ABSTRACT
The application of raw fish tail palm tree (Caryota urens) seed powder (RCUS), surface-modified powder (SMCUS), and ultrasonicated powder (UACUS) materials for the removal of methylene blue (MB) dye from aqueous solutions has been investigated under various operating conditions. Adsorbents were characterized by SEM, EDX, XRD, and FTIR analysis. Batch adsorption experimental studies were conducted by varying pH, adsorbent dose, initial MB dye concentration, temperature, and contact time. Optimum conditions for the adsorption of MB dye onto the adsorbent were found to be pH = 6.0; adsorbent dose of RCUS = 10 g/L, SMCUS = 2 g/L, UACUS = 1 g/L; contact time of RCUS = 60 minutes, SMCUS = 30 minutes, UACUS = 40 minutes; temperature = 30°C; and initial MB dye concentration = 50 mg/L. Adsorption isotherm data were analyzed by the Langmuir, Freundlich, Dubinin–Radushkevich, and Redlich–Peterson isotherm models. Experimental data were more successfully fitted with the Freundlich model than with the other isotherm models, and the maximum monolayer adsorption capacity was found to be 246.2, 117.4, and 23.59 mg/g for RCUS, SMCUS, and UACUS, respectively. Adsorption kinetics were tested with pseudo-first-order, pseudo-second-order, and Elovich kinetic models. The kinetic results indicated that the adsorption process follows the pseudo-first-order kinetic model. The results of this study show that the UACUS as well as SMCUS could be used as an effective and low-cost adsorbent for the removal of dyes from aqueous solutions.
