Gamma radiation induced synthesis of double network hydrophilic cryogels at low pH loaded with AuNPs for fast and efficient degradation of Congo red

Abstract

γ−radiation is a clean, fast and efficient synthetic route for polymeric materials. it is very powerful tool to generate free radicals during polymerization without any need of initiator and accelerator in both hydrophilic and hydrophobic media. Here in this work, for the first time, we fabricated acrylamide-methyl-propane sulfonic acid based-single and double network hydrophilic cryogels via γ−radiation at low pH. pH highly effects the synthesis of acrylamide-methyl-propane sulfonic acid based cryogels using redox initiation method. Along with pH, the effect of radiation time and radiation dose rate on cryo-polymerization was also studied. Gold hybrid cryogels (single and double network) were fabricated via self-reduction method at ambient conditions. Fourier transform infrared spectroscopy was implemented for chemical structure analysis of the synthesized material. The surface morphology of single and double network cryogels was observed via scanning electron microscopy. For the hybrid cryogels materials analysis x-ray diffraction, thermal gravimetric analysis, energy dispersive x-ray analysis, x-ray photoelectron spectroscopy and transmission electron microscopy and was used to confirm the presence of nanoparticles in the polymer network. The fabricated hybrid cryogels (0.15 g) were used for the degradation of Congo red (50 mL) as model dye in the presence of NaBH4 (0.02 g) with efficient and fast degradation activity. The apparent rate constant value (Kapp) for single and double network hybrid cryogels was 0.3652 min−1 and 0.2268 min−1, respectively. The activation energy, enthalpy and entropy was calculated (34.44 kJ.mol−1, –30.85 kJ.mol−1 and –146.30 J·mol−1k−1, respectively) using Arrhenius and Eyring equations for the fabricated catalyst. The catalyst was tasted in the tap water system and its efficiency was satisfied in real world too. The fabricated double wall hybrid catalyst will have a significant importance in the environmental field.