【作者】 郜如；

【导师】 常希俊；

【作者基本信息】 兰州大学 ， 分析化学， 2010， 硕士

【摘要】 近些年来,工业生产和经济技术的快速发展使得大量的重金属离子被不断地排出,造成日趋严重的环境污染,重金属离子的准确测定已成为分析化学工作者新的挑战。利用现代原子光谱分析直接测定低浓度金属离子有一定的困难,需要对溶液进行分离富集预处理,才能达到高的精密度和准确度。而样品的富集分离通常需要借助选择性高、吸附容量大的各种吸附材料和合适的分离方法。本论文以建立痕量组分的富集分离及分析为目的,合成了几种功能化吸附分离材料,并对材料的选择性吸附性能开展了系统研究。1.氨基硫脲修饰的活性炭作为一种新型吸附剂,用来分离富集水溶液中痕量的Cu(Ⅱ)、Hg(Ⅱ)和Pb(Ⅱ),用电感耦合等离子体原子发射光谱进行测定。详细研究了分离富集条件和性能(pH,振荡时间,样品流速和最大体积,洗脱条件等)。结果表明,在pH 3时该吸附剂对Cu(Ⅱ)、Hg(Ⅱ)和Pb(Ⅱ)最大饱和吸附量分别为78.20、67.80和48.56 mg g-1,吸附的金属离子可用3.0 mL 2% CS(NH2)2和2.0 molL-1HCl完全洗脱；大多数共存离子对该吸附剂没有影响；该方法对Cu(Ⅱ)、Hg(Ⅱ)和Pb(Ⅱ)的检出限分别是0.20、0.12和0.45 ng mL-1,相对标准偏差不超过4.0%,应用于水样中分离富集测定Cu(Ⅱ)、Hg(Ⅱ)和Pb(Ⅱ)得到了较好的结果。2.研究了以4-羟基水杨酸偶氮蒽醌修饰的纳米SiO2作为固相萃取剂,以ICP-AES为检测手段,用来富集分离和检测溶液中的Pb(Ⅱ)和Fe(Ⅲ)。采用静态吸附方法研究此吸附剂对Pb(Ⅱ)和Fe(Ⅲ)的吸附条件：pH值、振荡时间、洗脱条件和离子干扰等。最佳条件下,Pb(Ⅱ)和Fe(Ⅲ)最大的静态饱和吸附容量分别为65.0和58.3mg g-1,用2mL 0.1mol L-1HCl能够完全洗脱Pb(Ⅱ)和Fe(Ⅲ)。该法的检出限(3σ,n=8)为4.03和3.19 ng mL-1,相对标准偏差(RSD)小于4%,回收率>95%。此吸附剂用来富集检测黄河水样和自来水样中Pb(Ⅱ)和Fe(Ⅲ)的含量,得了满意的结果。3.合成了肼基甲酸苄基修饰的活性炭吸附剂,研究了这种吸附剂对Pb(Ⅱ)的分析性能,建立了富集测定Pb(Ⅱ)的新方法。实验表明在pH 4时其饱和吸附量达到48.64μmol g-1,该方法在15 min可以达到吸附平衡,检出限是1.04 ng mL-1,经计算方法的相对标准偏差(RSD)为2.5%。应用于生物样和水样中Pb(Ⅱ)的测定,结果令人满意。更多还原

【Abstract】 The rapid development of proceeding industrialization and economic technology leads to the draining of heavy metals. It has been a new challenge to determinate the metal ions exactly for analytical chemists.Direct determination of trace elements at low concentrations by modern atomic spectrometric techniques is often difficult, and various pre-treatment procedures are necessary before the more accurate measurement of solution so that reach to high precision and accuracy.The pre-concentration and analysis of trace elements have to depend on different adsorption materials with higher selectivity and bigger adsorption capacity and appropriate separation methods.This paper mainly described the preparation of several adsorption materials based on the pre-concentration and separation of trace components. At the same time,the adsorption selectivity characteristics for trace heavy metals have been investigated systematically.1. A new sorbent 1-acylthiosemicarbazide-modified activated carbon (AC-ATSC) was prepared as a solid phase extractant and applied for adsorbing of trace Cu(Ⅱ), Hg(Ⅱ) and Pb(Ⅱ) prior to their determination by inductively coupled plasma atom emission spectrometry (ICP-AES). The separation/preconcentration conditions of analytes were investigated, including effects of pH, the shaking time, the sample flow rate and volume, the elution condition and the interfering ions. At pH 3, the maximum static adsorption capacity of Cu(Ⅱ), Hg(Ⅱ) and Pb(Ⅱ) onto the AC-ATSC was 78.20,67.80 and 48.56 mg g-1, respectively. The adsorbed metal ions could be quantitatively eluted by 3.0 mL of 2% CS(NH2)2 and 2.0 mol L-1 HCl solution. Common coexisting ions did not interfere with the separation. According to the definition of IUPAC, the detection limit (3a) of this method for Cu(Ⅱ), Hg(Ⅱ) and Pb(Ⅱ) was 0.20,0.12 and 0.45 ng mL-1,respectively. The relative standard deviation under optimum conditions was less than 4.0%(n=8). The prepared sorbent was applied for the preconcentration of trace Cu(Ⅱ), Hg(Ⅱ) and Pb(Ⅱ) in certified and water samples with satisfactory results.2. In this study, a new sorbent 4-hydroxy salicylic acid (AZO) anthraquinone modified silica gel (SG-HSAA) sorbent was prepared as a solid phase extractant and applied for adsorbing of trace Pb(II) and Fe(III) prior to their determination by inductively coupled plasma atom emission spectrometry (ICP-AES). The separation/preconcentr-ation conditions of analytes were investigated, including effects of pH, the shaking time, the elution condition and the interfering ions. At pH 2, the maximum static adsorption capacity of Pb(Ⅱ) and Fe(Ⅲ) onto the SG-HSAA was 65.0 and 58.3 mg g-1. The adsorbed metal ions were quantitatively eluted by 2.0 mL 0.1 mol L-1 HCl solution. Common coexisting ions did not interfere with the separation. According to the definition of IUPAC, the detection limits (3σ) of this method for Pb(Ⅱ) and Fe(Ⅲ) was 4.03 and 3.19 ng mL-1. The relative standard deviation under optimum conditions is less than 4.0%(n=8). The prepared sorbent was applied for the preconcentration of trace Pb(Ⅱ) and Fe(Ⅲ) in certified and water samples with satisfactory results.3. A new sorbent benzyl carbazate-modified activated carbon AC-CBZH was synthesisedas a solid phase extractant, and applied for adsorbing of trace Pb(Ⅱ) prior to their determination by inductively coupled plasma atom emission spectrometry (ICP-OES). The experiments showed that the percentage extraction of Pb(Ⅱ) was achieved within 10 min. At pH 3, the maximum static adsorption capacity of Pb(Ⅱ) onto the AC-CBZH were 48.64μmol g-1. According to the definition of IUPAC, the detection limits (3a) of this method for Pb(Ⅱ) was 1.04 ng mL-1. The relative standard deviation under optimum conditions was 2.5%(n=8). The prepared sorbent was applied for the preconcentration of trace Pb(Ⅱ) in certified and water samples with satisfactory results.更多还原