Efficiently selective extraction of iron (III) in an aluminum‐based metal–organic framework with native N adsorption sites

Separation and recovery of metal ions from wastewater is greatly significant because of the non-negligible harm of heavy metal ions in water to human health and environment. A water-stable aluminum-based metal-organic framework material (MOF-303) with native N adsorption sites is proposed for the selective adsorption and separation of the mixture with heavy metal ions (Fe3+ and Cr3+). This type of material comprises the native N adsorption sites, evenly distributing on the organic linking group. It means that the adsorbent has a smoother transport channel for metal ion, resulting in high adsorption capacity and selectivity. The single-component adsorption results show that MOF-303 has excellent adsorption capacity for Fe3+, up to a maximum adsorption capacity of 104 mg center dot g(-1), which is about 5 times more than the counterpart capacity of Cr3+. Comprehensive separation studies show that the separation of the mixture with these ions can be achieved in the pH range of 1-3, and the selective adsorption is the most efficient. During 30 min of adsorption process, the removal rate of Fe3+ can be attained by 90%. And the adsorption property of this material can be recovered effectively through pickling process. In addition, the adsorption mechanism of MOF-303 is characterized by zeta potential analysis, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FT-IR). Our work shows that MOF-303 is not only a promising material for effective separation of Fe3+ from industrial wastewater but also providing a new perspective the specific adsorption capacity of MOF materials.