title: Carboxymethyl chitosan-modified magnetic-cored dendrimer as an amphoteric adsorbent.
abstract: Carboxymethyl chitosan-modified magnetic-cored dendrimers (CCMDs) were successfully synthesized in a three step method. The synthesized samples were characterized using X-ray diffraction, transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometer, thermogravimetry analysis, zeta potential analyzer, X-ray photoelectron spectroscopy, surface area analysis, and Fourier transform infrared spectroscopy. The CCMD exhibited selective adsorption for anionic and cationic compounds at specific pH conditions. With the substitution of amino groups of MD with carboxymethyl chitosan moieties, the adsorption sites for cationic compounds were greatly increased. Since the adsorption onto CCMD was mainly electrostatic interaction, the adsorption of MB and MO was significantly affected by the pHs. The optimal adsorption pH values were 3 and 11 for MO and MB. The maximal adsorption of MO and MB on the CCMD at pH values of 3 and 11 were 20.85mgg(-1) and 96.31mgg(-1), respectively. Reuse of the CCMD as an adsorbent was experimentally tested through adsorption and desorption with simple pH control. More than 99% and 91% of the initial adsorption of MB and MO on the CCMD was maintained with five consecutive recycling.
authors.affiliation: Department of Civil and Environmental Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791, South Korea.
authors.forename: Hye-Ran
authors.initials: HR
authors.lastname: Kim
authors.affiliation: Pohang Institute of Metal Industry Advancement, 56 Jigok-ro, Nam-gu, Pohang-si, Gyeongsangbuk-do 790-834, South Korea.
authors.forename: Jun-Won
authors.initials: JW
authors.lastname: Jang
authors.affiliation: Department of Civil and Environmental Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791, South Korea. Electronic address: jaewoopark@hanyang.ac.kr.
authors.forename: Jae-Woo
authors.initials: JW
authors.lastname: Park
keywords: Adsorption; Amphoteric adsorbent; Carboxymethyl chitosan; Dendrimer; Magnetite