$(1$pt$)$ What is a breakthrough curve and what is the breakthrough time?

$(2$pts$)$ Suppose you make a porous bed with a material that adsorbs CO$2$ selectively over N$2.$ If you want to make the $CO2$ breakthrough time longer, would you increase or decrease the following factors? $1)$ Velocity at which the gas mixture $($hence the $CO2)$ is flown through the bed, $2)$ Diffusion rate of $CO2$ into the porous pellets, $3)$ Selectivity of the material for $CO2,4$ adsorption capacity of the material, $5)$ Pressure, $6)$ Temperature.