酶促生物质前体改性对多孔炭孔隙结构与VOCs吸附性能的影响

Effects of enzymatic modification of biomass precursor on the pore structure and VOCs adsorption performance of porous carbon

  • 摘要: 针对传统热解法制备纤维素基多孔炭材料存在的孔隙结构单一、比表面积有限等问题,提出一种以纤维素酶发酵预处理结合KOH活化的协同造孔策略,用于制备高性能多孔炭材料,并探究其对挥发性有机物(VOCs)中乙酸丁酯的吸附性能。选用高结晶度纯纤维素与低结晶度甘蔗渣两种生物质前体,通过纤维素酶发酵进行预改性,随后经KOH活化制备多孔炭。系统考察了酶处理对生物质结晶度、微观形貌、孔隙结构及吸附性能的影响。结果表明:纤维素酶预处理效果显著依赖于生物质初始结晶度。对于高结晶度纯纤维素,酶处理虽未显著改变其结晶度(结晶度约为90%),但有效细化颗粒并松散结构,促进后续活化过程中极微孔的发育,极微孔体积由0.688 cm3/g增至0.989 cm3/g,乙酸丁酯吸附容量由685.4 mg/g提升至931.6 mg/g。而对于低结晶度甘蔗渣,酶处理导致其结晶度波动上升(从52.6%升至68.9%),并通过“生物蚀刻”作用在纤维表面引入孔洞与碎片化结构,极微孔体积由0.768 cm3/g增至0.926 cm3/g,吸附容量由756.3 mg/g提升至882.9 mg/g。多元线性回归分析进一步证实,极微孔体积是提升乙酸丁酯吸附性能的关键因素。

     

    Abstract: This study addresses the issues of uniform pore structure and limited specific surface area in cellulose-based porous carbon materials prepared by traditional pyrolysis methods. A synergistic pore-forming strategy combining cellulase fermentation pretreatment with KOH activation is proposed to fabricate high-performance porous carbon materials and investigate their adsorption performance for butyl acetate (a typical volatile organic compound, VOC). Two biomass precursors, namely highly crystalline pure cellulose and low-crystallinity sugarcane bagasse, were selected. Pretreatment modification was conducted via cellulase fermentation, followed by KOH activation to prepare porous carbon. The effects of enzymatic treatment on biomass crystallinity, microstructure, pore structure, and adsorption performance were systematically investigated. The results indicated that the efficacy of cellulase pretreatment significantly depended on the initial crystallinity of the biomass. For highly crystalline pure cellulose (crystallinity 90%), enzymatic treatment did not markedly alter its crystallinity. However, it effectively refined the particle size and made the structure looser, thereby promoting the development of supermicropores during subsequent activation. Specifically, the supermicropore volume increased from 0.688 cm3/g to 0.989 cm3/g, and the butyl acetate adsorption capacity increased from 685.4 mg/g to 931.6 mg/g. In contrast, for low-crystallinity sugarcane bagasse, enzymatic treatment led to a fluctuating increase in crystallinity (from 52.6% to 68.9%) and introduced pores and fragmented structures on the fiber surface through a "bio-etching" mechanism. Consequently, the supermicropore volume increased from 0.768 cm3/g to 0.926 cm3/g, and the adsorption capacity increased from 756.3 mg/g to 882.9 mg/g. Multiple linear regression analysis further confirmed that supermicropore volume was the key factor enhancing butyl acetate adsorption performance.

     

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