Preparation Of Nanomaterials And The Application Of Nano-PbS To Lead Ion Selective Electrode

Nanomaterial was different from any other materials in their speciality. It was made them have many performances in magnetism, light, electricity, sense and so on. Therefore, nanomaterial has widely used in these aspects. Here, novel methods were employed to prepare the nanomaterial and nanomaterial application in practice were also investigated. The content of this paper was consist of four parts as follows:1. A novel approach to prepare homogeneous PbS nanomaterial by phase-transfer method was developed. The preparatory conditions were studied in detail, and the nanomaterial was characterized by transmission electron microscopy (TEM) and UV-vis spectroscopy. In order to attain better PbS nanoparticles, the optimal pH was 6, and the concentration of lead ion was 1.0×10^-4 mol·L^-1. The optimal concentration of H2Dz in carbon tetrachloride solution and CH3NSCH2 in ethyl alcohol were 1.5×10^-4 mol·L^-1 and 1.0×10^-4 mol·L^-1, respectively. The results showed that lead sulfide nanomaterial prepared in this condition has uniform distribution and compact structure.2. Lead ion-selective electrode of polyvinyl chloride (PVC) membrane based on the lead sulfide nanomaterial as prepared, and the optimal ratio of components in the membrane was determined. The results indicated that the sensor exhibited a wide concentration range of 1.0×10^-5 to 1.0×10^-2 mol·L^-1. The response time of the electrode was about 10 s, and the optimal pH in which the electrode could be used was from 3.5 to 7.0. Selectivity coefficients indicated that the electrode was selective to the primary ion over the interfering ion. The electrode can be used for at least 3 months without any divergence in potential. It was successfully applied to directly determine lead ions in solution and used as an indicator electrode in potentiometric titration of lead ions with EDTA. It is hoped that this kind of lead ion selective electrode was a good prosperity for practical samples.3. Lead sulfide nanomaterial was also used to prepare sulfide ion-selective electrode. The optimal ratio of components in the membrane was investigated. The results indicated that the sensor exhibited a wide concentration range of 1.0×10^-7 to 1.0×10^-4 mol·L^-1. The response time of the electrode was about 24 s, and the optimal pH of the test solution was 11.0. It also testified that the sulfide ion selective electrode has a good selectivity to interfering ions. 4. Silver nanomaterial was obtained by a chemical reduction method using aqueous polymers as dispersant and was characterized by UV-Vis spectroscopy, transmission electron microscopy (TEM) and light-scattering spectroscopy. Solid polymer containing the silver nanomaerial was also prepared after evaporating the solvent, and then dried with existing polymer. The stability of the silver nanomaterial was compared between primary fresh silver nanomaterial solution and redissolved solid polymer containing silver nanomaterial by UV-Vis spectroscopy. The particle size ranged from 5 to 10 nm, and no obvious differences were found. Therefore, preparing solid nano-Ag/polymer was a novel and useful method in storage of silver nanomaterial.