ZnCl2络合法分离黑液木质素高效制备高吸附性能活性炭

Efficient Preparation of Activated Carbon with High Adsorption Capacity Using Lignin-Zn Complex from Black Liquor

中文关键词:  黑液  木质素-锌络合物  活性炭  染料吸附

Key Words:black liquor  lignin-Zn complex  activated carbon  dye adsorption

中文摘要:

      采用ZnCl₂络合的方式从黑液中分离出木质素并获得木质素-锌络合物，将其作为前驱体，经碳化高效制备高吸附性能活性炭（CAC）。结果表明，经ZnCl₂络合（0.5 mol/L ZnCl₂，0.6 mL/mL黑液）后，黑液中分离出89.5%的木质素，络合处理后黑液的COD_Cr值降低72.4%，pH值呈中性。同时，金属络合作用使得锌离子均匀分布在木质素-锌络合物中，有助于碳化过程中多孔结构的均匀分布。与传统酸析木质素浸渍工艺相比，木质素-锌络合物碳化法制备的活性炭具有更高的比表面积和吸附量。所制备的CAC活性炭对阳离子亚甲基蓝和阴离子甲基橙的最大平衡吸附量分别为1046.8和263.6 mg/g，优于大多数研究报道制备的吸附剂的吸附量。

Abstract:

      Lignin-Zn complex isolated from black liquor by ZnCl₂ complexation was used as the carbon precursor to prepare activated carbon with high adsorption performance. The results showed that after ZnCl₂ complexation （0.5 mol/L ZnCl₂， 0.6 mL/mL black liquor）， 89.5% of lignin in black liquor was isolated accompanied with COD_Cr reduction of 72.4% and neutral pH value for the treated black liquor. Meanwhile， the metal complexation rendered Zn²⁺ distributing evenly in the lignin-Zn complex， facilitating the well-proportioned formation of porous structure during carbonization process. The activated carbon prepared from lignin-Zn complex had higher specific surface area and adsorption capacity， compared with the conventional process of acid-precipitated lignin by impregnation. Moreover， maximum equilibrium adsorption capacities of the as-prepared activated carbon were 1046.8 mg/g and 263.6 mg/g for cationic methylene blue and anionic methyl orange， respectively， which were higher than those absorbents prepared in previous reports.