Synthesis of chelating polymer containing schiff base and sulfur for heavy metal adsorption

Abstract

Aldehydic polystyrene-divinylbenzene copolymer (CHO-PS-DVB) was initially prepared from the oxidation of chloromethylated polystyrene-divinylbenzene (Cl-PS-DVB) with approximately 57 % yield. The CHO-PS-DVB were subsequently used to prepare three new chelating resins by coupling reaction through a dual Schiff base linkage with two synthesized ligands; 2-[3-(2-amino ethylsulfanyl)-propylsulfanyl]-ethylamine (AEPE) and 2-[2-(2-amino-ethylsulfanyl)-ethylsulfanyl]-ethylamine (AEEE), and a commercial one; triethylenetetramine (TETA), called AEPE-PS-DVB, AEEE-PS-DVB and TETA-PS-DVB, respectively. The structure of the ligands was confirmed by FT-IR, 1H-NMR and 13C-NMR spectroscopic techniques. The effects of the reaction time, temperature and the amount of ligands were investigated. All derivative resins were characterized by elemental analysis, thermogravimetry, FT-IR and FT-Raman spectroscopy and ninhydrin test. The adsorption properties of the synthesized resins towards Pb(II), Cu(II), Cd(II), Zn(II), Ni(II), Co(II) and Cr(III) ions in aqueous solution were studied by batch method. The appropriate pH of all metal solutions was in the range of 5-7 for all resins. AEPE-PS-DVB and AEEE-PS-DVB showed the same sorption behavior. Their selectivity order was Pb(II)>Zn(II)>Cu(II)>Cd(II), Co(II), Ni(II), Cr(II). In addition, TETA-PS-DVB showed the selectivity towards only Pb(II) ion