含磷物料稳定化修复铅污染土壤的研究

发布时间：2019-05-05 15:36

【摘要】：随着我国工业快速的发展,场地土壤重金属污染状况加剧,致使人民健康受到严重威胁。铅是常见的土壤重金属污染元素之一,我国铅污染土壤总超标率达1.5%,因此,开展铅污染土壤的修复研究具有重要现实意义。本文以铅蓄电池生产场地受到铅污染的土壤为研究对象,通过添加磷酸二氢钾(MKP)、活化磷矿粉(APR)、牛粪(CD)和磷矿粉(PR)4种不同含磷物料进行稳定化修复试验,对比不同浸出条件下土壤有效铅浸出浓度以及铅赋存形态的变化,分析探讨不同含磷物料对铅污染土壤的稳定化修复效果的差别,筛选出稳定化修复效果最佳的物料；在此基础上,通过马弗炉高温煅烧(MF)和双氧水氧化(HP)两种方式去除土壤有机质,对比土壤TCLP-Pb浸出浓度、土壤有效磷含量及铅赋存形态的变化,探讨有机质对磷酸二氢钾稳定化修复铅污染土壤的影响,并通过扫描电镜(SEM)观察土壤表面结构特征的变化,探讨有机质对磷酸二氢钾修复铅污染土壤效果的影响。主要研究结果如下：(1)毒性浸出试验结果表明,添加4种含磷物料均可有效降低土壤TCLP-Pb浸出浓度。添加MKP后铅浸出浓度降到0.70 mg·L-1以下,土壤铅浸出浓度达到GB5085.3-2007浸出标准(5 mg·L-1),稳定效率为98.20%;APR、CD和PR的稳定效率分别为75.63%、67.14%和62.44%,TCLP提取铅的稳定化效果为MKPAPRCDPR。 CaCl2浸提结果表明,4个处理中铅稳定效果为MKPCDPRAPR,铅浸出浓度分别降低了43.82%、29.99%、15.77%、7.89%。因此,在添加的4种含磷物料中,MKP是对铅污染土壤的稳定化修复效果最好的物料。(2)MF和HP去除土壤有机质后,土壤自身有效磷含量及TCLP-Pb浸出浓度会升高,MF处理后土壤有机质减少7.97 g·kg-1,去除率为97.20%,HP处理后,有机质减少0.93 g·kg-1,去除率为11.34%,MF比HP去除率高85.86%；经MF和HP处理后,土壤TCLP-Pb浸出浓度分别增加43.35%和75.68%,土壤有效磷含量分别增加0.96 mg·kg-1和0.79 mg·kg-1,去除有机质会削弱土壤自身固定磷和铅的能力。(3)向原始土壤和去除有机质后的土壤中添加不同含量MKP进行稳定化处理,铅浸出浓度均表现为随着MKP添加量的增加而降低,当MKP添加量达到P/Pb摩尔比为0.6时,土壤铅浸出浓度趋于平稳；添加MKP后,通过SEM可明显观察到HP中形成了不易被生物吸收利用的磷酸铅盐沉淀,降低了铅污染土壤的环境风险。去除有机质后,铅污染土壤稳定化修复效果低于原始土壤稳定化修复效果。
[Abstract]:With the rapid development of industry in our country, the pollution of heavy metals in the field soil is aggravated, and the health of the people is seriously threatened. Lead is one of the common heavy metal pollution elements in soil, and the total excess rate of lead contaminated soil in China is 1.5%. Therefore, it is of great practical significance to carry out research on remediation of lead-contaminated soil. By adding potassium dihydrogen phosphate (MKP), to activate phosphate powder (APR), cow dung (CD) and phosphate rock powder (PR), the soil polluted by lead in lead storage battery production site was studied in this paper, and the experiment of stabilization and remediation was carried out by adding potassium dihydrogen phosphate to activate phosphate ore powder (CD) and phosphate rock powder (PR). The variation of available lead leaching concentration and Pb storage form in soil under different leaching conditions was compared, and the difference of stabilization and remediation effect of different phosphorus-containing materials on Pb-contaminated soil was analyzed and discussed, and the materials with the best stabilization and remediation effect were selected. On the basis of this, soil organic matter was removed by high temperature calcination of (MF) and oxidation of (HP) by hydrogen peroxide in muffle furnace. The changes of leaching concentration of soil TCLP-Pb, available phosphorus content of soil and form of Pb accumulation were compared. The effect of organic matter on the stabilization and remediation of lead-contaminated soil by potassium dihydrogen phosphate was investigated. The surface structural characteristics of the soil were observed by scanning electron microscope (SEM), and the effect of organic matter on the remediation of lead-contaminated soil by potassium dihydrogen phosphate was discussed. The main results are as follows: (1) the results of toxicity leaching test show that the TCLP-Pb leaching concentration of soil can be effectively reduced by adding four kinds of phosphorus-containing materials. After adding MKP, the leaching concentration of lead decreased to less than 0.70 mg 路L-1, the leaching concentration of lead in soil reached the standard of GB5085.3-2007 leaching (5 mg 路L-1), and the stability efficiency was 98.20%. The stabilization efficiency of APR,CD and PR were 75.63%, 67.14% and 62.44%, respectively. The stabilization effect of extraction of lead by TCLP was MKPAPRCDPR.. The results of CaCl2 extraction showed that the stabilizing effect of lead in the four treatments was 43.82%, 29.99%, 15.77%, 7.89% of the lead leaching concentration in the four treatments respectively, which was reduced by 43.82%, 29.99%, 15.77% and 7.89% respectively. Therefore, among the four kinds of phosphorus-containing materials added, MKP is the best material for the stabilization and remediation of lead-contaminated soil. (2) after the removal of soil organic matter by MF and HP, the soil available phosphorus content and TCLP-Pb leaching concentration will increase. After treatment with MF, the removal rate of soil organic matter decreased by 7.97 g / kg-1, to 97.20%, and by HP treatment, the removal rate of organic matter decreased by 0.93 g kg-1, to 11.34%, and MF was 85.86% higher than that of HP. After treatment with MF and HP, the leaching concentration of TCLP-Pb in soil increased by 43.35% and 75.68%, and the content of available phosphorus in soil increased by 0.96 mg kg-1 and 0.79 mg kg-1, respectively. Removal of organic matter would weaken the ability of soil itself to fix phosphorus and lead. (3) when different contents of MKP were added to the original soil and the soil after the removal of organic matter, the lead leaching concentration decreased with the increase of MKP content. When the molar ratio of MKP to P/Pb was 0.6, the leaching concentration of lead in soil tended to be stable. After the addition of MKP, it was observed that lead phosphate precipitated in HP was not easy to be absorbed and utilized by biology, which reduced the environmental risk of soil polluted by lead through SEM. After removal of organic matter, the stabilization and remediation effect of Pb-contaminated soil was lower than that of the original soil.
【学位授予单位】：沈阳农业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X53

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