Some considerations of the origins of porosity in carbons from chemically activated wood
Some considerations of the origins of porosity in carbons from chemically activated wood
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DOI：
10.1016/0008-6223(93)90071-h
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发表时间：
1993
期刊：
影响因子：
10.9
通讯作者：
M. Jagtoyen;F. Derbyshire
中科院分区：
文献类型：
--
作者：
M. Jagtoyen;F. Derbyshire
研究了白色橡木在650°C以下与磷酸反应生成活性炭的过程。在低温下，与酸的反应促进脱水反应和生物聚合物的再分布。认为随后形成的交联导致高于约300°C的碳产率增加。通过光学显微镜的详细观察和尺寸变化的测量，首次建立了孔隙率起源和反应机制之间的联系。在初始收缩之后，该结构在250至450°C之间经历相当大的膨胀，这对应于高表面积的发展。在450°C以上，存在二次收缩和伴随的可接近孔隙度的损失。可以得出结论，孔隙率的发展是直接相关的保留和膨胀的细胞材料，这创造了一个广泛的表面吸附剂分子。这些结果可能与理解含有生物聚合物或改变的生物聚合物的其他生物质和煤前体的等效过程有关。
Investigations have been made of the conversion of white oak to activated carbons by reaction with phosphoric acid at temperatures up to 650°C. At low temperatures, reaction with the acid promotes dehydration reactions, and the redistribution of biopolymers. It is considered that the subsequent formation of crosslinks leads to an increase in carbon yield above about 300°C. Detailed observations by optical microscopy, and measurements of dimensional changes, have established for the first time a link between the origins of porosity and reaction mechanisms. Following an initial contraction, the structure undergoes considerable expansion between 250 and 450°C, which corresponds to the development of high surface area. Above 450°C, there is secondary contraction and an accompanying loss of accessible porosity. It is concluded that porosity development is directly related to the retention and dilation of cellular material, which creates an extensive surface accessible to adsorbent molecules. The results may be relevant to understanding equivalent processes with other biomass and coal precursors that contain biopolymers or altered biopolymers.