Enhanced phosphate remediation of contaminated natural water by magnetic zeolitic imidazolate framework-8@engineering nanomaterials (ZIF8@ENMs)

The efficient enrichment and reutilization of phosphate from natural water still remains a daunting challenge to satisfy the increasingly stringent phosphate discharge criteria. In response to this problem, the presented study successfully synthesizes a series of magnetic zeolitic imidazolate framework-8@engineering nanomaterials (ZIF8@ENMs) via a two-step hydrothermal and coprecipitation method by facilely growing ZIF8 and/or Fe3O4 on various functional ENMs. Structure morphology, chemical composition and hysteresis curve characterizations demonstrate the successful formation of magnetic Fe3O4-ZIF8@ENM. Amongst the prepared magnetic ZIF8@ENMs hybrids, the Fe3O4-ZIF8@ENMs possessing massive hydroxyl groups is demonstrated to harvest the maximum adsorption capacity of 441.7 mg g−1 under neutral condition. Such-acquired adsorption capacity evidently surpass state-of-the-art adsorbents. Systematic assessment of the chemical condition effects on phosphate removal, revealing its conspicuous merits of robust pH independence (94.63–98.20%), high selectivity pinpointing phosphate within complex cations, ease-of-separation and satisfactory recycle. The outstanding performance of magnetic ZIF8@ENMs are mainly derived from the formed strong ZnOP, FeOP and electrostatic interactions between phosphate and adsorbents. Along this line, designing magnetic MOFs-based hybrids towards phosphate are anticipated to be promising avenues for advanced treatment of phosphate-like contaminants and efficient recycle in practical applications.