Nanocellulose/chitosan biohybrid aerogel bead adsorbent for removal of diclofenac sodium from wastewater: preparation, characterization, and adsorption mechanism

In this work, a novel nanocellulose/chitosan biohybrid aerogel (NCBA) bead adsorbent was successfully prepared from oxidized bamboo nanocellulose and chitosan to remove diclofenac sodium (DS) from wastewater. Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy were used to characterize the preparation of NCBA bead adsorbent. The results demonstrated that the adsorption kinetics were well described by the pseudo-second-order model, and the adsorption isotherms were well fitted by the Sips isotherm model with the maximum adsorption capacity of 321.26 mg/g on DS, which is much higher than most of the previously reported works. The absorption mechanism was governed by electrostatic interaction and hydrogen bond interaction. Moreover, the resulting bead remained a high removal efficiency after 5 regeneration cycles. In summary, it had been proved that the aerogel bead was an efficient bio-sorbent for removing DS from aqueous solutions.