Novel composites of Pennisetum glaucum with CNT: preparation, characterization and application for the removal of safranine O and methylene blue dyes from single and binary systems

Agricultural waste–based adsorbents offer an innovative, cost-effective, and environmentally benign approach for the removal of various dyes from wastewater. Herein, Pennisetum glaucum –based novel composites with functionalized carbon nanotubes (CNT) were developed for the effective and efficient removal of methylene blue (MB) and safranine O (SO) dyes from the single and binary systems for the first time. Characterization of as-synthesized composites was performed using various techniques such as field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). In batch studies, both the dyes were effectively removed at neutral pH with 0.01 g/10 mL of adsorbent dosage and 10 min of contact time at 30 °C. The adsorption isotherm and kinetic data were well fitted by the Langmuir isotherm and pseudo-second-order model, respectively. The maximum adsorption capacity of the composite containing 0.5% of CNT was 181.81 and 386.1 mgg −1 for MB and SO dyes, respectively, which were 267.29% and 94.61% greater than raw P. glaucum adsorbent. The adsorption was spontaneous, exothermic, and physisorption in nature, involving electrostatic, π-π, and H-bonding interactions. The as-prepared adsorbents exhibited excellent reusability, and their adsorption efficiency was maintained even after ten cycles. Finally, the present work suggests a promising strategy for the preparation and application of novel green adsorbents for wastewater remediation.