Removal of chromium from electroplating wastewater using chitosan-coconut shell composite: kinetics, thermodynamics and artificial neural networks modeling

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F. Batool, T.A. Kurniawan, B. Pasaribu, T.D. Kusworo, S. Silviana, H.S. Kusuma, M.I. Khan, S. Haddout, J.C.C. Casila, H. Harianingsih, W.O. Choo, M.A. Iqbal

2025 International Journal of Environmental Science and Technology Vol. 22 Issue 15 Article Cited by 4 Quartile Top Tier

Abstract

The electroplating industry releases large volumes of wastewater contaminated with toxic chromium, posing significant risks to both the environment and public health. Although progress has been made in water pollution control, the application of composite adsorbents for chromium removal, combined with simulations for process optimization, remains underexplored. In this study, the effectiveness of a chitosan-coated coconut shell composite in removing chromium from electroplating wastewater was investigated. Under optimal conditions (4 g/L dosage, pH 6.5, 308 K temperature, 200 rpm speed and 60 min time) the composite removed 99% of Cr and outperforming both chitosan and coconut shell. The adsorption process followed pseudo-second-order kinetics (R2 = 0.999) and the Langmuir isotherm with a maximum adsorption capacity of 66.66 mg/g. The adsorption efficiency increased with temperature (298–313 K), indicating an endothermic process. The composite retained 98% of its initial capacity after regeneration with HNO3, demonstrating its cost-effectiveness over multiple cycles. Simulations using artificial neural networks (ANNs) accurately predicted adsorption behavior by achieving a mean square error (MSE) as low as 0.0016. However, despite high Cr removal, the treated effluents did not meet legislative discharge standards, highlighting the need for further biological treatment using activated sludge. © The Author(s) under exclusive licence to Iranian Society of Environmentalists (IRSEN) and Science and Research Branch, Islamic Azad University 2025.

Affiliations

Department of Chemistry, Division of Science and Technology, University of Education, Lahore, 54770, Pakistan; College of the Environment and Ecology, Xiamen University, Fujian, Xiamen, 361102, China; Department of Marine Sciences, Faculty of Fisheries and Marine Sciences, University of Padjadjaran, Jatinangor, 45363, Indonesia; Department of Chemical Engineering, Faculty of Engineering, Diponegoro University, Semarang, 50275, Indonesia; Department of Chemical Engineering, Faculty of Industrial Technology, Universitas Pembangunan Nasional “Veteran” Yogyakarta, Yogyakarta, Indonesia; Department of Mechanical Engineering, College of Engineering, Prince Mohammad Bin University, Al Khobar, Saudi Arabia; Department of Physics, Faculty of Science, Ibn Tofail University, B.P. 133, Kenitra, Morocco; Land and Water Resources Engineering Division, IABE, CEAT, University of the Philippines-Los Baños, Laguna, Philippines; Department of Chemical Engineering, Universitas Negeri Semarang, Semarang, Indonesia; Faculty of Data Science and Information Technology, INTI International University, Persiaran Perdana, Negeri Sembilan, Putra Nilai, 71800, Malaysia; Department of Chemistry, University of Management and Technology, Lahore, Pakistan