Institute of New Rural Development, School of Electronics and Information Engineering, Tongji University, Shanghai, 201804, China.
Shanghai Research Institute of Pollution Control and Ecological Safety, Tongji University, Shanghai, China.
Environ Sci Pollut Res Int. 2024 May;31(22):32800-32812. doi: 10.1007/s11356-024-33230-z. Epub 2024 Apr 25.
The highly stable biomass structure formed by cellulose, hemicellulose, and lignin results in incomplete conversion and carbonization under hydrothermal conditions. In this study, pretreated corn straw hydrochar (PCS-HC) was prepared using a low-temperature alkali/urea combination pretreatment method. The Mass loss rate of cellulose, hemicellulose, and lignin from pretreated biomass, as well as the effects of the pretreatment method on the physicochemical properties of PCS-HC and the adsorption performance of PCS-HC for alkaline dyes (rhodamine B and methylene blue), were investigated. The results showed that the low-temperature NaOH/urea pretreatment effectively disrupted the stable structure formed by cellulose, hemicellulose, and lignin. NaOH played a dominant role in solubilizing cellulose and the combination of low temperature and urea enhanced the ability of NaOH to remove cellulose, hemicellulose, and lignin. Compared to the untreated hydrochar, PCS-HC exhibited a rougher surface, a more abundant pore structure, and a larger specific surface area. The unpretreated hydrochar exhibited an adsorption capacity of 64.8% for rhodamine B and 66.32% for methylene blue. However, the removal of rhodamine B and methylene blue by PCS-BC increased to 89.12% and 90.71%, respectively, under the optimal pretreatment conditions. The PCS-HC exhibited a favorable adsorption capacity within the pH range of 6-9. However, the presence of co-existing anions such as Cl, SO, CO, and NO hindered the adsorption capacity of PCS-HC. Among these anions, CO exhibited the highest level of inhibition. Chemisorption, including complexation, electrostatic attraction, and hydrogen bonding, were the primary mechanism for dye adsorption by PCS-HC. This study provides an efficient method for utilizing agricultural waste and treating dye wastewater.
纤维素、半纤维素和木质素形成的高度稳定的生物质结构导致在水热条件下不完全转化和碳化。在这项研究中，使用低温碱/尿素组合预处理方法制备了预处理玉米秸秆水热炭（PCS-HC）。研究了预处理生物质中纤维素、半纤维素和木质素的质量损失率，以及预处理方法对 PCS-HC 的物理化学性质和 PCS-HC 对碱性染料（罗丹明 B 和亚甲基蓝）吸附性能的影响。结果表明，低温 NaOH/尿素预处理有效地破坏了纤维素、半纤维素和木质素形成的稳定结构。NaOH 主要起溶解纤维素的作用，低温和尿素的结合增强了 NaOH 去除纤维素、半纤维素和木质素的能力。与未经处理的水热炭相比，PCS-HC 具有更粗糙的表面、更丰富的孔结构和更大的比表面积。未经处理的水热炭对罗丹明 B 的吸附容量为 64.8%，对亚甲基蓝的吸附容量为 66.32%。然而，在最佳预处理条件下，PCS-BC 对罗丹明 B 和亚甲基蓝的去除率分别提高到 89.12%和 90.71%。PCS-HC 在 pH 值为 6-9 的范围内表现出良好的吸附能力。然而，共存的阴离子，如 Cl、SO、CO 和 NO，会抑制 PCS-HC 的吸附能力。在这些阴离子中，CO 的抑制作用最高。化学吸附，包括络合、静电吸引和氢键，是 PCS-HC 吸附染料的主要机制。本研究为利用农业废弃物和处理染料废水提供了一种有效的方法。
