Reinforced-Concrete Structured Hydrogel Microspheres with Ultrahigh Mechanical Strength, Restricted Water Uptake, and Superior Adsorption Capacity

Abstract

Functional hydrogels own superior advantages in wastewater purification thanks to their abundant functional groups and porous structure. However, the hydrogels cannot be used as stable adsorbents due to their insufficient mechanical properties and exorbitant swelling ratio. Inspired by the strong mechanical properties of the reinforced-concrete structure, the novel reinforced-concrete structured hydrogel microspheres were prepared, and the structure endowed the hydrogel with superior mechanical properties (the compressive stress was 27.4 MPa with a strain of 80%) and restricted swelling ratio (the water uptake was less than 2.2 g/g under pH = 7) but caused no obviously negative effect on the originally outstanding adsorption ability. The adsorption column filled with the concrete-structured hydrogel microspheres reached stable and efficient removal of the cationic dyes and heavy metal salts (1246 mg/g for MB, 491 mg/g for MV, 1253 mg/g for Cu(II), 564 mg/g for Ni(II), 640 mg/g for Cd(II), and 252 mg/g for...