Iranian Research Organization for Science and Technology Journal of Particle Science and Technology 2423-4087 11 1 2025 11 01 Optimization of induced gas flotation parameters for removal efficiency of near-water-density oils using response surface methodology 27 37 1590 10.22104/jpst.2025.7531.1274 EN Sajad Bahador Department of Chemical Engineering, Faculty of Engineering, University of Sistan and Baluchestan, Zahedan, Iran Abdolreza Samimi Department of Chemical Engineering, Faculty of Engineering, University of Sistan and Baluchestan, Zahedan, Iran Davod Mohebbi-Kalhori Department of Chemical Engineering, Faculty of Engineering, University of Sistan and Baluchestan, Zahedan, Iran Journal Article 2025 04 03 Induced gas flotation (IGF) is an efficient physical method for separating dispersed oil from produced water. This study optimized IGF parameters for oils with near-water density (specific gravity ≈ 0.9 g.cm^-3) using response surface methodology (RSM). Experiments evaluated flotation time, air-flow rate, salinity, oil concentration, and temperature. Oil-separation efficiency, defined as the percentage ratio of recovered oil mass to the initial oil mass, was measured in a 2 lit glass column equipped with a silicone-membrane bubbler. The RSM model identified flotation time and salinity as dominant factors (<em>p </em>< 0.05). Optimum conditions (45 min, 0.5 L.min⁻¹ air flow, 20 g.lit⁻¹ salinity, 1000 ppm oil, 20 °C) yielded approximately 70 % removal efficiency, with higher temperatures reducing efficiency due to increased oil solubility. The results confirm the applicability of IGF to challenge near-density oil systems and provide an experimentally validated optimization framework. https://jpst.irost.ir/article_1590_a90c4abad0471c88d1334e93d89d7086.pdf