纳米TiO_2修饰的涂碳型PVC膜汞离子选择电极的研制与应用  

Preparation and application of carbon-coated PVC membrane mercury ion selective electrode modified with nano-titanium dioxide

作　　者：任秀丽[1] 张静[1] 邵新田 

机构地区：[1]辽宁医学院药学院,辽宁锦州121000

出　　处：《冶金分析》2015年第4期30-33,共4页Metallurgical Analysis

基　　金：国家自然科学基金(No.51202199);辽宁省科技厅项目(2013225305)

摘　　要：制备了以纳米TiO2为修饰剂的涂碳型PVC膜汞离子选择电极,并用于汞离子的测定。对比裸碳电极、普通涂碳型汞离子选择电极和纳米TiO2修饰的涂碳型PVC膜汞离子选择电极在1.0×10-3 mol/L铁氰化钾溶液中的循环伏安图,发现纳米TiO2修饰的涂碳电极的氧化还原峰电流明显增加,且可逆性良好。对比普通涂碳电极和纳米TiO2修饰涂碳电极的响应曲线,发现纳米TiO2修饰涂碳型汞离子选择电极的Nernst响应范围更广,为1.0×10-2~1.0×10-6 mol/L,级差为30mV/pC。而且,纳米TiO2修饰涂碳型汞离子选择电极比普通涂碳电极的pH值范围更广。此外,与普通电极相比,修饰电极的检测下限更低,为4.5×10-7mol/L。常见的离子如Cu2＋、Cd2＋、NH4＋、Zn2＋、Cl-、Ca2＋、Fe3＋、K＋、Na＋、I-、Fe2＋、Mg2＋、Al 3＋、SO42-、CH3COO-、NO3-等的选择性系数均小于0.01,在室温下电极的使用寿命约为3个月。电极用于电位分析法测定实际污水样品中汞离子,测定结果与原子吸收光谱法结果相一致,相对标准偏差为1.9%~2.4%。The carbon-coated PVC membrane mercury ion selective electrode was prepared using nano-TiO2 as modifier and applied to the determination of Hg2＋. The cyclic vohammograms of bare carbon electrode, normal carbon-coated mercury ion selective electrode and carbon-coated PVC membrane mercury ion selec- tive electrode after modification by nano-TiO2 were compared in K3Fe（CN）6 solution with concentration of 1.0 × 10 a mol/L. It was found that the redox peak current of carbon-coated electrode after modification by nano-TiO2 increased significantly and have a good reversibility. The response curves of normal carbon-coa- ted electrode and nano-TiO2 modified carbon-coated electrode were compared. The results showed that the Nernst response range of carbon-coated mercury ion selective electrode after modification by nano-TiO2 was wider, i. e. , 1.0 × 10-2-1. 0 × 10-6 mol/L with stage difference of 30 mV/pC. Moreover, the carbon-coa- ted mercury ion selective electrode after modification by nano-TiO2 exhibited wider pH range than that of normal carbon-coated electrode. In addition, the detection limit of modified electrode was lower, i. e. , 4.5X10 7 mol/L. The selectivity coefficient of common ions （such as Cu2＋ , Cd2＋ , NH4 ＋ , Zn2＋ , Cl- , Ca2＋, Fe3＋, K＋, Na＋, I- , Fe2＋, Mg2＋, AP＋, SO42 , CH3COO andNO3 ） was less than0.01. The lifetime of modified electrode at room temperature was about three months. The prepared electrode was applied to the determination of Hg2＋ in actual wastewater samples by potentiometric analysis. The found results were consistent with those obtained by atomic absorption spectrometry. The relative standard deviation （RSD） was between 1.9% and 2.4%.

关 键 词：纳米TIO2 汞离子 离子选择电极 检测下限 污水 

分 类 号：X832[环境科学与工程—环境工程] O646[理学—物理化学]