Nitrate removal from water using functionalized carbon nanotube sheets

Nitrogen-containing groups improve nitrate adsorption capacity of the O-CNT sheets. [Display omitted] ▸ Nitrate removal from water using functionalized CNT sheets was performed. ▸ Nitrogen-containing groups improve nitrate adsorption capacity of the O-CNT sheets. ▸ The results match well with the Langmuir and Freundlich isotherm models. Carbon nanotube (CNT) sheets were synthesized via chemical vapor deposition of cyclohexanol and ferrocene in nitrogen atmosphere at 750°C, functionalized using concentrated nitric acid and liquid ammonia and employed as adsorbents to study their nitrate adsorption characteristics. The results demonstrated that functionalization with nitrogen-containing groups improves nitrate adsorption capacity of the oxidized CNT sheets, significantly. Various isotherms and kinetic models were applied to fit the experimental data. Effects of contact time, initial nitrate concentration and adsorbent dosage were also investigated. Regeneration performance for the first time was also studied. For comparison, a similar study was performed with commercial activated carbon (AC). It was found out that the functionalized CNT sheets with higher nitrate adsorption capacity, shorter equilibrium time and better regeneration performance than AC, can be considered as potential adsorbents for nitrate removal from water in domestic applications.