Preparation and characterization of thermo and magnetic responsive hydrogel particles for removal of heavy metal ions

Abstract

The three-dimensional hydrophilic polymeric network of hydrogel achieved unprecedented and unique physicochemical properties with great potential in many fields. Due to the limitations of standard bulk hydrogel submicrometer-sized hydrogel has earned much interest in recent years. The submicrometer-sized hydrogel adds a new dimension to hydrogel research due to its quick stimuli response. Imparting magnetic field into the submicrometer-sized hydrogel provides a new strategy with a variety of additional advantages. The magnetic responsiveness of hydrogels can lead to the generation of functionality under magnetic fields. This work has established a facile route to prepare a dynamic thermo and magnetic responsive submicrometer-sized hydrogel using N-Isopropylacrylamide (NIPAM) as monomer and 2-Acrylamido-2-methylpropane sulfonic acid (AMPS) as co-monomer to remove heavy metals from an aquatic environment. Fabrication of magnetic submicrometer-sized hydrogels and their heavy metals removal capacity via electrostatic interactions have been studied systematically. The prepared nanocomposite and submicrometer-sized hydrogels were characterized by Fourier transform infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), Energy dispersive X-ray (EDX) and Dynamic light scattering (DLS). Removal of heavy metal ions from solution by submicrometer-sized hydrogels has been investigated by ultraviolet (UV) spectroscopy. Rare-earth Neodymium magnet is used for the external magnetic field generation. The vast surface area of submicrometer-sized hydrogel particles demonstrates high heavy metal removal effectiveness. Hg2+ and Cr6+ ions were removed using submicrometer-sized hydrogel particles and removal efficiency is around 167 mg/g and 8 mg/g respectively. The fabricated functional hydrogel particles are strongly magnetic responsive, and heavy metal removal efficiency is good.