催化剂对甘蔗渣碱木质素催化湿空气氧化降解的催化作用

摘要

In this paper, bagasse alkaline lignin was degraded by Catalytic Wet Air Oxidation (CWAO) with five different catalysts. The results showed that the main degradation products were; p-hydroxybenzaldehyde, vanillin, syringaldehyde, syringic acid, vanillic acid and acetosyringone. The concentration of aromatic substances increased when the reaction time increased. Catalysts had a significant effect on the concentration of aromatic substances. Using CO2O3 as catalyst, the concentration of vanillin, syringaldehyde and acetosyringone were 400.2 mg/L, 351.4 mg/L, and 248.7 mg/L respectively, and the concentration of vanillin increased 82.6% comparing to no catalyst was used. Using AQ as catalyst, the concentration of vanillin was 344. 9 mg/L which was 1. 5 times of that without using catalyst. Using Co2O3, CuSO4, MnO2, AQ, Fe2O3 as catalysts, the total concentrations of phenolic aldehyde compounds were 1696 mg/L, 1658 mg/L, 1584 mg/ L, 1347 mg/L and 1250 mg/L respectively,which explained that using Co2O3 as the catalyst was the best, and CuSO4 and MnO2 were the next, the catalysts of AQ and Fe2O3 only contributed to produce several kinds of phenolic aldehyde compounds with small molecules.%选取5种不同的催化剂对甘蔗渣碱木质素进行了催化湿空气氧化降解。结果表明，甘蔗渣碱木质素催化湿空气氧化降解的主要产物为对羟基苯甲醛、香草醛、丁香醛、丁香酸、香草酸和乙酰丁香酮；在实验条件下，反应时间对催化剂催化效果的影响较大，随着反应时间的延长，大部分小分子酚醛类化合物的浓度逐渐升高；使用催化剂能较大幅度地提高小分子酚醛类化合物的浓度。以Co2O3为催化剂，丁香醛、乙酰丁香酮、香草醛的浓度分别为400.2 mg/L、351.4 mg/L 248.7 mg/L，与未添加催化剂相比较，香草醛浓度提高了 82.6％；当以AQ为催化剂时，香草醛浓度为344.9mg/L，与空白样相比其浓度提高了1.5倍以上。在甘蔗渣碱木质素的催化湿空气氧化法降解过程中，以Co2O3、CuSO4、MnO2、AQ、Fe2O3作催化剂降解甘蔗渣碱木质素所得的酚醛类化合物总浓度分别为1696mg/L、1658 mg/L、1584mg/L、1347mg/L和1250 mg/L,实验选用的5种催化剂中，Co2O3催化效果最理想，CuSO4和MnO2次之，而AQ和Fe2O3仅对少量小分子酚醛类化合物的浓度贡献较大。