H3PW12O40/ZrO2催化降解酶解木质素及抗氧化性的研究

STUDY ON H3PW12O40/ZrO2-CATALYZED DEGRADATION OF CELLULOLYTIC ENZYME LIGNIN AND ITS ANTIOXIDANT ACTIVITY

采用浸渍法将H3PW12O40负载于ZrO2制备H3PW12O40/ZrO2,催化降解酶解木质素(CEL)。以扫描电子显微镜(SEM)、傅里叶变换红外光谱仪(FT-IR)、X-射线衍射(XRD)和比表面积测试法(BET)表征催化剂,以化学分析法、FT-IR、凝胶渗透色谱(GPC)等表征降解后酶解木质素,检测其抗氧化性能。结果表明:H3PW12O40均匀分散于ZrO2载体表面,且与载体表面羟基有较强的相互作用,H3PW12O40/ZrO2具备完整的Keggin结构。以H3PW12O40/ZrO2催化降解酶解木质素,较优工艺条件为时间6 h、温度60℃、木质素浓度5%、催化剂质量分数为25%,降解后酶解木质素重均分子量(Mw)与数均分子量(Mn)均降低,酚羟基和醇羟基分别提高143.76%和256.91%,抗氧化性能增强,且随浓度的增大而增强。

H3PW12O40/ZrO2 catalyst is prepared with tungstophosphoric acid(H3PW12O40)supported on ZrO2 by impregnation method for degradation of cellulolytic enzyme lignin(CEL).As-prepared catalyst is characterized by SEM,FT-IR,XRD and BET.H3PW12O40 was uniformly dispersed on the surface of ZrO2 carrier and has a strong interaction with hydroxyl groups on the carrier’s surface.H3PW12O40/ZrO2 remains a complete Keggin structure.Degradation of CEL catalyzed by H3PW12O40/ZrO2 is characterized by chemical analysis,FT-IR and GPC,and its antioxidant activity isdetected.The optimum condition for degradation of CEL by H3PW12O40/ZrO2 is 6 h and 60℃,lignin concentration 5%and catalyst mass fraction 25%.The weight-average molecular weight(Mw)and number-average molecular weight(Mn)of degraded CEL are decreased,the phenolic hydroxyl group and alcohol hydroxyl group of degraded CEL are increased by 143.76%and 256.91%,respectively.Attributed to this structure and the antioxidant activity of degraded CEL are improved with the increase of concentration.