One-step construction of silver–polyaniline nanocomposite modified multifunctional sponges for wastewater remediation: adsorption, catalysis and antimicrobial applications

Abstract

The escalating issue of industrial wastewater will result in the depletion of non-renewable resources and inflict significant damage on the ecological equilibrium, particularly in relation to wastewater containing dyes. To effectively remove refractory azo dyes from wastewater, silver–polyaniline modified polyvinyl alcohol sponges (Ag–PANI@PAS) with adsorption, catalytic degradation, and antibacterial properties were prepared via a one-step in situ polymerization and reduction method. Thanks to the three-dimensional porous structure and tunable surface properties, the fabricated Ag–PANI@PAS exhibited selective adsorption of anionic dyes, excellent capability for large-scale dye wastewater treatment with a maximum flux of 33.2 L m⁻³ s⁻¹ and improved recyclability performance. Remarkably, Ag–PANI@PAS not only successfully transferred dyes from wastewater, but additionally achieved rapid catalytic degradation of targets (with a kinetic constant k of 0.17 min⁻¹) and green regeneration of the adsorbent in one step, benefiting from the persulfate activation by polyaniline and the promotion of Ag NPs in electron transfer. Mechanistic investigations revealed that both free radical (SO₄˙⁻ and ˙OH) and non-radical (¹O₂ and electron transfer) pathways worked together for substrate degradation, which was confirmed through quenching tests, Raman spectroscopy and other techniques. Ag–PANI@PAS also demonstrated high removal capacity and high mineralization of organic pollutants in real aquatic environments, with a removal efficiency of COD up to 98.4%. Moreover, Ag–PANI@PAS exhibited a desirable synergistic photothermal antibacterial effect. Therefore, the as-prepared multifunctional sponges are promising for sustainable water remediation.