Formation and Phase Selection of CaCO3 in the Intervention of Lignin Monomer Model Compounds

The single crystal form and uncontrollable topography of CaCO 3 in nature severely restrict its product grade and application. Meanwhile, lignin is still not utilized efficiently. In order to improve this, three types of lignin monomer model compounds as p -coumaric acid (PCA), ferulic acid (FA), and sinapic acid (SA) are employed to induce the growth of CaCO 3 to investigate the relationship between lignin structure and CaCO 3 crystallization. The synthesized PCA and CaCO 3 composite crystals (PC-ACCs), FA and CaCO 3 composite crystals (F-ACCs), and SA and CaCO 3 composite crystals (S-ACCs) are characterized by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and Fourier transmission infrared spectroscopy (FTIR) to ascertain their molecular structures and crystal information. The growth rule of the acid and CaCO 3 composite crystals (ACCs) induced by the three units is also explored. The results show that the vaterite and calcite of ACCs can be formed selectively. In the presence of PCA, FA, and SA, pH is the key factor on the phase selection of ACCs. The temperature and organic acid type also play important roles on the formation of CaCO 3 . The ACCs present distinguishing surface topographies at different temperatures. The number of methoxyl in the PCA, FA, and SA decides the phase ratio of vaterite and calcite in the ACCs.