Synergistic effect of GN-Ag NPs enhancing the efficient catalytic degradation of MB and CR by PDA@MMT composite hydrogel.

A novel composite hydrogel prepared from polyacrylamide (PAM), polydopamine-modified montmorillonite (PDA@MMT), graphene and hydroxypropyl cellulose (HPC), loaded with Ag NPs, was prepared for the catalytic degradation of methylene blue (MB) and Congo red (CR) using in situ reduction. HPC significantly enhanced the dispersion of PDA@MMT within the hydrogel, endowing the hydrogel with excellent mechanical properties, with stress and strain of 1773 kPa and 4005 %, and elastic modulus and toughness of 43.4 kPa and 29.54 MJ/m, respectively. The introduction of graphene (GN) increased the rate of electron transfer during the catalytic process and significantly improved the catalytic efficiency, with catalytic rate constants of 1.360 and 0.803 min for MB and CR at 20 °C, respectively. The hydrogels were endowed with excellent antimicrobial properties due to the introduction of Ag NPs. In the future, this hydrogel is expected to play an important role in environmental pollution control.