Fabrication of novel covalently-coupled graphene oxide-per-6-amino-β-cyclodextrin composite with abundant active oxygen- and nitrogen-containing sites for azo dyes removal

The presence of diverse pollutants in wastewater highlights critical opportunities and urgent needs to develop effective strategies and technologies for their removal. In the present study, a novel composite of per-6-amino-β-cyclodextrin (PACD) covalently modified graphene oxide (GO) was fabricated by a facile one-step procedure. The morphologies, composition and bonding modes of GO-PACD composite were investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermalgravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and specific surface analysis by the Brunauer-Emmett-Teller (BET) method. The prepared GO-PACD composite was used as an efficient adsorbent for the removal of azo dyes (alizarin yellow R) from colored wastewater. The maximum adsorption capacity of GO-PACD was 130.92 mg g −1 at 298 K. The influencing factors such as contact time, solution pH, initial dye concentration and temperature were investigated and optimized by a batch adsorption experiment. Adsorption kinetics, isotherms and thermodynamics were also investigated to reveal the possible adsorbent-adsorbate mechanisms. GO-PACD composite could be regenerated by a facile acid-soaking process. The results showed that the GO-PACD composite exhibited high stability and excellent reusability during 10 cycles of consecutive loading and regeneration. In summary, the developed GO-PACD composite is highly-efficient, regenerable, stable and facile-to-synthesize, making it be a potential candidate for azo dyes removal by adsorption.