Potential Applications of Cucurbit[n]urils and Their Derivatives in the Capture of Hazardous Chemicals

Cucurbit[n]urils (Q[n]s) are a relatively young family of macrocycles, consisting of glycoluril units bridged by methylene groups, and their unique structures have attracted extensive attention from chemists in recent decades. Due to the presence of a rigid hydrophobic inner cavity and two polar outer portals lined with carbonyl groups, Q[n]s not only encapsulate guest species into the cavity, but also coordinate with metal ions/clusters. Considerable achievements have been obtained in the fields of Q[n]s-based host-guest chemistry, coordination chemistry, as well as the combination of host-guest and coordination chemistry. Furthermore, the outer surface of Q[n]s has been demonstrated to be capable of interacting with definite species to generate supramolecular architectures in recent years. With more in-depth research into Q[n]s, their application studies have also emerged as a hot topic. This Minireview focuses on recent advances in the potential applications of solid-state materials based on Q[n]s and their derivatives for the capture and adsorption of hazardous chemicals from a solution or a gas mixture.

Environmentally friendly synthesis of Fe2O3@SiO2 nanocomposite: characterization and application as an adsorbent to aniline removal from aqueous solution

Silica-based nanocomposite syntheses employ many harmful substances, which, in turn, demand the development of new synthetic environmental-friendly routes that meet the principles of green chemistry. In this work, we present a novel magnetic adsorbent, Fe₂O₃@SiO₂ nanocomposite (Fe@SiNp), successfully obtained without surfactant, employing an electrochemical method. We characterized the nanocomposite and then applied it to remove aniline from the water medium. Characterization was carried out by vibrating-sample magnetometry (VSM), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FT-IR). The parameters to the adsorptive removal of aniline were successfully optimized, which made possible to remove 71.04 ± 0.06% (126.6 ± 2.0 mg/g) from a 100 mg/L aniline solution at pH 6 and 323 K, by employing around 50 mg of Fe@SiNp, at a contact time of 40 min. The adsorption of aniline by Fe@SiNp is a spontaneous and exothermic process according to the pseudo-second-order kinetic model (r² = 1 at 20 mg/L aniline concentration) and the Freundlich isotherm model (r² = 0.9986).

Supramolecular chemistry of substituted cucurbit[n]urils

This review covers important advances in the field of substituted cucurbit[n]urils.