氮磷双改性酚醛树脂基有序介孔碳电极对水中痕量铅的测定

Determination of trace lead in water by nitrogen and phosphorus double modified phenolic resin-based ordered mesoporous carbon electrode

以常见的磷氮双成份磷酸二氢铵为改性剂,间苯二酚/甲醛和F127为碳源和模板剂,成功制备了对痕量铅具有高灵敏度的氮磷双改性介孔碳OMC-MAP改性玻碳电极。通过N2吸附脱附等温线、FT-IR、XPS和阳极溶出伏安法对OMC-MAP的物化性质及其改性玻碳电极电化学性能进行了表征和分析。结果表明:OMCMAP具有较高的孔容(0.835 mL·g^(-1))、比表面积(579 m^(2)·g^(-1))和丰富的氨基、羧基、羰基等氮氧官能团,以及P—C、P—O—C等含磷官能团,介孔主要分布在5~10 nm区域,峰值在7.45 nm;OMC-MAP良好的介孔结构及其分散在微介孔表面的氮、磷、氧活性官能团为其改性玻碳电极传感器提供了良好的电子传递通道和高识别铅离子的活性位点。在醋酸-醋酸钠支持电解质底液下,OMC-MAP介孔碳改性玻碳电极传感器对溶液铅显示极优的电催化还原活性,当pH=3.8、富集电位为-1.2 V和富集时间为240 s时,循环伏安溶出电流的响应值达到最大。在该条件下,OMC-MAP改性玻碳电极在1~10000μg·L^(-1)宽范围内对铅离子均表现出极优的响应性,R2>0.98,灵敏度高、检测范围广,说明OMC-MAP是一种潜在痕量铅的电极材料。

N/P co-doped OMC-MAP modified glassy carbon electrode with high sensitivity for lead ions was prepared when common ammonium dihydrogen phosphate,formaldehyde/resorcinol and F127 were taken as modifier,carbon source and template agent of OMC-MAP,respectively.N2 adsorption-desorption isotherm,FTIR,XPS and anodic stripping voltammetry were used to characterize the physicochemical properties of OMCMAP and electrochemical performance of modified glassy carbon electrode.The results showed that OMCMAP had high pore volume(0.835 mL·g^(-1))and large specific surface area(579 m^(2)·g^(-1)),which contained amino nitrogen,carboxyl,carbonyl and other nitroxide functional groups,as well as P—C,P—O—C and other phosphorus functional groups.The mesopores were mainly distributed in the region of 5~10 nm,with a peak at 7.45 nm.The great mesoporous structure of OMC-MAP and the active functional groups of nitrogen,phosphorus and oxygen dispersed on the surface of the micro-mesopores provided a good electron transfer channel and active sites for high lead ions identification.Under the condition of acetic acid-sodium acetate supporting electrolyte solution,modified glassy carbon electrode sensor of OMC-MAP showed excellent electrocatalytic reduction activity on lead solution.When pH was 3.8,enrichment potential was-1.2 V and enrichment time was 240 s,the cyclic voltammetric stripping current response value reached the maximum.Under this condition,the OMC-MAP modified glassy carbon electrode showed excellent responsiveness and regularity to lead ions within a wide range of 1~10000μg·L^(-1).The linear correlation of R2 was higher than 0.98,with high sensitivity and wide detection range.This indicated that OMC-MAP modified glassy carbon electrode was a potential electrode material for trace lead ions detection.