Adsorption Properties of Folic Acid onto Functionalized Carbon Nanotubes: Isotherms and Thermodynamics Studies

In the present research, we report the results of a systematic study on the adsorption properties of folic acid (FA) over functionalized single-walled carbon nanotubes (SWCNTs) using the various factors, such as adsorbent dose, contact time, temperature, and initial FA concentration. Our results reveal that SWCNT is an excellent adsorbent for folic acid, with an adsorption percentage of up to 76.2 % at initial folic acid concentration of 20 ppm and temperature of 298.15 K. Interpreting equilibrium isotherms on the basis of various adsorption models, including Freundlich and Langmuir, shows that the Langmuir model can describe the adsorption process better than the other one. To further examine the adsorption behavior, we perform thermodynamic calculations which indicate that the adsorption reaction of FA onto SWCNTs is an exothermic and spontaneous procedure in the temperature range of 298.15–313.15 K. Based on this experimental study, the functionalized SWCNTs are expected to be a potential efficient adsorbent and also can be used as a suitable drug delivery vehicle within biological systems.