Linde Type a Zeolite and Type Y Faujasite as a Solid-Phase for Lead, Cadmium, Nickel and Cobalt Preconcentration and Determination Using a Flow Injection System Coupled to Flame Atomic Absorption Spectrometry

作     者：Yaneira Petit de Pena Wendy Rondón 

作者机构：Laboratorio de Espectroscopía MolecularFacultad de CienciasUniversidad de Los AndesMéridaVenezuela Laboratorio de Química AnalíticaCentro de QuímicaInstituto Venezolano de Investigaciones CientíficasCaracasVenezuela 

出 版 物：《American Journal of Analytical Chemistry》 (美国分析化学（英文）)

年 卷 期：2013年第4卷第8期

页      面：387-397页

学科分类：07[理学] 0703[理学-化学] 

基　　金：The authors are grateful to the FondoNacional de Ciencia y Tecnología(FONACIT)and Consejo de Desarrol-loCientífico Humanístico Tecnológico y de lasArtes(CDCHTA)for financial support Proyects S1-97001192 and C-133105-08B respectively Laboratorio de Análisis Químico Estructural de Materiales(LAQUEM)and La-boratorio de Cristalografía of the Universidad de Los Andes(ULA)Mérida-Venezuela 

主　　题：Cobalt Nickel Cadmium Lead Flow Injection Preconcentration Zeolites Atomic Absorption 

摘      要：In this work, a flow injection analysis (FIA) method for the trace determination of lead, cadmium, nickel and cobalt in natural waters by formation of neutral chelates with ammonium pyrrolidine dithiocarbamate (APDC) was developed. The neutral chelates formed was retained in a mini-column packed with Linde type A zeolite (LTA) and type Y Faujasite zeolite (FAU) and then eluted with methyl isobutyl ketone (MIBK) to flame atomic absorption spectrometry (EAA) for its detection. Physicochemical characterization of this zeolite was carried out by Fourier Transform infrared spectroscopy and attenuated total reflectance (FTIR and IR-ATR), scanning electron microscopy and energy dispersive X-ray microanalysis (SEM-EDX) and X-ray power diffraction (XRD). Then, a FIA configuration was used with a column preconcentration system coupled to the detection system at room temperature (22?C). The detection limit and the relative standard deviation for 5 determinations of different solutions of Pb2+, Co2+, Ni2+ and Cd2+ for FAU and LTA zeolite were calculated. The sampling frequency ranged from 18-35 h-1 and preconcentration factors from 21-250 were achieved, for a sample volume of 6 mL using 20 mg of sorbents, indicating a high retention of the analytes on the zeolites material. The recoveries obtained in natural waters samples were close to 100% for all ions metal using synthetic zeolites, confirming the applicability of the method. The isotherm models of Langmuir, Scatchard, Freundlich and Dubinin-Radushkevich were used to study the equilibrium data, indicating that successfully followed the Freundlich and Dubinin-Radushkevich (D-R) isotherms at low metal ion concentration. The Freundlich parameter n varied between 0.35-1.01, whereas D-R isotherm yields the sorption free energy E 8 ***-1 indicating psysisorption.