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 TPMADA 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.