Synthesis of diatomite/Fe3O4/Teff straw activated carbon composite adsorbent for Cr(VI) removal from wastewater
Shewatatek S. Gonfa G. Mekuria S. Tessema B. Kezembayeva G. Ghosh K.S. Mushtaq M. Diyanatizadeh M.H. Isinkaralar K. Hosseini-Bandegharaei A.
July 2025Elsevier B.V.
Results in Chemistry
2025#16
Heavy metal pollution, particularly chromium (Cr), poses a significant environmental challenge. This study addresses this issue by developing a novel composite adsorbent consisting of diatomite (DE), Fe3O4, and an activated carbon from teff straw (TSAC). The nanocomposite was characterized, exploiting FT-IR, BET, SEM, and XRD analyses, revealing a substantial BET surface area of 347.45 m2/g. Response surface methodology (RSM) with central composite design (CCD) was exploited to optimize adsorption parameters, including pH, adsorbent dose, initial Cr(VI) concentration, and adsorption time. Optimal conditions yielded a removal efficiency of 93.28 % at pH 4, an adsorbent dose of 0.024 g/100 mL, an initial Cr(VI) level of 15 mg/L, and an adsorption time of 60 min. The results showed that the Freundlich and Langmuir isotherm models, along with Toth model, best matched the data. This implies that both monolayer and heterogeneous surface adsorptions are the main mechanism, with a maximal sorption capacity of 131 mg/g and followed the pseudo-second-order kinetic model. Thermodynamic analyses uncovered the spontaneous and endothermic nature of the Cr (VI) adsorption by DE/Fe3O4/TSAC. The composites recyclability was demonstrated over five cycles, maintaining significant removal efficiency. Such findings highlight the potentials of the DE/Fe3O4/TSAC composite for effective Cr (VI) removal from water, offering a promising solution to mitigate chromium pollution.
Adsorption properties , Chromium (VI) adsorption , Diatomite , Magnetic composite adsorbent , Sustainability , Teff straw waste
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Department of Chemical Engineering, Addis Ababa Science and Technology University, Addis Ababa, 16417, Ethiopia
Biotechnology and Bioprocess Center of Excellence, Addis Ababa Science and Technology University, Addis Ababa, 16417, Ethiopia
Nanotechnology Center of Excellence, Addis Ababa Science and Technology University, Addis Ababa, 16417, Ethiopia
Mining and Metallurgical Institute named after O.A. Baikonurov, Department Chemical Processes and Industrial Ecology, Satbayev University, Almaty, Kazakhstan
Department of Chemistry, National Institute of Technology Hamirpur, Hamirpur, India
Department of Chemistry, Government College University Lahore, Pakistan
Research & Development Division, Zarmehr Tehran Oxin Co., Shahrak Gharb (Ghods), Tehran, 1468943815, Iran
Department of Environmental Engineering, Faculty of Engineering and Architecture, Kastamonu University, Kastamonu, 37150, Turkey
Faculty of Chemistry, Semnan University, Semnan, Iran
Research and Innovation Cell, Rayat Bahra University, Punjab, Mohali, India
Department of Sustainable Engineering, Saveetha School of Engineering, SIMATS, Tamil Nadu, Chennai, 602105, India
Department of Chemical Engineering
Biotechnology and Bioprocess Center of Excellence
Nanotechnology Center of Excellence
Mining and Metallurgical Institute named after O.A. Baikonurov
Department of Chemistry
Department of Chemistry
Research & Development Division
Department of Environmental Engineering
Faculty of Chemistry
Research and Innovation Cell
Department of Sustainable Engineering
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