Artocarpus odoratissimus Leaves as an Eco-friendly Adsorbent for the Removal of Toxic Rhodamine B Dye in Aqueous Solution: Equilibrium Isotherm, Kinetics, Thermodynamics and Regeneration Studies

The present study investigates the use of cheap, readily available natural adsorbent, Artocarpus odoratissimus leaves (TL), for the removal of toxic rhodamine B (RhB) dye from simulated wastewater. TL showed resilience when tested in a wide range of pH and was able to maintain its adsorption capacity with the highest removal of RhB at pH 3. Investigation of the effect of ionic strength was carried out using four different salts, namely KNO3, NaCl, NaNO3 and KCl. Of these, only KNO3 influenced the removal of RhB dye, while the other three salts did not show any significant effect. Maximum adsorption capacity, q(max), of 104.96 mg/g was based on the Langmuir isotherm being the best fit model with highest R-2 value close to unity and lowest error values. Adsorptionmechanism followed the pseudo second-order kinetics with rate constant k(2) of 1.274 and 0.616 g/mmol min using 100 and 500 mg/L dye, respectively. Regeneration studies confirmed TL can be regenerated and reused thereby adding value to TL as a potential adsorbent in remediation of dye wastewater. SEM and FTIR were used to characterize the adsorption of RhB onto TL.