Highly efficient removal from aqueous solution by adsorption of Maxilon Red GRL dye using activated pine sawdust

Pine sawdust, to which sulfuric acid was applied (APSD), was utilized as an inexpensive adsorbent to perform the batch adsorptive removal from a synthetic dye solution of Maxilon Red GRL (MR GRL). The activated adsorbent was characterized by the points of zero charge, FTIR, N-2 adsorption-desorption, SEM, and SEM-EDX analyses. According to the removal results, the highest efficiency of the dye adsorption was reached at 180min. MR GRL removal of 99.35% was achieved using APSD under the optimum conditions (pH=5.7-6.0, temperature=298 K, dye concentration= 250mg/L, and adsorbent dosage=8 g/L). The Langmuir isotherm represents the best explanation model for the experimental data, which has the highest adsorption capacity of 312.5mg/g at 318 K. The compatibility of adsorption with the Langmuir isotherm showed that adsorption was reversible and physical. The other results obtained confirmed this situation. The kinetic research demonstrated that the sorption process was realized in accordance with the pseudo-second-order kinetic model. The thermodynamic parameters revealed that the MR GRL adsorption occurred spontaneously and was exothermic. The findings of the present research confirm that acid-activated pine sawdust may be utilized to remove MR GRL dye from aqueous solutions as a low-cost and efficient adsorbent.