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We report the application of Fe 3 O 4 -functionalized boron nitride nanosheets (BNNS-Fe 3 O 4 nanocomposite) for the remediation of As(III) ions from contaminated water. The specific surface area of the nanocomposite has been found as 179.5 m 2 g −1 .Due to its superparamagnetic nature at room temperature, the nanocomposite can be easily isolated from the solution under an external magnetic field. For As(III) ions, the maximum adsorption capacity of the nanocomposite is obtained as 30.3 mg g −1 , which is approximately 4 times more than that of the bare BNNSs (8.5 mg g −1 ). The results from density functional theory calculations are also in close agreement with experimental findings and show that As(OH) 3 binds more (∼4 times) efficiently to the BNNS-Fe 3 O 4 nanocomposite than the bare BNNSs, implying a 4 times higher adsorption capacity of the nanocomposite. Especially, it is found that the synthesized nanocomposite could lessen the concentration of As(III) ions from 134 to 2.67 ppb in a solution at 25 °C. On increasing the temperature to 35 °C, the level of As(III) ions could be reduced from 556 to 10.29 ppb, which is close to the limit prescribed by the World Health Organization. The adsorbent was easily separable and showed regeneration properties. These outcomes depict the prospect of using BNNS-Fe 3 O 4 nanocomposites as commercial adsorbents for the removal of As(III) ions from contaminated water.

Insights into observed efficient adsorption of methyl orange from water by boron nitride nanosheets are presented using theoretical studies.

It is widely known that the existence of arsenic (As) in water negatively affects humans and the environment. We report the synthesis, characterization, and application of boron nitride nanosheets (BNNSs) and Fe3O4-functionalized BNNS (BNNS–Fe3O4) nanocomposite for removal of As­(V) ions from aqueous systems. The morphology, surface properties, and compositions of synthesized nanomaterials were examined using scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, surface area analysis, zero-point charge, and magnetic moment determination. The BNNS–Fe3O4 nanocomposites have a specific surface area of 119 m2 g–1 and a high saturation magnetization of 49.19 emu g–1. Due to this strong magnetic property at room temperature, BNNS–Fe3O4 can be easily separated in solution by applying an external magnetic field. From the activation energies, it was found that the adsorption of As­(V) ions on BNNSs and BNNS–Fe3O4 was due to physical and chemical adsorption, respectively. The maximum adsorption capacity of BNNS–Fe3O4 nanocomposite for As­(V) ions has been found to be 26.3 mg g–1, which is 5 times higher than that of unmodified BNNSs (5.3 mg g–1). This closely matches density functional theory simulations, where it is found that binding energies between BNNS–Fe3O4 nanocomposite and As­(OH)5 are 5 times higher than those between BNNSs and As­(OH)5, implying 5 times higher adsorption capacity of BNNS–Fe3O4 nanocomposite than unmodified BNNSs. More importantly, it was observed that the synthesized BNNS–Fe3O4 nanocomposite could reduce As­(V) ion concentration from 856 ppb in a solution to below 10 ppb (>98.83% removal), which is the permissible limit according to World Health Organization recommendations. Finally, the synthesized adsorbent showed both separation and regeneration properties. These findings demonstrate the potential of BNNS–Fe3O4 nanocomposite for commercial application in separation of As­(V) ions from potable and waste water streams.

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