Calix[4]arene-clicked clay through thiol-yne addition for the molecular recognition and removal of Cd(II) from wastewater

Abstract

A novel type of hybrid Clay/Calix[4]arene (denoted as B-S-Calix), was prepared through fast photo-induced radical-mediated thiol–yne addition between a thiolated clay and an alkynylated calix[4]arene. The photo-induced radical-mediated thiol-yne reaction is a smart, low-cost, efficient, and fast pathway for tailoring low cost, reactive, and functional clay-based materials for potential wastewater treatment applications. The obtained materials were analyzed using X-ray photoelectron spectrometry (XPS), Fourier transform infrared spectroscopy (FTIR), and proton nuclear magnetic resonance spectroscopy (HNMR), which all displayed the successful formation of B-S-Calix. The as-synthesized B-S-Calix was used as an adsorbent for toxic Cd(II) metal from wastewater compared to mercaptosilanized bentonite (B-S) at room temperature. The adsorption of Cd(II) on B-S-Calix followed Langmuir isotherm models and pseudo-second-order kinetic, with a maximum removal efficiency of (92.8%) and adsorption capacity of 114 mg g−1 within only 1.5 min at pH 8 and room temperature. The presented B-S-Calix may serve as good candidates for emergent wastewater applications.