Proposta de aula experimental utilizando a perlita expandida modificada com ortofenantrolina na remoção do negro de eriocromo T em resíduos de titulometria de complexação

In this paper, an approach to the removal of the eriochrome black T in an actual effluent (generated from the test to determine the water hardness by complexometric titration) using perlite modified with orthophenanthroline by the adsorption technique is proposed. A preliminary assessment of the removal of eriochrome black T in a synthetic effluent (aqueous solution of eriochrome black T) was executed for subsequent application of the optimized conditions in actual residual water (titration residue of complexation). The removal of dye at pH 10, the natural pH of the actual effluent, was not significant reaching 8.12% of color removal, on the other hand, the removal of dye at pH 3 achieved the maximum color removal (100%), indicating that the eriochrome black T interacts more effectively with the adsorbent at acidic pH (pH 5 or 3), and more efficiently at pH 3. Therefore, by the results obtained under conditions established in this present study were concluded that expanded perlite (an amorphous and naturally acidic aluminosilicate) modified with orthophenanthroline (a Bronsted base) is an easy to prepare, cheap and effective material for removal of acid dyes (eriochrome black T) applied to residues containing eriochrome T black generated during practical chemistry classes.