Removal of the methyl violet 2B dye from aqueous solution using sustainable adsorbent Artocarpus odoratissimus stem axis

This study investigates the potential of the stem axis of Artocarpus odoratissimus fruit (TSA) as an adsorbent for the removal of methyl violet 2B (MV). The functional group analysis was carried out using Fourier-transform infrared spectroscopy. Investigation of the effects of pH and ionic strength provide insights on the involvement of electrostatic attraction and hydrophobic–hydrophobic attraction between the adsorbent and adsorbates. Kinetics models (pseudo-first-order, pseudo-second-order, Weber–Morris and Boyd) and isotherm models (Langmuir, Freundlich and Dubinin–Raduskevich) were used for characterising the adsorption process. The Langmuir model predicted a high q m of 263.7 mg g−1. Thermodynamics studies indicate the adsorption system is spontaneous, endothermic and physical sorption dominant. The spent adsorbent was successfully regenerated using water and obtained adsorption capacity close to the unused adsorbent even after fifth cycle of washing.