沙柳生物炭对铜污染改良作用研究

发布时间：2018-08-27 16:53

【摘要】：生物质炭以其良好的物理结构,丰富的比表面积,逐渐成为一种新兴的环境修复材料被广泛应用于环境修复治理中,将平茬后剩余的沙柳条经高温限氧裂解后制作成生物炭,既可以避免生物质资源的浪费,又可以吸附重金属,修复受污染的草原土壤。本研究以锡林郭勒盟峰雷铜矿区为例,通过野外试验,对矿区的重金属污染情况进行调查评价后,以沙柳生物炭为修复材料进行室内模拟,分别对不同吸附条件下水溶液中Cu2+进行吸附试验,以探究沙柳生物炭的吸附性能;并以当地优势种冰草进行室内盆栽试验,依据单因子污染指数法,确定矿区尾矿砂与未污染草原土的污染配比,分别为:0%(无污染CK)、2.5%(轻度污染)、5%(中度污染)、7.5%(重度污染),通过添加不同比例的沙柳生物炭后,对不同污染的土壤理化性质、冰草生长状况及铜的迁移过程进行研究。主要结论如下:(1)研究区受当地主风向西北风的影响,该地区整体污染情况的空间分布为东南东北西南西北,其中Cu和Cd都为重度污染,且Cu的单项污染指数Pi最大为18.59,Cd的单项污染指数Pi最大为4.42,均高于单项污染指数评价的重度污染(Pi3),Pi(Cu)Pi(Cd)。故确定Cu为当地土壤污染的主要金属。(2)沙柳生物炭吸附水溶液中的Cu2+过程是表面和内部同时进行的复合吸附过程。Lagergren准二级动力学模型和颗粒内扩散模型(R20.99)均能较好描述出沙柳生物炭吸附Cu2+的过程;当Cu2+浓度为512mg/L时,沙柳生物炭的吸附量最大19.13mg/g;经过16h,沙柳生物炭对Cu2+的吸附量和吸附率均达平衡;因此在矿区铜污染修复的过程中应该依据矿区铜污染程度结合矿区土壤环境来决定生物炭的添加量。(3)轻度、中度、重度污染条件下,随沙柳生物炭添加比例的增加,铜在各部位的浓度含量随之减少,且在各部分的富集程度表现为:冰草根系土壤冰草茎叶。轻度、中度、重度污染条件下,沙柳生物炭添加比例为1%时,铜在土壤冰草中的迁移系数最小,分别为0.05、0.04、0.04。添加0.8%-1%沙柳生物炭对土壤和冰草的表现最优。
[Abstract]:Because of its good physical structure and rich specific surface area, biomass carbon has gradually become a new environmental remediation material, which has been widely used in environmental remediation. It can not only avoid the waste of biomass resources, but also adsorb heavy metals, and repair the polluted grassland soil. Taking the Fenglei copper mine area of Xilingol Mengmeng as an example, the heavy metal pollution in the mining area was investigated and evaluated through field tests, and the indoor simulation was carried out with Salix biochar as the restoration material. Adsorption experiments of Cu2 in aqueous solution under different adsorption conditions were carried out to explore the adsorption properties of biochar, and pot experiments were carried out with local dominant species of ice grass, according to the method of single factor pollution index. The proportion of pollution of mine tailings and unpolluted grassland soil was determined to be: 0% (non-polluted CK) 2.5% (mild pollution) 5% (moderate pollution) and 7.5% (heavy pollution). The physicochemical properties of different polluted soils were obtained by adding different proportion of Salix biochar. The growth status and copper migration process of Icegrass were studied. The main conclusions are as follows: (1) the spatial distribution of the whole pollution situation in the study area is southeast, northeast, southwest, northwest, and Cu and Cd are both serious pollution. The maximum single pollution index (Pi) of Cu is 18.59% CD and the maximum of Pi is 4.42, which is higher than that of Pi3 (heavy pollution index) Pi (Cu) Pi (Cd). Evaluated by single pollution index. It is concluded that Cu is the main metal in local soil pollution. (2) the adsorption of Cu2 in aqueous solution by biochar is a complex adsorption process both on the surface and inside. Lagergren quasi-second-order kinetic model and intraparticle diffusion model (R20.99) can be compared with each other. The process of adsorption of Cu2 by biochar was described. When the concentration of Cu2 was 512mg/L, the adsorption capacity of Salix biochar was 19.13 mg / g, and the adsorption capacity and adsorption rate of Cu2 reached equilibrium after 16 h. Therefore, in the process of copper pollution remediation in mining area, the amount of biochar should be determined according to the degree of copper pollution and soil environment. (3) under mild, moderate and severe pollution conditions, the ratio of biochar added to Salix willow increased with the increase of the proportion of biochar. The concentration of Cu in different parts decreased, and the enrichment degree of Cu in each part was as follows: the root of Icegrass was the stem and leaf of Icegrass. Under the condition of mild, moderate and severe pollution, when the ratio of biochar of Salix was 1, the transport coefficient of copper in soil ice grass was the lowest, which was 0.05 ~ 0.04 ~ 0.04 ~ 0.04, respectively. The best performance of soil and ice grass was obtained by adding 0.8-1% of Salix biochar.
【学位授予单位】：内蒙古农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X53;X173

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