A SIMPLE METHOD FOR ESTIMATION OF NEWSPRINT DYES IN EFFLUENTS AND THEIR MIGRATION FROM PAPER SAMPLES

An analytical method for the estimation of basic dyes, such as crystal violet (C.I. Basic Violet 3), malachite green (C.I. Basic Green 4), a nd methylene blue (C.I. Basic Blue 9), in newsprint effluents and wate r samples has been developed. Several solid-phase extraction (SPE) sor bents available for sample preparation have been evaluated for concent rating the dyes prior to analysis by high-pressure liquid chromatograp hy (HPLC). Results show that only strong cation-exchange sorbents are capable of complete dye retention from newsprint effluents. However, a suitable eluent for the quantitative desorption of dyes from the stro ng cation-exchange sorbents was not found. All cation-exchange materia ls and some other sorbents retained dyes from dilute aqueous solutions . Unmodified silica was the most effective sorbent for recovering dyes dissolved in distilled water. Elution of dyes from the silica sorbent was achieved by countercurrent washing with a 1% solution of formic a cid in aqueous methanol. For estimation of the dyes in effluents, a qu alitative test is proposed that involves sorption of dyes from effluen ts onto a silica-based cation-exchange sorbent and comparison of the r esulting color band (if dyes are present) with a standard template. Ex traction results of newsprint samples in hot solvents show that, in wa ter, no dye migrated form the paper.