Researchers developed a nanoscale magnesium oxide-modified pyro-hydrochar composite from Rhus typhina residues to remove fluoride from water, according to a study published on 30 September 2026 in Biochar X.
nMGO/Py-HyC Material Shows High Fluoride Adsorption Capacity
Led by Jiunian Guan’s team at Northeast Normal University, the research evaluated how the nMgO/Py-HyC material handles fluoride under varying conditions. Microscopy showed a porous framework covered with coral-reef-like stacked nanoscale sheets, while diffraction verified crystalline magnesium oxide phases.
The Langmuir adsorption model demonstrated a maximum capacity of 469.64 milligrams per gram at 298 kelvin, while both Langmuir and Freundlich models described the adsorption data well. When tested against a starting fluoride level of 100 milligrams per liter, the material captured 86.44 milligrams per gram, surpassing the combined uptake calculated from its individual components tested separately. Uptake increased sharply during the initial 24 hours before approaching equilibrium after 48 hours.
Thermodynamic analysis confirmed that adsorption occurred spontaneously through substantial chemical interactions. Performance remained statistically stable across pH levels from 5 to 11, though efficiency declined in strongly acidic or alkaline environments. Nitrate and sulfate concentrations up to 10 millimoles per liter caused no significant interference, whereas bicarbonate levels exceeding 1 millimole per liter inhibited fluoride capture.
Increasing ionic strength also reduced uptake, demonstrating that water composition can affect treatment performance. Separate tests with the carbon support and magnesium oxide assessed whether combining them improved performance, and the carbon framework helped expose reactive sites and supported interactions between fluoride and magnesium-containing phases.
A study published in Biochar X on 30 September 2026 by Jiunian Guan’s team, Northeast Normal University, develops a biomass-supported composite with high fluoride uptake through multiple complementary capture mechanisms.#Nano-MgO #Defluoridation Details: https://t.co/8qg4MHsUXl pic.twitter.com/Q91Bc5J3Z4
Broader Remediation Frameworks
Integrations of pyrolyzed carbon into crosslinked polymer hydrogels offer sustainable avenues for wastewater treatment, as examined in a systematic review in Carbon Research titled “Enhancing water remediation using biochar-hydrogel composites: the critical role of surface functional groups” by M. N. Uddin, M. A. H. Badsha, Y. Yang, J. G. Hunter, S. Sherchan, B. Talukder, A. Samwini, and D. H. Kang (2026).
During the biomass pyrolysis process, raw biochar naturally develops oxygen-containing chemical moieties on its surface, including hydroxyl, carboxyl, and carbonyl configurations. To analyze the structural factors that control how well these composites work, the researchers carried out a systematic search of peer-reviewed studies published between 2010 and 2025 across key academic platforms like Web of Science, Scopus, and ScienceDirect.
This carbon composite features a mesoporous texture with a surface area of 693 m2 g-1 and thermal stability up to 230 °C, with Fe3O4/carbon mass ratios of 38% and 58%, offering sustainable potential for applications including electromagnetic interference shielding, microwave absorption, and electrode materials.
