Study of reaction mechanism between guaiacol and Ca(OH)2 in water: Development of a novel phenol extraction method

Experiments were conducted to elucidate the mechanism of reaction between guaiacol and Ca(OH) 2 in water based on in situ FT-IR, 1 H NMR, ICP-AES and TGA analyses. Three phases were revealed for this reaction when guaiacol was dropped into the solution of Ca(OH) 2 , and the final molar ratio of guaiacol to Ca 2+ reaches 4. It was found that an acid–base reaction occurs in the first reaction phase. However, the second reaction phase includes not only the acid-base reaction, but also the accompanied coordination reaction between oxygen atom of hydroxyl group in guaiacol and Ca 2+ . The third reaction phase is also the coordination reaction, particularly, the one between the hydrogen atom in guaiacol and Ca 2+ . Based on the mechanism study, a novel circulating precipitation agent was developed and tested for the extraction of phenolic compounds from the simulated wastewater. The result showed that 96.63% guaiacol could be extracted from the simulated wastewater with the novel extraction technology at the optimum reaction conditions.