Adsorption performance of polyvinylpyrrolidone for phenols in oil

Effective separation of phenols in coal tar is essential for enhancing its application value. In this work, polyvinylpyrrolidone (PVP) was used as a sorbent in the separation of phenols in model oils; the adsorption performance of PVP towards o-cresol, m-cresol, p-cresol, 1-naphthol, and 2-naphthol was then comparatively investigated. The results indicate that PVP possesses high adsorption capacity towards the phenols; the maximum adsorbance of PVP towards m-cresol, p-cresol, 1-naphthol, and 2-naphthol is higher than 1000 mg/g. For the adsorption of phenols on PVP, H-bonds are formed between the Lewis basic sites (C=O and N) of PVP and the phenolic -OH group and the H-bonding intensity is influenced by the steric hindrance of phenols. Furthermore, PVP shows high adsorption selectivity; 2-naphthol can be adsorbed effectively on PVP even in the presence of benzofuran or quinoline. Moreover, PVP can be regenerated for recycling where phenols are recovered as well. As a result, PVP is a promising sorbent for the separation of phenols from the coal tar oil.