Edward Hartman Ernest, Maria Stefani, Immanuel Joseph Ondang, Artik Elisa Angkawijaya, Shella Permatasari Santoso, Hsien-Yi Hsu, Felycia Edi Soetaredjo, Kuan-Chen Cheng, Shin-Ping Lin, Chang-Wei Hsieh, Suryadi Ismadji
This study presents a comparative evaluation of phosphate adsorption on pristine ZIF-8 and Fe3O4-doped ZIF-8 (Fe3O4/ZIF-8), a hybrid adsorbent combining high surface area with magnetic separability. Structural integrity and composition were confirmed using SEM, XRD, FTIR, and XPS. Comparative studies on phosphate removal by Fe3O4/ZIF-8 are scarce, and this work provides a direct evaluation against pristine ZIF-8 under identical conditions. ZIF-8 exhibited a higher maximum adsorption capacity (521 mg/g equivalent to 170 mg P/g at 50°C) but slower adsorption rates (k1 = 0.0852–0.1303 min−1). In contrast, Fe3O4/ZIF-8 showed a lower capacity (187 mg/g, 61 mg P/g, at 50°C) but faster kinetics (k1 = 0.1513–0.2533 min−1), along with improved selectivity in the presence of competing anions, and superior reusability, retaining ~60% efficiency after 4 cycles versus ~33% for ZIF-8. Adsorption followed the pseudo-second-order and Sips models, and both materials were effective at acidic to neutral pH. These findings demonstrate that Fe3O4 incorporation does not necessarily increase adsorption capacity but provides operational advantages such as magnetic retrievability, faster adsorption, and greater regeneration stability. The comparative perspective offers valuable insight into the rational design of multifunctional MOF-based adsorbents, positioning Fe3O4/ZIF-8 as a promising candidate for sustainable phosphate removal in complex water environments. © 2025 The Author(s). Asia-Pacific Journal of Chemical Engineering published by Curtin University and John Wiley & Sons Ltd.
Chemical Engineering Master Program, Faculty of Engineering, Universitas Katolik Widya Mandala Surabaya, East Java, Surabaya, Indonesia; Center for Sustainable Resource Science, RIKEN, Yokohama, Japan; Chemical Engineering Department, Faculty of Engineering, Universitas Katolik Widya Mandala Surabaya, East Java, Surabaya, Indonesia; Collaborative Research Center for Zero Waste and Sustainability, East Java, Surabaya, Indonesia; School of Energy and Environment, Department of Materials Science and Engineering, City University of Hong Kong, Kowloon Tong, Hong Kong; Shenzhen Research Institute of City University of Hong Kong, Shenzhen, Hong Kong; Institute of Biotechnology, National Taiwan University, Taipei, Taiwan; Graduate Institute of Food Science and Technology, National Taiwan University, Taipei, Taiwan; Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, Taiwan; Department of Optometry, Asia University, Taichung, Taiwan; School of Food Safety, Taipei Medical University, Taipei, Taiwan; TMU Research Center for Digestive Medicine, Taipei Medical University, Taipei, Taiwan; Research Center of Biomedical Device, Taipei Medical University, Taipei, Taiwan; Department of Food Science and Biotechnology, National Chung Hsing University, Taichung City, Taiwan; Department of Medical Research, China Medical University Hospital, Taichung City, Taiwan