Adsorption of dichromate ions from aqueous solution onto magnetic graphene oxide modified by β-cyclodextrin.

In this work, the β-cyclodextrin modified magnetic graphene oxide (β-CD/MGO) composite was fabricated by the in situ co-precipitation method and characterized by Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM), and particle size analysis. The adsorption behavior of dichromate ions on the β-CD/MGO was investigated, and the mechanism of adsorption was also studied using FT-IR and XPS. The results from SEM and TEM showed that the graphene oxide (GO) layer became rough, and many fine particles were attached after compounding with ferroferric oxide and β-cyclodextrin. The characterization results of FT-IR and XPS show that that β-cyclodextrin and ferroferric oxide have been perfectly compounded to the graphene oxide layer and β-CD/MGO has a particle size of about 460 nm, a specific surface area of 252.3 mg, and a saturation magnetization of 73.5 emu g. The adsorption amount of dichromate ions on the β-CD/MGO is affected by pH, adsorbent dosage, and adsorption time. Kinetic studies showed that the adsorption process followed a pseudo-second-order kinetic model. Equilibrium data agreed very well with the Langmuir model, the maximum adsorption amount of dichromate ions on the β-CD/MGO was 49.95 mg g. After five successive adsorbent reuses, the reuse rate is still 73%, indicating the excellent potential reusability of β-CD/MGO adsorbent. β-CD/MGO exhibits excellent adsorption performance for dichromate ions. As an environmentally friendly magnetic adsorbent, β-CD/MGO is suitable for the treatment of dichromate-containing wastewater.