Micro-mesoporous divinyl benzene-based polymer for ultrafast, effective and selective removal of cationic dyes

Abstract

Poly(divinyl benzene-co-maleic anhydride) (PDVB-MAH) with hierarchically micro-mesoporous structure was fabricated by a facile sol-gel method, which was used as an adsorbent for the removal of cationic dyes including methylene blue (MB), rhodamine B (RhB), methyl violet (MV) and malachite green (MG) from wastewater. The resulting PDVB-MAH possessed micro-mesoporous structure with the surface area of 209 m2 g−1, which could facilitate the mass transfer process. The effects of pH (2–10), adsorbent dosage (0.2–2.0 g L−1), contact time, salt concentrations (0.1–0.6 mol L−1), initial concentrations (50–600 mg L−1) of dyes and temperature (298, 308 and 318 K) on the adsorption performance were investigated. The selective adsorption for cationic dyes was rapid and quantitative where removal efficiencies of 100% were obtained for MB and RhB within 5 and 15 min, respectively. The adsorption capacities of PDVB-MAH were 315.9 mg g−1 and 420.4 mg g−1 for MB and RhB, respectively. The adsorption behaviors on MB and RhB were accordance with the pseudo-second-order model and Sips model. The estimated thermodynamic parameters indicated the adsorption process was spontaneous and exothermic. Furthermore, the synergistic effect of π–π stacking interaction and electrostatic attraction was confirmed with the help of FTIR spectroscopy and DFT method. These results demonstrated that the PDVB-MAH could be a potential polymeric adsorbent with efficient dye removal from colored wastewater.