SOLID-PHASE EXTRACTION OF NICKEL (II) ION BY STUDYING THE EFFECTS OF SAMPLE VOLUME ON COATED SILICA GEL AND PRODUCTION OF SCHIFF’S BASE (BHPDE)

ABSTRACT
Bis-(4-hydroxypent-2-ylidene)-diaminoethane(BHPDE) is a Schiff base resulting from the condensation of pentane-2-,4 dione and 1,2-diaminoethane.Solid-phase Extraction of Ni (II) ion by column method in the pH range 1- 12 have been studied in trichloromethane using bis-(4-hydroxypent-2-ylidene)-diaminoethane(BHPDE). Ni (II) ion extraction using 2% BHPDE in CHCl3 is sufficient or abundant in the pH of 4.0.  The aqueous BHPDE shows a maximum absorption at 320nm. The Ni (II) ion complex has maximum absorption at 375nm. The acid dissociation constants of H2B (BHPDE) are obtained by titrating with 0.179 M NaOH and are found to be pka1D = 11.55 and pka2D = 11.5 corresponding to the formation of HB-   and B2 respectively. Pka1D and pka2D share the same value since H2B (BHPDE) has two protons located in the same chemical environment. Electronic Spectrum of BHPDE confirms that BHPDE absorbs maximally in the ultraviolet region of the spectrum and not in the visible region since it is not displayed in the spectrum. The physical modification of the silica gel using BHPDE has also been studied.