Cu(II)Multi
IntroductionCarbon nanotubes (CNTs) are considered to be superior adsorbents of pollutants due to their unique properties and relative high reactivity. (Li et al., 2003a;Lu and Chiu, 2006;Wang et al., 2005). Oxidation removes impurities and hemispherical caps, hence increases surface area and introduces oxygen-containing functional groups (Li et al., 2003a;Lu and Chiu, 2006;Wang et al., 2005). Modification of the structure and surface properties of CNTs affected sorption capacity and sorption mechanisms of metals and organic chemicals (Li et al., 2003a;Lu and Chiu, 2006;Wang et al., 2005;Lu et al., 2005;Chin et al., 2007;Cho et al., 2008). The adsorption capacity of Cu 2þ at a given pH followed the order NaOClmodified CNTs > HNO 3 -modified CNTs > as-produced CNTs (Wu, 2007). The extraordinary increase in sorption capacity and decrease in desorption rate of w a t e r r e s e a r c h 4 3 ( 2 0 0 9 ) 2 4 0 9 -2 4 1 8