本文關(guān)鍵詞：磺胺嘧啶在土壤及組分中的吸附遷移特征及模擬　出處：《青島大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 磺胺嘧啶 吸附遷移 土壤 Hydrus-1D 數(shù)值模擬

【摘要】：隨著抗生素使用量的逐年增加,抗生素污染問題已成為環(huán)境領(lǐng)域的研究熱點之一,而土壤作為重要的環(huán)境介質(zhì),其抗生素污染也成為一個不容忽視的問題�；前奉惪股刈鳛槿蜃顝V泛使用的抗生素之一,每年都有大量藥物排入水土環(huán)境中,且排放水平逐年提高�；前奉惪股卦谒镰h(huán)境中的降解速度較慢,危害甚大。本文以磺胺嘧啶(Sulfadiazine,SDZ)為研究對象,通過大量的室內(nèi)實驗,研究其在土壤及土壤組分中的吸附遷移行為,以便為抗生素在土壤和地下水中的污染評價及修復(fù)提供科學(xué)依據(jù)。本文的研究主要包括兩部分內(nèi)容:一是不同陽離子類型、有機(jī)質(zhì)含量和重金屬條件下,SDZ在土壤中吸附的實驗,以及pH、陽離子類型、離子強(qiáng)度對SDZ在土壤組分(高嶺石、蒙脫石和腐殖酸)中的吸附實驗,并對反應(yīng)前后的高嶺石、蒙脫石和腐殖酸進(jìn)行傅里葉紅外光譜(Fourier transform infrared,FTIR)表征,分別用Langmuir、Freundlich和線性方程對靜態(tài)吸附特征進(jìn)行擬合;二是探討了SDZ在原狀和填裝土柱中的遷移特征,用Hydrus-1D軟件對其進(jìn)行模擬獲得相關(guān)參數(shù),并對不同流速下SDZ的遷移行為進(jìn)行預(yù)測。得出以下結(jié)論:(1)在土壤的靜態(tài)吸附實驗中,陽離子價態(tài)、有機(jī)質(zhì)和重金屬含量均對SDZ的吸附產(chǎn)生影響。離子價態(tài)越低,有機(jī)質(zhì)含量越高,SDZ吸附量越大;當(dāng)Cd濃度為10.0 mg/kg時,會促進(jìn)SDZ的吸附,當(dāng)Cd濃度為1.0、300.0 mg/kg時會抑制SDZ吸附,當(dāng)Cd濃度為100.0 mg/kg時對SDZ的吸附無影響;Cd、Cu、Pb存在時,SDZ吸附量大小的順序為CdCuPb。用Freundlich方程和Langmuir方程擬合實驗數(shù)據(jù)的R2均在0.96以上,但由于吸附偏線性,Langmuir方程并不能很好地解釋SDZ的吸附特征,線性方程擬合的R2均在0.98以上,模擬結(jié)果最好。(2)SDZ在土壤及其組分中的動態(tài)吸附實驗表明,SDZ在土壤及其組分中的吸附在24 h左右達(dá)到平衡,達(dá)到吸附平衡時吸附量大小順序為腐殖酸高嶺石土壤蒙脫石。在土壤組分的靜態(tài)批平衡實驗中,pH、離子類型和離子強(qiáng)度對SDZ在不同土壤組分中的吸附有不同的影響。這些因素對SDZ在高嶺石中的吸附影響,均不明顯;在蒙脫石中,SDZ吸附量與pH呈正相關(guān),與離子強(qiáng)度呈負(fù)相關(guān);除Na+會降低SDZ在蒙脫石中的吸附外,K+、Ca2+、Mg2+影響不大;對于腐殖酸,除離子類型對SDZ的吸附有一定影響,pH和離子強(qiáng)度的影響也不大。Freundlich方程擬合的R2在0.8以上,Langmuir方程擬合的R2在0.78以上,線性方程擬合的R2在0.92以上,線性方程對這些吸附特征擬合效果更好。(3)SDZ在同一土壤剖面不同深度處所取原狀土中遷移的穿透曲線是不同的,在原狀土柱Ⅱ(15.0-30.0 cm)中的穿透曲線相較于原狀土柱Ⅰ(0.0~15.0 cm)的發(fā)生左移,即較深層土壤中,SDZ的遷移速度更快。這主要是受土壤理化性質(zhì)的影響,前者的有機(jī)質(zhì)含量、陽離子交換量(CEC)比后者低,而pH比后者高,從而減少了SDZ的吸附,增強(qiáng)了其流動性。(4)不同化學(xué)因素對SDZ在填裝土柱中的遷移產(chǎn)生不同影響。陽離子價態(tài)越高、有機(jī)質(zhì)含量越少,SDZ的出流濃度峰值越高、出流越快、遷移性越強(qiáng);當(dāng)土壤中Cd含量為10.0 mg/kg,SDZ在土壤中的遷移速度最慢,峰值最低,其它濃度Cd對SDZ的遷移影響不大;當(dāng)Cu、Pb和Cd的含量相同時,SDZ的含Cu土壤中,遷移最快,其相對濃度峰值可達(dá)0.8;其次為含Pb土壤,在含Cd土壤中遷移最慢。出流液中pH變化均呈現(xiàn)先下降后逐漸趨于平穩(wěn),EC變化不大,出流液中的Ca2+濃度則均呈現(xiàn)先下降后上升的趨勢。(5)用單點吸附模型(OSM)、兩點吸附模型(TSM)和兩區(qū)模型(TRM)分別對SDZ在原狀土中的遷移過程進(jìn)行模擬并用TRM對不同水流下SDZ的遷移行為進(jìn)行預(yù)測。結(jié)果表明,TRM對SDZ的遷移過程擬合最好,TSM中瞬時吸附所占比例很小,所以SDZ在原狀土中基本上不存在瞬時吸附,TRM表明不動水體也是SDZ吸附的重要組成部分。TRM的R20.91,RMSE0.061,擬合結(jié)果優(yōu)于OSM和TSM。在用TRM模擬過程中,當(dāng)水流速度從0.017 cm/min增加到0.030 cm/min再到0.100 cm/min,磺胺嘧啶在土壤中的遷移速度也不斷加快,出流濃度也越來越高,當(dāng)流速為0.100 cm/min時,SDZ可快速穿過土層進(jìn)入地下水。(6)分別用OSM和TSM對填裝土柱中SDZ的遷移進(jìn)行模擬。結(jié)果表明,OSM的R20.881,RMSE0.069,TSM的R20.907,RMSE0.051,瞬時吸附f所占分?jǐn)?shù)較高,說明SDZ在遷移過程中存在較大程度的瞬時吸附。與OSM相比,TSM能更好地模擬SDZ的遷移過程。兩個模型擬合的系數(shù)α均較小。
[Abstract]:With the usage of antibiotics increased year by year, antibiotics pollution problem has become one of the research focus in the field of environment, and the soil environment as an important medium, the antibiotics pollution has become a problem that can not be ignored. Sulfa antibiotics as the world's most widely used antibiotics, every year a large number of drugs into the soil and water environment. And the level of emissions increased year by year. The degradation speed of sulfonamide antibiotics in the soil water environment, the harm is very great. In this paper, sulfadiazine (Sulfadiazine, SDZ) as the research object, through a lot of experiments, to study the migration behavior in soil and soil adsorption component, so as to provide scientific basis for the evaluation of antibiotics in pollution in the soil and groundwater and repair. This paper mainly includes two parts: one is the different types of cation, the content of organic matter and heavy metals in soil conditions, SDZ The soil adsorption experiments, and pH, cationic type, ionic strength of SDZ in soil components (kaolinite, montmorillonite and humic acid) in the adsorption experiments, and before and after the reaction of kaolinite, montmorillonite and humic acid by Fourier transform infrared spectroscopy (Fourier transform infrared, FTIR) were respectively Langmuir, Freundlich and linear the equation to fit the static adsorption characteristics; two is to explore the characteristics of SDZ migration in undisturbed and filled in the soil column, were simulated to obtain the relevant parameters by Hydrus-1D software on it, and the different flow velocity SDZ migration behavior prediction. Draw the following conclusions: (1) in the static adsorption experiment of soil, cation valence state, heavy metals and organic matter content were affected. The adsorption of SDZ ion valence lower organic matter content was high, the adsorption capacity of SDZ increased; when the concentration of Cd was 10 mg/kg, will promote the adsorption of SDZ, when the concentration of Cd 1.0300.0 mg/kg can inhibit the adsorption of SDZ, when the Cd concentration was 100 mg/kg adsorption had no influence on the SDZ; Cd, Cu, Pb, SDZ adsorption quantity in the order of CdCuPb. Freundlich equation and Langmuir equation fit the experimental data of R2 were above 0.96, but due to the adsorption of Langmuir equation and partial linear. Can not well explain the adsorption characteristics of SDZ, the linear equation of R2 was above 0.98, the best (2). The simulation results show that the dynamic SDZ adsorption in soil and its components, the adsorption of SDZ in soil and its components in the balance in about 24 h, the equilibrium adsorption capacity of the order as the soil humic acid kaolinite montmorillonite. In soil component static batch equilibrium experiment, pH, have different effects on adsorption of ionic type and ionic strength of SDZ in different soil fractions. The influence of these factors on the adsorption of SDZ on kaolinite, were Is not obvious; in montmorillonite, the adsorption capacity of SDZ was positively correlated with pH and negatively correlated with the ionic strength; in addition to the Na+ will reduce the absorption of SDZ in montmorillonite using, K+, Ca2+, Mg2+ had little effect; for humic acid, in addition to a certain effect of ion adsorption type on SDZ, effects of pH and ionic strength of the little.Freundlich equation R2 is above 0.8, the Langmuir equation R2 in more than 0.78, linear equation R2 in more than 0.92 linear equations for these adsorption characteristics of the fitting effect is better. (3) SDZ in the same soil profile in different depth spaces through curve migration in undisturbed soil is different, in the original column II (15.0-30.0 cm) breakthrough curve compared to the undisturbed soil column 1 (0.0~15.0 cm) the left shift is deeper in the soil, the migration speed of SDZ is faster. This is mainly influenced by the physicochemical properties of the soil, organic matter content of the former, cation exchange 閲，

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