Decontamination of fenitrothion from aqueous solutions using rGO/MoS2/Fe3O4 magnetic nanosorbent: synthesis, characterization and removal application.

In the present work, rGO/MoS2/Fe3O4 nanocomposite was synthesized and after confirmation of the structure by FTIR, XRD, and FESEM techniques, its performance as nanosorbent was investigated for the removal of fenitrothion pesticide from the aqueous media. The parameters affecting the removal process including agitation time, pH of the reaction medium, adsorbent content, initial analyte concentration as well as desorption parameters were investigated and optimized. Under optimum conditions (pH = 7, adsorbent amount: 30 mg, adsorption and desorption time: 5 min, eluent type and volume: 0.01 M ethanol-acetic acid and 4 mL), the synthesized adsorbent was able to remove fenitrothion pesticide up to 98% with an adsorption capacity of 33.4 mg/g. By investigation of the line equation and the correlation coefficient value, it was found that the adsorption process, in this study, follows the Langmuir model.

Preconcentration of trace amounts of Pb(II) ions without any chelating agent by using magnetic iron oxide nanoparticles prior to ETAAS determination.

This work investigates the potential of magnetic Fe(3)O(4) nanoparticles as an adsorbent for separation and preconcentration of trace amounts of lead from water samples prior to electrothermal atomic absorption spectrometry (ETAAS) determination. No chemical modifier is required in graphite furnace. Pb(II) ion was adsorbed on magnetic Fe(3)O(4) nanoparticles in the pH range of 5.5-6.5, and then magnetic nanoparticles (MNPs) were easily separated from the aqueous solution by applying an external magnetic field; so, no filtration or centrifugation was necessary. After extraction and collection of MNPs, the analyte ions were eluted using HNO(3) 1.0 mol L(-1). Several factors that may affect the preconcentration and extraction process, such as pH, type, and volume of eluent, amount of MNPs, sample volume, salting out effect, and interference ions were studied and optimized. Under the best experimental conditions, linearity was maintained between 0.005-0.5 ng mL(-1). Detection limits for lead were 0.8 ng L(-1) based on 3S(b). The relative standard deviation of seven replicate measurements of 0.05 ng mL(-1) of Pb(II) ions was 3.8%. Finally, the method was successfully applied to extraction and determination of lead ions in the water and standard samples.