Sodium Alginate–Aldehyde Cellulose Nanocrystal Composite Hydrogel for Doxycycline and Other Tetracycline Removal

Abstract

A novel composite hydrogel bead composed of sodium alginate (SA) and aldehyde cellulose nanocrystal (DCNC) was developed for antibiotic remediation through a one-step cross-linking process in a calcium chloride bath. Structural and physical properties of the hydrogel bead, with varying composition ratios, were analyzed using techniques such as BET analysis, SEM imaging, tensile testing, and rheology measurement. The optimal composition ratio was found to be 40% (SA) and 60% (DCNC) by weight. The performance of the SA–DCNC hydrogel bead for antibiotic remediation was evaluated using doxycycline (DOXY) and three other tetracyclines in both single- and multidrug systems, yielding a maximum adsorption capacity of 421.5 mg g−1 at pH 7 and 649.9 mg g−1 at pH 11 for DOXY. The adsorption mechanisms were investigated through adsorption studies focusing on the effects of contact time, pH, concentration, and competitive contaminants, along with X-ray photoelectron spectroscopy analysis of samples. The adsorption of DOXY was confirmed to be the synergetic effects of chemical reaction, electrostatic interaction, hydrogen bonding, and pore diffusion/surface deposition. The SA–DCNC composite hydrogel demonstrated high reusability, with more than 80% of its adsorption efficiency remaining after five cycles of the adsorption–desorption test. The SA–DCNC composite hydrogel bead could be a promising biomaterial for future antibiotic remediation applications in both pilot and industrial scales because of its high adsorption efficiency and ease of recycling.

Antibacterial and Osteogenic Doxycycline Imprinted Bioglass Microspheres to Combat Bone Infection

“…Depending on the prevailing pH conditions, DOX can exist in three different forms: cationic (DOX+), zwitterionic (DOX ± ), and anionic (DOX−). Under acidic conditions, DOX+ predominates, while DOX ± is the dominant form under moderately acidic to neutral conditions, and DOX– is prevalent under alkaline conditions . Despite electrostatic repulsion between the negatively charged BGMs@Cs-MIP-1 and DOX– at alkaline conditions (pH 9), there was a notable increase in the equilibrium adsorption capacity.…”

“…Under acidic conditions, DOX+ predominates, while DOX ± is the dominant form under moderately acidic to neutral conditions, and DOX− is prevalent under alkaline conditions. 45 Despite electrostatic repulsion between the negatively charged BGMs@Cs-MIP-1 and DOX− at alkaline conditions (pH 9), there was a notable increase in the equilibrium adsorption capacity. It might be due to the O�C−NH and OH groups on the Cs-g-NIPAm network in imprinted cavities undergoing deprotonation under alkaline conditions.…”