Use of a floating adsorbent to remove dyes from water: A novel efficient surface separation method

In this study, our group grafted 2-acrylamido-2-methylpropane sulfonic acid (AMPS) onto the surface of hollow glass microspheres (HGM) and successfully prepared AMPS grafted floating adsorbent (AFA). The prepared AFA carries a large amount of negative charges, and the adsorptions of cationic dyes are achieved under the action of strong electrostatic interaction. Furthermore, due to the unique shell structure of AFA, it has a stable self-floating ability, which may change the traditional separation method to make the adsorbent easier to enrich and separate from water surface. Characterizations of AFA by scanning electron microscope, energy dispersive spectrometry, X-ray photoelectron spectroscopy. Fourier transform infrared spectra, Brunauer-Emmett-Teller surface areas, thermogravimetric analysis, and X-ray diffractometer shows the successful grafting of AMPS. Adsorption experiments confirmed that the adsorption capacities of AFA for methylene blue, malachite green, basic fuchsin and crystal violet under optimum conditions were 436.8 mg g^-1, 637.6 mg g^-1, 457.8 mg g^-1, and 399.4 mg g^-1, respectively. At the same time, AFA has excellent recyclability, and its adsorption capacity can be maintained after 6 cycles of reuse.