Eutrophication, driven by excessive phosphate in water bodies, threatens aquatic ecosystems by causing algal blooms and oxygen depletion. Addressing this issue requires effective and sustainable phosphate (PO43−) removal techniques. Bentonite clay, known for its higher surface area and ion-exchange capacity, is a promising adsorbent but has limited anion adsorption due to its negative charge. Integrating iron oxide (Fe3O4) nanoparticles into bentonite offers a solution, enhancing adsorption while enabling magnetic recovery. In this study, magnetic bentonite clay was synthesized via co-precipitation, incorporating Fe3O4 nanoparticles to improve PO43− adsorption. Characterization using XRD, FTIR, SEM, and BET analysis confirmed successful Fe3O4 nanoparticles integration into bentonite, increasing its surface area from 68.04 to 247.25 m2 g−1. Adsorption experiments optimized parameters like temperature, contact time, adsorbent dose, and pH. This material achieved 87% PO43− removal by attaining the capacity of 5.55 mg g−1, fitting the Langmuir isotherm model. Optimal removal occurred within 60 min at pH 3–7, demonstrating adaptability to varying conditions. Adsorption kinetic experiments revealed pseudo-second-order behavior (R2 = 0.99), indicating chemisorption as dominant mechanism. The thermodynamic analysis confirmed the process was endothermic (∆H° = + 23 kJ mol−1) as well as spontaneous (∆G° = -2.9 kJ mol−1 at 298 K). At higher temperature (333 K), the efficiency was enhanced up to 90%. Comparative analysis highlighted magnetic bentonite’s superior performance over other adsorbents, emphasizing its cost-effectiveness and environmental friendliness. Hence, our study reveals the capability of magnetic bentonite clay as a scalable, viable solution for PO43− decontamination from wastewater. Its high efficiency, ease of synthesis, and magnetic recovery make it suitable for real-world applications. Therefore, the current study advances adsorption technology and contributes to combatting eutrophication, promoting sustainable water management. Future studies can focus on improving the performance of this adsorbent under complex environmental conditions and integrating it into water treatment systems.

Magnetic Bentonite for Efficient Phosphate Removal from Wastewater: A Sustainable Strategy to Combat Eutrophication

期刊论文
发表日期：

2025年11月10日

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Khizar Hussain Shah,
Muhammad Imtiaz Rashid,
Javairia Zubair,
Saba Zafar,
Abdul Amir,
Akhtar Iqbal,
Khurram Shahzad,
Arshid Mahmood Ali

摘要

Eutrophication, driven by excessive phosphate in water bodies, threatens aquatic ecosystems by causing algal blooms and oxygen depletion. Addressing this issue requires effective and sustainable phosphate (PO₄³⁻) removal techniques. Bentonite clay, known for its higher surface area and ion-exchange capacity, is a promising adsorbent but has limited anion adsorption due to its negative charge. Integrating iron oxide (Fe₃O₄) nanoparticles into bentonite offers a solution, enhancing adsorption while enabling magnetic recovery. In this study, magnetic bentonite clay was synthesized via co-precipitation, incorporating Fe₃O₄ nanoparticles to improve PO₄³⁻ adsorption. Characterization using XRD, FTIR, SEM, and BET analysis confirmed successful Fe₃O₄ nanoparticles integration into bentonite, increasing its surface area from 68.04 to 247.25 m² g⁻¹. Adsorption experiments optimized parameters like temperature, contact time, adsorbent dose, and pH. This material achieved 87% PO₄³⁻ removal by attaining the capacity of 5.55 mg g⁻¹, fitting the Langmuir isotherm model. Optimal removal occurred within 60 min at pH 3–7, demonstrating adaptability to varying conditions. Adsorption kinetic experiments revealed pseudo-second-order behavior (R² = 0.99), indicating chemisorption as dominant mechanism. The thermodynamic analysis confirmed the process was endothermic (∆H° = + 23 kJ mol⁻¹) as well as spontaneous (∆G° = -2.9 kJ mol⁻¹ at 298 K). At higher temperature (333 K), the efficiency was enhanced up to 90%. Comparative analysis highlighted magnetic bentonite’s superior performance over other adsorbents, emphasizing its cost-effectiveness and environmental friendliness. Hence, our study reveals the capability of magnetic bentonite clay as a scalable, viable solution for PO₄³⁻ decontamination from wastewater. Its high efficiency, ease of synthesis, and magnetic recovery make it suitable for real-world applications. Therefore, the current study advances adsorption technology and contributes to combatting eutrophication, promoting sustainable water management. Future studies can focus on improving the performance of this adsorbent under complex environmental conditions and integrating it into water treatment systems.