Structural features of polymer adsorbent LiChrolut EN and interfacial behavior of water and water/organic mixtures

The structural and adsorption characteristics of polymer adsorbent LiChrolut EN and the behavior of adsorbed water and water/organic mixtures were studied using adsorption, microcalorimetry, transmission and scanning electron microscopy, mass spectrometry, infrared spectroscopy, 1H NMR spectroscopy with layer-by-layer freezing-out of liquids (190–273 K), and thermally stimulated depolarization current method (90–265 K). This adsorbent is characterized by large specific surface area (∼1500 m2/g) and pore volume (0.83 cm3/g) with a major contribution of narrow pores (R<10 nmR<10 nm) of a complicated shape (long hysteresis loop is in nitrogen adsorption–desorption isotherm). The adsorbent includes aromatic and aliphatic structures and oxygen-containing functionalities and can effectively adsorb organics and water/organic mixtures. On co-adsorption of water and organics (dimethyl sulfoxide, chloroform, methane), there is a weak influence of one on another adsorbate due to their poor mixing in pores. Weakly polar chloroform displaces a fraction of water from narrow pores. These effects can explain high efficiency of the adsorbent in solid-phase extraction of organics from aqueous solutions. The influence of structural features of several carbon and polymer adsorbents on adsorbed nitrogen, water and water/organics is compared on the basis of the adsorption and 1H NMR data.

Graphical abstractStructural features of polymer adsorbent LiChrolut EN differently influence the behavior of water and water/organic mixtures confined in micropores and mesopores.Figure optionsDownload full-size imageDownload as PowerPoint slide