Sustainable catalytic properties of silver nanoparticles supported montmorillonite for highly efficient recyclable reduction of methylene blue

Water contamination by organic dyes has become a serious environmental pollution. Here, a facile, green and cost-effective synthesis approach was developed to in situ grow silver nanoparticles (Ag NPs) on the eco-friendly and low cost natural material montmorillonite (Mt) through dopamine chemistry. The loading amount of silver on the montmorillonite reached 20 mass %. The Ag NPs supported montmorillonite (Ag NPs@Mt) exhibited excellent catalytic performances to reduce a model organic dye methylene blue in the presence of NaBH4 with catalytic efficiency higher than 98% and apparent reduction rate constant kip higher than 1.70 min(-1). More importantly, the Ag NPs@Mt was proven to show excellent recyclability for at least 20 cycles and long-term stability for one month soaking in water. This low-cost and recyclable Ag NPs@Mt shows great potential in large scale application to treat dye containing wastewater.