Heavy metal and organic dye removal via a hybrid porous hexagonal boron nitride-based magnetic aerogel

Numerous adsorbents have been introduced to efficiently remove heavy metals and organic dyes from environmental water samples. However, magnetic a porous network aerogels are rarely developed to capture inorganic and organic pollutants from aqueous. We herein fabricated hexagonal boron nitride nanosheets (h-BNNSs)-based on magnetic hybrid aerogels (MHAs) as a lightweight adsorbent for robust uptake of Cr(VI), As(V), methylene blue (MB) and acid orange (AO). The synthetic procedure of poly(ethyleneimine)-modified h-BNNSs (PEI-h-BNNSs) involved thermal poly condensation of melamine and boric acid, pyrolysis of the resultant products which allowed exfoliated by ultra-sonication process further functionalization with PEI-mediated modification of h-BNNSs. The as formed PEI-h-BNNSs allowed in-situ formation of magnetite nanoparticles (Fe3O4 NPs) decorated on their surfaces, which are turned to be PEI-h-BNNSs@Fe3O4 NPs. The lyophilization treatment of PEI-h-BNNSs@Fe3O4 NPs-loaded PVA hydrogels generated the MHAs with large porous structures, diverse and numerous functional groups, good superparamagnetic and a zero net surface charge. These features enabled the proposed adsorbent (MHAs) to be utilized to efficiently remove Cr(VI), As(V), MB, and AO from an aqueous solution, with maximum adsorption capacity estimated to be 833, 426, 415, 286 mg g(-1), respectively. The adsorption kinetics and isotherm data demonstrated that MHAs mediated adsorption of Cr(VI), As(V), MB and AO followed the Freundlich isotherm model and a pseudo-second-order kinetics model. This finding signifies that the MHAs exhibit heterogeneous binding behavior with multilayer chemisorption of Cr(VI), As(V), MB and AO. Subsequently, the practical application were validated by conducting their detoxification of chromium and arsenic in soli-sludge samples.

Automated summary

A new lightweight adsorbent has been developed for efficient removal of Cr(VI), As(V), MB, and AO pollutants from water, with good adsorption performance and practical application for detoxification of chromium and arsenic.