Iranian Research Organization for Science and Technology Advances in Environmental Technology 2476-6674 3 2 2017 04 01 Response Surface Methodology for Optimizing Adsorption Process Parameters of Reactive Blue 21 onto Modified Kaolin 89 98 505 10.22104/aet.2017.505 EN Parvin Gharbani Department of Chemistry, Ahar Branch, Islamic Azad University, Ahar, Iran Azam Nojavan Department of Chemistry, Ahar Branch, Islamic Azad University, Ahar, Iran Journal Article 2017 01 31 In this research modified Kaolin by Cetyltrimethylammonium bromide is used as an adsorbent for the removal of Reactive Blue 21 from aqueous solutions. Response Surface Methodology was used to study the effect of independent variables, such as Reactive Blue 21 dye concentration (20, 40, 60, 80 and 100 mg/L), time (10, 20, 30, 40 and 50), initial pH (2, 4, 6, 8 and 10) and modified Kaolin dosage (0.05, 0.1, 0.15, 0.2 and 0.25 g/50 mL) on dye removal efficiency from aqueous solutions. At the optimum conditions, predicted removal of Reactive Blue 21 by modified Kaolin was 98.26%. The confirmatory experiment was conducted, which confirmed the results by 94.42 % dye removal. Thus, the experimental investigation and statistical approach enabled us to predict Reactive Blue 21 removal by modified Kaolin. Also, the kinetics and isotherm adsorption of Reactive Blue 21 onto modified Kaolin was obeyed pseudo-second order kinetics and Langmuir isotherm. https://aet.irost.ir/article_505_bd1cb70d11d6e8c89d9faa82e77a918b.pdf