Wide-Spectrum Dye Adsorption Performance of Alginic Acid Carbon Aerogel

Multifunctional adsorbents are significant for the treatment of water-soluble dyes in contaminated aquatic systems and oily dyes in colored organic effluents. However, the existing adsorbent for both water-soluble and oil-soluble dyes is rare and the cleanup effect is not ideal. In this study, alginic acid carbon aerogel (AACA) as an effective wide-spectrum adsorbent was prepared through wet-spinning, ion-exchanging, drying, and high-temperature carbonization. AACA obtained a specific surface area of 1046.0 m² g⁻¹ and a mean pore size of 2.82 nm. The adsorption capacities of AACA for methylene blue (cationic dye), methyl orange (anion dye), and oil red O (oil-soluble dye) were 493.5, 389.5, and 244.2 mg g⁻¹, respectively, which were improved in comparison with those of previously reported calcium alginate and ferric alginate carbon aerogels. The adsorption kinetics of AACA for the three dyes were fit for the pseudo-second-order kinetic model and the adsorption isotherms could be explained by the Langmuir model. ACCA revealed good adsorption performance for other eleven different sorts of dyes and binary dye systems. The adsorption mechanism was mainly confirmed to be π–π interactions.