High-efficacy adsorption of Cr(VI) and anionic dyes onto β-cyclodextrin/chitosan/hexamethylenetetramine aerogel beads with task-specific, integrated components

To significantly enhance the adsorption efficacy of hexavalent chromium from aqueous medium, a novel and non-toxic chitosan-based composite beads were prepared by integrating task-specific components into one sample, namely β-cyclodextrin/chitosan/hexamethylenetetramine (β[email protected]). The pseudo- second-order kinetic and Langmuir isotherm model was used to describe the adsorption process. The maximum capacity Cr(VI) removal reached 333.8 mg/g which was superior to most of reported CS derivative adsorbents. The sorption mechanism of composite was investigated by employing FT-IR, SEM-EDS and XPS techniques. It showed that the reason for efficient removal of Cr(VI) onto resultant sample including chemisorption and reduction of Cr(VI) to the non-toxic Cr(III), and the two components of β-CD and HMTA with task-specific had played a crucial role during the adsorption process. Most importantly, for fixed-bed column sorption testing, the breakthrough curves were well fitted by Thomas model under different flow rates (1, 2 and 3 mL/min). Moreover, the β[email protected] had also manifested perfect adsorption capability towards anionic dyes in initial concentration 500 mg/L. This research indicated that as-fabricated chitosan-based composite beads are promising adsorbents for Cr(VI) and anionic dyes because of its superiority of low-cost, easy regeneration and environmental friendly.