Advanced Adsorption Mechanisms of Copper Ions in Wastewater Utilizing a Tailored COF-MWCNTs Nanocomposite: A...

The persistent contamination of water by toxic heavy metals threatens the environment and public health. Herein, a covalent organic framework-multiwalled carbon nanotube (30 wt % COF-70 wt % MWCNTs) nanocomposite was synthesized via a modulator-solvent-induced polymerization method for efficient Cu²⁺ removal from wastewater. X-ray diffraction (XRD), scanning electron microscopy/transmission electron microscopy (SEM/TEM), S _BET, and spectroscopic characterizations confirmed the successful integration of the porous COF with conductive MWCNTs, providing accessible active sites and enhanced surface properties. Batch adsorption experiments revealed rapid uptake, reaching equilibrium within 120 min with optimal performance at pH 3.0. The maximum adsorption capacity reached 55.6 mg/g, and the adsorption increased with temperature, indicating an endothermic process. The pseudo-second-order kinetic model and the Freundlich isotherm model have adequately described the adsorption process of Cu²⁺ ions, suggesting that chemisorption was the predominant mechanism for these ions' adsorption. The nanocomposite maintained stable performance over five cycles without significant capacity loss. These results demonstrate the synergistic effect of COF porosity and MWCNTs conductivity, highlighting the nanocomposite as a robust and reusable adsorbent for wastewater remediation. The observed optical properties (band gap of 1.6 eV and suppressed PL) suggest potential for future photocatalytic applications, although such studies are beyond the scope of this work.