PAA/TiO₂@C composite hydrogels with hierarchical pore structures as high efficiency adsorbents for heavy metal ions and organic dyes removal

Hydrogel-based adsorbents have good application prospects in wastewater treatment, but their low porosity and specific surface area pose challenges to their practical applications. In this study, a porous hydrogel (T-PMADA) was prepared by copolymerization of acrylic acid (AA) and methacrylamide dopamine (MADA) in the presence of Ti₃C₂ MXene. The porous structure not only increased the specific surface area (44.2 m²/g) of the hydrogel, but also provided abundant active sites for the treatment of the pollutant, which led to the maximum adsorption capacity of T-PMADA hydrogel for Pb (II) and Cd (II) of 609.9 mg/g and 250.2 mg/g, respectively. In addition, the TiO₂@C formed by the oxidation of Ti₃C₂ MXene also endows the hydrogel with the photocatalytic degradation ability for organic dyes. In treating the wastewater containing heavy metal ions and organic dyes, the T-PMADA hydrogel shows good treatment performance for heavy metal ions and organic dyes simultaneously. The above facts indicate that T-PMADA hydrogel can provide a brand-new strategy for water pollution treatment in complex polluted environments by its ability to treat heavy metals and organic dye pollutants.