蚕沙生物炭混施不同铁基材料对土壤镉、铅、砷钝化修复效果研究

发布时间：2018-04-24 16:47

本文选题：蚕沙生物炭 + 铁　；参考：《广西大学》2017年硕士论文

【摘要】：镉、铅、砷都是典型的土壤重金属,土壤体系中经常存在这种复合重金属污染的情况,使生态环境和人体健康受到潜在的威胁。生物炭(Biochar,BC),因其具有丰富的孔隙结构、较大的比表面积和丰富的含氧官能团,这些特点使得生物炭对重金属有较大的吸附能力,成为土壤重金属修复方面的研究热点。铁基材料对重金属的钝化作用也逐渐被人们所重视。本研究选择水稻土为研究对象,以蚕沙生物炭(BC)、硫酸亚铁(FeS04)、氯化铁(FeC13)、还原铁粉(Fe)和纳米铁(纳米Fe)为研究材料,进行室内土培试验。研究不同培养时间(7d、14d、28d和56d)下,BC配施铁基材料对土壤镉、铅、砷化学形态的影响,并从土壤理化性质、酶活性和土壤结构变化角度初步探讨了不同处理钝化修复的机理,以期探明蚕沙生物炭和铁基材料钝化修复重金属复合污染土壤的可行性及其机理。主要研究结果如下:1)施加钝化剂的处理均能降低土壤重金属的有效性,钝化效果明显。综合看来,(BC+FeS04)处理对Cd、Pb、As的钝化效果最好。与对照相比,(BC+FeS04)处理使有机和硫化物结合态和残渣态Cd含量增加了 40.90%,离子交换态和碳酸盐结合态Cd含量降低了 28.44%;有机和硫化物结合态和残渣态Pb含量增加了 23.51%;有机和硫化物结合态和残渣态As含量增加了 1.89%,离子交换态和碳酸盐结合态As含量降低了 10.81%。2)不同处理均能通过改变土壤性质(pH值和CEC)从而改变土壤中Cd、Pb、As的化学形态。不同处理下土壤pH值和CEC均有所增加。培养结束(56 d)时,土壤pH值与对照相比显著增加了 1.65~2.01个单位,(BC+Fe)处理土壤pH值增加最多;CEC与对照相比增加了 2.01~2.58 cmol·kg-1,(BC+Fe)处理 CEC 增加最多。3)随着培养天数的增加,不同处理土壤脲酶活性基本处于上升的趋势,在56 d达到最高值。脲酶活性最高的处理是(BC+Fe),为31.27μg·g-1。不同处理下土壤过氧化氢酶的活性变化不一致,培养结束(56 d)时,土壤氧化氢酶活性显著增加了 86.70%~110·00%,(BC+Fe)和(BC+纳米Fe)两个处理过氧化氢酶的活性最高,为0.210 mL·g-1。4)XRD 谱图分析可知 Cd、Pb、As 分别以 Cd(OH)N03、Cd(OH)2、Pb504、Pb3(CO3)2(OH)2、As205和As204等矿物相的形式被固定在土壤中。(BC+Fe)和(BC+FeS04)两个处理Pb504的矿物相较其他处理高。综合各处理的结果,(BC+FeSO4)处理可以显著改善土壤环境,增加土壤pH值和CEC,增强脲酶的活性,同时对三种的重金属也能起到较好的钝化作用。
[Abstract]:Cadmium, lead and arsenic are typical heavy metals in soil. Because of its rich pore structure, large specific surface area and abundant oxygen-containing functional groups, biochar has a large adsorption capacity for heavy metals, which has become a research hotspot in soil heavy metal remediation. The passivation of heavy metals by iron-based materials has been paid more and more attention. In this study, paddy soil was selected as the research object, and the laboratory soil culture experiments were carried out with silkworm sand biochar (BCN), ferrous sulfate (FeS04), ferric chloride (FeC13), reducing iron powder (Fe3) and nanometer iron (nano Fe) as the research materials. The effects of ferment-based materials on the chemical forms of cadmium, lead and arsenic in soil were studied under different culture time (7d ~ 14d ~ (28 d) and 56d). The mechanism of passivation and remediation of different treatments was discussed from the aspects of soil physical and chemical properties, enzyme activity and soil structure change. The feasibility and mechanism of passivation of silkworm sand biochar and iron based materials for remediation of heavy metal compound contaminated soil were investigated. The main results are as follows: (1) the treatment of passivating agent can reduce the availability of heavy metals in soil, and the passivation effect is obvious. It is shown that the best passivation effect is obtained by BC-FeS04) treatment. Compared with the control, the organic and sulfide-bound and residual CD contents were increased by 40.90, the ion exchange and carbonate bound CD contents decreased by 28.44%, and the organic and sulfide-bound and residual Pb contents increased. The contents of organic and sulfide-bound and residual as increased by 1.89, and the contents of ion exchange and carbonate-bound as decreased by 10.81. 2) the chemical forms of CdPbAs in soil could be changed by changing the soil properties, pH value and CEC). Soil pH and CEC increased under different treatments. At the end of 56 days, the pH value of soil increased significantly by 1.65 ~ 2.01 units per unit of BC Fe compared with the control. The soil pH value of the treatment increased the most than that of the control. Compared with the control, the soil pH value of the treatment increased by 2.01 ~ 2.58 cmol 路kg ~ (-1) cmol 路kg ~ (-1) and the CEC of the treatment increased the most. 3) with the increase of the days of culture, the soil pH value of the treatment increased the most. The soil urease activity of different treatments was on the rise and reached the highest value at 56 days. The highest urease activity was treated with FeBC, 31.27 渭 g / g 路g ~ (-1). The activity of catalase in soil was different under different treatments. At the end of culture, the activity of hydrogen oxide increased significantly (86.70%) and (11000000) and nano-Fe2 (Fe3), respectively. The activity of catalase was the highest at the end of the incubation period, and the activity of catalase was the highest at the end of culture. For the analysis of 0.210 mL g-1.4)XRD spectra, the mineral facies of Pb504 treated with Pb504 were higher than that of other treatments, respectively, in the form of the mineral phases, such as the mineral phases of CDOHHN03C03OHHX 2Pb504 and Pb3CO3CO3OHf2As205 and As204) in the soil. The results showed that the mineral phases of the two treatments were higher than those of the other treatments, and the results showed that the mineral phases of the two treatments were higher than those of the other treatments, and the mineral phases of the two treatments were higher than those of the other treatments. Combined with the results of each treatment, the treatment could significantly improve soil environment, increase soil pH value and CEC, enhance urease activity, and also play a better role in passivation of three heavy metals.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X53

【参考文献】