Preparation of Grafted Sodium Alginate/Sodium p‐Styrenesulfonate Fibrous Foams for Efficient Cationic Dye Adsorption

ABSTRACT The chemical modification of natural polysaccharides is an effective way to synthesise high‐performance adsorbents to deal with complex wastewater. Herein, by means of graft copolymerization of sodium alginate and sodium p‐styrenesulfonate combined with thermally induced phase separation technology, a foam with both abundant negative charge sites and a 3D porous and fibrous structure was constructed, realizing efficient adsorption of cationic dyes. The adsorption capacity for crystal violet reached 807.1 mg/g, 2.55 times greater than that of the pure sodium alginate foam. The efficiency remained over 90% after 5 cycles. Moreover, the fibrous foams exhibited superior adsorption performance under alkaline conditions. The adsorption process was well described by the pseudo‐second‐order kinetic equation and conformed to the Langmuir isotherm, suggesting that the uptake was primarily governed by chemical interactions. The thermodynamic results demonstrated that the dye adsorption was spontaneous. This work introduces a valuable approach for enhancing the adsorption performance of natural polysaccharide‐based materials, offering great potential in the treatment of dye‐contaminated wastewater.