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Developing adsorbent materials based on biomass that can be easily recycled and reused to remove water pollutants has received widespread attention. A novel method for the preparation of calcium alginate/poly (vinyl alcohol)/boric acid (as–synthesized Ca-APB) aerogel fibers for highly efficient adsorption of methylene blue by directed freezing wet–spinning was presented in this paper. The Ca-APB-0.5 aerogel fibers exhibited a hierarchical structure consisting of a honeycomb micron pore structure with mesopores walls, with a maximum adsorption capacity of 508.99 mg/g in 5 h at 293 K. Meanwhile, the experimental data for Ca-APB-0.5 aerogel fibers showed the best fit to the Freundlich model and pseudo–second–order model. Moreover, the adsorption capacity was investigated for three consecutive cycles, with 469.37, 457.19, and 439.77 mg/g in the first, second, and third cycles, respectively. This paper proves that the hierarchical structure of alginate-based aerogel fiber is an effective dye adsorption material with high efficiency, reusability, and eco-friendliness. [Display omitted] • Robust alginate–based aerogel fibers via directed freezing–wet spinning. • Restriction of Ca2+ complexation by boric acid reduces the consumption of active groups. • Efficient adsorbent based on multi-active groups and hierarchical structure. • Micron macropores for channeling and nanopores for adsorption, inspired by soil pores. • Aerogel fibers realized high efficiency, reusability, and eco-friendliness. [ABSTRACT FROM AUTHOR]

To solve the inherent problems of conductive hydrogels, such as relatively low mechanical properties and fatigue resistance, inability to work after water loss, and difficulty weaving. In this study, the borax-crosslinked polyvinyl alcohol/k-carrageenan (kC) conducting hydrogels (BPK KOH) were prepared by a simple one-pot method, and KOH treatment was used instead of the cumbersome and time-consuming freeze-thaw cycle to improve the comprehensive properties. The KOH treatment increased the hydrogel hydrogen bonding content by 7.72 % and synergized with the induction of kC by K+ to enhance the tensile and compressive strengths by 8.12 and 34.6 times, respectively. Meanwhile, the BPK KOH hydrogel's fatigue resistance and shape recovery after water loss were improved. Additionally, the BPK KOH hydrogels can be monitored for finger bending, showing clear and stable differences in electrical signals. BPK KOH hydrogels combined with Morse code realize applications in information transmission and encryption/decryption. Notably, introducing KOH ensures the molding and preparation of BPK KOH hydrogel fibers while having good signal responsiveness and monitoring ability. More importantly, it can be woven into fabrics that can be loaded with heavy weights, which has the potential to be directly applied in smart wearables. This work provides new ideas for applying flexible sensors and wearable smart textiles. [Display omitted] • The KOH treatment can replace the traditional freeze-thaw cycles and improve the comprehensive properties of the hydrogels. • Hydrogen bonding and densely crosslinked network structure endow BPK KOH hydrogels with good mechanical properties. • The sensors assembled by BPK KOH hydrogels combined with Morse code to achieve information transfer and encryption/decryption. • Wet spinning confirms BPK composite system's spinnability, while KOH treatment similarly affects BPK hydrogel fibers. [ABSTRACT FROM AUTHOR]