By combining the advantages of poly(4-styrenesulfonic acid-co-maleic acid) sodium (PSSMA) with abundant anionic functional groups (-COO − and -SO 3 − ), graphene oxide (GO) with high specific surface area and Fe 3 O 4 nanoparticles with excellent magnetic responsiveness, a novel type of PSSMA-modified magnetic reduced graphene oxide nanocomposites (PSSMA/M-rGO) were synthesized via simple and facile one-step solvothermal method and used for removing cationic dyes from aqueous solutions in this study. The as-synthesized PSSMA/M-rGO were characterized by Fourier transform infrared spectroscopy, UV-vis spectroscopy, scanning electron microscope, transmission electron microscope, thermogravimetric analysis, χ-ray diffraction, vibrating sample magnetometer, dynamic light scattering and nitrogen adsorption-desorption technique. Three typical cationic dyes, basic fuchsin (BF), crystal violet (CV) and methylene blue (MB) were used as model dye pollutants to evaluate the adsorption performance of the resultant PSSMA/M-rGO. The adsorption of three cationic dyes onto both PSSMA/M-rGO and M-rGO without PSSMA modification on the surface were systematically investigated at different experiment conditions. The results indicate that the binding of PSSMA on M-rGO can significantly enhance the adsorption capacities and removal efficiencies of the three dyes. This is due to that the rich -COO − and -SO 3 − groups on PSSMA/M-rGO have strong electrostatic interactions with the positively charged dye molecules. The adsorption kinetics and isotherms of three dyes onto both two adsorbents demonstrate that the kinetics and equilibrium adsorptions can be well-described by the pseudo-second-order kinetic and Langmuir model, respectively. Moreover, the PSSMA/M-rGO nanocomposites also demonstrate high removal efficiencies toward mixed dyes of BF, CV and MB. Such functional nanocomposites with high adsorption capacity, lowproduction cost and excellent recyclability, are promising as candidate adsorbents for highly-efficient removal of cationic organic pollutants from aqueous solutions.

Multifunctional graphene oxide nanocomposites simultaneously possessing high enantioselectivity, excellent thermosensitivity, and magnetism demonstrate great application potentials in direct enantioseparation. We herein report one novel smart graphene oxide nanocomposite (MGO@PNG-CD) with high enantioselectivity, excellent thermosensitivity, and magnetism for highly efficient chiral identification and enantioseparation of tryptophan enantiomers. The MGO@PNG-CD is composed of graphene oxide nanosheets with immobilized superparamagnetic Fe 3 O 4 nanoparticles and grafted PNG-CD smart polymer brushes. The PNG-CD is made up of poly(N-isopropylacrylamide-co-glycidyl methacrylate) (PNG) chains with numerous appended β-cyclodextrin (β-CD) units, which play a significant role in effective chiral discrimination and resolution of DL-tryptophan (DL-Trp). The β-CD units serve as chiral selectors capable of selectively recognizing and binding L-tryptophan (L-Trp) into their cavities to form stable host−guest inclusion complexes of β-CD/L-Trp. The PNIPAM chains in PNG act as a microenvironmental adjustor for the inclusion constants of β-CD/L-Trp complexes. The resulted MGO@PNG-CD demonstrates high thermosensitive enantioselectivity toward L-Trp over D-Trp based on the chiral discrimination ability of β-CD toward L-Trp and the thermosensitive volume phase transition of PNIPAM chains. Operating temperature and initial concentrations of DL-Trp are two significant factors affecting the separation efficiency of DL-Trp enantiomers. Moreover, the MGO@PNG-CD also displays satisfactory recycling and convenient magnetic separability from enantiomeric solution. Such a multifunctional graphene oxide nanocomposite developed in this study can serve as a high-performance nanoselector for highly efficient chiral recognition and enantioseparation of various chiral compounds.

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A novel type of multifunctional magnetic nanoparticle with highly chiral recognition capability, excellent thermo-sensitive adsorption and decomplexation properties toward amino acid enantiomers, and recyclability was developed in this study.

Co-solute significantly enhanced the sorption affinity of phenanthrene and iodine by bacterial biomass.