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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]

• Magnetic biosorbents (PMCCs) were designed and fabricated by radical polymerization. • PMCCs had specific morphological and molecular structure for ciprofloxacin removal. • PMCCs exhibited excellent adsorption capacity of 527.93 mg·g−1 for ciprofloxacin. • The adsorption mechanisms of ciprofloxacin by PMCCs were systematically elucidated. • PMCCs displayed rapid separation and favorable reusability. Magnetic biosorbents with specific morphological and molecular structure (PMCCs) were designed for the removal of ciprofloxacin (CIP) from water. Radical polymerization method was applied to immobilize the designed polymer brushes onto core-shell shaped magnetic microspheres to fabricate PMCCs. PMCCs exhibited a maximum adsorption capacity of 527.93 mg·g−1, which is much higher than reported adsorbents, owing to the complete stretch of polymer brushes and increased active sites as well as enhanced interaction. The investigation on the adsorption behavior of PMCCs for CIP manifested that CIP adsorption well fitted the Langmuir isotherm model and pseudo-second-order kinetic model. The calculated thermodynamic parameters suggested that CIP adsorption onto PMCCs was spontaneous and exothermic. Further recycling experiments showed a loss of less than 20% in the CIP adsorption capacity after five times, demonstrating the reusability of the as-designed biosorbents. [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]

The selective separation and recovery of valuable metals from complex polluted wastewater is of great significance to the protection of water resources and the realization of resource recycling. Herein, the chitosan-coated magnetic silica core-shell nanoparticles (FO@SD@CS) were fabricated and applied as adsorbents for highly selective removal of precious metals silver ions (Ag(I)) from complex wastewater. In multi-ion compound polluted solutions, FO@SD@CS showed excellent selective adsorption of Ag(I) in a wide pH range, and an enhancement of the highly selective adsorption capacity of Ag(I), which was increased from 85.86 to 126.74 mg g−1 when the concentrations of methyl blue (MB) coexisted in the solution from 0 to 40 mg L−1 at pH 6.0. The results of Ag(I) single system batch adsorption experiments illustrated that the adsorption behavior of FO@SD@CS to Ag(I) shows obvious pH responsiveness, the adsorption capacity of Ag(I) increases with the increasing of pH value. The results of the adsorption isotherm and kinetics demonstrated that Langmuir and pseudo-second-order kinetics can better describe the adsorption behavior of Ag(I) on FO@SD@CS, indicating that the adsorption process was controlled by chemisorption and the maximum monolayer adsorption capacity reached 116.28 mg g−1 at room temperature. Additionally, in the dye-metal binary system, the coexisting MB promoted the adsorption capacity of FO@SD@CS to Ag(I) from 116.28 to 156.25 mg g−1, showing a synergistic adsorption effect. This study shows that the enhanced selective separation and recovery of metal ions from wastewater based on anion-synergistic not only provides new ideas for wastewater treatment, but also has important significance for water resources reuse. [Display omitted] • A magnetic adsorbent with core-shell structure was successfully prepared. • FO@SD@CS exhibited higher acid resistance than uncoated silica adsorbent. • FO@SD@CS showed high selectivity in capturing silver from multi-ion solutions. • Coexisting MB enhanced the selective adsorption of Ag(I) in complex wastewater. • Possible adsorption mechanisms in both single and binary systems were proposed. [ABSTRACT FROM AUTHOR]