Facile synthesis and highly reactive silver ion adsorption of novel microparticles of sulfodiphenylamine and diaminonaphthalene copolymers

A series of novel copolymer microparticles from 4-sulfonic diphenylamine (SDP) and 1,8-diaminonaphthalene (DAN) was facilely prepared by a chemically oxidative polymerization. The structures and properties of the microparticles were systematically characterized by several important techniques. The microparticles exhibit good water resistance and high thermostability. Their electrical conductivity significantly rises after HCl doping or Ag adsorption. The Ag+ reactive adsorbability of the microparticles was optimized by carefully regulating the SDP/DAN ratio, particle size, and Ag+ solution pH. Both the introduction of SDP units into DAN polymer chains and the diminution of the particle size can effectively increase the capacity and rate of Ag+ adsorption. In particular, the Ag+ adsorbance on SDP/DAN (30/70) copolymer microparticles reaches 2.0 g g(-1), which is the highest silver adsorption capacity reported thus far. A novel mechanism of Ag+ reactive adsorption on the microparticles containing a large number of reactive groups such as amino, imino, and sulfonic groups has been proposed. The microparticles could be very applicable to elimination and recovery of noble metallic ions in wastewater.