0 votes
32 views
in Surface Chemistry by (138k points)
What is the surface area of a sample of activated charcoal determined by gas adsorption using the BET method? Calculate the surface area of the activated charcoal sample given its mass, pore volume, and the adsorption isotherm data.

1 Answer

0 votes
by (138k points)
To calculate the surface area of an activated charcoal sample using the BET  Brunauer-Emmett-Teller  method, we need the following information:1. Adsorption isotherm data: This includes the equilibrium gas pressure  P  and the amount of gas adsorbed  n  at each pressure point.2. Mass of the activated charcoal sample  m 3. Pore volume of the activated charcoal sample  V_pore 4. Cross-sectional area of the adsorbed gas molecule  A_gas The BET equation is given by:n /  P0 - P  = 1 /  n_m * C  + [ C - 1  * P /  P0 * n_m * C ]where:n = amount of gas adsorbed at pressure PP0 = saturation pressure of the adsorptiveP = equilibrium pressuren_m = monolayer capacityC = BET constantTo calculate the surface area, follow these steps:1. Plot the BET plot using the adsorption isotherm data, which is a plot of [n /  P0 - P ] versus [P / P0].2. Perform a linear regression on the BET plot to obtain the slope  S  and y-intercept  I  of the linear portion of the plot.3. Calculate the monolayer capacity  n_m  and BET constant  C  using the slope and y-intercept:n_m = 1 / [ S / I  - 1]C = 1 + [ S / I ]4. Calculate the surface area  A  of the activated charcoal sample using the following equation:A =  n_m * m * A_gas  / N_Awhere:A_gas = cross-sectional area of the adsorbed gas molecule  e.g., 0.162 nm for nitrogen N_A = Avogadro's number  6.022 x 10 molecules/mol 5. If needed, you can also calculate the specific surface area  SSA  by dividing the surface area  A  by the mass of the activated charcoal sample  m :SSA = A / mPlease note that without the specific adsorption isotherm data, mass, and pore volume, it is not possible to provide a numerical answer. However, you can use the steps and equations provided above to calculate the surface area once you have the required information.

Related questions

Welcome to Sarvan Science Q&A, where you can ask questions and receive answers from other members of the community.
...