Preparation of novel magnetic chemically modified chitin nanocomposites and their application for environmental remediation of cadmium ions in model and real water samples

Abstract

In this research work, for the first time, the biopolymer chitin was modified chemically through activation followed by covalent linking to 8-hydroxyquinoline, and was then modified magnetically with the magnetic nanomaterial magnetite to produce magnetic chitin 8-quinolyl ether (C8QE). The prepared C8QE was studied by scanning electron microscopy, transmission electron microscopy, attenuated total reflection Fourier transform IR spectroscopy, and surface area analysis for characterization of the morphological structure, functional groups, and surface area of the magnetic C8QE solid, and also for its use as an adsorbent for removal of cadmium ions from contaminated water. The experimental results indicate the uniform and homogeneous formation of magnetic C8QE. The effects of the C8QE mass, adsorption time, ionic strength, solution pH, and temperature on Cd(II) ion removal by C8QE were studied. The optimum removal capacity of C8QE was about 119.9 mg Cd(II)/g with 20 mL of 100 mg L−1 cadmium solution and 15.0 mg C8QE within 10.0 min at pH 7.0 and 298 K. Cd(II) ion removal by C8QE was studied kinetically as well as thermodynamically, and the findings showed the suitability of the pseudo-second-order kinetic model for the removal process and the electrostatic, exothermic, and chemical nature and the spontaneity of the removal process. Moreover, C8QE could be used four consecutive times for the efficient removal of Cd(II) ions with high efficiency. Finally, the applicability of C8QE for removal of Cd(II) ions in different water samples was explored, and solid C8QE showed great potential for eliminating Cd(II) ions from water.