Resource mining from stainless steel pickling wastewater to produce metal-organic frameworks

Metal-organic frameworks (MOFs) exhibit large potential in many fields while the high cost limits their large-scale use. Herein, stainless steel pickling wastewater was successfully transformed to Fe/Cr-MIL-100, during which Ni2+ was largely purified. As an integration of metal, solvent and acid modifier, the use of the wastewater simplifies the preparation units and reduces the cost of MOFs. Conversion of the pickling wastewater to MOFs is feasible under wide reaction conditions and is not interfered by discharge batch of the wastewater. The obtained MIL-100 s products exhibit excellent porosity, long-term acid/base stability, and large adsorption capacities for methylene blue, moxifloxacin hydrochloride, and zirconium (IV) ion. Thus, our work provides a new insight for effective reuse of industrial wastewater and a feasible method for reducing MOFs cost.