Naltrexone Removal from Aqueous Media by Multi-Walled Carbon Nanotubes

Background: Extensive researches with different techniques are being carried out for removal of pharmaceuticals from aqueous media. The aim of this study was to use multi-walled carbon nanotubes (MWCNTs) to remove naltrexone as a pollutant of the aquatic environment and to investigate the mechanism of absorption and factors affecting it. Methods: In this experimental study, different amounts of MWCNTs were added to different concentrations (۲۰۰ to ۴۰۰ mg/L) of naltrexone and adsorption at various conditions including temperature, pH, and time of adsorption was studied. Adsorption on multi-walled carbon nanotubes was adopted on isotherm model equations to estimate the adsorption mechanism. Results: Optimum conditions to remove ۹۰% of naltrexone from ۲۰ ml of its ۴۰۰mg/ml solution were at adsorbent amount of ۰.۱g and time of ۲۰ to ۳۰ minutes. Temperature and pH had no effect on adsorption in the examined ranges. The drug can be absorbed as one layer and according to the Langmuir isotherm, on carbon nanotubes. Conclusion: Naltrexone removal by MWCNTs, due to higher surface area and therefore more efficient adsorption properties, is more efficient than by activated carbon and requires no specific conditions in regard to pH, temperature, and concentration. Substances with similar structures, like morphine, compete with naltrexone on adsorption.

Keywords:

Naltrexone , MWCNTs , Removal , Aqueous Media