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Development of magnetic graphene oxide adsorbent for the removal and preconcentration of As(III) and As(V) species from environmental water samples

Rashidi Nodeh, Hamid, Wan Ibrahim, Wan Aini, Ali, Imran, Sanagi, Mohd Marsin
Environmental science and pollution research international 2016 v.23 no.10 pp. 9759-9773
Fourier transform infrared spectroscopy, World Health Organization, X-radiation, adsorbents, adsorption, arsenic, detection limit, energy-dispersive X-ray analysis, graphene oxide, iron oxides, lakes, nanoparticles, pH, rivers, scanning electron microscopy, silica, solid phase extraction, sorption isotherms, tap water, thermodynamics
New-generation adsorbent, Fe₃O₄@SiO₂/GO, was developed by modification of graphene oxide (GO) with silica-coated (SiO₂) magnetic nanoparticles (Fe₃O₄). The synthesized adsorbent was characterized using Fourier transform infrared spectroscopy, X-ray diffractometry, energy-dispersive X-ray spectroscopy, and field emission scanning electron microscopy. The developed adsorbent was used for the removal and simultaneous preconcentration of As(III) and As(V) from environmental waters prior to ICP-MS analysis. Fe₃O₄@SiO₂/GO provided high adsorption capacities, i.e., 7.51 and 11.46 mg g⁻¹ for As(III) and As(V), respectively, at pH 4.0. Adsorption isotherm, kinetic, and thermodynamic were investigated for As(III) and As(V) adsorption. Preconcentration of As(III) and As(V) were studied using magnetic solid-phase extraction (MSPE) method at pH 9.0 as the adsorbent showed selective adsorption for As(III) only in pH range 7–10. MSPE using Fe₃O₄@SiO₂/GO was developed with good linearities (0.05–2.0 ng mL⁻¹) and high coefficient of determination (R ² = 0.9992 and 0.9985) for As(III) and As(V), respectively. The limits of detection (LODs) (3× SD/m, n = 3) obtained were 7.9 pg mL⁻¹ for As(III) and 28.0 pg mL⁻¹ for As(V). The LOD obtained is 357–1265× lower than the WHO maximum permissible limit of 10.0 ng mL⁻¹. The developed MSPE method showed good relative recoveries (72.55–109.71 %) and good RSDs (0.1–4.3 %, n = 3) for spring water, lake, river, and tap water samples. The new-generation adsorbent can be used for the removal and simultaneous preconcentration of As(III) and As(V) from water samples successfully. The adsorbent removal for As(III) is better than As(V).