Food dye adsorption in single and ternary systems by the novel passion fruit peel biochar adsorbent

This study evaluated the passion fruit peel biochar (PFPB) as a novel adsorbent for synthetic food dyes indigotine blue (IB), tartrazine yellow (TY), and ponceau 4R (P4R) removal in single and ternary systems. A macroporous structure and a predominance of basic groups characterized PFPB. The pH study revealed better adsorption at pH 2.0. The response surface methodology optimization for adsorbent dosage and temperature predicted removal efficiencies of 100 % for IB, 79.8 % for TY, and 84.4 % for P4R. Elovich and Redlich-Peterson models better described kinetic and equilibrium, respectively, suggesting the contribution of chemical interactions. Thermodynamic data revealed endothermic, with an inordinate degree and spontaneous adsorption. In the ternary systems, antagonistic effects of interaction were noticed. The adsorption of synthetic effluents showed promising results with removal efficiencies of 99.6 % (IB), 60.2 % (TY), and 51.8 % (P4R). Therefore, we concluded that PFPB is a potential alternative low-cost synthetic food dye removal adsorbent. [Display omitted] •Passion fruit peel biochar (PFPB) for IB, TY, and P4R adsorption.•Elovich and Redlich-Peterson models for kinetic and isotherm of food dyes onto PFPB.•Ternary adsorption showed antagonic effects for the food dyes investigated.•PFPB adsorbed 99.6% of IB, 60.2 % of TY, and 51.8 % of P4R from synthetic wastewater.•Electrostatic attraction and hydrogen and covalent bonding as adsorption mechanisms.