Maria Stefani, Kuan-Chen Cheng, Theresia Angeline Veronica, Shella Permatasari Santoso, Edward Hartman Ernest, Shin-Ping Lin, Jindrayani Nyoo Putro, Wiyanti Fransisca Simanullang, Hsien-Yi Hsu, Chang-Wei Hsieh, Suryadi Ismadji
Lead (Pb2+) contamination in water poses persistent environmental and public health risks, driving the need for efficient and sustainable treatment technologies. In this study, a process-intensified and low-energy route is developed to valorize peanut shell waste into a high-performance sulfonated carbon adsorbent via an integrated dilute acid hydrolysis and simultaneous sulfonation–partial carbonization (DAH–SS-PC) strategy. The DAH step partially hydrolyzes the lignocellulosic matrix while generating a sugar-rich hydrolysate as a value-added co-product and retaining a reactive solid precursor. Subsequent low-temperature SS-PC treatment (80–120 °C) introduces sulfonic and oxygen-containing functional groups, yielding a chemically heterogeneous surface enriched with coordination-active sites. The optimized SPS-Char exhibits a high Pb²⁺ adsorption capacity of 3126.9 mg/g, while sigmoidal modeling yields an apparent asymptotic capacity of 3711.9 mg/g. The adsorption behavior deviates from classical monolayer models and follows a sigmoidal isotherm, indicating cooperative, multi-site adsorption driven by heterogeneous surface chemistry. Kinetic analysis reveals pseudo-second-order behavior, consistent with coordination-driven adsorption. Spectroscopic evidence (FTIR and XPS) confirms the involvement of sulfonic and oxygen-containing groups in Pb2+ binding through surface complexation. The adsorbent maintains high removal efficiency under competitive ionic conditions, highlighting its selectivity and robustness in complex aqueous environments. This work establishes a clear structure–function relationship linking low-temperature synthesis, surface chemical heterogeneity, and cooperative adsorption, offering a scalable and energy-efficient pathway for advanced heavy metal remediation. © 2026 Elsevier Ltd.
Chemical Engineering Master Program, Faculty of Engineering, Universitas Katolik Widya Mandala Surabaya, Jl. Kalijudan No. 37, East Java, Surabaya, 60114, Indonesia; Institute of Food Science and Technology, National Taiwan University, Daan District, Taipei City, 10617, Taiwan; Institute of Biotechnology, National Taiwan University, No. 1, Section 4, Roosevelt Rd., Taipei, Taiwan; Department of Optometry, Asia University, 500, Lioufeng Rd., Taichung, Wufeng, Taiwan; Department of Medical Research, China Medical University Hospital, China Medical University, 91, Hsueh-Shih Rd., Taichung, Taiwan; Department of Food Science, Fu Jen Catholic University, No. 510, Zhongzheng Rd., Xinzhuang Dist., New Taipei City, 242062, Taiwan; Chemical Engineering Department, Faculty of Engineering, Universitas Katolik Widya Mandala Surabaya, Jl. Kalijudan No. 37, East Java, Surabaya, 60114, Indonesia; School of Food Safety, Taipei Medical University, 250 Wu-Hsing Street, Taipei, 11031, Taiwan; Ph.D. Program in Drug Discovery and Development Industry, College of Pharmacy, Taipei Medical University, 250 Wu-Hsing Street, Taipeif, 11031, Taiwan; Research Center of Biomedical Device, Taipei Medical University, 250 Wu-Hsing Street, Taipei, 11031, Taiwan; Research Center for Chemistry, National Research and Innovation Agency of the Republic of Indonesia, Jakarta, 10340, Indonesia; School of Energy and Environment, Department of Materials Science and Engineering, Centre for Functional Photonics (CFP), City University of Hong Kong, Kowloon Tong, Hong Kong; Shenzhen Research Institute of City University of Hong Kong, Shenzhen, 518057, China; Department of Food Science and Biotechnology, National Chung Hsing University, South Dist., Taichung City, 402202, Taiwan; Department of Food Science, National Ilan University, Shennong Road, Yilan City, 260007, Taiwan; Department of Medical Research, China Medical University Hospital, Taichung City, 404333, Taiwan