Development of Zinc Oxide-Sawdust Composite Adsorbent for Methylene Blue Removal: Synthesis, Characterization, and Adsorption Mechanism

Abstract

The natural world provides sawdust, also known as wood shaving, which is a reasonably abundant and affordable lignocellulosic compound. It is a waste product of agriculture and industry that is abundant and has disposal issues. A zinc oxide nanocomposite based on sawdust (ZnO@SD) was synthesized to efficiently remove the dye methylene blue (MB) from aqueous solutions. FTIR, SEM, TEM, and XRD analyses were used to characterize the freshly made sawdust material. Trial and error was used to optimize the adsorption experimental parameters, including initial dye concentration, contact time, solution pH, temperature, and adsorbent dosage, in order to achieve the maximum removal of MB dye from wastewater. To forecast the behavior of the system, the obtained experimental results were applied to various theoretical models. For an initial MB dye concentration of 50 mg/L, the ideal parameters for the maximum removal of MB dye from aqueous solution were determined to be: 40 mg of adsorbent, 80 minutes of contact time, a pH of 6.0 solution, and 25 °C. The models that best fit the examined experimental data were Freundlich and pseudo-second order. For removal of MB dye, the Langmuir maximum monolayer-adsorption capacity of ZnO@SD was found to be 555.5 mg/g. According to the obtained results, the novel material was thought to be an inexpensive and efficient adsorbent material for wastewater dye removal.