Evaluation of Tea Waste as Biobased Sorbent of Cationic Dyes for Wastewater: Kinetic and Thermodynamic Analysis

In this study, methyl blue (MB) is used as representative cationic dye to assess the removal performance of tea waste. The adsorption of the MB using the tea waste is confirmed using FTIR spectral data. The adsorption efficiency is studied on function of various adsorption factors (adsorbent amount, medium concentration, pH, temperature and contact time), in addition of using mathematics models as Lungmer, Freundlich and Temkin models for describing the adsorption of the studied organic color using the tea waste powder. The results confirm that the optimal removal efficiency reaches 93% at a contact time of approximately 60 min, with an adsorbed amount of about 135 mg/g and a pH close to 6.5. The thermodynamic parameters (variation of standard enthalpy ΔH, standard entropy ΔS, and Gibbs free energy ΔG) are also investigated in order to determine the adsorption nature of BM dye on the studied bio-adsorbent. Thereby, the ability of tea waste to remove cationic dye enhances the ability to use it for developing new composite materials for waste water treatment.