Secondly: what should i consider as initial concentration (Co) ? is it the initial concentration of the solution in ppm or the initial absorbance of the solution? and what should be final concentration (ppm or Absorbance after adsorption)?
The amount of equilibrium adsorption, qe (mg /g), was calculated using the following equation
qe = (CO-Ce) V/m
The amount of sorption at time t, qt (mg/g), was calculated using the following equation:
qt = (CO-CT) V/m
Therefore, you should convert the Absorbance after adsorption (The measured value from you instrument A) to the corresponding conc in mg/l
This paper can be helpful: TArticle Opportunities and constraints of using the innovative adsorb...
It is always better to use the concentration, whether molar (mol/m3, SI) or mass (kg/m3, SI). If the absorbance is proportional to the concentration of the adsorbate, you can also use absorbance. You can calculate the values of qe and qt by definition. You will find it in every publication from this range. Finally, an advice: avoid graphical methods
Mirosław Grzesik Md. Aminul Islam Hossam A. Ghaly Thank you for your response. it is really helpful.