Laser induced fabrication of mono-dispersed Ag_2S@Ag nano-particles and their superior adsorption performance for dye removal

A novel and versatile strategy for the convenient synthesis of mono-dispersed Ag2S@Ag hybrid nano-particles is developed by simply using laser ablation of Ag target in thioaetamide (TAA) solution. The as-prepared Ag2S@Ag nano-particles exhibit superior adsorption performance for the removal of methyl blue (MB) and methyl orange (MO) from wastewater. Most importantly, without any centrifugal process, the new adsorbents can be removed from solutions easily by filters after adsorbing dyes, since the Ag2S@Ag nano-particles are agglomerated and deposited on the bottom. We demonstrated that the excellent features are highly related to Ag structures in the Ag2S@Ag nano-particles. The unique excited and polarized Ag species with positive charge regions enable the Ag2S@Ag nano-particles to have much more active sites as adsorption sites. Then, it will result in the generation of strong ionic bounds via electron-static interaction between positive active site of the adsorbent and negative charge of the dye molecules. Our results provide a breakthrough in the complicated process including the removal of adsorbents that arises from the separate process after adsorption of organic contaminants. Thus, these findings are of great significance for the practical application in water purification.