Studies On The Optical Chemical Membranes For Lead Ion Based On Organically Modified Sol-gel

Among the various kinds of heavy metals, the concentration of lead is the highest in the enviroment, so it's the most harmful metal to people's health. Lead will lead to the pathological changes of the assimilation system, nerve system and heart disease. Moreover, lead will bring more serious harms to the children, like dysgnosia. Lead in the environment exists as bivalent lead ion (Pb2+), so the research and development of a sensitive chemical sensor of Pb2+ has brought more and more attention around the world. This article prepared the optic-chemical sensor membrane of Pb2+ with three Pb2+ sensitive fluorescence indicators which were synthesized in the lab, by utilizing the technology of Optical Fibre of Chemical Sensor(FOCS), and technology of organic modification Sol-gel as well.This thesis consists of four chapters: (1) a review; (2) study on the optical chemical membrane for detection of lead ion by using 2-hydroxy-1-naphthaldehydene-8-aminoquinoline as fluorescence indicator; (3) study on the optical chemical membrane for detection of lead ion by using meso-(4-Methyloxyphenyl) Porphyrin as fluorescence indicator; (4) study on the optical chemical membrane for detection of lead ion by using 2-methene-benzimidazole monoaza-18-crown-6 as fluorescence indicator.In Chapter one, the laboratory method for determination of lead ion, the progresses of chemical sensor for detection of lead ion recently and the introduction of the basic theory, relative merits of sol-gel and its application in optical chemical sensor were involved. At the end of this chapter, the aims of this thesis and the main research contents were also described.In chapter two, a optical chemical membrane was prepared for detection of lead ion base on 2-hydroxy-1-naphthaldehydene-8-aminoquinoline by using organically modified sol-gel. By being optimized the compounding ration of dopant, water, catalyst and additive, the membrane has a good respond to lead ion in water. The linear response range of membrane was 1.0×10-7~5.0×10-5mol/L, and the detection limit was 3.6×10-8 mol/L. In addition, capabilities of the membrane were studied. The experimental results showed that this membrane has a good stability, good reversibility and good repeatability.In Chapter three, a optical chemical membrane was prepared for detection of lead ion base on meso-(4-Methyloxyphenyl) Porphyrin by using organically modified sol-gel, and this membrane has a good respond to lead ion in water. The linear response range of membrane was 1.0×10-6～1.0×10-5mol/L, and the detection limit was 2.5×10-7 mol/L. The experimental results showed that this membrane has a...