흑액에서 응집제 처리를 이용한 리그닌의 분리 및 특성

Inorganic acids are mainly used to isolate lignin from black liquor. This study was conducted to isolate lignin from black liquor using coagulants instead of inorganic acids. The coagulants used in this study are aluminum sulfate (alum), poly aluminum chloride (PAC), and anion polyacrylamide (A-PAM). It is found that when the pH of the coagulant is low, more lignin can be precipitated when alum and PAC are used in a 1:1 mass ratio. An elemental analysis, inductively coupled plasma mass spectroscopy (ICP-MS) analysis, gel permeation chromatography, phosphorus-31 nuclear magnetic resonance spectroscopy (31P-NMR), thermogravimetric analysis (TGA), and Fourier-transform infrared spectroscopy (FT-IR) analysis were performed on Alum-5 (lignin isolated by reducing the pH of black liquor to 5 with alum), A:P(2:1)-4 (lignin isolated by lowering the pH of black liquor to 4 using alum and PAC at a 2:1 mass ratio), and A:P(1:1)-4 (lignin isolated by lowering the pH of black liquor to 4 using alum and PAC at a 1:1 mass ratio). There are no significant differences in the properties of Alum-5, A:P(2:1)-4, and A:P(1:1)-4. Compared with KL (lignin isolated by reducing the pH of black liquor to 2 using hydrochloric acid), the lignin samples isolated with the aforementioned coagulants have high aluminum contents, average molecular weights and hydroxyl contents, and low polydispersity indices (PDIs). KCI Citation Count: 0