Abstract:
The Iigand 3. 3!, 4!: 5. 7-Pentahydroxyflavylium chloride was extracted in
methanoI/HCl (85:15 v/v) from the flowers of Hibiscus rosa-sinesis. The
extraction process was inexpensive, efficient and fast. The UV/Visible spectra were
also in agreement with those reported by past workers. Using methano1, as a solvent, the Alphamax was 532nm in the visibIe region, and 279nm in the ultraviolet
region. The solubility of the crystals were tested in different organic solvents and
found to be high in 1-butanol. Liquid-liquid extraction studies were also carried out
on six heavy metal [Cd, Cu, Cr, Fe. Pb and Zn) complexes of 3, 3!, 4!, 5, 7-
pentahydroxy flavylium chloride in I-butanol as the organic solvent. The effect of
pH on the extraction was aIso investigated. Complex formation with the heavy
metals was confirmed from spectrophotometric analysis of both the free ligand and
the complexed Iigancl with various metals in I-butuno1,The sensitivity of thc
extraction process was enhanced through pH adjustment which gave pH 7 as
optimum. The mean percentage recoveries of the metals in tap water were: Cd
(101.44), Cr (102.03), Pb (103.33), Fe (149.73), Zn (5.23) and Cu (1 17.94) while
the mean rec~verics in the river water, (in ppb) were; Cr (0.1 I), Cd (2.951, 21s.
(5.27), Pb (10.85), Cu (14.95) and Fe (30.81). Considering the cheapness and ready availability of this reagent over the conventional igands, it could be very useful as an extractant for heavy metals recovery and concentration in natural waters.
