不同活化材料提高蜈蚣草富集重金属能力的效果研究

发布时间：2019-04-25 12:03

【摘要】：近年来,砷超富集植物—蜈蚣草已成功应用于我国南方矿区污染农田土壤的实地修复,并在复合重金属污染土壤修复技术中表现出巨大潜力。针对我国重金属复合污染及砷污染修复技术研究的现状,本试验分为两部分：(1)通过采集潮土和棕壤进行室内土壤培养试验和盆栽试验,以超富集植物蜈蚣草作为研究对象,研究不同活化材料对土壤砷、铅、镉有效性和形态转化的影响,及蜈蚣草各部位吸收富集砷、铅、镉的影响；(2)选择北京化工场地砷污染土壤为研究对象,通过田间试验,研究不同类型磷肥对蜈蚣草不同生长时期生长及砷的吸收的影响,为植物修复中选择合适的磷肥类型提供科学依据。主要结果如下：(1)添加不同活化材料,在一定程度上活化了土壤中的砷、铅、镉,土壤重金属的有效性得到提高。磷酸二氢铵表现出更好的释放砷的能力,EDTA表现出更好的释放铅、镉的能力。(2)添加EDTA明显增加土壤中可交换态和碳酸盐结合态铅、镉含量,减少Fe/Mn结合态和有机结合态铅、镉含量,残渣态铅、镐含量变化不明显。说明EDTA能促进土壤铅、镉的形态由生物难利用态向生物可利用态转化。(3)盆栽试验中,磷酸二氢铵、柠檬酸的添加显著促进蜈蚣草的生长发育,添加EDTA则显著抑制了蜈蚣草的生长。磷酸二氢铵、柠檬酸均能显著增加蜈蚣草各部位砷含量。EDTA处理下蜈蚣草各部位吸收累积铅、镉含量显著高于其他处理。(4)盆栽试验中,蜈蚣草根部吸收的砷向地上各部位的转运能力为羽叶／茎杆茎杆／根系,铅和镉向地上各部位的转运能力均为茎杆／根系羽叶／茎杆。磷酸二氢铵和柠檬酸在一定程度上提高了蜈蚣草根部吸收的砷向地上部迁移转运的能力,添加EDTA在一定程度上提高了蜈蚣草根部吸收的铅、镉向地上部迁移转运的能力。(5)蜈蚣草种植前后,磷酸二氢铵处理下土壤有效态砷含量均明显高于其他处理,EDTA处理下土壤有效态铅、镉含量最高。蜈蚣草种植后,各处理土壤有效态重金属含量均有下降,这意味着蜈蚣草吸收累积了土壤释放的重金属,活化材料的添加增加了土壤非专性吸附态和专性吸附态砷含量,增加了生物可利用态砷含量,EDTA处理促进土壤各形态铅、镉向生物可利用态转化,即有利于提高蜈蚣草的植物修复效率。(6)田间试验中,施用磷肥明显促进了蜈蚣草的生长、增加了蜈蚣草对砷的吸收富集。随着种植时间的延长,蜈蚣草地上部生物量呈现稳定增加的趋势；蜈蚣草生长第6个月时,地上部砷含量均达到最大。三种磷肥的效果从高到低的顺序为：磷酸二氢铵磷酸二氢钾磷酸二氢钙,说明蜈蚣草修复化工砷污染土壤时,施用磷酸二氢铵肥料是强化蜈蚣草植物修复效果的有效的辅助措施。
[Abstract]:In recent years, the super-enriched arsenic plant-centipede grass has been successfully applied to the field remediation of contaminated farmland soil in mining areas of southern China, and has shown great potential in the remediation of soil contaminated by complex heavy metals. In view of the present situation of remediation technology of heavy metal compound pollution and arsenic pollution in China, the experiment is divided into two parts: (1) the indoor soil culture experiment and pot experiment were carried out by collecting tidal soil and brown soil. The effects of different activated materials on soil arsenic, lead, cadmium availability and transformation, and the absorption of arsenic, lead and cadmium in different parts of centipede grass were studied by using hyperenriched plant centipede grass as the research object. (2) the effects of different types of phosphate fertilizer on the growth and arsenic absorption of Centipede grass in different growth stages were studied by field experiment with arsenic-contaminated soil in Beijing chemical field as the research object. It provides scientific basis for selecting suitable phosphate fertilizer types in phytoremediation. The main results are as follows: (1) the availability of arsenic, lead, cadmium and heavy metals in soil was improved by adding different activated materials to a certain extent. Ammonium dihydrogen phosphate showed a better ability to release arsenic, and EDTA showed a better ability to release lead and cadmium. (2) adding EDTA significantly increased the content of exchangeable and carbonate-bound lead and cadmium in soil. The contents of Pb, CD, Pb and Ho in Fe/Mn-bound and organic-bound state were reduced, but the contents of lead and pickaxe in residue were not changed obviously. The results showed that EDTA could promote the transformation of Pb and CD forms from bioavailability to bioavailability. (3) in pot experiment, the addition of ammonium dihydrogen phosphate and citric acid significantly promoted the growth and development of Pteris vittata. The addition of EDTA significantly inhibited the growth of Pteris vittata. Ammonium dihydrogen phosphate and citric acid could significantly increase arsenic content in different parts of centipede grass. EDTA treatment absorbed accumulated lead and cadmium content was significantly higher than other treatments. (4) in pot experiment, the contents of lead and cadmium in different parts of centipede grass were significantly higher than those in other treatments. The transfer capacity of arsenic absorbed from the root of centipede grass to the above-ground parts was pinnacle / stem / root, and the transport capacity of lead and cadmium to the above-ground parts was stem / root / stem / stem. Ammonium dihydrogen phosphate and citric acid increased the ability of migration and transport of arsenic absorbed from the roots of Centipede to some extent, and the addition of EDTA increased the uptake of lead from the roots of Centipede to a certain extent. (5) the content of available arsenic in soil treated with ammonium dihydrogen phosphate was significantly higher than that in other treatments before and after planting, and the content of available lead and cadmium in soil under EDTA treatment was the highest. After planting the centipede grass, the contents of available heavy metals in the soil of each treatment decreased, which meant that Centipede grass absorbed and accumulated the heavy metals released from the soil, and the addition of activating materials increased the contents of non-specific adsorptive and specialized adsorptive arsenic in the soil. The increase of bioavailable arsenic content, EDTA treatment to promote soil lead, cadmium to bioavailable state transformation, that is, to improve the phytoremediation efficiency of centipede grass. (6) in the field experiment, The application of phosphate fertilizer significantly promoted the growth of Pteris vittata and increased the absorption and enrichment of arsenic by centipede grass. With the extension of planting time, the biomass of the upper part of centipede grassland increased steadily, and the content of arsenic in the shoot reached the maximum at the 6th month after the growth of Centipede grass. The order of effect of three phosphate fertilizers from high to low is: ammonium dihydrogen phosphate, potassium dihydrogen phosphate, calcium dihydrogen phosphate, indicating that centipede grass can be used to repair arsenic contaminated soil in chemical industry. The application of ammonium dihydrogen phosphate fertilizer is an effective auxiliary measure to strengthen the phytoremediation effect of centipede grass.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;X173

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