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[Display omitted] • The magnetic nanoadsorbent with specific core-shell structure was synthesized. • Fe 3 O 4 @Carbon@ZIF-8 showed excellent adsorption capacities for Congo red and Cu(II). • The good adsorption ability was attributed to abundant active sites from ZIF-8. • Fe 3 O 4 @Carbon@ZIF-8 can selectively remove CR and Cu(II) from complex wastewater. • Nanoadsorbent's good stability and reusability indicated its practical application. Efficient and convenient removal of organic dyes and heavy metals from complex wastewater is still a challenge for human health and ecosystem remediation. Novel adsorbent, Fe 3 O 4 @Carbon@ZIF-8 with specific core-shell structure was synthesized by layer-by-layer self-assembly. The hydrophilic carbonaceous shell acts as both a linker and stabilizer between Fe 3 O 4 and ZIF-8. The characteristics of self-made adsorbent were comprehensively identified by numerous characterization methods. The adsorption kinetics, isotherms and the influence of various reacting parameters on its adsorption capacity of Congo red (CR) and Cu(II) were systematically investigated. Compared with other reported adsorbents, the maximum adsorption capacities of Fe 3 O 4 @Carbon@ZIF-8 towards CR (806.45 mg g−1) and Cu(II) (234.74 mg g−1) were much higher. Moreover, the adsorption process followed pseudo-second-order kinetics and Langmuir isotherm models. Selective adsorption of CR was investigated in the presence of cationic and anionic dyes, and the same as Cu(II) in the existence of competitive ions, which revealed that it was appropriate for selective adsorption toward CR and Cu(II) in complex wastewater. On the basis of FT-IR and XPS analyses, electrostatic interaction, hydrogen bonding, π-π bonding and ion exchange were involved in the mechanism of adsorption. Fe 3 O 4 @Carbon@ZIF-8 is suitable for practical application because of its good stability and reusability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Magnetic alginate-based biosorbents are prepared by free radical polymerization. • FSSEB-20 shows excellent adsorption capacities for DS and X-3B, respectively. • FSSEB-20 still shows satisfactory recycling rate after five runs. • The mechanism includes electrostatic action, hydrogen bonding and π-π interaction. In this work, we unveiled a novel magnetic biosorbent, poly (Benzyldimethyl[2-[(2-methyl-1-oxoally) oxy] ethyl] ammonium chloride)-immobilized magnetic sodium alginate composite-20 (FSSEB-20), and studied its adsorption behavior for two groups of toxic anionic organic pollutants, DS and X-3B from simulation wastewater. Results demonstrated that the Langmuir model could well describe the adsorption behavior of DS and X-3B on FSSEB-20, the maximum adsorption capacity of FSSEB-20 towards DS and X-3B are 340.58 mg g−1 and 370.85 mg g−1, respectively; according to kinetic results, the adsorption processes of both DS and X-3B on FSSEB-20 followed the pseudo-second-order kinetic model. To test the reusability of FSSEB-20, five runs of regeneration tests were performed. The removal rates of FSSEB-20 towards DS and X-3B are more than 74%. In addition to these, the surface interactions between FSSEB-20 and DS/X-3B were systematically analyzed based on the characterization results of FT-IR and XPS, which provided significant insights into the interactions between biosorbents and pollutants in wastewater. The mechanism of DS and X-3B adsorption by FSSEB-20 includes electrostatic interaction, hydrogen bonding and π-π interaction. Furthermore, this study also provides a new enlightenment for expanding the treatment of pollutants in wastewater with sodium alginate-based magnetic biosorbent. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel floating-separation adsorbent (APHGS-g-P(AMPS)) was designed and synthesized. • APHGS-g-P(AMPS) showed outstanding self-floating separation ability. • APHGS-g-P(AMPS) with satisfactory adsorption capacity was rich in –OH, –NH 2 and -SO 3 -. • The electrophilic addition strategy facilitated the grafting of P(AMPS) polymerized chains. • The sulfonic acid group exhibited excellent universal adsorption for MB and Pb(II). Inferior solid–liquid separation behavior and inadequate adsorption capacity are the main bottlenecks of current wastewater treatment adsorbents, especially in the purification of wastewater containing dyes and heavy metals. Accordingly, a novel floating separation adsorbent with polymeric chain structure, hollow glass sphere-g-(3-aminopropyl) triethoxysilane-g-poly(2-acrylamide-2-methyl-1-propanesulfonic acid) (APHGS-g-P(AMPS)), was fabricated through an electrophilic addition post-grafting strategy. The obtained APHGS-g-P(AMPS) exhibited satisfactory adsorption for methylene blue (MB) and lead ion (Pb(II)), as well as efficient flotation. Adsorption behavior analysis showed that the Pseudo-second-order kinetic model and Langmuir isotherm model were suitable for describing the adsorption process, and the maximum adsorption capacities for MB and Pb(II) were 249.33 and 345.93 mg·g−1 (313.15 K), respectively. Analysis of the adsorption mechanism indicated that the sulfonic acid group exhibited excellent universal adsorption for MB and Pb(II), which played a crucial role in the adsorption process. Furthermore, the efficient grafting of P(AMPS) polymerized chains onto the adsorbent was the pivotal factor to enhance adsorption. This study provided an efficient electrophilic addition post-grafting strategy for the structural design and functional modification of floating separation adsorbents. The results of this study are expected to have positive implications for the efficient purification of dyes and heavy metals wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • A hollow self-floating adsorbent was specially designed and prepared. • HGM was decorated with dopamine and taurine to enhance adsorption properties. • HGM@PDA-SO 3 H exhibited satisfactory reusability and resistance to ion interference. • TC was efficiently removed over a wide pH range. • The hollow structure endowed HGM@PDA-SO 3 H with self-floating separation capability. Hollow glass microspheres (HGM), as a promising hollow spherical ultra-light material, have the advantages of uniform particle size, regular shape, high mechanical strength and stable physical and chemical properties. It has been widely utilized in many fields but its application in water treatment is yet to be developed. Herein, a novel self-floating composite adsorbent was obtained by forming a poly(dopamine) (PDA) biomass coating on the surface of HGM and introducing sulfonic acid groups. The hollow composite material (HGM@PDA-SO 3 H) was utilized in the adsorptive elimination of tetracycline (TC) from aqueous solutions. In addition to great adsorption performance, HGM@PDA-SO 3 H also exhibited satisfactory self-floating solid-liquid separation capability. Langmuir, pseudo second-order and Elovich models correlate isotherms and kinetic data relatively well, respectively. The theoretical saturated TC adsorption amount of HGM@PDA-SO 3 H evaluated by Langmuir model reached 333.70 mg g−1. Thermodynamic analysis confirmed the spontaneous exothermic property of the adsorption process. There was no serious decline in the adsorption of TC by the material after 5 adsorption cycles, and the adsorbent saturated with contaminants could be easily regenerated via solution desorption, reflecting its satisfactory renewability and stability. Based on the results of batch experiments and characterization analysis, it could be concluded that the corresponding adsorption mechanisms mainly involve electrostatic attraction, hydrogen bonding and π-π stacking interactions. This research aimed to decorate HGM with biomaterials and apply it in the adsorptive purification of TC-contaminated water, which brought some insights and inspiration for the environmental application of HGM, and proved its potential applicability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Self-floating cyclodextrin-modified polymer was prepared. • The adsorption performance of TFCD and FTFCD was compared. • FTFCD simplified the recycling process by wrapping a hollow glass microsphere. • Porous structure and hydrophobic cavity favor the dye adsorption. • Polymers exhibited excellent selectivity toward cationic dyes. The separation and recycling processes of current cyclodextrin (CD)-based adsorbents are complicated. Thus, a novel composite based on a large surface area, porous, and self-floating tetrafluoroterephthalonitrile (TFN)-crosslinked CD polymer (FTFCD), was fabricated, characterized and applied to treat cationic dye pollutants. The characterization showed a porosity, good thermal stability, a stable crystal structure, and abundant functional groups on the prepared FTFCD, which had demonstrated great improvement on its adsorption capacity towards attention grabbing pollutants. The removal efficiency of the adsorbents for malachite green (MG) remained above 95% at pH 1 ∼ 10. In addition, the adsorbents were found to rapidly reach equilibrium governed by the pseudo-second-order kinetic model, and the maximum adsorption capacity of FTFCD was 1390.263 mg/g, as corroborated by the Langmuir isotherm model. While the phenolate groups of FTFCD found to electrostatically interacts with the MG strong cationic quaternary amine group, hydrogen-bonding was responsible for the hydroxyl group of FTFCD and the quaternary amine group binding. Meanwhile, the triangular cone configuration of MG makes it easy to be entrapped and absorbed in the hydrophobic cavity. Besides, after regeneration of exhausted FTFCD for five successive cycles, the MG removal efficiency still reached more than 80%. Thus, FTFCD could be applied as a potential alternative adsorbent for cationic dye removal owing to its excellent adsorption performance, convenient recycling, wide pH application, and environmental friendliness. [ABSTRACT FROM AUTHOR]