Preparation of hyperbranched polymers from oxidized lignin modified with triazine for removal of heavy metals

This work describes the development of hyperbranched polymer from eucalyptus Kraft lignin for the removal of heavy metals present in water. The lignin versatile structure and reactive functional groups, such as phenolic hydroxyl groups have been explored. The oxidation of Kraft lignin was prepared under acid conditions, triazine was added in order to incorporate nitrogen heteroatoms and modify the lignin structure generating a hyperbranched polymer. Infrared spectroscopy, gel permeation chromatography, SEM-EDS Microscopy and Physisorption of N₂ at 77 K were employed fot the characterization of adsorbents. It was also made a comparison of the amount of heavy metal removal using Kraft lignin (KL), oxidized Kraft lignin (OKL) and oxidized Kraft lignin cross-linked with triazine (OKL-CC). These were used in the adsorption of nickel and cadmium at 20 ppm, a pH of 4 and at 25 °C, with an amount of adsorbent of 25 mg. By atomic absorption was determined the concentration of the metals. The removal of cadmium was 96.1% for OKL-CC, 92.48% for OKL, while for KL it was 24.4%. The nickel removal with OKL-CC was 80.4%, with OKL was 68.8% and for the KL was 20.99%.