A novel aminated Fe3O4/GO/carboxylated cross-linked β-CDP composite for effective sorption of cationic and anionic dyes from water

A novel adsorbent, aminated Fe3O4 (Fe3O4-NH2)/graphite oxide (GO)/carboxylated cross-linked β-cyclodextrin polymer (CDP-COOH) composite, was fabricated for influential removal of various types of dyes from waters. The morphology and structure of resulting Fe3O4-NH2/GO/CDP-COOH composite was studied by SEM, two-dimensional EDS map, FTIR, WAXD, XPS, TGA, and zeta potential meter, and its saturation magnetization was determined to be 46.3 emu/g by VSM. The maximal sorption capacities of Fe3O4-NH2/GO/CDP-COOH composite for methylene blue (MB, as a model of cationic dyes) and Congo red (CR, as a model of anionic dyes) at 303 K were 201.75 mg/g and 2211.05 mg/g, respectively, which can be mainly assigned to multiple adsorptive forces like electrostatic attractions, hydrogen bonds, host–guest self-assembly interactions, π-π electron cloud interactions, and Lewis acid-base interactions. The dye sorption by the Fe3O4-NH2/GO/CDP-COOH composite had a spontaneous nature according to the sorption thermodynamic calculation and can be well explained by pseudo-second-order model. The Langmuir and Freundlich models could explain the sorption isotherms of Fe3O4-NH2/GO/CDP-COOH composite for MB and GO, respectively. The Fe3O4-NH2/GO/CDP-COOH composite possessed many other advantages including the good sorption capability for different heavy metal ions (like Pb2+, Ni2+, and Cu2+) and organic compounds (like dichlorophenol and propranolol) as well as the good recyclability and reusability.