Iranian Research Organization for Science and Technology Advances in Environmental Technology 2476-6674 8 4 2022 11 01 Low-cost magnetic char derived from oily sludge for Methylene Blue dye removal: optimization, isotherm, and kinetic approach 329 343 1215 10.22104/aet.2022.5795.1595 EN Saeedeh Rastgar Department of Environmental Sciences, Faculty of Fisheries and Environmental Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran Hassan Rezaei Department of Environmental Sciences, Faculty of Fisheries and Environmental Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran 0000-0002-5022-5078 Habibollah Younesi Department of Environmental Science, Faculty of Natural Resources, Tarbiat Modares University, Noor, Iran Hajar Abyar Department of Environmental Sciences, Faculty of Fisheries and Environmental Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran 0000-0003-1796-3527 Journal Article 2022 08 13 The excessive increase of dye-contaminated wastewater has become an environmental challenge worldwide, menacing human beings, the environment, and the ecosystem. In light of this subject, the current study for the first time evaluated the potential of oily sludge with its intrinsic magnetic characteristics for Methylene Blue adsorption. A single-step pyrolysis approach was employed to convert oily sludge to magnetic char (Fe3O4/Char). The effects of operational parameters such as pH, contact time, Methylene Blue concentration, and adsorbent dose were examined. The maximum adsorption was 84% with a capacity of 88.71 mg/g at a pH of 3, 100 mg/L Methylene Blue concentration, 100 mg Fe3O4/Char concentration, and 120 min contact time. The Redlich-Peterson isotherm model (R2= 0.9854) best described the adsorption experiment, which revealed that the adsorption process followed a mixed adsorption mechanism, namely physical and chemical adsorption. Moreover, the Elovich kinetic model was more suitable to represent the Methylene Blue adsorption onto Fe3O4/Char, confirming a chemisorption process. The significant function of the sludge-based char with high iron content in the adsorption of Methylene Blue provides insight into the inherent potential of oily sludge as a promising approach for removing hazardous dyes.  https://aet.irost.ir/article_1215_a4d2f0d23dcc84ce983ff9157f8b7f88.pdf