Investigating the extraction performance and mechanism of a multifunctional thiourea molecule for the effective removal of Ag() from aqueous solutions

Highly efficient and selective extraction of silver ions from wastewater remains a formidable challenge in ensuring public health and protecting ecosystems. Herein, an acyl-based thiourea extractant known as N -benzoyl- N ′, N ′-dibutyl thiourea (BDBTU) was used for the selective extraction of silver ions from aqueous solution by a solvent extraction method. BDBTU displayed an outstanding extraction efficiency of Ag( i ) with an extraction ratio of 96.7% under the optimal extraction conditions, surpassing its effectiveness for Cu( ii ) and Mn( ii ) ions. In addition, BDBTU retained high effectiveness even after undergoing eight regeneration cycles, with only a slight decrease in the extraction efficiency from 96.7% to 95.2%. Moreover, it displayed selective extraction towards Ag( i ) ions under the interference of metal ions ( i.e. , Cu( ii ), Pb( ii ), Mn( ii ), Zn( ii ), Ni( ii ), Co( ii ) and Na( i )). The investigation into the extraction mechanism of BDBTU towards Ag( i ) unveiled that BDBTU provided a high affinity for Ag( i ) accompanied by the formation of Ag-O-C and Ag-S-C bonds. These results indicated that the exceptional extraction stability and selectivity of BDBTU offer promising prospects for diverse applications, highlighting its potential in silver-containing wastewater treatment fields. Highly efficient and selective extraction of silver ions from wastewater remains a formidable challenge in ensuring public health and protecting ecosystems.