镉、铅污染土壤的苎麻—化学联合修复

发布时间：2017-12-27 14:29

本文关键词：镉、铅污染土壤的苎麻—化学联合修复　出处：《西北农林科技大学》2015年硕士论文　论文类型：学位论文

更多相关文章：苎麻 固化剂 EDTA EDDS 土壤修复

【摘要】：土壤污染特别是土壤中重金属镉、铅的污染日趋严重。目前镉、铅污染土壤的修复和治理措施主要有物理措施、化学措施、生物措施、生态修复措施、农艺修复措施等。其中,植物修复措施是用于修复重金属污染土壤方法中效果较好的绿色生态修复技术,其机制主要是利用一些特定的植物对重金属元素进行吸收、富集、积累和转化,从而达到减轻重金属污染土壤的目的。和其他土壤修复治理措施不同,植物修复措施具有简便、安全、经济、环保等优势。苎麻为荨麻科苎麻属草本植物,宿根生存寿命长,一般在10~30年以上,其根系发达,固土力强,生物量大,起到较好水土保持效果和重金属修复效果。但在实际土壤修复中,利用苎麻提取修复重金属土壤仍存在具有效果不明显的等问题,而改良剂的应用能强化苎麻对重金属污染土壤修复。本研究选取多年生经济纤维植物苎麻,选择生物可降解螯合剂乙二胺二琥珀酸(EDDS)和非生物螯合剂(EDTA),以及硅藻土、膨润土、石灰石粉、沸石粉4种固化剂,分别设置不同施用水平,通过土培试验和盆栽试验研究了镉、铅复合污染土壤中施加螯合剂、固化剂对土壤重金属各形态含量、苎麻生物量、叶片中丙二醛含量以及重金属富集吸收特性的影响。主要研究结果如下:(1)相比单独利用苎麻进行污染土壤的植物修复,非生物螯合剂EDTA和生物可降解螯合剂EDDS的添加均会促进土壤中镉、铅的酸可提取态含量增加,促进苎麻各部分对镉、铅的吸收累积,有较好的诱导作用。应用螯合剂浓度相同时,EDTA诱导效果优于EDDS,且随着施用螯合剂浓度的升高,苎麻各部分镉、铅的含量增加。(2)EDTA和高浓度EDDS的施加会对苎麻植株生长产生不利影响,使得苎麻生物量明显降低,叶片中丙二醛含量增加。在同等浓度水平下,EDDS对苎麻生长产生的不利影响更小,低浓度EDDS不会对苎麻产生不利影响。(3)在浓度为1.5~3 mmol?kg-1时,EDDS强化苎麻修复镉的效果较好,土壤镉的去除效率相比对照提高了16%~27%,在更高浓度(6~9 mmol?kg-1)时,EDTA强化苎麻修复镉的效果较好。EDTA强化苎麻修复土壤铅的效果好于EDDS,对土壤铅的去除效果提高可达22.6%。(4)添加沸石粉和高浓度(9~12 g?kg-1)硅藻土、膨润土能够显著减少土壤中镉的酸可提取态含量。添加固化剂硅藻土、膨润土和沸石粉能有效降低土壤中酸可提取态铅含量,且固化效果硅藻土膨润土沸石粉。单独施用固化剂,其添加量越多对土壤中镉和铅的固化效果越好,石灰石粉对镉和铅酸可提取态含量影响不显著,固化效果不佳。(5)固化剂的施加使得苎麻各部位吸收镉、铅的含量降低,且随着固化剂添加量的增加各部位镉、铅含量降低更加显著。石灰石粉的添加使得苎麻生物量减小,硅藻土、膨润土和沸石粉的添加使得苎麻生物量增加,生长胁迫降低。(6)相比单独利用固化剂修复,添加固化剂后种植苎麻进行植物修复,能够进一步对土壤中的酸可提取态镉和铅进行吸收累积,且适当的固化剂处理下,苎麻对土壤中镉和铅的累积量仍较高。其中添加9 g?kg-1硅藻土以及3~9 g?kg-1沸石粉配合苎麻对土壤中的镉能产生很好的联合修复效果,硅藻土、膨润土和沸石粉均可以配合苎麻对土壤中的铅产生较好的联合修复效果,联合修复效果硅藻土沸石粉膨润土。
[Abstract]:The pollution of heavy metals, cadmium and lead, in soil pollution, especially in the soil, is becoming more and more serious. At present, remediation and control measures for cadmium and lead contaminated soils include physical measures, chemical measures, biological measures, ecological restoration measures and agronomic rehabilitation measures. Among them, phytoremediation measures is used to repair the technical effect of remediation of heavy metal contaminated soil in green ecological good, its mechanism is the main absorption, enrichment, accumulation and transformation of certain plants to heavy metal elements, so as to achieve the purpose of reducing heavy metal pollution in soil. Different from other soil remediation measures, phytoremediation has the advantages of simple, safe, economic and environmental protection. Ramie for Urticaceae Boehmeria herb, perennial survival and long life, generally in 10~30 years, the developed root system, soil strength, large biomass, has a good effect of soil and water conservation and restoration of heavy metal. However, in practical soil remediation, there are still some problems such as ramie extraction and heavy metal remediation, but the application of modifiers can enhance the remediation of heavy metal contaminated soil by ramie. This study selects perennial economic plants of ramie fiber, select biodegradable chelating agent ethylenediamine two succinic acid (EDDS) and non biological chelating agent (EDTA), as well as diatomite, bentonite, limestone powder, zeolite powder 4 kinds of curing agents, different application levels were set by soil culture experiment and pot experiment was conducted to study the cadmium and lead compound the pollution of soil chelators and curing agent on the influence of MDA content and enrichment of Heavy Metals Absorption Characteristics of various forms of soil heavy metals content, biomass, leaf of ramie. The main results are as follows: (1) compared to phytoremediation of contaminated soil by using ramie alone, adding non biological chelating agents EDTA and EDDS are biodegradable chelating agents can promote the cadmium and lead in soil acid extractable content increased, the ramie promote the absorption and accumulation of cadmium and lead, have good induction. When the concentration of chelating agent was the same, the induction effect of EDTA was better than that of EDDS, and the content of cadmium and lead in every part of ramie increased with the increase of the concentration of chelating agent. (2) the effect of EDTA and high concentration of EDDS on the growth of ramie plants resulted in a significant decrease in the biomass of ramie and the increase of malondialdehyde content in the leaves. At the same concentration level, the negative effect of EDDS on Ramie growth was smaller, and low concentration of EDDS would not have adverse effects on ramie. (3) when the concentration was 1.5~3 mmol? Kg-1, EDDS enhanced the effect of cadmium recovery from ramie, and the cadmium removal efficiency of soil increased by 16%~27% compared with the control. At higher concentration (6~9 mmol? Kg-1), EDTA enhanced ramie for cadmium recovery. The effect of EDTA strengthening Ramie on soil lead is better than that of EDDS, and the effect of soil lead removal can be increased by 22.6%. (4) adding zeolite powder and high concentration (9~12 G? Kg-1) diatomite and bentonite can significantly reduce the content of the extractable state of cadmium in soil. Adding the curing agent diatomite, bentonite and zeolite can effectively reduce the content of the Acid Extractable Lead in the soil, and the effect of the curing effect of diatomite bentonite zeolite powder. The better the curing effect of cadmium and lead is, the more the amount of added agent is applied alone. The influence of limestone powder on the content of cadmium and lead acid extractable content is not significant, and the curing effect is not good. (5) the amount of cadmium and lead absorbed by different parts of ramie decreased with the addition of curing agent, and the content of cadmium and lead decreased significantly with the increase of curing agent. The addition of limestone powder reduced the biomass of ramie. The addition of diatomite, bentonite and zeolite made the biomass of ramie increased and the growth stress decreased. (6) compared with the use of curing agent alone and the addition of curing agent after planting, ramie can be further phytoremediation, which can further absorb and accumulate the acid extractable CD and Pb in soil. Under the proper curing agent, the accumulation of CD and Pb in the soil is still high. With the addition of 9 g? Kg-1 3~9 g kg-1 diatomite and zeolite powder with ramie? Can produce a good effect on remediation of cadmium in soil, diatomite, bentonite and zeolite powder can be produced with ramie combined with good results for the lead in the soil remediation effect of bentonite diatomite and zeolite powder.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53

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