A facile dip-coating method for the preparation of separable MoS2 sponges and their high-efficient adsorption behaviors of Rhodamine B

Abstract

Molybdenum disulfide (MoS₂) nanoflowers synthesized by a hydrothermal route were successfully grafted on a melamine-formaldehyde sponge through a facile dip-coating method to form MoS₂ nanoflowers sponges. The MoS₂ sponges exhibited high-efficient adsorption performance to cationic dye, Rhodamine B (RhB), with a maximum adsorption capacity of 104.78 mg RhB g⁻¹ product (equal to 213.84 mg RhB g⁻¹ MoS₂ by conversion) within 60 min, which was primarily attributed to the strong electrostatic interactions between electronegative MoS₂ nanoflowers and positively charged RhB molecules. The equilibrium adsorption and kinetics data fitted well with the Sips isotherm model and the pseudo-second-order kinetic model, respectively. The recyclability experiments showed that the MoS₂ sponge adsorbent could be reused for 10 times with above 86.7% of the adsorption capacity retained. More remarkably, the as-prepared sponge adsorbent can be separated from the dye solution easily through a simple salvage instead of any tedious centrifugation or filtration processes. Thus, the separable MoS₂ sponge adsorbent with remarkable adsorption capacity and excellent reusability for organic dyes shows promise for large scale water remediation in the future.