Synthèse et caractérisations d’un Hydroxyde Double Lamellaire modifié par un polymère neutre (Brij 35) : Application à la détection électrochimique du plomb

Abstract

In this work, a lamellar double hydroxide (HDL) was synthesized from magnesium (II) and aluminum (ⅠⅠⅠ) in the proportions 3/1 in basic medium by the low saturation coprecipitation method under an atmosphere of nitrogen. The material called MgAlNO3 was functionalized with a neutral : Brij35 (polyoxyethylene lauryl ether) using the intercalation method. The modified or unmodified materials were characterized on the one hand by X-ray diffractometry (XRD) and by Fourier transform infrared spectroscopy (FTIR). These methods made it possible to confirm firstly the success of the synthesis of HDL and secondly the presence of Brij35 in the interfoliar space of the HDL material, characterized by an increase in the interfoliar distance. These materials were also characterized electrochemically using the cyclic voltammetry (VC) method. It consists of modifying the carbon paste electrode with HDLs or HDL-brij using. The [Fe (CN)6] and [Ru (NH)6] ions as a probe. The voltammograms obtained indicate that the functionalized HDL-brij material accumulates the cationic probe better and the anionic probe with difficulty. To assess the effectiveness of the modification of HDL by brij, the electroanalysis of Pb ions was carried out by square wave voltammetry coupled with anodic redissolution (SWASV). The results obtained show that the carbon paste electrode modified by brij 35 (EPC-HDL-brij) gives a signal 3 times more intense than that obtained on the carbon paste electrode modified by simple HDL (EPC -HDL). The sensor thus proposed showed great stability and good reproducibility. After having optimized a certain number of parameters: the detection medium, the deposition potential, the electrolysis time and the percentage of material in the paste, the calibration line was drawn in the concentration range going from 5.10 to 5.10- 5 M under optimal conditions and a detection limit evaluated from a signal/background noise ratio equal to 3 was 9 ,57.10 M.