Self-assembly of alginate/polyethyleneimine multilayer onto magnetic microspheres as an effective adsorbent for removal of anionic dyes

A novel magnetic adsorbent alginate/polyethyleneimine (ALG/PEI) n /MN was developed for removal of anionic dyes from aqueous solution in this study. (ALG/PEI) n /MN was prepared by depositing ALG/PEI multi-layers onto amine-modified Fe 3 O 4 microspheres through layer-by-layer method. The morphologies and structures of the adsorbent were characterized by scanning electron microscopy, X-ray diffractometer, and Fourier transform infrared spectrometer, respectively, and its performance in adsorption of anionic dye (acid orange 10, AO10) under varied experimental conditions were also investigated. The results revealed that the uptake capacity of AO10 by (ALG/PEI) n /MN increased with the number of coated (ALG/PEI) bilayer on the adsorbents, and the maximum adsorption capacity for AO10 by (ALG/PEI) 4 MN was 246.3 mg g −1 at 25 °C. The adsorption process was exothermic and well described by the pseudo-second order kinetic model and the Langmuir isothermal model. Moreover, (ALG/PEI) 4 /MN showed good reusability and excellent magnetic separability. All the results demonstrate that (ALG/PEI) 4 /MN is a potential recyclable adsorbent for removal of anionic dyes from wastewater. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 45876.