Hair dying is a continuously growing industry of personal care. This growth increases the release of colored solutions into water, which needs remediation techniques that are appropriate and cost-effective. This study proposes the use of spent tea leaves for the elimination of the basic yellow 57 (BY57) hair dye. American (GT), Peruvian (PGT) and decaffeinated (DGT) spent tea leaves were used in batch experiments to eliminate BY57 at room temperature. Equilibrium parameters like pH, adsorbent mass, dye concentration, salinity, and effect of the presence of heavy metals and crowding agents were investigated to maximize dye removal. DGT shows the highest adsorption (qmax = 57 mg g-1) at pH = 8 with only 100 mg of adsorbent. Adsorption was modeled by Langmuir and Freundlich theories and followed the trend: DGT>PGT>GT. Salinity and presence of a crowding agent decreased adsorption. Heavy metals had negligible effect on the adsorption onto DGT and GT. Desorption experiments indicate that diluted HCl is able to recover the adsorbent and recycle the adsorbents in repetitive cycles. Finally, point zero charge, surface area and porosity, and scanning electron microscopy indicate that the surface ionization and morphology are appropriate for the use of these novel materials as a model hair dye in the removal of BY57 from aqueous solutions.
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