Removal and adsorption of p -nitrophenol from aqueous solutions using carbon nanotubes and their composites

In an attempt to explore the possibility of using carbon nanotubes (CNTs) as efficient adsorbents for removal of pollutants from the contaminated water, the adsorption of p-nitrophenol (PNP) on raw multiwalled carbon nanotubes (r.MWNTs) with different outer diameters, various functionalized multiwalled carbon nanotubes (f-MWNTs), raw single-walled carbon nanotubes (r.SWNTs) and oxidized single-walled carbon nanotubes (ox-SWNTs) has been investigated. The ox-SWNTs showed better adsorption ability for PNP with different concentrations, while lower uptake capacity was found for all of the r.MWNTs and f-MWNTs. The removal efficiency of PNP by ox-SWNTs was around 98%, indicating that ox-SWNTs possess a great potential application prospect for removing PNP from aqueous solutions.