Abstract:Multiwall carbon nanotubes (MWCNTs) were chemically modified to yield products that remove selective pollutants from wastewater stream (Scheme 1). It was found that when the surface of MWCNTs is modified with the cationic surfactant cetyltrimethyl ammonium bromide (CTAB), a product that can remove Cr(VI) selectively was obtained.(98%). On the other hand, surface modification with the anionic surfactant sodium lauryl sulfate (SLS) after magnetization yielded a product that can remove Cr(III) selectively (99%). Langmuir isotherm model was the best fit for the removal of Cr(III) by MWCNTs-M-SLS and Cr(VI) by MWCNTs-CTAB, with an adsorption capacity of 66.2 mg/g and 27.8 mg/g, respectively. Adsorption kinetics for the removal of Cr(III) by MWCNTs-M-SLS and Cr(VI) by MWCNTs-CTAB, demonstrated that the adsorption is very fast (< 5min) for both ions. A regeneration study on saturated MWCNTs-CTAB was performed at 25oC and 35oC, in two cycles of desorption-adsorption with some reduction in performance. Surface modification with SLS, was found also to improve the removal lead ions from aqueous solution (from q = 3.81 to 141 mg/g).
