Sulfur-modified covalent triazine polymer (S-CTP) is used for the ultra-efficient capture of silver ions in aqueous solutions

• The S-CTP preparation process is simple and inexpensive. • The adsorption capacity of S-CTP for Ag(I) ions was as high as 1675 mg/g. • The primary mode of coordination between S-CTP and Ag(I) ions is the formation of stable six-membered rings. Many adsorbents have been used to capture Ag(I) ions in water. However, most of these materials have poor adsorption efficiency and high costs. Consequently, there is a need to develop a simple, efficient and low-cost adsorbent material. In this study, a sulfur-modified covalent triazine polymer (S-CTP) was successfully synthesized using two inexpensive triazine derivatives. The capture of Ag(I) by S-CTP is a fast chemisorption process, with a maximum adsorption capacity of 1675 mg/g. The adsorption of Ag(I) ions by S-CTP is spontaneous, and there is an increase in adsorption efficiency with increasing temperature. The primary coordination mode of S-CTP with Ag(I) ions involves the formation of two rings: a stable six-membered ring formed between the nitrogen atoms of the two triazine rings and the Ag(I) ion, and a three-membered ring formed between the sulphur atom and the nitrogen of one of the triazine rings. In addition, the S-CTP preparation method is both simple and high-yielding, and exhibits ideal adsorption performance. Thus, S-CTP can be applied to the removal of Ag(I) ions from real industrial wastewater.