Adsorption studies of cadmium onto magnetic Fe3O4@FePO4 and its preconcentration with detection by electrothermal atomic absorption spectrometry

Xiaoxing Zhang; Changle Sun; Li Zhang; Hui Liu; Binxia Cao; Libo Liu; Weimin Gong

doi:10.1016/j.talanta.2018.01.023

Adsorption studies of cadmium onto magnetic Fe₃O₄@FePO₄ and its preconcentration with detection by electrothermal atomic absorption spectrometry

Talanta. 2018 May 1:181:352-358. doi: 10.1016/j.talanta.2018.01.023. Epub 2018 Jan 11.

Authors

Xiaoxing Zhang¹, Changle Sun², Li Zhang³, Hui Liu³, Binxia Cao³, Libo Liu³, Weimin Gong³

Affiliations

¹ College of Environmental Sciences and Engineering, Dalian Maritime University, Dalian 116026, China. Electronic address: zhangxiaoxing@dlmu.edu.cn.
² College of Ship and Ocean Engineering, Dalian Maritime University, Dalian 116026, China.
³ College of Environmental Sciences and Engineering, Dalian Maritime University, Dalian 116026, China.

PMID: 29426524
DOI: 10.1016/j.talanta.2018.01.023

Abstract

Superparamagnetic Fe₃O₄@FePO₄ nanoparticles with core shell structure were prepared by coating iron phosphate on the surface of Fe₃O₄ nanoparticles by liquid phase deposition method. The prepared materials were characterized by vibrating sample magnetometer, scanning electron microscopy, X-ray diffractometer, Fourier transform infrared spectrometer, nano Zetasizer, X-ray photoelectron spectroscopy and Raman spectrometer. These characterization methods were also used to describe the adsorption mechanism. The obtained composite material was used for the adsorption of a heavy metal element, cadmium. Its unique magnetic properties are favorable for rapid separation and preconcentration of trace cadmium from aqueous solutions. About 100% sorption was achieved at pH 7 for 1mL, 10μgL^-1 of cadmium. Batch adsorption experiments show that the adsorption fits Langmuir model, and a maximum adsorption capacity 13.51mgg^-1 is derived for Cd(II). The retained Cd(II) could be readily recovered by 200μL of HNO₃ (0.01molL^-1). The cadmium in the eluate is quantified with detection by electrothermal atomic absorption spectrometry (ETAAS). A sample volume of 2000μL creates an enrichment factor of 10.3, along with a detection limit of 0.021µgL^-1 (3σ, n=7) and a RSD of 1.3% (0.1µgL^-1, n=7) within a linear calibration range of 0.05-0.5µgL^-1. The practical applicability of this procedure was validated by analyzing cadmium contents in a certified reference material (GBW08608) and two environmental water samples.

Keywords: Adsorption; Cadmium; ETAAS; FePO(4); Magnetic; Preconcentration.