Efficient Removal of Cationic Dyes From Aqueous Solutions Using the Low-Cost Algerian Olive Cake Waste Adsorbent

The objective of our study was to evaluate the operating conditions for the removal of two dyes used in the textile industry, namely methylene blue (MB) and yellow basic 28 (BY28), from aqueous solutions. To do this, the low-cost agricultural Algerian olive cake waste (AAOCW) was used as an adsorbent. Equilibrium and kinetics tests were performed to define the applicability of this new adsorbent for the removal of selected dyes. The adsorption of the dyes on the AAOCW depends on the nature of the dye, the contact time, the pH, the initial concentration, and the amount of adsorbent. Two kinetic models including pseudo-first order and pseudo-second order were used to analyze the kinetic experimental data. The pseudo-second-order model provides the best results, suggesting that the chemisorption of dyes on the surface of the adsorbent plays an important role in the overall kinetics of the process. Finally, the characterization of the experimental isothermal data of MB and BY28 adsorption on AAOCW was performed using the Langmuir and Freundlich isotherms. Good fit results were obtained. The maximum adsorption capacity in monolayer was 25.98 mg g−1 and 38.95 mg g−1 for MB and BY28, respectively. The proposed adsorbent is a suitable candidate for removing dyes from aqueous media.