Quaternized Cellulose Hydrogels as Sorbent Materials and Pickering Emulsion Stabilizing Agents

Area of Science:

• Materials Science
• Polymer Chemistry
• Environmental Engineering

Background:

• Cellulose hydrogels are versatile materials with tunable properties.
• Developing efficient adsorbents for contaminants like naphthenates is crucial for environmental remediation.
• Quaternization and cross-linking can modify cellulose hydrogel characteristics.

Purpose of the Study:

• To synthesize and characterize quaternized (QC) and cross-linked/quaternized (CQC) cellulose hydrogels.
• To evaluate the colloidal and thermal stability of the synthesized hydrogels.
• To investigate the adsorption performance of CQC hydrogels for naphthenates and 2-naphthoxy acetic acid (NAA).

Main Methods:

• Hydrogel synthesis via cross-linking cellulose with epichlorohydrin (ECH) and grafting glycidyl trimethyl ammonium chloride (GTMAC).
• Material characterization using CHN analysis, TGA, FTIR, and 13C solid-state NMR.
• Sorption studies using oil sands process water (OSPW) naphthenates and NAA, analyzed with Langmuir isotherm and kinetic models.

Main Results:

• CQC hydrogels exhibited enhanced thermal stability compared to native cellulose.
• CQC demonstrated higher affinity and sorption capacity for OSPW naphthenates (33.0 mg/g) and NAA (69.5 mg/g) than QC.
• Optimal NAA uptake was observed at 303 K, with minor effects of pH and dosage on sorption kinetics.

Conclusions:

• CQC cellulose hydrogels are effective adsorbents for naphthenates from OSPW.
• The adsorption mechanism involves enthalpy-driven electrostatic interactions and an ion-based associative process.
• These findings advance the understanding of cellulose-based hydrogels for environmental applications.