A high-capacity malleable cellulose aerogel with layered double hydroxide decorating ZIF-8 for efficient adsorption of ciprofloxacin

The misuse of ciprofloxacin (CIP) poses significant risks to our ecosystems by causing serious environmental pollution and the development of antibiotic-resistant bacteria, which requires effective remediation technologies. Herein, we developed a composite material (CMC/CoNiFe-LDH/ZIF-8, abbreviated as CLZ) of loading layered double hydroxide (CoNiFe-LDH) decorating zeolitic imidazolate framework (ZIF-8) on the carboxymethylcellulose sodium (CMC) aerogel as an adsorbent for CIP removal. The CMC aerogel in the composite provided a porous structure as the growth template of CoNiFe-LDH, while CoNiFe-LDH provided growing points for ZIF-8, and ZIF-8 could be used as a carrier for loading CIP, resulting in a high adsorption property of CLZ with optimized mass ratios of CMC/CoNiFe-LDH aerogels and ZIF-8 at 5:1 (denoted as CLZ-1). The adsorption process of CLZ-1 followed the pseudo-second-order kinetic model and Langmuir isotherm model, and the maximum capacity of CLZ-1 to adsorb CIP was 1397.5 mg·g−1. The results of characterization, data fitting and parameter revealed that strong hydrogen bonding, complexation of unsaturated metals, electrostatic interaction, and π–π stacking between CLZ-1 and CIP were the main mechanisms for CIP adsorption. In addition, the CLZ-1 was successfully used as a solid phase extraction material combined with high performance liquid chromatography (HPLC) for the detection of CIP. Meanwhile, the CLZ-1 adsorbed CIP showed excellent antibacterial activity. Hence, CLZ-1 demonstrated great potential and promising practicability in separation and removal of antibiotic contaminants.