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Application of oxidized activated red mud to treat phosphorus-contaminated water

Nguyen Dinh Trung, Ning Ping, Ho Kim Dan

Abstract

Rationale: Oxidized activated red mud (O-RM) materials have a high adsorption capacity for phosphorus, are easy to synthesize, are low-cost, have a short adsorption time, and are readily applicable in practice. Methodology: Morphological and compositional analysis of O-RM materials was performed based on the EDS spectroscopy, XRD diagram, FTIR spectrum, BET surface area, and porosity, as well as SEM and TEM images. Phosphorus content was measured by a colorimetric method based on ISO 6878:2004 standard. Results: This study investigated the activation process of red mud using an oxidation method at a temperature of 100°C. The O-RM materials have a large surface area, while key components such as FeO(OH), Fe2O3, AlO(OH), and Al(OH)3 are preserved. As a result, O-RM materials become the efficient adsorbent for phosphorus with a high adsorption capacity (218.15 mg/g) and a short adsorption time (20 minutes). O-RM materials are inexpensive, easy-to-synthesize, stable, reusable, and environmentally friendly materials, making them a highly promising option for treating phosphorus-contaminated wastewater. Discussion: The morphology and chemical composition of O-RM materials, including FeO(OH), Fe₂O₃, AlO(OH), and Al(OH)₃, have been confirmed. Factors affecting the phosphorus adsorption process by O-RM materials, such as pH, contact time, adsorption thermodynamics, stability, reusability of the material, and the influence of other ions, have also been studied and validated.

EN24076  Accepted 19 August 2025

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