本文關(guān)鍵詞： 生物炭 BDE-47 BDE-99 吸附解吸　出處：《北京林業(yè)大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：多溴聯(lián)苯醚具有良好的阻燃效果,被廣泛應(yīng)用在工業(yè)生產(chǎn)中。由于其具有較高的生物富集效應(yīng)和致癌性,且其在環(huán)境中的暴露水平日益提高,因此掌握多溴聯(lián)苯醚在環(huán)境介質(zhì)中的遷移轉(zhuǎn)化途徑非常有必要。本文選取全球污染比較廣泛的2,2',4,4',5-五溴聯(lián)苯醚(BDE-99)和2,2',4,4'-四溴聯(lián)苯醚(BDE-47)作為研究對象,探究了其在土壤介質(zhì)及生物炭組分上的吸附解吸行為,同時考察了生物炭添加量及環(huán)境溫度對BDE-99在土壤介質(zhì)上吸附解吸行為的影響。本論文中,生物炭樣品隨著熱解溫度升高,含氧官能團(tuán)逐漸減少,脫氧作用加劇,烷烴縮合增強(qiáng),極性程度降低,芳香性特征表現(xiàn)明顯。炭化溫度的升高促進(jìn)了生物炭樣品內(nèi)部孔隙結(jié)構(gòu)形成。對于BC300和BC500,中孔和微孔是其主要孔結(jié)構(gòu)；對于BC700,微孔為其主要孔結(jié)構(gòu)。雙室一級動力學(xué)模型能較好地擬合BDE-47/BDE-99在生物炭及土壤樣品上的吸附過程,其中快吸附過程占主導(dǎo)地位。BDE-47/BDE-99在生物炭及土壤樣品上的吸附過程是自發(fā)進(jìn)行的。BDE-47/BDE-99在生物炭樣品上的吸附呈現(xiàn)非線性,其吸附能力為BC700BC500BC300。對于BC300和BC500,孔隙的吸附作用存在于吸附過程中,同時有部分吸附發(fā)生微孔或介孔的表面上；對于BC700,在吸附過程中,微孔的吸附貢獻(xiàn)比較大。BDE-47/BDE-99在生物炭樣品上存在明顯的解吸滯后現(xiàn)象,相對于BC300、BC500,BC700的解吸滯后程度比較顯著,其主要是因為BC700能夠提供更多的高能吸附位點。土壤樣品對BDE-99的吸附呈非線性,土壤樣品隨著吸附初始濃度升高,單點分配系數(shù)(Koc)逐漸減小。有機(jī)質(zhì)含量是影響土壤樣品對BDE-99吸附的主要因素。相對于生物炭樣品,BDE-99在土壤樣品上的解吸滯后性變化規(guī)律不明顯,主要可能因為土壤樣品中不存在高能吸附位點和低能吸附位點的顯著區(qū)分。生物炭添加含量及環(huán)境溫度對BDE-99在生物炭混合土壤體系上的吸附解吸行為也存在顯著影響。生物炭的添加增強(qiáng)了土壤體系對BDE-99的吸附能力,吸附的非線性程度有所增加,BDE-99在土壤體系上的解吸滯后程度明顯增強(qiáng)。環(huán)境溫度從10℃升高到35℃,BDE-99在生物炭混合土壤上的解吸滯后程度有所減弱。
[Abstract]:Polybrominated diphenyl ethers (PBDEs) have good flame retardancy and are widely used in industrial production. Because of their high bioconcentration and carcinogenicity, PBDEs are exposed to a higher level of exposure to the environment. Therefore, it is necessary to master the translocation and transformation pathway of PBDEs in environmental media. In this paper, we select the globally polluted PBDEs BDE-99 and BDE-47. In this paper, the adsorption and desorption behavior of BDE-99 in soil media and biochar components were investigated, and the effects of biochar addition and ambient temperature on the adsorption and desorption behavior of BDE-99 on soil media were also investigated. In this paper, the adsorption and desorption behavior of biochar samples increased with the increase of pyrolysis temperature. The oxygen functional groups decreased gradually, the deoxidation increased, the condensation of alkanes increased, and the degree of polarity decreased. The aromaticity characteristic is obvious. The increase of carbonization temperature promotes the formation of pore structure in biological carbon sample. For BC300 and BC500, mesoporous and micropore are the main pore structures. For BC700, micropore is the main pore structure. The two-chamber first-order kinetic model can fit the adsorption process of BDE-47/BDE-99 on biochar and soil samples. The adsorption process of BDE-47 / BDE-99 on biochar and soil samples was spontaneous and the adsorption of BDE-47 / BDE-99 on biochar was nonlinear. The adsorption capacity of BC700BC500BC300. for BC300 and BC500, the adsorption of pores exists in the adsorption process, and some micropores or mesoporous surfaces occur at the same time, for BC700, during the adsorption process, The adsorption contribution of micropore is relatively large. BDE-47 / BDE-99 has obvious desorption hysteresis in biochar samples, and the desorption hysteresis degree of BC300, BC500 and BC700 is more significant than that of BC300, BC500, BC700, BC700, BC500 and BC700. The main reason is that BC700 can provide more high energy adsorption sites. The adsorption of BDE-99 on soil samples is nonlinear, and soil samples increase with the initial concentration of adsorption. The content of organic matter is the main factor affecting the adsorption of BDE-99 on soil samples. It is possible that there is no significant difference between high energy adsorption sites and low energy adsorption sites in soil samples. The adsorption and desorption behavior of BDE-99 on biochar mixed soil system is also significant due to the addition of biochar and ambient temperature. The addition of biochar enhanced the adsorption ability of BDE-99 in soil system. The degree of nonlinearity of adsorption increased and the desorption hysteresis degree of BDE-99 in soil system increased obviously, and the degree of desorption hysteresis of BDE-99 in biochar mixed soil decreased from 10 鈩，

本文編號：1515876