Clays, carbonaceous materials and magnetic nanoparticles confined in polyvinyl alcohol cryogels.

LAURA M. SANCHEZ; GRACIELA ZANINI; PETER S. SHUTTLEWORTH; VERA ALVAREZ; CAROLINA WAIMAN; ROMINA OLLIER

Conferencia; Webinar on Revolutions in Renewable Energy in 21st Century (FOREN-2020); 2020

Hydrogels typically are hydrophilic crosslinked three-dimensional (3D) polymer networks,with the ability to absorb large quantities of water or biological fluids, resulting in their drasticswelling, whilst maintaining their 3D structure and without dissolving. With increasing technologicaldemand for newer and better materials, incorporation of different fillers has been found to result intailored or improved hydrogel properties (mechanical, thermal, optical, electrical etc.) andresponsiveness (such as, magnetic response). In this sense, nanotechnology offers many opportunities to develop optimized composite materials with synergistic properties. Controlling the design of the 3D hydrogel structure at the nanometre scale provides a powerful strategy to incorporate versatility and customized functionality into the resulting nanocomposite system.In this work, we focused particularly on the development and characterization of compositePolyvinyl alcohol (PVA)-based hydrogels with fillers of different physical and chemical nature:clays, iron oxides and carbonaceous materials. The composite hydrogels were synthesized via an eco- friendly freeze-thawing technique, which is a simple and non-toxic crosslinking methodology. After thorough characterisation using X-Ray Diffraction (XRD), Scanning Electron microscopy (SEM),Dynamic Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA) and swelling assessmentthe nanocomposites were better known. Furthermore, the prepared materials were tested in order toexplore their cadmium adsorption potential, a heavy metal usually found as a pollutant in waterbodies. The data obtained showed that PVA has no affinity for cadmium ions but the incorporation of the different fillers makes the materials develop important adsorbent characteristics. Under theselected working conditions, and for a contact time of 1440 min, the maximum amount of cadmiumions adsorbed was 50.9 mg/g, 33.9 mg/g, 42.6 mg/g and 30.5 mg/g for composites containingbentonite; acid-modified bentonite; magnetic nanoparticles and carbonaceous materials, respectively. For all cases the higher the filler amounts the higher the adsorption efficiency.