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  本文關(guān)鍵詞： 重金屬 底泥 穩(wěn)定化 有機膨潤土 錳基硅藻土 酸改性海泡石　出處：《安徽建筑大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：南淝河是合肥市的母親河,它由西向東貫穿市區(qū),接納沿岸工礦企業(yè)生產(chǎn)污水和生活廢水,致使河水和表層沉積物受到不同程度的重金屬污染。為了緩解水體壓力,減少重金屬危害,本研究采用向污染底泥中添加穩(wěn)定化劑的方法對表層底泥進行無害化處理。該方法依靠固化/穩(wěn)定化技術(shù),固化側(cè)重于添加如水泥、石灰之類的固化劑,包裹污染物以形成浸出性較低的固體材料,并且在固化劑和污染物之間不涉及化學(xué)作用;穩(wěn)定化注重于轉(zhuǎn)化污染物的有毒形態(tài)至穩(wěn)定狀態(tài),削弱污染物的可溶性和遷移性,是通過化學(xué)方式降低污染物毒性的修復(fù)技術(shù)。穩(wěn)定化劑選擇膨潤土、硅藻土和海泡石,并經(jīng)過十六烷基三甲基溴化銨有機改性、氫氧化鈉和氯化錳無機改性及鹽酸改性進行處理,得到有機膨潤土、錳基硅藻土和酸改性海泡石。改性處理的影響主要在于不僅增加了粘土礦物的表面積,也擴大了膨潤土的層間距、增加了硅藻土電負性并在其表面形成了氫氧化錳、清除了海泡石雜質(zhì)并打通了內(nèi)部通道和增加了Si-OH含量,從而提升各穩(wěn)定化劑對重金屬的吸附能力。底泥樣品采集自南淝河長江路橋河段,并經(jīng)預(yù)處理備用。實驗分為兩階段:第一階段向天然污染底泥中分泵添加10%質(zhì)量比的穩(wěn)定化劑,進行為期兩月的穩(wěn)定化實驗,定期取樣,輔以毒性浸出實驗和BCR順序提取實驗,考察穩(wěn)定化劑對低濃度污染底泥中重金屬釋放情況和形態(tài)分布的影響;第二階段則于實驗室中人工配制高濃度重金屬溶液,并混于天然污染底泥中,熟化30天,然后重復(fù)階段一實驗過程,考察穩(wěn)定化劑對高濃度污染底泥中重金屬釋放情況和形態(tài)分布的影響。同時,每階段另設(shè)對比組,按照同一實驗過程將改性前粘土礦物混于底泥中,考察改性后粘土礦物吸附重金屬的能力是否得到改善。本研究獲得結(jié)論如下:(1)經(jīng)BCR順序提取法測得底泥中重金屬Cu、Pb、Cr各形態(tài)含量,計算得到每種重金屬總量分別為166.63 mg·kg-1、36.84 mg·kg-1、249.15 mg·kg-1,遠超于本地區(qū)土壤背景值和化學(xué)基線值,且生物有效態(tài)含量皆超過50%以上,存在較大生物風(fēng)險。(2)天然污染底泥各重金屬的浸出濃度較低,中性條件下浸出濃度皆在1.2mg·kg-1以下,酸性條件下浸出濃度在3.2mg·kg-1以下:中性浸提時,MB、MD、MS對Pb和Cr的浸出抑制率分別為68.67%、26.67%、42%和16.67%、20.83%、18.33%;酸性浸提時,MB、MD、MS對Pb和Cr的釋放均產(chǎn)生抑制作用,抑制率分別為:31.79%、39.749%、19.87%和10%、30%、10%。形態(tài)分布結(jié)果表明,MB、MD、MS均可用于修復(fù)低濃度重金屬污染底泥Pb和Cr污染,并對Pb污染具有修復(fù)優(yōu)勢,大量弱酸提取態(tài)F1和可還原態(tài)F2向可氧化態(tài)F3和殘渣態(tài)F3轉(zhuǎn)化,F3與F4聯(lián)合增幅基本在75%以上。綜上所述,三種穩(wěn)定化劑對低濃度重金屬污染底泥中的Pb和Cr具有修復(fù)效果。(3)高濃度重金屬污染底泥各重金屬的浸出濃度較高,MB組Cu的浸出抑制率最高,中性和酸性條件下分別為30.09%和22.54%;MD組對Cu、Pb、Cr浸出皆具有抑制作用,兩種浸出條件下對Pb和Cr抑制效果較為突出,抑制率分別為30.99%和33.97%(中性)、60.71%和51.05%(酸性);MS組則對Cu表現(xiàn)出一定抑制效果,中性和酸性條件下抑制率分別為19.67%和14.94%。形態(tài)分布結(jié)果表明,MD組Pb的弱酸提取態(tài)F1降低了51.98%,Cr的弱酸提取態(tài)降低了36.96%,其他組形態(tài)分布變化微弱。綜上所述,錳基硅藻土對高濃度重金屬污染底泥中的Pb和Cr具有較明顯的修復(fù)效果。(4)對比組實驗顯示,改性方法的使用抑制了粘土礦物本身重金屬的浸出量,側(cè)面說明了改性方法提升了各粘土礦物對重金屬的吸附性能。在修復(fù)低濃度重金屬污染底泥時,因浸出量過低,導(dǎo)致改性的粘土礦物的優(yōu)勢未能完全發(fā)揮;在修復(fù)高濃度重金屬污染底泥時,改性組MB和MS對Cu和Pb的浸出皆有明顯抑制優(yōu)勢,MD則對Cu、Pb、Cr的浸出均有抑制優(yōu)勢,特別是抑制Pb的作用尤為突出。
[Abstract]:Nanfeihe river is the mother river of Hefei. It runs through the city from west to East, accepting and living sewage along the industrial and mining enterprises production, resulting in water and surface sediments polluted by heavy metals in different degrees. In order to alleviate the pressure of water, reduce the hazards of heavy metals, the method of adding stabilizing agent to the contaminated sediments on the surface sludge harmless treatment. This method relies on the solidification / stabilization technology, focused on adding curing curing agent such as cement, lime and so on, wrapped to form a solid material leaching of pollutants is low, and does not involve the chemical interaction between the curing agent and stabilizing pollutants; focus on the transformation of pollutants toxic form to steady state soluble contaminants and mobility, weakening, is to reduce the toxicity of pollutants by chemical remediation technology. Stabilizing agent of bentonite, diatomite and sepiolite, and After sixteen alkyl three methyl bromide organic modification, sodium hydroxide and manganese chloride inorganic modification and hydrochloric acid modified processing, organic bentonite, diatomite and sepiolite modification of manganese based acid. The effect of modification treatment mainly lies in not only increases the surface area of clay minerals, also expanded the bentonite layer spacing increases the electronegativity of diatomite and its surface formed manganese hydroxide, removing impurities and sepiolite opened up the internal channel and increase the content of Si-OH, so as to enhance the ability of stable adsorption agent on heavy metals. Sediment samples were collected from the South Feihe River in Luqiao reach of Yangtze River, and the pretreatment experiment reserve. The two stage is the first stage to the natural sediment pollution in pump agent stable 10% mass ratio of the added stabilization experiment, two month regular sampling, extraction experiments with the leaching test and BCR sequence, stability study Fixed agent on the influence and distribution of the release of low concentration of heavy metals in contaminated sediments; the second stage in the laboratory of artificial high concentration of heavy metal solution, and mixed with natural sediment pollution, aging for 30 days, and then repeat the process on the stabilization stage, the effects of additives on the situation and distribution of heavy metal in high concentration the pollution in the sediment. At the same time, each stage of a comparison group, according to the same process before modification of clay minerals mixed in the sediment, effects of modified clay mineral adsorption ability is improved. The research conclusions are as follows: (1) by BCR sequential extraction method for heavy metal Cu, Pb in the sediment Cr, various forms of content, calculate the total amount of each kind of heavy metals were 166.63 Mg - kg-1,36.84 Mg - kg-1249.15 Mg - kg-1, far beyond the local soil background value and chemical baseline, and bio available content Is more than 50%, there is a big risk. (2) the leaching concentration of the heavy metals pollution of natural sediment is low, under neutral conditions, the leaching concentration are in the 1.2mg below kg-1, the leaching concentration under acidic conditions in the 3.2mg kg-1 the following: neutral leaching, MB, MD, MS, Pb and Cr on leaching inhibition rates were 68.67%, 26.67%, 42% and 16.67%, 20.83%, 18.33%; acid leaching, MB, MD, MS on the release of Pb and Cr were inhibited, the inhibition rate were 31.79%, 39.749%, 19.87% and 10%, 30%, 10%. distribution. The results showed that MB, MD, MS are for the repair of low concentration of heavy metal pollution in sediments of Pb and Cr pollution, and has the advantages of repair Pb pollution, a large number of weak acid extractable F1 and reducible to F2 can be oxidized F3 and residual F3 conversion, F3 and F4 growth in more than 75%. To sum up, three kinds of stabilizing agent with low concentration of heavy metal pollution in the sediment of Pb and Cr Repair effect. (3) high leaching concentration of heavy metal pollution in sediments of the heavy metal leaching, MB group Cu the highest inhibition rate, neutral and acidic conditions were 30.09% and 22.54%; MD group of Cu, Pb, Cr leaching has inhibitory effect, two kinds of leaching conditions on Pb and Cr suppression effects more prominent, the inhibition rate were 30.99% and 33.97%, 60.71% and 51.05% (neutral) (acid); MS group of Cu showed a certain inhibitory effect, neutral and acidic conditions inhibition rates were 19.67% and 14.94%. distribution. The results show that the MD group of Pb acetic acid extractable F1 decreased 51.98%, Cr acid extractable was reduced by 36.96%, the other group distribution changed slightly. In summary, manganese based diatomite has repair effect is obvious for the high concentration of heavy metal pollution in the sediment of Pb and Cr. (4) shows the contrast experiments, using the modified method of inhibiting clay minerals itself heavily The leaching amount of the side of the modified method to improve the adsorption properties of the clay minerals in the heavy metal pollution of heavy metals. Low concentration of sediments, due to leaching amount is too low, resulting in modified clay minerals advantage not fully play; heavy metal pollution in high concentration sediments, modified group MB and MS leaching Cu and Pb have obvious inhibitory advantages, MD on Cu, Pb, Cr were inhibited leaching, especially the inhibitory effect of Pb is particularly prominent.

【學(xué)位授予單位】：安徽建筑大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X522

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