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This work aims to prepare a composite adsorbent with a fixed shape to improve the performance of carbon materials and to solve the problem of adsorbent in powder form which is difficult to recycle after use. The BC-ZnS composite system was successfully prepared by hydrothermal method based on the preparation of biomass carbon (BC) using alginate (Alg), while the ZnS component was grown in-situ on the surface of BC. The effects of Alg, Zn source, hydrothermal temperature and time on the synthesis of BC-ZnS were explored, the results indicated that ZnS was successfully grown in-situ on the BC surface, while the BC maintained its original morphology. BC-ZnS showed excellent adsorption capacity for methylene blue (MB), basic fuchsin (BF), and copper ions (Cu2+), reaching 301.50 mg/g for MB and exhibiting good cyclic stability. The adsorption of MB/BF/Cu2+ by BC-ZnS was characterized by the presence of multiple forces, where the BC component mainly depended on the electrostatic force of Alg residue, while the ZnS involves electrostatic forces, ion exchange and Lewis acid/base soft-soft interactions. The adsorption process conforms to pseudo-first-kinetics and is a spontaneous entropy-increasing process. BC-ZnS can be a candidate for reusable wastewater treatment and has excellent potential for application. [Display omitted] • One-pot hydrothermal preparation of BC-ZnS composite system • Realized the growth of ZnS on the surface of BC • Realized efficient synergistic adsorption of BC-ZnS • High adsorption capacity, stable performance, stable morphology, convenient recycling • The mechanism of dyes and heavy metal ion adsorption by BC-ZnS is revealed. [ABSTRACT FROM AUTHOR]

[Display omitted] • The amphoteric C/A composite sponges were prepared and characterized. • C/A composite sponges possess self-cleaning and multi-active sites. • Sponges' adsorption capacity for MB and AB dyes is 656.33 mg/g and 502.49 mg/g. • The selective adsorption ability of sponges could be modulated by various pH. • C/A composite sponges can be loaded with photocatalysts for dye degradation. To address the complex dyeing wastewater containing oil pollution and bacterial microorganisms in practical environments, in this work, amphoteric (CHI/ALG) C/A composite sponges with self-cleaning and multi-active sites were prepared by composite chitosan (CHI) and alginate (ALG) using urea/alkali composite solutions. The C/A composite sponges have good water wettability and demonstrated underwater anti-oil and anti-bacterial microbial adhesion. The adsorption process was spontaneous entropy-increasing and could be accurately described using the Pseudo-First-Order and Langmuir models. Notably, the adsorption capacity of C/A composite sponges for methylene blue and acid blue dye reached 656.33 mg/g and 502.49 mg/g, respectively. The amphoteric C/A composite sponges can selectively adsorb both anionic and cationic dyes. Additionally, epichlorohydrin (ECH) cross-linking and intermolecular self-assembly molding enabled the C/A composite sponges to form a three-dimensional network structure with nanofiber weaving and a specific surface area of 67.63 m2/g. Interestingly, this endowed the C/A composite sponges with the potential to serve as dyes photocatalyst substrates, and the photocatalytic degradation of dyes was successfully achieved by loading TiO 2 on the C/A composite sponges. More importantly, the C/A composite sponge remained self-cleaning after loading TiO 2. The amphoteric C/A composite sponges have great potential in complex dyeing wastewater treatment containing oil and bacterial microbes. [ABSTRACT FROM AUTHOR]

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]