Synthesis of Thermo-Responsive Polymer/Ferrite Composite for Heavy Metal Ion Recovery

In this study, preparation and characterization of thermo-responsive polymer/ferrite composite for heavy metal ion recovery were examined. This composite was prepared in two steps. First, a straight-chained thermo-responsive copolymer was synthesized by free radical copolymerization of N-isopropylacrylamide (NIPAM) as a thermo-responsive part and acrylic acid (AA) as ligand part for metal ions. This copolymer has a high chelating group content and a high adsorption capacity of heavy metal ions. Secondly, the copolymer was immobilized onto amine modified ferrite particle through amide bond formation. At first, thermo-responsive properties and adsorption/desorption characteristics of four different heavy metal ions of Cu(II), Mn(II), Ni(II) and Co(II) were examined for the obtained straight chained copolymer before immobilized onto the ferrite particle. The result showed that the copolymer exhibited the Langmuir type adsorption for all the heavy metal ions used in this study, and the adsorption capacity at above LCST (60 °C) was larger than that at below LCST (10 °C). The order of the adsorption amount of these heavy metal ions was Cu(II)>Co(II)>Mn(II)>Ni(II) . Then, adsorption/desorption properties of copolymer/ferrite composite were examined. The result showed that the composite reversibly adsorbed and desorbed heavy metal ions just by changing temperature between 10 and 60 °C.