Abstract:

Zn²⁺ was used as template with paraffin as dispersant agent，formaldehyde as pre-crosslinking agent，and epichlorohydrin as crosslinking agent to prepare a imprinted chitosan polymer. The structure of the polymer was characterized by X ray diffractometer （XRD）.. The dosage of the polymer and the influence of temperature on the adsorption of Zn²⁺ were studied. Studies on the kinetics of the adsorption of Zn²⁺ by the imprinted polymer and the isothermal adsorption properties were also performed. The result showed that the regularity of the chitosan crystals was broken in the preparation of the imprinted polymer，adding a large amount of coordination group which enlarged adsorption capacity. Meanwhile the polymer acquired a highly selective adsorption capacity to Zn²⁺，and the separation factor of Zn²⁺，Cd²⁺，Mg²⁺，Mn²⁺ were all greater than 1.5. The imprinted polymer adsorbed the Zn²⁺ rapidly，and the whole adsorption process fitted the pseudo-second-order kinetic model well，t/Q_t=8.1744+2.0186t and the correlation coefficient was 0.998. The calculated equilibrium adsorption capacity was satisfactory compared with the experiment data. The adsorption process at a constant temperature fitted the Langmuir equation of isothermal adsorption：C_e/Q_e=1.3297+0.02701C_e and the maximum adsorption capacity was 37.023 mmol/g. The adsorption mainly proceeded in the form of monolayer.