Solid-phase extractants based on carbon nanotubes for the concentration of noble metals from hydrochloric acid media

Effective solid-phase extractants (SPE) have been developed based on multi-walled carbon nanotubes (CNTs) of various structures modified with an organic reagent – 2-mercaptobenzothiazole. Using scanning and transmission electron microscopy, the morphological and structural features of SPE samples and their elemental composition were determined. It has been shown that the specific surface area of modified CNTs is approximately two times lower compared to the original CNTs. It was revealed that the modified materials are coils of CNTs coated with a uniform organic shell 10-15 nm thick. The sorption capacity of the original nanotubes in 1 M HCl and their modified forms (0.1-3.0 M HCl) at room temperature and at 80°C was determined. It was found that in strongly acidic media, SPE based on G-183 CNTs and 2-mercaptobenzothiazole is effective, which sorbs Pt, Pd and Au at room temperature, and also Ru and Rh at a temperature of 80°C. The possibility of selective extraction of platinum group metals and gold with this sorbent in the presence of macroquantities of Al, Fe, Cu, Ca and Mg was assessed.