A soft hydrogel reactor for cobalt nanoparticle preparation and use in the reduction of nitrophenols
Bulk poly(2-acrylamido-2-methyl-1-propansulfonic acid) (p(AMPS)) hydrogels were prepared by irradiation of an aqueous solution of AMPS in the presence of crosslinker and photoinitiator. These p(AMPS) hydrogel networks were utilized for in situ cobalt nanoparticle synthesis by reduction of metal ions absorbed into the hydrogel network with a reducing agent, i.e., NaBH4. TEM images confirmed that Co particles are about 100 nm in size. The hydrogel network with embedded Co nanoparticles was utilized as a catalyst in the reduction of 4-nitrophenol (4-NP) and 2-nitrophenol (2-NP) in aqueous media in the presence of an excess amount of NaBH4. The kinetics of the reduction reaction under different reaction conditions was investigated to determine the activation parameters. Activation energies are 27.8 kJ mol−1 and 39.3 kJ mol−1 for 4-NP and 2-NP, respectively. It was found that hydrogel–Co composites were 99% active after 5 days storage.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights▶ Elastic hydrogel reactor. ▶ In situ catalyst synthesis. ▶ Hydrogel-composite catalyst systems. ▶ Co nanoparticle embedded in environmentally sensitive flexible hydrogel network.
Journal: Applied Catalysis B: Environmental - Volume 101, Issues 1–2, 22 November 2010, Pages 137–143