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Cellulose-polyethyleneimine (PEI) composite has been widely used in water remediation. However, most of these composites are synthesized using chemical cross-linkers, which usually cause secondary contamination and extra cost. To address these issues, a stable TEMPO-oxidized cellulose nanofibril (TCNF)-PEI composite hydrogel (TCNF/PEI) was synthesized through self-assembly mechanisms involving cationic chelation and physical adsorption. These hydrogels were tested for the removal of methyl blue and Cu (II) ions -used as model emerging contaminants- from aqueous solutions. Interactions of the hydrogels with methyl blue dyes and Cu (II) ions were pH dependent. Interestingly, methyl blue dye removal using these hydrogels occurred through both adsorption and precipitation phenomena. Between the pH values of 3.7 and 5.7, most of the dyes were removed by adsorption, obtaining the highest adsorption efficiency (88.3 %) at pH 4.7. At pH of 2.7, these hydrogels promoted rapid precipitation of methyl blue removing up to 91.5 % after 6 h of exposure. Importantly, the structure of precipitated methyl blue dyes remained unchanged as demonstrated by FTIR and XRD, indicating the potential use of this technology on the recovery of reusable methyl blue dyes from wastewater. However, Cu (II) can only be removed by adsorption at pH range from 4 to 8, with an efficiency up to 72.6 % at pH 8. FTIR and XPS analysis revealed that the adsorption mechanism of methyl blue is mainly driven by electrostatic attraction and hydrogen bonding, while Cu (II) removal occurs mainly through electrostatic attraction and coordination. These processes are primarily governed by interactions between the nitrogen and oxygen-containing groups in the hydrogel and the contaminants. This work sheds light on the fundamental understanding of TCNF/PEI hydrogels and their potential for removal emerging contaminants such as anionic dyes and heavy metal ions from industrial wastewater.
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Sodium Alginate–Aldehyde Cellulose Nanocrystal Composite Hydrogel for Doxycycline and Other Tetracycline Removal
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.
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- Award ID(s):
- 2216585
- PAR ID:
- 10432291
- Date Published:
- Journal Name:
- Nanomaterials
- Volume:
- 13
- Issue:
- 7
- ISSN:
- 2079-4991
- Page Range / eLocation ID:
- 1161
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.3390/nano13071161
