MOF@COF functionalized cotton fiber as a platform for high performance extraction and removal of bisphenols from water samples

In the present work, a novel composite CCF@UiO-66-NH₂@TpBD (CCF stands for carboxyl cotton fiber) was fabricated for the extraction and removal of BPs from aqueous samples. Both the UiO-66-NH₂ (MOF) and TpBD (COF) were immobilized on CCF through feasible layer-by-layer and Schiff base reaction, and characterized using field emission scanning electron microscopy (FESEM) equipped with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) techniques. The CCF@UiO-66-NH₂@TpBD was packed in pipette tip as micro-column to investigate the adsorption of BPs using a pipette tip solid-phase extraction (PT-SPE) method. Various parameters (sampling flow rate, sample pH, amount of adsorbent, ionic strength, methanol concentration, and flow rate of eluent) affecting the extraction efficiency were optimized. Based on strong π-π conjugation, hydrogen bonding, and hydrophobic interactions, the adsorbent exhibited good extraction and removal capability. A low limit of detection (0.16–0.75 ng/mL) and a high adsorption (4.3–5.6 mg/g) were obtained. Accordingly, the composite CCF@UiO-66-NH₂@TpBD material was shown to be a suitable adsorbent for the extraction and removal of BPs from aquatic samples due to excellent reusability, reproducibility, and high adsorption capacity.