Synergistic adsorption-photocatalytic degradation of levofloxacin using Zn_1−xCu_xS-modified cellulose/chitosan sponge

Abstract

Antibiotics have revolutionized infectious disease management; however, their incomplete absorption and metabolism by humans lead to environmental discharge, posing severe threats to ecosystems. Levofloxacin (LEV), a typical broad-spectrum fluoroquinolone antibiotic, is highly resistant to microbial biodegradation in aqueous environments and poses a major threat to human health and ecological systems. This paper presents a facile and robust strategy for fabricating Zn_1−xCu_xS nanoparticle (NP)-decorated cellulose–chitosan composite sponges (denoted as ZnCuCCS). The synthetic route integrates hydrothermal xanthate decomposition and in situ deposition, producing a porous composite characterized by homogeneous Zn_1−xCu_xS NPs dispersion, strong Nanoparticle anchoring, and superior mechanical stability. Benefiting from the abundant adsorption sites provided by the polysaccharide sponge matrix and the high surface exposure of Zn_1−xCu_xS NPs, ZnCuCCS possesses a narrow bandgap (1.31 eV), which endows the composite with superior adsorption capability and prominent photocatalytic activity, achieving a LEV removal efficiency of up to 90.12%. Notably, ZnCuCCS maintains a stable degradation rate of 72.9% even after five consecutive reuse cycles. Systematic investigations of the adsorption–photocatalytic degradation behavior and intrinsic mechanism of LEV removal provide novel theoretical insights for the rational design and practical application of advanced photocatalytic materials in wastewater treatment.

Graphical abstract

Keywords

cellulose / chitosan / Zn_1−xCu_xS nanoparticles / levofloxacin removal / adsorption–photocatalytic degradation

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