【摘要】：腐殖質(zhì)作為一種復(fù)雜的天然大分子有機(jī)質(zhì),根據(jù)溶解性差異,可分為胡敏酸(Humicacid)、富里酸(Fulvicacid)和胡敏素(Humin)。富里酸含有多種酸性基團(tuán),對重金屬有較強(qiáng)的吸附絡(luò)合能力,影響著重金屬的地球化學(xué)行為。不同級分富里酸在元素組成、結(jié)構(gòu)特征等方面存在差異,決定了不同級分富里酸與重金屬相互作用的機(jī)理機(jī)制方面存在差異。本文以連續(xù)堿提法獲得烏梁素海沉積物不同級分富里酸為基礎(chǔ),以不同級分富里酸對重金屬的吸附機(jī)制研究為主線,研究不同環(huán)境條件(pH、離子強(qiáng)度、離子類型、溫度、光照)下不同級分FA對Cu2+、Pb2+、Cd2+的吸附特征,結(jié)合光譜學(xué)、形貌學(xué)、ligand binding模型和bi-Langmuir模型分析吸附機(jī)理,以期為湖泊生態(tài)系統(tǒng)中重金屬污染的防控提供理論依據(jù)。主要結(jié)論如下:(1)隨提取次數(shù)增加,FA有機(jī)碳含量、酸性官能團(tuán)含量、芳香性、分子極性均減小;分子量、脂肪性和腐殖化程度增大。(2)動力學(xué)實(shí)驗(yàn)結(jié)果表明,各級分FA對Cu2+、Pb2+、Cd2+的吸附在10分鐘左右達(dá)到平衡,吸附速率為Cu2+Cd2+Pb2+;隨提取次數(shù)的增大,FA對重金屬的吸附速率常數(shù)遞減,表明后提出的FA對重金屬吸附速率較慢。等溫吸附實(shí)驗(yàn)結(jié)果表明,隨提取次數(shù)的增加,FA對重金屬的吸附量減少。(3)低于臨界pH值時(shí),各級分FA對Cu2+、Pb2+、Cd2+的吸附量隨pH升高而升高。隨離子強(qiáng)度的增大,各級分FA對Cu2+、Pb2+、Cd2+的吸附量逐漸降低;不同離子類型對FA的吸附影響不同,具體表現(xiàn)為Ca2+Mg2+K+,這是由于Ca2+水合半徑小且電荷數(shù)大,對Cu2+、Pb2+、Cd2+的影響大。FA對重金屬的吸附為自發(fā)的放熱反應(yīng),反應(yīng)后無序程度增加。光照可以降解FA,對重金屬離子吸附量減少。(4)Ligand binding 模型和 bi-Langmuir 模型擬合效果良好。Ligand binding模型擬合結(jié)果表明,FA對重金屬的吸附存在強(qiáng)弱兩種點(diǎn)位,強(qiáng)點(diǎn)位可能為FA中含氮、含硫的官能團(tuán),對重金屬吸附能力強(qiáng)但含量少;弱點(diǎn)位主要為羧基、羥基,吸附能力弱但含量多,在吸附重金屬中起主導(dǎo)作用;bi-Langmuir模型擬合結(jié)果表明,隨級分增加,理論吸附量減少,吸附量與酸性官能團(tuán)呈正相關(guān),與脂肪性、分子量呈負(fù)相關(guān)。(5)吸附前后表征結(jié)果揭示,不同級分FA吸附重金屬后,其組成和結(jié)構(gòu)均發(fā)生改變。紫外分析結(jié)果表明,FA的共軛度、脂肪性和分子量增加;紅外分析結(jié)果表明,羥基、羧基特征峰發(fā)生明顯偏移和減弱,表明這些官能團(tuán)對Cu2+、Pb2+、Cd2+的吸附貢獻(xiàn)較大;三維熒光光譜分析結(jié)果表明,peakC發(fā)生明顯藍(lán)移,peakB和peakC發(fā)生淬滅反應(yīng),peakA熒光強(qiáng)度有所增強(qiáng),表明FA中羧基參與了對Cu2+、Pb2+和Cd2+的吸附且反應(yīng)過程中伴隨π-π*躍遷;掃描電鏡結(jié)果表明,吸附后FA聚集成團(tuán),結(jié)構(gòu)發(fā)生改變。
[Abstract]:As a complex natural macromolecular organic matter, humus can be divided into Hu Min acid (Humicacid), fulvic acid (Fulvicacid) and humin (Humin). According to their solubility differences. Fulvic acid contains many acidic groups and has a strong adsorption and complexing ability to heavy metals, which affects the geochemical behavior of heavy metals. There are differences in elemental composition and structural characteristics of different fractions of fulvic acids, which determine the mechanism of interaction between different fractions of fulvic acids and heavy metals. Based on the continuous alkali extraction of different fractions of fulvic acid in Wuliangsu Sea sediments, the adsorption mechanism of different fractions of fulvic acid on heavy metals was studied in this paper. The different environmental conditions (pH, ion strength, ion type, temperature) were studied. The adsorption characteristics of Cu2, Pb2 and Cd2 by different fractions of FA under light, combined with spectroscopic, morphologic, ligand binding and bi-Langmuir models, were analyzed in order to provide theoretical basis for the prevention and control of heavy metal pollution in lake ecosystem. The main conclusions are as follows: (1) with the increase of extraction times, the content of FA organic carbon, acidic functional group, aromaticity and molecular polarity decrease; Molecular weight, fatty property and humification degree increased. (2) Kinetic experiments showed that the adsorption of Cu2, Pb2 and Cd2 by FA reached equilibrium in about 10 minutes, and the adsorption rate was Cu2 Cd2 Pb2; With the increase of extraction times, the adsorption rate constant of heavy metals by FA decreased, which indicated that the rate of heavy metal adsorption by FA was slow. The results of isothermal adsorption experiments showed that the adsorption of heavy metals by FA decreased with the increase of extraction times. (3) when the value of FA was lower than the critical value of pH, the adsorption of Cu2, Pb2 and Cd2 increased with the increase of pH. With the increase of ionic strength, the adsorption of Cu2, Pb2 and Cd2 by FA decreased gradually. The effect of different ion types on the adsorption of FA is different, which is manifested by Ca2 Mg2 K, which is due to the small radius of Ca2 hydration and the large number of charges, and the great influence on Cu2, Pb2 and Cd2. The adsorption of heavy metals by FA is a spontaneous exothermic reaction. The degree of disorder increased after reaction. (4) the fitting results of) Ligand binding model and bi-Langmuir model showed that there were two sites for heavy metal adsorption by FA. The strong sites may be nitrogen-containing and sulfur-containing functional groups in FA, which have strong adsorption ability to heavy metals but little content. The weak spots are mainly carboxylic groups, hydroxyl groups, weak adsorption ability but high content, which play a leading role in the adsorption of heavy metals. The fitting results of bi-Langmuir model showed that the theoretical adsorption capacity decreased with the increase of fraction, and the adsorption capacity was positively correlated with acidic functional groups, negatively correlated with fatty property and molecular weight. (5) the results of characterization before and after adsorption revealed that, The composition and structure of heavy metals were changed after adsorption of heavy metals by FA with different fractions. The results of UV analysis showed that the conjugation degree, fat property and molecular weight of FA increased, and the characteristic peaks of hydroxyl and carboxyl groups shifted and weakened obviously, which indicated that these functional groups contributed significantly to the adsorption of Cu2, Pb2 and Cd2. The results of three dimensional fluorescence spectra show that peakC is blue shifted, peakB and peakC are quenched, and the fluorescence intensity of peakA is enhanced, which indicates that the carboxyl groups in FA are involved in the adsorption of Cu2, Pb2 and Cd2 and the 蟺-蟺 * transition is accompanied by the reaction process. The SEM results show that the FA aggregates and the structure changes after adsorption.
【學(xué)位授予單位】：內(nèi)蒙古大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：X524

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 吳云;鄧祥敏;張賢明;;富里酸紅外特征差異與其吸附瀝青質(zhì)行為間關(guān)系的研究[J];環(huán)境工程;2017年02期

2 李雨清;何江;呂昌偉;樊明德;王維;張瑞卿;謝志磊;汪精華;于波;恩和;丁濤;;富里酸對重金屬在沉積物上吸附及形態(tài)分布的影響[J];環(huán)境科學(xué);2016年03期

3 范春輝;張穎超;王家宏;;pH值對秸稈腐殖化溶解性有機(jī)質(zhì)紫外光譜和熒光光譜的影響[J];光譜學(xué)與光譜分析;2015年07期

4 YE YuanLv;CHEN ZongYuan;MONTAVON Gilles;JIN Qiang;GUO ZhiJun;WU WangSuo;;Surface complexation modeling of Eu(Ⅲ) adsorption on silica in the presence of fulvic acid[J];Science China(Chemistry);2014年09期

5 崔婷婷;竇森;楊軼囡;陳麗珍;黃毅;王瑞麗;;秸稈深還對土壤腐殖質(zhì)組成和胡敏酸結(jié)構(gòu)特征的影響[J];土壤學(xué)報(bào);2014年04期

6 姜杰;李黎;孫國新;;基于三維熒光光譜特征研究土壤腐殖質(zhì)氧化還原特性[J];環(huán)境化學(xué);2012年12期

7 林櫻;吳豐昌;白英臣;謝發(fā)之;曹政;蘇海磊;;我國土壤和沉積物中富里酸標(biāo)準(zhǔn)樣品的提取和表征[J];環(huán)境科學(xué)研究;2011年10期

8 毛海芳;何江;呂昌偉;梁英;劉華琳;王鳳嬌;;烏梁素海和岱海沉積物有機(jī)碳的形態(tài)特征[J];環(huán)境科學(xué);2011年03期

9 毛海芳;何江;呂昌偉;梁英;劉華琳;王鳳嬌;;沉積物中微生物量與有機(jī)碳形態(tài)的相關(guān)性研究[J];農(nóng)業(yè)環(huán)境科學(xué)學(xué)報(bào);2010年12期

10 翟瑩雪;魏世強(qiáng);;土壤富里酸對鉛的吸附作用與影響因素的研究[J];農(nóng)業(yè)環(huán)境科學(xué)學(xué)報(bào);2010年S1期

相關(guān)博士學(xué)位論文 前4條

1 汪精華;湖泊沉積物中富里酸與重金屬的作用機(jī)制研究[D];內(nèi)蒙古大學(xué);2016年

2 熊娟;土壤活性組分對Pb（Ⅱ）的吸附及其化學(xué)形態(tài)模型模擬[D];華中農(nóng)業(yè)大學(xué);2015年

3 薛紅喜;黃河包頭段沉積物重金屬吸附機(jī)制及污染生態(tài)學(xué)研究[D];內(nèi)蒙古大學(xué);2007年

4 傅平青;水環(huán)境中的溶解有機(jī)質(zhì)及其與金屬離子的相互作用——熒光光譜學(xué)研究[D];中國科學(xué)院研究生院（地球化學(xué)研究所）;2004年

相關(guān)碩士學(xué)位論文 前10條

1 丁濤;烏梁素海不同粒徑沉積物中黑碳對重金屬吸附特征的研究[D];內(nèi)蒙古大學(xué);2016年

2 恩和;湖泊沉積物中不同級分胡敏酸對重金屬吸附特征研究[D];內(nèi)蒙古大學(xué);2016年

3 聞麗;白洋淀植物腐解DOM特性及其與重金屬相互作用的研究[D];北京化工大學(xué);2014年

4 吉凡;土壤/有機(jī)物料中腐殖物質(zhì)組分結(jié)構(gòu)特征及對銅離子吸附作用的研究[D];吉林農(nóng)業(yè)大學(xué);2014年

5 李會杰;腐殖酸和富里酸的提取與表征研究[D];華中科技大學(xué);2012年

6 李紅;富里酸對β阻滯劑的光敏化降解研究[D];華中科技大學(xué);2012年

7 張孟孟;溶解性有機(jī)質(zhì)對土壤吸附汞的影響及其機(jī)理的研究[D];山東大學(xué);2011年

8 張曉晶;烏梁素海沉積物污染特征及營養(yǎng)鹽釋放規(guī)律試驗(yàn)研究[D];內(nèi)蒙古農(nóng)業(yè)大學(xué);2010年

9 張杰;重金屬汞在典型土壤腐殖酸上的吸附解吸特性研究[D];山東大學(xué);2008年

10 呂金妹;崇明東灘沉積物腐殖酸與重金屬生物地球化學(xué)研究[D];華東師范大學(xué);2008年

，

本文編號：2309412