Nanocomposite hydrogels 3D printed for application in water remediation

Abstract

Three-dimensional (3D) printing of bioinks for the development of nanocomposite hybrid adsorbenthydrogels was performed. Sodium alginate (SA) matrix hydrogels and bentonite clay (SA-B) nanocompositehydrogels were synthesized for this purpose. The bioinks used were characterized rheologicallyand the devices obtained were characterized physicochemically and morphologically. The efficiencyof the hydrogels in the adsorption of the pesticide paraquat (PQ) was also studied. The results revealedthe efficient formation of hybrid hydrogels and that the presence of clay in the biopolymer matriximproved the rheological, mechanical, thermal, and porous properties of the SA-B hydrogels. Both theSA-B30 bioink and corresponding 3D-printed device were found to be the best systems for use. PQadsorption tests showed equilibrium adsorption capacities of 1.16, 1.33, 1.45, 2.10, 2.29, and 1.64 mg/g forSA, SA-B5, SA-B10, SA-B20, SA-B30, and SA-B50, respectively. Adsorption was exothermic and spontaneousin nature, involving physisorption processes. In addition, it exhibited a correlation mainly with theFreundlich isotherm model and the pseudo-first-order kinetic model used for nanocomposite devices.The SA-B30 hydrogel exhibited the best PQ adsorption performance. Recovery and reusability of thedevices were achieved at least six times. This indicates that the synthesized eco-friendly, biodegradable,and low-cost materials can contribute to the circular economy. Thus, the developed adsorbent materialssignificantly contribute to ensuring that water is safe for human consumption.