Fibrous Aerogel-Templated Nanostructured Boron Carbon Oxynitride Networks for Preferential Adsorptive Separation of Cationic Dyes

Organic dyes in wastewater jeopardize aquatic ecosystems and biodiversity, besides having several concerns of health hazards. Nanostructured materials of controlled textural features with active surface functionalities are gaining immense interest as effective adsorbents for wastewater treatment. The present work addresses a facile approach to synthesize fibrous aerogel-templated nanostructured boron carbon oxynitride (BCNO). The surface functionalities, structural heterogeneity, crystalline phases, and morphological features of BCNO are probed by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, Raman, X-ray diffraction, and high-resolution transmission electron microscopy analyses. The nanostructured BCNO showed preferential and remarkably high adsorption of cationic dyes with a removal capacity of 1258 mg g-1 for malachite green (MG) dye. The adsorption of MG dye by nanostructured BCNO is carried out at different pH, ionic strength, and temperature to emphasize the influence of environmental factors. The spectroscopic analyses suggested multiple adsorption pathways, viz. electrostatic, pi-pi, hydrogen, and Lewis acid-base interactions for unprecedentedly higher adsorption of cationic dyes by BCNO. Batch-mode findings promise the potential of nanostructured BCNO for wastewater treatment applications.