Kinetics and Isotherm Analysis of Methylene Blue Adsorption Onto Layered Tungsten Disulfide for Water Purification

Abstract Tungsten disulfide nanosheets (WS 2 NS) have emerged as promising materials for environmental remediation due to their distinctive physicochemical properties. In this study, WS 2 NS were synthesized via a single‐step solvothermal method using dimethylformamide (DMF) as the solvent. Structural, morphological, and elemental analyses were carried out using XRD, FESEM‐EDAX, FTIR, UV–vis, BET, and XPS techniques, confirming the formation of sheet‐like WS 2 with high surface area. The adsorption performance of WS 2 NS was evaluated for methylene blue (MB) dye removal under batch conditions. Notably, 87% of MB was removed within 5 min at neutral pH, demonstrating the material's excellent potential for rapid water purification. Key parameters such as contact time, pH, and adsorbent dosage were systematically studied to optimize the adsorption process. The adsorption behavior followed the Langmuir isotherm and pseudo‐second‐order kinetic models, indicating monolayer chemisorption as the dominant mechanism. Desorption and reuse studies further confirmed that WS 2 NS maintained high removal efficiency across five cycles, highlighting their stability and reusability. These findings emphasize that WS 2 NS are efficient, fast‐acting, and sustainable adsorbents suitable for the treatment of dye‐contaminated industrial and domestic wastewater.