【作者】 胡聪；

【导师】 周家斌；

【作者基本信息】 武汉理工大学 ， 环境工程， 2012， 硕士

【摘要】 由于环境介质比较复杂或待测污染物浓度很低,通常环境样品需要经过前处理,即分离富集后再进入分析仪器进行准确地测定。固相萃取技术由于富集效率高、有机溶剂用量少、易于自动化等优点被广泛应用于样品前处理领域。固相萃取剂是影响固相萃取富集效率最重要的因素之一。竹炭具有较大的比表面积、发达的孔隙结构和良好的吸附性能,对废水中的一些污染物质有一定的吸附作用。本文制备了一系列竹炭吸附剂,将其作为固相萃取剂建立了环境样品中典型污染物的分析方法,并应用于实际环境样品分析。主要进行了以下几个方面的研究：1.以竹炭作为固定相制作了固相萃取小柱,用来分离富集水中的溴代阻燃剂六溴环十二烷,优化了萃取条件,建立了环境样品中六溴环十二烷的检测方法,该方法基于竹炭固相萃取和快速分辨液相色谱-电喷雾串联质谱。在最优条件下,方法在0.1-10μg·L-1范围内呈现良好的线性关系,方法的检出限和精密度分别为0.005-0.015μg·L-1和4.59-7.47%。该方法被成功应用于实际环境水样中痕量六溴环十二烷的检测,实际样品加标回收率为88.5-98.3%。2.选用竹炭作为固相萃取剂,并将此固相萃取体系与高效液相色谱紫外检测器联用,建立了环境水样中三种人工合成的雌激素物质的分析检测方法。实验详细考察了洗脱液种类和体积、样品流速、样品pH和体积等几个因素对竹炭固相萃取体系分离富集性能的影响,结果表明,当洗脱液为8mL丙酮,样品流速为4mL·min-1,样品pH和体积分别为2和500mL时,分离富集效率最好。在此条件下测定了方法的的分析特性参数,根据实验结果可知,该方法的线性范围为1-100μg·L-1,检出限和精密度分别为0.03-0.06μg·L-1和4.46-8.65%。该方法被成功应用于三种实际环境水样的分析,实际样品加标回收率为85.0-97.0%。3.通过控制毛竹的炭化温度(500、700、900℃)制备出了三个竹炭样品。运用扫描电子显微镜(SEM)、元素分析、比表面积及孔径分布测试等手段对竹炭样品进行表征。结果发现竹炭样品表面有大量的微孔的介孔存在,使其有很高的比表面积。炭化温度对竹炭的微观结构和组成有很大影响,随着炭化温度的升高,比表面积和孔体积显著增大,含碳量也明显提高。将所制得的竹炭样品用于水中Cr(Ⅵ)的吸附研究,结果表明,竹炭对水中Cr(Ⅵ)有很好的吸附效果,吸附在120min左右达到平衡。Langmuir等温模型和准二级动力学方程可以很好的描述整个吸附过程,其Cr(Ⅵ)最大吸附量为38.91mg·g-1。热动力学研究表明吸附过程是一个自发和吸热的物理吸附过程。竹炭由于其独特的孔结构和较高的比表面积,对于去除废水中的Cr(Ⅵ)污染物是很有效的吸附材料。更多还原

【Abstract】 Due to the complexity of environmental sample matrix and the low concentration of analytes, pretreatment of samples and preconcentration of analytes are usually involved prior to instrument analysis for accurate measurement. The solid-phase extraction (SPE) is widely used in sample pretreatment field owing to the high enrichment efficiency, low dosage of organic solvent and easy automation. The choice of adsorbent is one of most important influence factors. Bamboo charcoal is a new environmental protection material with large specific surface area, advanced pore structure and excellent adsorption property to the pollutants in wastewater. Hense, bamboo charcoal is selected as the research object and the thesis focused on its application potential in SPE technique. A series of bamboo charcoals with different performance were prepared. Using bamboo charcoal as SPE adsorbent, the analysis methods of typical pollutants in environmental samples were developed. The main results are as follows:The SPE cartridges using bamboo charcoal as stationary phase were prepared to separation and enrichment of brominated flame retardants hexabromocyclododecane diastereomers (HBCDs). The conditions affecting the extraction efficiencies were investigated and optimized in detail, and the method for simultaneous preconcentration and sensitive determination of HBCDs in environmental water samples has been developed. It was based on SPE and rapid resolution liquid chromatography-electrospray tandem mass spectrometry (RRLC-ESI-MS/MS). Under the optimum conditions, experimental data exhibited excellent linear relationships between peak area and concentrations over the range of0.1-10μg·L-1. The limits of detection and precision were in the range of0.005-0.015μg·L-1and4.59-7.47%, respectively. The proposed method has been successfully applied for the trace analysis of HBCDs in real-world environmental water samples, the recoveries of standard addition obtained were in the range of88.5-98.3%.Bamboo charcoal was used as SPE adsorbent in this work as well as the analytical method based on SPE combined with high-performance liquid chromatography-ultraviolet detector (HPLC-UV) was established for simultaneous preconcentration and sensitive determination of estrogens hexestrol, diethylstilbestrol and dienestrol in environmental water samples. Important parameters affecting extraction efficiencies, including eluant and its volume, flow rate, sample pH and volume were investigated and optimized in detail. It indicated that the highest enrichment efficiency was obtained when8mL acetone was selected as eluent, the sample flow rate, pH and volume were4mL-min-1,3and500mL, respectively. Under the optimum conditions, analytical performance parameters of the proposed method were determined. Experimental results showed that the linear ranges were1-100μg·L-1, the limits of detection and precision were in the range of0.03-0.06μg·L-1and4.46-8.65%, respectively. The proposed method has been successfully applied for the trace analysis of these estrogens in real-world environmental water samples with satisfactory results, the the recoveries of standard addition were85.0-97.0%.Three bamboo charcoal samples were prepared by carbonization of Moso bamboo at different temperatures (500,700,900℃). The as-prepared samples were characterized by scanning electron microscopy, nitrogen adsorption-desorption and element analysis. It is found that a large number of micro-/mesoporous in bamboo charcoal surface as well as high surface area. The carbonization temperature has a significant impact on micro structure and composition of bamboo charcoal:with the carbonization temperature increases, BET specific surface areas and pore volume increased significantly as well as the carbon content. Adsorption of Cr(VI) onto the as-prepared bamboo charcoal sample from aqueous was investigated and discussed. The bamboo charcoal samples exhibit excellent adsorption property towards Cr(VI) ions in aqueous solutions and about120min to reach adsorption equilibrium. The adsorption data can better described by Langmuir model and pseudo-second-order equation with maximum monolayer adsorption capacity of38.91mg·g-1. The bamboo charcoal samples are found to be effective adsorbents for the removal of Cr(VI) pollutant from wastewater as a result of its unique porous structure and high specific surface areas. Bamboo charcoal materials are expected to be useful in adsorption and separation areas for removal of pollutants from the wastewater.更多还原