Synthesis and properties of surface molecular imprinting adsorbent for removal of Pb(2+)

A new chitosan imprinting adsorbent using diatomite as core material was prepared by using the surface molecular imprinting technology with the Pb(2+) as imprinted ion. The preparation process conditions of the surface molecular imprinting adsorbent were studied. The adsorbent was characterized by using Fourier transform infrared (FTIR) spectrum. FTIR spectrum indicated that it was cross-linked by epichlorohydrin. The new imprinting adsorbent could provide a higher adsorption capacity for Pb(2+), which reached 139.6 mg/g increasing 32.3% compared with cross-linking chitosan adsorbent (the initial Pb(2+) concentration of 600 mg/L). The adsorption velocity was quick and the equilibration time of the imprinting adsorbent for Pb(2+) was 3 h that shortened about 40% compared with cross-linking chitosan adsorbent. It had a more wide pH range of 5-7 than that of cross-linking chitosan adsorbent. The new imprinting adsorbent can be reused for up to ten cycles without loss of adsorption capacity. In the kinetics and isotherm study, the pseudosecond order model and Langmuir model could represent the adsorption process.