Investigation of sorption capabilities of chelating agents loaded and unloaded polymeric sorbents towards trace metal ions

Poly(styrene-divinylbenzene) (poly(Str/DVB), sulphonated styrene-divinylbenzene copolymer and polyester-styrene polymer were synthesized using high internal phase emulsion method and characterized by FT-IR and SEM analysis. 5,10,15,20-tetrakis (hydroxyl phenyl) porphyrin (THPP) and pyrocatechol violet (PCV) were loaded on poly(styrene-divinylbenzene) and sulphonated styrene-divinylbenzene copolymer and were characterized by FTIR. The amounts of attached THPP and PCV onto poly(Str/DVB) and sulphonated Str/DVB were calculated as 0.2840, 0.2993, 0.5716 and 0.4384 mmol g-1 polymer, respectively. Metal (Pb(II), Cu(II), Cd(II), Ni(II), Zn(II)) sorption capabilities of poly(Str/DVB) and sulphonated Str/DVB copolymers were much low in high acidity medium, moderate at pH 4-7. Polyester-styrene polymer has no tendency towards metal ions.The sorption tendency of poly(Str/DVB)-THPP and sulphonated Str/DVB-THPP polymeric sorbents towards studied metal ions were much higher than PCV loaded polymeric sorbents except Pb. By eluting with 2 or 4 mol L-1 HNO3, the quantitative recovery of studied metal ions from poly(Str/DVB)-THPP and sulphonated Str/DVB-THPP was obtained. The precision of sorption process as relative standard deviation (RSD%) for 2 µg mL-1 metal ion was between 0.02 and 5.12. The sorption capacities of poly(Str/DVB)-THPP and sulphonated Str/DVB-THPP for Cu(II), Ni(II), Zn(II) and Pb(II) were found as around 5000 µg g-1 sorbent. The sufficient sorption capabilities of THPP based sorbent at pH 10 and PCV based sorbent at pH 8 (for only Pb(II)) was ? 8 µg metal ion g-1 sorbent. These synthesized polymeric sorbents loaded with THPP can be used for separation and preconcentration of the studied metal ions in aqueous solutions.