科研之友
微信
新浪微博
Facebook
分享链接
摘要
Silver ions in wastewater streams are a major pollutant and a threat to human health. Given the increasing demand and relative scarcity of silver, these streams could be a lucrative source to extract metallic silver. Wastewater is a complex mixture of many different metal salts, and developing recyclable sorbents with high specificity towards silver ions remains a major challenge. Here we report that molybdenum oxide (MoOx) adsorbent with mixed-valence (Mo(V) and Mo(VI)) demonstrates high selectivity (distribution coefficient of 6437.40mLg(-1)) for Ag+ and an uptake capacity of 2605.91mgg(-1). Our experimental results and density functional theory calculations illustrate the mechanism behind Ag+ adsorption and reduction. Our results show that Mo(V) species reduce Ag+ to metallic Ag, which decreases the energy barrier for subsequent Ag+ reductions, accounting for the high uptake of Ag+ from wastewater. Due to its high selectivity, MoOx favorably adsorbs Ag+ even in the presence of interfering ions. High selective recovery of Ag+ from wastewater (recovery efficiency=97.9%) further supports the practical applications of the sorbent. Finally, MoOx can be recycled following silver recovery while maintaining a recovery efficiency of 97.1% after five cycles. The method is expected to provide a viable strategy to recover silver from wastewater. @@@ Silver ions in wastewater are a major health hazard, and there is an urgent need to develop methods to reliably extract them. Here, the authors show that mixed-valence molybdenum oxide can selectively adsorb and reduce Ag+ from wastewater and be easily recycled while maintaining high selectivity towards Ag+.
-
单位南昌航空大学
