Novel 3D polyethyleneimine functionalized konjac glucomannan aerogel for selective removal of anionic dye from water

The severe environmental pollution and ecological risks caused by dyeing wastewater are currently issues that need to be urgently addressed. Herein, a novel environmental-friendly ternary hybrid aerogel (KGP), composed of konjac glucomannan (KGM), ghatti gum (GG), and polyethyleneimine (PEI), was designed and simply fabricated for the highly efficient and selective removal of methyl orange (MO) from water. The structure and composition of KGP-2 were characterized using SEM, FT-IR, XRD, and XPS. The effects of PEI content, pH, contact time, and temperature on MO sorption were systematically investigated. The experimental maximum adsorption capacity of KGP-2 was 135.39 mg/g, which was three times higher than that of KGM/GG aerogel (43.8 mg/g). With the integration of the adsorption kinetics, isotherms, and thermodynamic studies, along with the various spectroscopic characterizations before and after adsorption, the adsorption mechanisms of KGP-2 for MO were investigated in detail. Selective adsorption tests demonstrated the high selectivity of KGP-2 for MO, and after six cycles of adsorption-desorption, the MO removal rate remained above 80%, highlighting the stability and reusability of KGP-2. Consequently, this newly developed composite aerogel is expected to serve as a highly promising sorbent for the adsorptive removal of MO from practical water systems.