In Situ Synthesis of Bacterial Cellulose-Supported CoAl-Layered Double Hydroxide as a Peroxymonosulfate Activator for Enhancing the Removal of Tetracycline

This study employed the hydrothermal coprecipitation method to grow CoAl-layered double hydroxide (LDH) onto bacterial cellulose (BC) in situ, successfully preparing the CoAl-LDH@BC composite. This composite was then used to activate peroxymonosulfate (PMS) for tetracycline (TC) degradation. According to the results, the CoAl-LDH@BC/PMS system demonstrated a remarkable removal efficiency of 99.9% for TC within 15 min. Moreover, the influencing factors of catalyst dosage, PMS dosage, TC concentration, reaction temperature, initial pH, and inorganic ions were evaluated. Notably, the system demonstrated broad-spectrum contaminant removal capabilities, which could simultaneously eliminate more than 99.7% of oxytetracycline hydrochloride (TCH) and 87.9% of ciprofloxacin (CFX) within 20 min. Additionally, the removal rates for several dyes reached more than 95.7% in 20 min. Phytotoxicity assessment (using mung bean seeds) confirmed a significant reduction in the biotoxicity of post-treatment TC solutions. The identification of TC degradation intermediates was enabled, alongside the subsequent proposal of plausible degradation pathways. Furthermore, mechanistic investigations based on radical quenching experiments revealed the coexistence of dual radical (•OH and<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mrow><mo> </mo><mi>SO</mi></mrow><mrow><mn>4</mn></mrow><mrow><mo>−</mo></mrow></msubsup><mo>•</mo></mrow></semantics></math></inline-formula>) and non-radical (¹O₂) oxidation pathways in the reaction of the CoAl-LDH@BC/PMS system. Overall, this research broadens the potential applications of bacterial cellulose-based porous materials and provides an innovative insight into antibiotic wastewater treatment.