The capability of nanomagnetite carboxymethyl kappa-carrageenan coated to adsorp metal ions

Nanomagnetite is a nano-sized iron oxide Fe3O4. One of the utilization of nanomagnetite is as a metal ion binder. Nanomagnetite has a hydrophobic surface, so they difficult to interact with polar environments and tends to agglomerated. Agglomeration can reduce the magnetization of nanomagnetite. Modification of nanomagnetite was carried out to reduce agglomeration and to add a functional group on the surface of nanomagnetite. Carboxymethyl kappa carrageenan (CMKC) is a result of kappa carrageenan carboxymethylation, having an active group of carboxyl that can interact with metal ions. The research aims to synthesize CMKC coated nanomagnetite and characterize them by SEM and VSM and use it as metal ions adsorbent. This research is part of adsorption of metal ions with nanomagnetite CMKC coated research. The research was conducted in several stages including first synthesis of CMKC, secondly synthesis of magnetite, and thirdly synthesis of nanomagnetite CMKC coated, fourthly, sample preconcentration by adsorption of metal ions Cr(III), Ni(II), Cu(II), and Co(II) at pH 6, 40 minutes adsorption contact time, with nanomagnetite CMKC coated as adsorbent. The results showed that magnetite can be synthesized from a mixture of FeCl3.6H2O and FeSO4.7H2O and NaOH as reagent. The peak of FTIR spectrum at 586cm-1 peak confirmed that magnetite was formed, XRD's difractogram at 30°; 35°; 42°; 57°; 63°; and 74° peaks were confirmed the formation of magnetite. Morphological analysis was conducted with SEM that indicates that the average of magnetite sizes is 31 nm, so the magnetite that was synthesized can be categorized as nanomagnetite. Nanomagnetite that was coated with CMKC, and then analyzed with SEM, based on the SEM image, CMKC coated of nanomagnetite's size is larger than the original nanomagnetite, there are differences of magnetization of coated nanomagnetite and nanomagnetite without coating, the magnetization of nanomagnetite without coating is 24 emu/g and the magnetization of CMKC coated is 23.5 emu/g.