Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario, Canada M5S3E5.
Water Sci Technol. 2010;62(11):2637-46. doi: 10.2166/wst.2010.981.
The goal of this work is to establish the technical feasibility of producing activated carbon from pulp mill sludges. KOH chemical activation of four lignocellulosic biomass materials, two sludges from pulp mills, one sludge for a linerboard mill, and cow manure, were investigated experimentally, with a focus on the effects of KOH/biomass ratio (1/1, 1.5/1 and 2/1), activation temperature (400-600 °C) and activation time (1 to 2 h) on the development of porosity. The activation products were characterized for their physical and chemical properties using a surface area analyzer, scanning electron microscopy and Fourier transform infrared spectroscopy. Experiments were carried out to establish the effectiveness of the lignocellulosic biomass-derived activated carbon in removing methylene blue (MB), a surrogate of large organic molecules. The results show that the activated carbon are highly porous with specific surface area greater than 500 m²/g. The yield of activated carbon was greater than the percent of fixed carbon in the dry sludge, suggesting that the activation process was able to capture a substantial amount of carbon from the organic matter in the sludge. While 400 °C was too low, 600 °C was high enough to sustain a substantial rate of activation for linerboard sludge. The KOH/biomass ratio, activation temperature and time all play important roles in pore development and yield control, allowing optimization of the activation process. MB adsorption followed a Langmuir isotherm for all four activated carbon, although the adsorption capacity of NK-primary sludge-derived activated carbon was considerably lower than the rest, consistent with its lower specific surface area.
本工作旨在确定从纸浆厂污泥中生产活性炭的技术可行性。通过实验研究了 KOH 化学活化四种木质纤维素生物质材料，两种纸浆厂污泥、一种衬纸板厂污泥和牛粪，重点考察了 KOH/生物质比（1/1、1.5/1 和 2/1）、活化温度（400-600°C）和活化时间（1-2 小时）对孔隙发展的影响。使用比表面积分析仪、扫描电子显微镜和傅里叶变换红外光谱对活化产物的物理化学性质进行了表征。进行了实验以确定源自木质纤维素生物质的活性炭在去除亚甲基蓝（MB，大有机分子的替代品）方面的有效性。结果表明，所制备的活性炭具有高度多孔性，比表面积大于 500 m²/g。活性炭的产率大于干污泥中固定碳的百分比，表明活化过程能够从污泥中的有机物中捕获大量的碳。400°C 太低，而 600°C 足以维持衬纸板污泥的高活化速率。KOH/生物质比、活化温度和时间都在孔发展和产率控制中发挥重要作用，允许优化活化过程。所有四种活性炭的 MB 吸附均遵循 Langmuir 等温线，尽管 NK-初级污泥衍生的活性炭的吸附容量明显低于其他三种，这与其较低的比表面积一致。
