Preparation of magnetic Fe3O4 nanocomposites modified with MnO2, Al2O3, Au and their application for preconcentration of arsenic in river water samples

In this study, the nanometer-sized ferrous-ferric oxide magnetic nanocomposite (Fe3O4@MnO2@Al2O3@Au) was successfully synthesized using co-precipitation and sol gel methods The structural, morphological and magnetic properties of the nanocomposite material were characterized by FTIR, BET, XRD, SEM/EDS, Zeta-potential measurements, TEM and VSM. The nanocomposite was applied as a sorbent for preconcentration of As via ultrasound assisted magnetic solid phase extraction (UA-MSPE). The preconcentrated arsenic was quantified using ICP-MS. A 2(5-1) fractional factorial design was used as a tool for optimizing the developed analytical methodologies. Under optimized conditions, the limit of detection and quantification were 8.6 and 28.5 ng L-1 respectively. The intraday (n = 15) and interday (n = 5) precisions of the developed UA-MSPE method expressed in terms of relative standard deviation (%RSD) were 4.1 and 6.2% and the enrichment factor was found to be 95. The extraction efficiency of the current method was greater than 95%. The developed UA-MSPE method was successfully applied in the preconcentration of arsenic in environmental water samples and nanocomposites modified with MnO2, Al2O3, Au and their application for preconcentration of arsenic in river water sample and the concentration ranged from 0.13-0.18 mu g L-1. The Fe3O4@MnO2@Al2O3@Au nanoadsorbent combined the advantages of magnetic separability and high affinity toward arsenic adsorption.