本文選題：氯鹽 + 熱脫附��； 參考：《北京化工大學(xué)》2015年碩士論文

【摘要】：土壤是人類(lèi)賴(lài)以生存的根基,隨著汞礦開(kāi)采、氯乙烯生產(chǎn)、有色金屬冶煉等工業(yè)過(guò)程,土壤汞污染已經(jīng)日趨嚴(yán)重。本文在常規(guī)熱脫附修復(fù)技術(shù)基礎(chǔ)上提出“氯鹽誘導(dǎo)汞污染土壤熱脫附修復(fù)技術(shù)”,通過(guò)添加氯鹽的方式將土壤污染物中難于熱脫附去除的HgS、HgO、HgS04等化合物轉(zhuǎn)化為熱脫附溫度范圍低的HgCl2或HgCl,達(dá)到降低熱脫附溫度,縮短熱脫附時(shí)間的目的。本文首先向HgS、HgO、HgSO4三種汞化合物中分別加入NaCl,CaCl2, MgCl2, NH4Cl, FeCl3五種氯鹽反應(yīng)后熱重分析,發(fā)現(xiàn)NH4Cl與FeCl3對(duì)三種汞化合物熱脫附促進(jìn)作用最明顯,在200℃～300℃范圍有明顯的失重過(guò)程,通過(guò)自配含單一汞化合物土壤XRD分析可知有HgCl2或者HgCl生成,達(dá)到了促進(jìn)HgS、HgO、HgSO4熱揮發(fā)的目的。其次,通過(guò)不同氯鹽添加方式對(duì)熱脫附總汞去除率的影響對(duì)比,發(fā)現(xiàn)“濕法-攪拌-冷干”處理效果最好,相較于直接加氯鹽處理總汞去除率提高了10%以上；五種不同來(lái)源的污染土壤加入氯鹽處理后發(fā)現(xiàn),NH4Cl適合汞觸媒回收、PVC生產(chǎn)與氯堿生產(chǎn)污染土壤的熱脫附除汞,200℃,1h時(shí)總汞去除率分別提高了16.96%、12.07%、36.93%,FeCl3處理后汞礦區(qū)自然土壤與原生汞生產(chǎn)污染土壤總汞去除率分布提高了34.78%、27.66%；隨著溫度、停留時(shí)間的增加,氯鹽誘導(dǎo)熱脫附在200℃,1h以后優(yōu)勢(shì)逐漸減小,對(duì)比發(fā)現(xiàn)200℃、1h更利于氯鹽誘導(dǎo)方式對(duì)汞污染土壤的修復(fù),總汞去除率在加入氯鹽后提高了12%以上,含汞鹽泥污染土壤在加入NH4Cl處理后更提高了36.93%。最后,對(duì)氯鹽誘導(dǎo)熱脫附后產(chǎn)生的白色晶體進(jìn)行熱重分析與XRD分析,確定熱脫附揮發(fā)產(chǎn)物主要由HgCl2與HgCl組成。應(yīng)用HSC Chemistry軟件對(duì)各反應(yīng)△G進(jìn)行計(jì)算,發(fā)現(xiàn)對(duì)于任一汞化合物,△G (FeCl3) 0, NH4Cl與HgO、HgSO4在自然條件下即能發(fā)生反應(yīng),生成HgCl2,但是與HgS在500℃以后才能反應(yīng),HgO與NH4Cl反應(yīng)生成的NH3,NH3與HgCl2反應(yīng)能夠生成HgCl。
[Abstract]:Soil is the foundation of human survival. With mercury mining, vinyl chloride production, non-ferrous metal smelting and other industrial processes, soil mercury pollution has become more and more serious. In this paper, based on the conventional thermal desorption and remediation techniques, a new method of thermal desorption remediation for mercury contaminated soils induced by chloride salt was proposed. By adding chlorine salt, some compounds such as HgSU HgS04, which are difficult to be desorbed and removed by thermal desorption, are transformed into HgCl2 or HgCl4 with low thermal desorption temperature, which can reduce the thermal desorption temperature and shorten the desorption time. In this paper, the thermogravimetric analysis of three kinds of mercury compounds, NaCl-CaCl _ 2, MgCl _ 2, NH _ 4Cl _ 4 and FeCl3, respectively, was carried out. It was found that NH4Cl and FeCl3 promoted the thermal desorption of the three mercury compounds most obviously, and there was an obvious weight loss process in the range of 200 鈩，

本文編號(hào)：1840492