扩散
多孔性
化学工程
体积热力学
化学
扩散过程
材料科学
纳米技术
热力学
有机化学
知识管理
物理
创新扩散
工程类
计算机科学
作者
Jingjing Xiong,Guancong Jiang,Yu Qian,Liwen Mu,Xin Feng,Xiaohua Lü,Jiahua Zhu
标识
DOI:10.1016/j.susmat.2021.e00248
摘要
Physical activation of activated carbon (AC) is a pore-formation and pore-widening process via gasification, which involves gas diffusion and reaction in micro-channels. Existing efforts focus on the reaction part by optimizing reaction temperature, reactive species, type of mixing, etc. In this work, a cycling pressure-switching (CPS) process has been developed to expedite the gas transport between bulk gas phase and internal surface of particles. Specifically, intermittent vacuumization operation is introduced during activation, that is to create a negative system pressure to facilitate reactive gas (CO2) diffusion into porous channels for activation reaction and then extract product gas (CO) out of the pores through vaccumization. CPS accelerates the gas exchange and breaks the diffusion-reaction balance in traditional atmospheric pressure process. Thus, richer porous structure can be created in CPS process. By using spent mushroom substrate as precursor, AC with specific surface area of 1175 m2/g and pore volume of 0.52 cm3/g can be obtained after optimizing the cycle number, CO2 pressure and activation time. By investigating the effect of precursor size and bulk density on pore structure development, it is found that internal diffusion is the rate-limiting factor of AC activation that can be alleviated by the CPS process.
科研通智能强力驱动
Strongly Powered by AbleSci AI