Hierarchical Aramid Nanofibers/Carbon Nanotubes Composite Aerogel Engineered for High-Efficiency Tetracycline Hydrochloride Removal

To address the growing concern over tetracycline (TCH) pollution in aquatic systems, this study employed high-temperature, corrosion-resistant, and acid-base-resistant aramid nanofibers (ANF) as the substrate material. By integrating physical cross-linking combined with π-π conjugation, ANFs/CNT aerogels were prepared using sol-gel and freeze-drying methods with cost-effective and chemically stable multi-walled carbon nanotubes (CNT). The optimized composite, Ca@ANFs/CNT, was identified through systematic optimization of solid-phase ratios and salt solution coagulation baths. Critical environmental parameters governing TCH removal by Ca@ANFs/CNT were investigated. Experimental results demonstrated that Ca@ANFs/CNT attained a 94.6% TCH elimination efficiency for 20 mg/L TCH solution under ambient conditions, coupled with a maximum adsorption capacity of 104.18 mg/g. The material maintained superior stability and efficiency across a wide pH range of 5 ~ 11, exhibiting resilience against interference from ubiquitous anions (Cl⁻, SO₄²⁻) in water had minimal impact on its performance. Notably,‌ ‌elevated CO₃²⁻ concentrations and humic acid reduced reaction efficiency due to competitive adsorption and pH changes. Combined Kinetic and thermodynamic modeling established chemical adsorption as the rate-limiting mechanism. Characterization techniques such as FT-IR, XPS, and SEM elucidated that Ca²⁺ mediated chelation is the cornerstone of TCH sequestration, augmented by synergistic contributions from electrostatic attraction, hydrogen bonding, and π-π conjugation effects. Additionally, the material’s pore structure contributed to adsorption. This study advances the rational design of antibiotic-capturing materials by unraveling structure-function relationships ‌while demonstrating Ca@ANFs/CNT’s practical viability for real-world water purification.‌ These findings establish a paradigm for developing multifunctional adsorbents targeting emerging contaminants in aquatic systems.