Gels

This research designed a high-performance superabsorbent gel aligned on the integration of lignite humic residue (LHR) with a polymeric organic network in order to address ecological restoration challenges in the arid mining area in Xinjiang. This water-retaining agent was synthesized by employing solution polymerization techniques using acrylic acid (AA) and acrylamide (AM) as monomers, lignite hydrothermal residue (LHR) as a functional additive, and ammonium persulphate (APS) as the initiator. The resulting lignite hydrothermal residue–polyacrylic gel composite material was obtained by using N,N′-methylene-bisacrylamide (MBA) as the primary crosslinking agent. The water absorption capacity and mechanical strength of the acrylic gel were further enhanced by specifically incorporating low-cost, safe, and non-toxic lignite humic residue (LHR). The performance test indicated that this gel achieved a maximum water absorption of 522 g·g⁻¹ in distilled water and 65.5 g·g⁻¹ in 0.9% sodium chloride solution. Its reusability and water absorption capacity remained above 81.8% even after five cycles of natural dehydration and reabsorption. The method for synthesizing this superabsorbent gel effectively constructs a soil water retention network structure, improving the soil microenvironment, and enhancing plant salt tolerance. The field trial results showed that the application of this LHR-AA-AM superabsorbent gel considerably improved vegetation coverage in mining areas. Hence, this study provides an efficient and economical superabsorbent material for ecological restoration of saline–alkali land in arid regions without soil replacement, demonstrating promising application prospects.

The valorization of wine by-products aligns with circular bioeconomy principles. This study investigates the ultrasound-assisted aqueous extraction (UAE) of bioactive compounds and cell wall polysaccharides from Syrah grape stems (Vitis vinifera L.) to produce polysaccharide extracts with the intrinsic potential to form cellulose-rich gels with enhanced antioxidant properties. Extractions were performed at three temperatures (10, 20, and 50 °C) and three ultrasonic power densities (120, 206, and 337 W/L), and compared to conventional extraction (CE, 200 rpm). The results demonstrated that UAE significantly accelerated the extraction kinetics for total phenolics (TP), flavonols, and antioxidant capacity (ABTS, FRAP), achieving up to a 3.1-fold increase in TP yield at 20 °C. Notably, UAE at 337 W/L and 20 °C produced antioxidant levels equivalent to those obtained by CE at 50 °C, enabling high efficiency at lower, compound-preserving temperatures. Carbohydrate analysis revealed that the extracts were inherently “cellulose-rich” (glucose ~49–52 mol%), with co-extracted pectins and hemicelluloses constituting a composite polysaccharide matrix with inherent gel-forming capacity, as evidenced by its composition. While total polysaccharide yield was maximized at 10 °C, UAE’s primary effect was the facilitation of extraction and potential structural modification of polymers rather than increasing bulk yield. The process reduced extraction times by 3- to over 6-fold to achieve equivalent bioactive yields compared to CE. This work establishes UAE with water as a process aligned with green chemistry principles, an efficient strategy for the integrated, one-step recovery of antioxidant phenolics and gel-forming polysaccharides from grape stems, transforming this underutilized residue into a multifunctional extract precursor for cellulose-rich hydrogels suitable for food and pharmaceutical applications.

The aim of this study was to synthesize alginate hydrogel beads using ionotropic gelation containing pH-sensitive magnetic reduced graphene oxide (MGO). MGO was prepared using a hydrothermal method and surrounded by alginate beads. FTIR, XRD, FESEM, TEM, VSM and TGA showed that the synthesized beads have a quasi-spherical structure, exhibit superparamagnetic behavior, and are thermally stable up to 350 °C. The model drug, quercetin, was loaded into these particles with an efficiency of 25.8%. These particles showed a pH-dependent release. HFF-2 and Caco-2 cells were used to investigate cytotoxicity. At a concentration of 140 μg/mL, more than 80% viability was observed in HFF-2 cells and anticancer effects were observed on Caco-2 cells with a decrease in viability of less than 50% at a concentration of 200 μg/mL. The obtained cell culture results indicate that the hydrogel beads are biocompatible and act as a drug delivery system.