Oxygen and phosphorus enriched carbons from lignocellulosic material
Oxygen and phosphorus enriched carbons from lignocellulosic material
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DOI：
10.1016/j.carbon.2007.06.014
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发表时间：
2007-09
期刊：
影响因子：
10.9
通讯作者：
Alexander M Puziy;O. Poddubnaya;A. Martínez-Alonso;A. Castro-Muñiz;F. Suárez-García;J. Tascón
中科院分区：
文献类型：
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作者：
Alexander M Puziy;O. Poddubnaya;A. Martínez-Alonso;A. Castro-Muñiz;F. Suárez-García;J. Tascón
在400-1000°C的温度下，通过在空气中磷酸活化果核来制备活性炭。用元素分析、阳离子交换容量、红外光谱和电位滴定等方法对表面化学进行了研究。从吸附等温线（N2在77 K和CO2在273 K）分析了多孔结构。结果表明，所有碳都显示出相当大的阳离子交换能力，在700°C时达到最大值（2.2mmolg−1），这与磷和氧的最大含量相一致。在热处理期间使用空气代替氩气增加了在400-700°C下获得的碳的阳离子可交换表面基团的量。所有碳的质子亲合性分布显示存在三种类型的表面基团，其pK为1.8-3.1（羧酸和多磷酸盐）、4.8-6.3（羧酸的二次解离、多磷酸盐中的弱酸和烯醇结构）和8.1-9.7（酚和烯醇结构）。在400-600°C的空气中获得的碳在酸性溶液中对0.001molL−1Cu（NO3）2的铜吸附比在氩气中获得的碳增强。在空气中获得的碳显示出发达的多孔结构，其与在氩气中获得的碳相比是相等或更高的;随着处理温度的升高，差异逐渐增大。
Activated carbons were prepared by phosphoric acid activation of fruit stones in air at temperatures 400–1000°C. The surface chemistry was investigated by elemental analysis, cation exchange capacity, infrared spectroscopy and potentiometric titration. The porous structure was analyzed from adsorption isotherms (N2at 77K and CO2at 273K). It was demonstrated that all carbons show considerable cation exchange capacity, the maximum (2.2mmolg−1) being attained at 700°C, which coincides with the maximum contents of phosphorus and oxygen. The use of air instead of argon during thermal treatment increased the amount of cation exchangeable surface groups for carbons obtained at 400–700°C. Proton affinity distributions of all carbons show the presence of three types of surface groups with pK 1.8–3.1 (carboxylic and polyphosphates), 4.8–6.3 (second dissociation of carboxylic, weak acid in polyphosphates and enol structures) and 8.1–9.7 (phenols and enol structures). Carbons obtained in air at 400–600°C show enhanced copper adsorption from 0.001molL−1Cu(NO3)2in acidic solutions as compared to carbons obtained in argon. Carbons obtained in air show well-developed porous structure that is equivalent or higher as compared with carbons obtained in argon; the difference being progressively increased with increasing treatment temperature.