/kg的Cd，土壤理化性质如下：砂粒(0.075～2mm)含量61.6％，粉粒(0.005～0.075mm)含量15.6％，黏粒(＜0.005mm)含量22.8％，pH值6.8，有机质含量16.7g/kg；4. The microplastic content of the soil to be repaired is 0-10%, and the heavy metal pollution is 3000mg/kg of Pb and 400mg/kg of Cd. The physical and chemical properties of the soil are as follows: sand content (0.075-2mm) is 61.6%, silt content (0.005-0.075mm) is 15.6%, clay content (<0.005mm) is 22.8%, pH value is 6.8, and organic matter content is 16.7g/kg;
5、将制备得到的改性生物炭按照1：100的质量比例添加到上述微塑料和重金属污染土壤中，混合搅拌均匀；5. Add the prepared modified biochar to the microplastics and heavy metal contaminated soil at a mass ratio of 1:100, and mix and stir evenly;
6、定时灌溉以维持土壤水分含量在田间最大持水量的70％，并维持10d。6. Irrigate regularly to maintain soil moisture content at 70% of the maximum field water holding capacity and maintain it for 10 days.
7、修复完成后，利用BCR形态分析污染土壤中重金属的有效态含量。7. After remediation is completed, use BCR morphology to analyze the effective content of heavy metals in the contaminated soil.
表6污染土壤中重金属有效态钝化效果Table 6 Passivation effect of effective heavy metals in contaminated soil
由表6可以看出，添加改性生物炭后，微塑料和重金属复合污染土壤中重金属的有效态含量均出现一定下降，其中2％微塑料污染浓度的土壤中，添加改性生物炭后Cr钝化效率达到了73.4％，Pb钝化效率为26.5％；10％微塑料污染浓度土壤中，添加改性生物炭后Cr钝化效率达到了71.9％，Pb钝化效率为22.0％It can be seen from Table 6 that after adding modified biochar, the effective content of heavy metals in the soil contaminated by microplastics and heavy metals decreased to a certain extent. In the soil with a microplastic pollution concentration of 2%, the Cr passivation efficiency reached 73.4% after adding modified biochar, and the Pb passivation efficiency was 26.5%; in the soil with a microplastic pollution concentration of 10%, the Cr passivation efficiency reached 71.9% after adding modified biochar, and the Pb passivation efficiency was 22.0%.
实施例7Example 7
1、按照重量比3：1，称取干燥的梧桐皮和软木屑并混合，经过80℃加热20h，制得生物炭前驱体；1. Weigh and mix dried sycamore bark and cork chips at a weight ratio of 3:1, and heat at 80°C for 20 hours to obtain a biochar precursor;
2、生物炭前驱体在900℃、氧气含量为1％以下的条件下进行限氧热解，热解时间2h，冷却至室温。将制备得到的生物炭研磨后用筛网筛分为不同粒径的生物炭颗粒(10～100目、100～200目、200～400目)。2. The biochar precursor was subjected to oxygen-limited pyrolysis at 900°C and an oxygen content of less than 1% for 2 hours, and then cooled to room temperature. The prepared biochar was ground and sieved with a sieve to form biochar particles of different particle sizes (10-100 mesh, 100-200 mesh, 200-400 mesh).
3、将步骤2中得到的生物炭(100～200目)与10％改性溶液(H2SO4与HNO3配比为1：1)混合(质量比1：500)，搅拌6h，然后经水洗后在90℃下烘干，得到改性生物炭钝化剂。3. The biochar (100-200 mesh) obtained in step2 was mixed with 10% modified solution (H2SO4 andHNO3 ratio of 1:1) (mass ratio 1:500), stirred for 6h, then washed with water and dried at 90°C to obtain a modified biochar passivator.
4、待修复的微塑料和重金属复合污染土壤中微塑料含量在0～10％、污染重金属为1000mg/kg的Pb和200mg/kg的Cr，土壤理化性质如下：砂粒(0.075～2mm)含量61.6％，粉粒(0.005～0.075mm)含量15.6％，黏粒(＜0.005mm)含量22.8％，pH值6.8，有机质含量16.7g/kg；4. The microplastic content of the soil to be repaired is 0-10%, the heavy metal pollution is 1000mg/kg of Pb and 200mg/kg of Cr. The physical and chemical properties of the soil are as follows: sand content (0.075-2mm) is 61.6%, silt content (0.005-0.075mm) is 15.6%, clay content (<0.005mm) is 22.8%, pH value is 6.8, and organic matter content is 16.7g/kg;
5、将制备得到的改性生物炭按照1：100的质量比例添加到上述微塑料和重金属污染土壤中，混合搅拌均匀；5. Add the prepared modified biochar to the microplastics and heavy metal contaminated soil at a mass ratio of 1:100, and mix and stir evenly;
6、定时灌溉以维持土壤水分含量在田间最大持水量的70％，并维持10d。6. Irrigate regularly to maintain soil moisture content at 70% of the maximum field water holding capacity and maintain it for 10 days.
7、修复完成后，利用BCR形态分析污染土壤中重金属的有效态含量。7. After remediation is completed, use BCR morphology to analyze the effective content of heavy metals in the contaminated soil.
表7污染土壤中重金属有效态钝化效果Table 7 Passivation effect of effective heavy metals in contaminated soil
由表7可以看出，添加改性生物炭后，微塑料和重金属复合污染土壤中重金属的有效态含量均出现一定下降，其中2％微塑料污染浓度的土壤中，添加改性生物炭后Cr钝化效率达到了75.5％，Pb钝化效率为27.9％；10％微塑料污染浓度的土壤中，添加改性生物炭后Cr钝化效率达到了72.3％，Pb钝化效率为24.1％。It can be seen from Table 7 that after adding modified biochar, the effective content of heavy metals in the soil contaminated by microplastics and heavy metals decreased to a certain extent. In the soil with a microplastic pollution concentration of 2%, the Cr passivation efficiency reached 75.5% after adding modified biochar, and the Pb passivation efficiency was 27.9%; in the soil with a microplastic pollution concentration of 10%, the Cr passivation efficiency reached 72.3% after adding modified biochar, and the Pb passivation efficiency was 24.1%.
实施例8Example 8
1、按照重量比1：1，称取干燥的梧桐皮和软木屑并混合，经过80℃加热20h，制得生物炭前驱体；1. According to the weight ratio of 1:1, dry sycamore bark and cork chips were weighed and mixed, and heated at 80°C for 20 hours to obtain a biochar precursor;
2、生物炭前驱体在300℃、氧气含量为1％以下的条件下进行限氧热解，热解时间2h，冷却至室温。将制备得到的生物炭研磨后用筛网筛分为不同粒径的生物炭颗粒(10～100目、100～200目、200～400目)。2. The biochar precursor was subjected to oxygen-limited pyrolysis at 300°C and an oxygen content of less than 1% for 2 hours, and then cooled to room temperature. The prepared biochar was ground and sieved with a sieve to form biochar particles of different particle sizes (10-100 mesh, 100-200 mesh, 200-400 mesh).
3、将步骤2中得到的生物炭(10～100目)与2％改性溶液(H2SO4与HNO3配比为1：1)混合(质量比1：500)，搅拌6h，然后经水洗后在60℃下烘干，得到改性生物炭钝化剂。3. The biochar (10-100 mesh) obtained in step2 was mixed with 2% modified solution (H2SO4 andHNO3 ratio of 1:1) (mass ratio 1:500), stirred for 6h, then washed with water and dried at 60°C to obtain a modified biochar passivator.
4、待修复的微塑料和重金属复合污染土壤中微塑料含量在0～10％、污染重金属为1000mg/kg的Pb和200mg/kg的Cr，土壤理化性质如下：砂粒(0.075～2mm)含量61.6％，粉粒(0.005～0.075mm)含量15.6％，黏粒(＜0.005mm)含量22.8％，pH值6.8，有机质含量16.7g/kg；4. The microplastic content of the soil to be repaired is 0-10%, the heavy metal pollution is 1000mg/kg of Pb and 200mg/kg of Cr. The physical and chemical properties of the soil are as follows: sand content (0.075-2mm) is 61.6%, silt content (0.005-0.075mm) is 15.6%, clay content (<0.005mm) is 22.8%, pH value is 6.8, and organic matter content is 16.7g/kg;
5、将制备得到的改性生物炭按照1：100的质量比例添加到上述微塑料和重金属污染土壤中，混合搅拌均匀；5. Add the prepared modified biochar to the microplastics and heavy metal contaminated soil at a mass ratio of 1:100, and mix and stir evenly;
6、定时灌溉以维持土壤水分含量在田间最大持水量的70％，并维持10d。6. Irrigate regularly to maintain soil moisture content at 70% of the maximum field water holding capacity and maintain it for 10 days.
7、修复完成后，利用BCR形态分析污染土壤中重金属的有效态含量。7. After remediation is completed, use BCR morphology to analyze the effective content of heavy metals in the contaminated soil.
表8污染土壤中重金属有效态钝化效果Table 8 Passivation effect of effective heavy metals in contaminated soil
由表8可以看出，添加改性生物炭后，微塑料和重金属复合污染土壤中重金属的有效态含量均出现一定下降，其中2％微塑料污染浓度的土壤中，添加改性生物炭后Cr钝化效率达到了69.3％，Pb钝化效率为12.9％；10％微塑料污染浓度的土壤中，添加改性生物炭后Cr钝化效率达到了62.6％，Pb钝化效率为13.4％。It can be seen from Table 8 that after adding modified biochar, the effective content of heavy metals in the soil contaminated by microplastics and heavy metals decreased to a certain extent. In the soil with a microplastic pollution concentration of 2%, the Cr passivation efficiency reached 69.3% after adding modified biochar, and the Pb passivation efficiency was 12.9%; in the soil with a microplastic pollution concentration of 10%, the Cr passivation efficiency reached 62.6% after adding modified biochar, and the Pb passivation efficiency was 13.4%.
实施例9Embodiment 9
1、按照重量比3：1，称取干燥的梧桐皮和软木屑并混合，经过60℃加热20h，制得生物炭前驱体；1. Weigh and mix dried sycamore bark and cork chips in a weight ratio of 3:1, and heat at 60°C for 20h to obtain a biochar precursor;
2、生物炭前驱体在600℃、氧气含量为1％以下的条件下进行限氧热解，热解时间3h，冷却至室温。将制备得到的生物炭研磨后用筛网筛分为不同粒径的生物炭颗粒(10～100目、100～200目、200～400目)。2. The biochar precursor was subjected to oxygen-limited pyrolysis at 600°C and an oxygen content of less than 1% for 3 hours, and then cooled to room temperature. The prepared biochar was ground and sieved with a sieve to form biochar particles of different particle sizes (10-100 mesh, 100-200 mesh, 200-400 mesh).
3、将步骤2中得到的生物炭(100～200目)与10％改性溶液(H2SO4与HNO3配比为1：1)混合(质量比1：200)，搅拌6h，然后经水洗后在90℃下烘干，得到改性生物炭钝化剂。3. The biochar (100-200 mesh) obtained in step2 was mixed with 10% modified solution (H2SO4 andHNO3 ratio of 1:1) (mass ratio 1:200), stirred for 6h, then washed with water and dried at 90°C to obtain a modified biochar passivator.
4、待修复的微塑料和重金属复合污染土壤中微塑料含量在0～10％、污染重金属为1000mg/kg的Pb和200mg/kg的Cr，土壤理化性质如下：砂粒(0.075～2mm)含量61.6％，粉粒(0.005～0.075mm)含量15.6％，黏粒(＜0.005mm)含量22.8％，pH值6.8，有机质含量16.7g/kg；4. The microplastic content of the soil to be repaired is 0-10%, the heavy metal pollution is 1000mg/kg of Pb and 200mg/kg of Cr. The physical and chemical properties of the soil are as follows: sand content (0.075-2mm) is 61.6%, silt content (0.005-0.075mm) is 15.6%, clay content (<0.005mm) is 22.8%, pH value is 6.8, and organic matter content is 16.7g/kg;
5、将制备得到的改性生物炭按照1：100的质量比例添加到上述微塑料和重金属污染土壤中，混合搅拌均匀；5. Add the prepared modified biochar to the microplastics and heavy metal contaminated soil at a mass ratio of 1:100, and mix and stir evenly;
6、定时灌溉以维持土壤水分含量在田间最大持水量的60％，并维持5d。6. Irrigate regularly to maintain soil moisture content at 60% of the maximum field water holding capacity and maintain it for 5 days.
7、修复完成后，利用BCR形态分析污染土壤中重金属的有效态含量。7. After remediation is completed, use BCR morphology to analyze the effective content of heavy metals in the contaminated soil.
表9污染土壤中重金属有效态钝化效果Table 9 Passivation effect of effective heavy metals in contaminated soil
由表9可以看出，添加改性生物炭后，微塑料和重金属复合污染土壤中重金属的有效态含量均出现一定下降，其中2％微塑料污染浓度的土壤中，添加改性生物炭后Cr钝化效率达到了56.6％，Pb钝化效率为17.9％；10％微塑料污染浓度的土壤中，添加改性生物炭后Cr钝化效率达到了52.5％，Pb钝化效率为17.4％。It can be seen from Table 9 that after adding modified biochar, the effective content of heavy metals in the soil contaminated by microplastics and heavy metals decreased to a certain extent. In the soil with a microplastic pollution concentration of 2%, the Cr passivation efficiency reached 56.6% after adding modified biochar, and the Pb passivation efficiency was 17.9%; in the soil with a microplastic pollution concentration of 10%, the Cr passivation efficiency reached 52.5% after adding modified biochar, and the Pb passivation efficiency was 17.4%.
实施例10Example 10
1、按照重量比3：1，称取干燥的梧桐皮和软木屑并混合，经过80℃加热30h，制得生物炭前驱体；1. Weigh and mix dried sycamore bark and cork chips in a weight ratio of 3:1, and heat at 80°C for 30h to obtain a biochar precursor;
2、生物炭前驱体在900℃、氧气含量为1％以下的条件下进行限氧热解，热解时间3h，冷却至室温。将制备得到的生物炭研磨后用筛网筛分为不同粒径的生物炭颗粒(10～100目、100～200目、200～400目)。2. The biochar precursor was subjected to oxygen-limited pyrolysis at 900°C and an oxygen content of less than 1% for 3 hours, and then cooled to room temperature. The prepared biochar was ground and sieved with a sieve to form biochar particles of different particle sizes (10-100 mesh, 100-200 mesh, 200-400 mesh).
3、将步骤2中得到的生物炭(100～200目)与10％改性溶液(H2SO4与HNO3配比为1：1)混合(质量比1：500)，搅拌6h，然后经水洗后在90℃下烘干，得到改性生物炭钝化剂。3. The biochar (100-200 mesh) obtained in step2 was mixed with 10% modified solution (H2SO4 andHNO3 ratio of 1:1) (mass ratio 1:500), stirred for 6h, then washed with water and dried at 90°C to obtain a modified biochar passivator.
4、待修复的微塑料和重金属复合污染土壤中微塑料含量在0～10％、污染重金属为1000mg/kg的Pb和200mg/kg的Cr，土壤理化性质如下：砂粒(0.075～2mm)含量61.6％，粉粒(0.005～0.075mm)含量15.6％，黏粒(＜0.005mm)含量22.8％，pH值6.8，有机质含量16.7g/kg；4. The microplastic content of the soil to be repaired is 0-10%, the heavy metal pollution is 1000mg/kg of Pb and 200mg/kg of Cr. The physical and chemical properties of the soil are as follows: sand content (0.075-2mm) is 61.6%, silt content (0.005-0.075mm) is 15.6%, clay content (<0.005mm) is 22.8%, pH value is 6.8, and organic matter content is 16.7g/kg;
5、将制备得到的改性生物炭按照1：100的质量比例添加到上述微塑料和重金属污染土壤中，混合搅拌均匀；5. Add the prepared modified biochar to the microplastics and heavy metal contaminated soil at a mass ratio of 1:100, and mix and stir evenly;
6、定时灌溉以维持土壤水分含量在田间最大持水量的70％，并维持10d。6. Irrigate regularly to maintain soil moisture content at 70% of the maximum field water holding capacity and maintain it for 10 days.
7、修复完成后，利用BCR形态分析污染土壤中重金属的有效态含量。7. After remediation is completed, use BCR morphology to analyze the effective content of heavy metals in the contaminated soil.
表10污染土壤中重金属有效态钝化效果Table 10 Passivation effect of effective heavy metals in contaminated soil
由表10可以看出，添加改性生物炭后，微塑料和重金属复合污染土壤中重金属的有效态含量均出现一定下降，其中2％微塑料污染浓度的土壤中，添加改性生物炭后Cr钝化效率达到了76.9％，Pb钝化效率为31.4％；10％微塑料污染浓度的土壤中，添加改性生物炭后Cr钝化效率达到了74.0％，Pb钝化效率为27.2％。It can be seen from Table 10 that after adding modified biochar, the effective content of heavy metals in the soil contaminated by microplastics and heavy metals decreased to a certain extent. In the soil with a microplastic pollution concentration of 2%, the Cr passivation efficiency reached 76.9% after adding modified biochar, and the Pb passivation efficiency was 31.4%; in the soil with a microplastic pollution concentration of 10%, the Cr passivation efficiency reached 74.0% after adding modified biochar, and the Pb passivation efficiency was 27.2%.
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