Effect of Nitrogen Flow Rate

FIGURE 1.16 N2 adsorption isotherms for activated carbons prepared from an anthracite by chemical activation with KOH using different N2 flow rates during the heat treatment. Preparation conditions impregnation method KOH/anthracite 2/1 (weight) heating rate 5°C/min to 700°C soaking time 1 h (redrawn from Lozano-Castelld, D., Lillo-Rode-nas, M.A., Cazorla-Amoros, D., and Linares-Solano, A. Carbon 39(5) 741-749, 2001. With permission). 

From a practical point of view, of course, not only are the surface area and MPV of porous materials important but so is their pore size distribution. The value of the difference 2 CO2 (Table 1.6) suggests that the flow rate does 

The important finding here is that, contrary to the effect of hydroxide/anthra-cite ratio, an increase in N2 flow rate does not appreciably change the MPSD of the samples. Thus, a flow characteristic (N2 flow rate during the heat treatment process) opens anew way to prepare AC with both high adsorption capacity (high values of micropore volume and surface area) and narrow MPSD, which cannot be obtained by adjusting the other variables (i.e., hydroxide/carbon ratio, HTT, and soaking time). 

Effect of nitrogen flow rate on porous texture (KOH/anthracite 2/1, 5°C/min, 700°C, 1 h) 

FIGURE 1.17 MPSD calculated by applying the DPT method to the Nj adsorption data for samples prepared using different N2 flow rates. 

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