Preconcentration of Cu (II) from seawater using a novel and stable phenol-formaldehyde resin

Preconcentration of Cu (II) from seawater using a novel phenol-formaldehyde (P-F) resin was investigated. 1,2-dihydroxybenzene-4-azo-3-hydroxybenzene-formaldehyde resin (DAHBF) was prepared by condensing 1,2-dihydroxybenzene-4-azo-3-hydroxybenzene with formaldehyde (1:2 mole ratio) in the presence of oxalic acid as catalyst. Polychelates were obtained when the DAHBF was treated with the aqueous solution of Cu (II) ions. The polymeric resin and polymer-metal complexes were characterized with thermal analysis and spectral studies. The IR spectra of polychelates suggest that the metal was coordinated through the oxygen atoms of the dihydroxybenzene moiety. The TGA data revealed the thermal stability of the resin and the polychelates. X-ray diffraction study revealed the incorporation of the metal ion significantly enhanced the degree of crystallinity. The sorption properties of the chelate forming resin towards divalent metal ion [Cu(II)] was studied as a function of pH, preconcentration time, metal concentration, amount of resin, aqueous phase volume and presence of electrolyte. This procedure was validated for recovery of copper from seawater samples. The method has adequate accuracy and it can be used for determination of copper in sea water samples.