Adsorption of arsenic on multiwall carbon nanotube-zirconia nanohybrid for potential drinking water purification

The adsorptive removal of arsenic from water using a multiwall carbon nanotube-zirconia nanohybrid (MWCNT-ZrO2) is presented. The MWCNT-ZrO2 with 4.85% zirconia was effective in meeting the drinking water standard levels of 10 mu g L-1. The absorption capacity of the composite were 2000 mu g g(-1) and 5000 mu g g(-1) for As(III) and As(V) respectively, which were significantly higher than those reported previously for iron oxide coated MWCNTs. The adsorption of As(V) on MWCNT-ZrO2 was faster than that of As(III), and a pseudo-second order rate equation effectively described the uptake kinetics. The adsorption isotherms for As(III) and As(V) fitted both the Langmuir and Freundlich models. A major advantage of the MWCNT-ZrO2 was that the adsorption capacity was not a function of pH. (C) 2012 Elsevier Inc. All rights reserved.