School of Environmental Science and Engineering, Tianjin University/Tianjin Key Lab of Biomass/Wastes Utilization, Tianjin, 300072, PR China.
School of Environmental Science and Engineering, Tianjin University/Tianjin Key Lab of Biomass/Wastes Utilization, Tianjin, 300072, PR China.
Environ Res. 2021 Nov;202:111687. doi: 10.1016/j.envres.2021.111687. Epub 2021 Jul 15.
Fungi residue, vinasse, and biogas residue differ from general biomass waste due to natural microbial action. Microbial fermentation helps create natural channels for the permeation of activators and produces proteins for natural nitrogen doping. Inspired by these advantages on porous carbon synthesis, this study adopted dual activators of KOH and KHCO to synthesize porous carbon with different pore ratios for efficient adsorption of volatile organic compounds (VOCs). The fungi residue possessed the least lignin due to the most severe microbial action, contributing to the best pore structures after activation. The etching effect from potassium compounds and gas foaming from the carbonate decomposition contributed to creating hierarchical porous carbon with ultra-high surface area, ca. 1536.8-2326.5 m/g. However, KHCO addition also caused nitrogen erosion, such that lower adsorption capacity was attained even with a higher surface area when the mass ratio of KOH/KHCO decreased from 2.5:0.5 to 2:1. The maximum adsorption capacities of chlorobenzene (CB) and benzene (PhH) reached 594.0 and 394.3 mg/g, respectively. Pore structure variations after adsorption were evaluated by freeze treatment to discover the adsorption mechanism. The surface area after CB and PhH adsorption decreased 40.3% and 34.5%, respectively. Most of the mesopores might transform into micropores due to the mono/multilayer stacking of adsorbates. The VOC adsorption kinetics were simulated by the Pseudo-first- and -second-order models and Y-N model. This paper provides a new approach for high-value biomass waste utilization after microbial action to synthesize efficient adsorbents for VOCs.
真菌残渣、酒糟和沼气残渣与一般生物质废物不同，因为它们受到自然微生物的作用。微生物发酵有助于为活性剂的渗透创造自然通道，并产生用于自然氮掺杂的蛋白质。受此启发，本研究采用 KOH 和 KHCO3 双重活性剂，合成具有不同孔比的多孔碳，以有效吸附挥发性有机化合物（VOCs）。由于受到最严重的微生物作用，真菌残渣中的木质素含量最少，因此在活化后具有最佳的孔结构。钾化合物的刻蚀效应和碳酸盐分解产生的气体发泡有助于形成具有超高比表面积（约 1536.8-2326.5 m/g）的分级多孔碳。然而，KHCO3 的添加也会导致氮侵蚀，因此即使具有更高的比表面积，当 KOH/KHCO3 的质量比从 2.5:0.5 降低到 2:1 时，吸附容量也会降低。氯苯（CB）和苯（PhH）的最大吸附容量分别达到 594.0 和 394.3 mg/g。通过冷冻处理评估吸附后孔结构的变化，以发现吸附机制。CB 和 PhH 吸附后的比表面积分别降低了 40.3%和 34.5%。由于吸附质的单/多层堆积，大部分中孔可能转化为微孔。通过拟一级和二级动力学模型和 Y-N 模型模拟了 VOC 吸附动力学。本文为微生物作用后高附加值生物质废物利用合成高效 VOC 吸附剂提供了一种新方法。
