Controlled epitaxial synthesis of copper silicate nanotube clusters featuring multiple active sites for superior antibiotic removal

Abstract

Self-assembled nanoclusters have emerged as promising functional materials for water decontamination. Herein, we developed unique flower-like copper silicate nanotube clusters (denoted as SepSiCu-24) through controlled epitaxial growth of silica nanofibers derived from natural sepiolite (Sep). The hierarchical hollow architecture of SepSiCu-24, incorporating well-distributed Cu(II) and Si-O- active sites, exhibits exceptional adsorption capacities for tetracycline (TC) (188.3 ± 7.8 mg/g, pH = 4, 303 K) and oxytetracycline (OTC) (217.6 ± 8.9 mg/g, pH = 6, 303 K). In complex water matrices including seawater and tap water, SepSiCu-24 outperforms commercial activated carbon at equivalent doses, achieving removal efficiency of >99 %. The nanocluster demonstrates broad-spectrum antimicrobial activity, with TC-loaded SepSiCu-24 achieving complete sterilization (100 % inhibition for each bacteria) through enhanced generation of reactive oxygen species (ROS). Combined DFT calculations and structural characterization reveal that the exceptional performance of SepSiCu-24 originates from: optimized mass transport efficiency through its porous architecture, and enhanced antibiotic affinity via synergistic Cu(II) coordination and nanoconfined pore adsorption. This multifunctional nanocluster, combining efficient pollutant removal with antimicrobial properties, presents a promising solution for antibiotic contamination in aquatic systems while demonstrating significant potential for practical wastewater treatment and antibacterial applications.