化学改性提高木质素水溶性及其对Zn^2＋的络合能力

Modification of lignin for improvement it's water-soluble property and ability to complex with Zn^(2+)

以生物炼制并通过酸沉淀获得的玉米芯工业碱木质素(L)为原料,经过酚化(PL)及酚化+羟甲基化(HPL)两种前处理,增加反应活性位点,再分别对前处理产物PL和HPL进行羧甲基化改性得到CMPL和CMHPL。以期通过化学改性增强木质素水溶性和对Zn^(2+)的络合能力,从而使改性木质素具有作为水溶性螯合微肥施用的价值,进一步运用红外、热重、荧光显微镜、元素、电位滴定分析方法对木质素和改性木质素的结构及化学性质进行了探究,结果表明:通过酚化和羟甲基化两步前处理再经羧甲基化改性可以显著提高木质素的水溶性和对Zn^(2+)的络合能力。

In this study, corn cob lignin（L） from biorefining followed by acid precipitation was pretreated to increase the reaction activity sites. Lignin was modified by phenolation to obtain PL and further treatment by hydroxymethylation to obtain HPL. Then the acquired PL and HPL were modified through carboxymethylation to synthesize CMPL and CMHPL, respectively. L, PL, HPL, CMPL and CMHPL were further characterized by FTIR and elemental analyses, and L and CMHPL were determined by thermogravimetric analysis. The microscopic states of L, CMPL and CMHPL dispersed in water were observed by using a fluorescence microscope. The acid-base properties and the complexation phenomenon between lignins and Zn^2＋ were further analyzed by using a potentiometric titrator. Results showed that CMHPL had the best water-soluble property and the strongest ability to complex with Zn^2＋.