Hi,you can do it before and after to compare you result, by filtration you can recover you simple after adsorption

To know the dye removal capacity, the surface area along with pore sizes and volumes need to be judged in the beginning. After dye removal experiment, the materials surface can be compared to the initial structure of the porous materials.

to: Tayyaba Waheed

Of course you can first perform the nitrogen adsorption/desorption test in order to find surface area or pore size of your sample before the dye removal test. For low quantity please be careful about any possible pour-out when filling and emptying the test cell or box. Recovery of nitrogen is normally achieved through vacuum in high temperature in a night-long period in vacuum oven. One more thing is always carrying your sample in a closed cell in order to avoid humidification. In case of weighing finish it as soon as possible.

For more detailed information about characterization test you are referred to the following publications:

1.

Article Extra-Framework Charge and Impurities Effect, Grand Canonica...

2.

Article Molecular Simulation, Experiments and Modeling of Single Ads...

3.

http://jpst.ripi.ir/article_953.html

4.

https://pubs.acs.org/doi/abs/10.1021/acs.jced.9b00204

thank you so much for your informative replies