![Sample our Physical Sciences journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/110819/TOC-Subject-Sample-2021-Physical-Sciences.jpg"})
Abstract
Polymeric resins with phosphonate esters, phosphinate esters, and phosphine oxide ligands are synthesized via Arbusov reaction, characterized and used in the removal of Au(III) from hydrochloric acid solutions. It is found that phosphonate ethyl and butyl esters are able to adsorb as much as 100–120 mg Au/g of the resin. Affinity of these two resins towards gold, measured as the logarithm of distribution coefficient, is very high: 4.0–5.1 for the Au(III) in 0.1–6.0 M hydrochloric acid solutions. Other metal chlorocomplexes, typical for the processing of the electronic parts scrap, such as Fe(III) and Ag(I), are removed to a lesser extent and, what is most important is that these resins do not absorb Cu(II) chlorocomplexes. This allows for the use of the synthesized resins in the selective removal of Au(III) from concentrated copper solution.
Some of the studied resins are sulfonated in order to increase their swelling in aqueous solutions and to achieve greater accessibility of the phosphorous containing groups. All sulfonated resins displayed better swelling in aqueous solutions but the affinity and capacity of resins towards tetrachloroaurate at equilibrium Au(III) concentration of 20 mg/L was decreased. This effect is ascribed to an increasing distance between phosphonate groups and more difficult formation of their complexes with tetrachloroaurate.