Characterization of Alginate-Crystalline Nanocellulose Composite Hydrogel as Polyphenol Encapsulation Agent

Floating BiOBr/Ti3C2 aerogel spheres for efficient degradation of quinolone antibiotics: Rapid oxygen transfer via triphase interface and effective charges separation by internal electric field

The limited transport of oxygen at the solid-liquid interface and the poor charge separation efficiency of single catalyst significantly impedes the generation of reactive oxygen species (ROS), thereby weakening the application potential of photocatalytic technology in water pollution control. Herein, a hollow porous photocatalytic aerogel sphere (calcium alginate/cellulose nanofibers (CA/CNF)) loaded BiOBr/Ti3C2, combining a favourable mass transfer structure with effective catalytic centers was firstly presented. The floatability and hollow pore structure facilitated rapid O2 transfer via a triphase interface, thereby promoting the generation of ROS. The oxygen diffusion flux of aerogel spheres' upper surface in triphase system exhibited a 0.151 μmol·(m2·S)-1 increase compared to that of the diphase one based on Finite element simulation (FEM). Furthermore, owing to the regulation of charge spatial distribution by Schottky junction of BiOBr/Ti3C2, internal electric field (IEF) of CA/CNF@BiOBr/Ti3C2 achieved 1.8-fold improvement compared with CA/CNF@BiOBr, thus enhancing the separation of photogenerated charges. Accordingly, the degradation efficiency and catalytic rate constant of moxifloxacin (MOX) by CA/CNF@BiOBr/Ti3C2 in triphase system have improved by 20.1% and 1.5 times compared to those of diphase system, respectively. Moreover, the potential to mineralize multiple quinolone antibiotics (FQs), high resistance to complex water disturbances and excellent stability were revealed in CA/CNF@BiOBr/Ti3C2. Besides, the triphase system based on CA/CNF@BiOBr/Ti3C2 confirmed the potential for large-scale water treatment application in 500 mL MOX circular flow, reaching 90% MOX removal within 120 min. This research clarifies the oxygen mass transfer mechanism and pathways to the enhanced ROS production in a triphase system, and provides new insights into designing efficient floatable photocatalyst and adaptive reaction devices for new pollutants remediation.

Ginger residue-derived nanocellulose as a sustainable reinforcing agent for composite films

Nanocellulose extracted from agricultural waste for the development of reinforced sustainable composites is needed, due to a greater environmental responsibility and awareness of environmental pollution. In this work, the extraction of nanocellulose (GNC) from ginger residue was conducted via acid hydrolysis without complicated pretreatments. The potential application of GNC as a reinforcing agent for sustainable composite films was also explored. The results showed that the obtained GNC exhibited a rod-like shape with a high aspect ratio (15.75 ± 4.25). X-ray diffraction patterns revealed a cellulose II structure with a crystallinity index of 88.47 %. The reinforcing effects of GNC were evaluated in composite films made from different matrices, including sodium alginate (SA) and chitosan (CS), to assess its performance in enhancing material properties. The incorporation of 5 % of GNC significantly improved the tensile strength of SA and CS by 94 % and 64 %, respectively. Notably, the addition of GNC also enhanced the elongation at break of the SA-based films. This study demonstrates that ginger residue is a promising and sustainable feedstock for extracting nanocellulose, which can serve as an effective reinforcing agent in biocomposite films.