A selenium nanozyme: Light/mercury dual-enhanced oxidase mimicry for simultaneous ultra-sensitive detection and efficient removal of mercury ions, and superior photocatalytic bacterial disinfection

Abstract

Wastewater from aquatic product processing, often laden with heavy metals like Hg²⁺ and organic waste that promotes harmful bacterial proliferation, poses substantial environmental and public health risks if left untreated. This study introduces a novel gallic acid-modified chitosan stabilized selenium nanoparticle (GA-CS@SeNPs) capable of simultaneously detecting and removing Hg²⁺ while eradicating harmful bacteria. GA-CS@SeNPs exhibit light-stimulated and light/Hg²⁺ dual-enhanced oxidase-like activity, with a remarkable adsorption capacity of 1895.8 mg g⁻¹. This nanomaterial enables rapid and ultrasensitive detection of Hg²⁺, achieving a detection limit as low as 1.3 nM, a broad detection range (5-700 nM), and a swift response time (≤ 1 min) under light irradiation (420 nm). Furthermore, GA-CS@SeNPs demonstrate excellent selectivity (K_d =6.0 × 10⁵ mL g⁻¹), fast kinetics (k₂=2.79×10⁻³ mg g⁻¹ min⁻¹), and a broad working pH range (4-10). In addition to its Hg²⁺ removal efficiency, the material also displays potent photocatalytic antimicrobial and antibiofilm activity. This multi-functionality makes GA-CS@SeNPs a highly promising candidate for treating wastewater from aquatic product processing, offering both efficient heavy metal remediation and superior photocatalytic bacterial disinfection. The multifunctional attributes of GA-CS@SeNPs highlight its potential for future applications in environmental remediation.

Keywords: Detection; Mercury; Nanozymes; Photocatalytic bacterial disinfection; Removal; Selenium nanoparticles.