Cost-effective and eco-friendly synthesis of MIL-101(Cr)-CS from chromium-containing sludge waste and its exploration of adsorption anddehumidification performance

Abstract

In the context of a circular economy, there is an increasing need for more sustainable waste management solutions to recycle and utilize elements in waste. Chromium-containing sludge is a common and difficult to treat industrial waste, but there is currently no effective treatment method to recycle the “chromium resource” in it. On the other hand, the metal-organic framework material MIL-101(Cr) has high specific surface area and large pore volume, good thermal and chemical stability, usually analytically pure Cr(III) is used with the help of hydrofluoric acid (HF) which salt is prepared, and its preparation cost is high, and HF is toxic and harmful to the environment. Here, we report a new method for treating industrial chromium-containing sludge. The method uses the chromium in the chromium-containing sludge as the chromium source, and adopts X-ray diffraction (XRD), scanning electron microscope (SEM), infrared and pore size analysis. The experimental results show that the particle morphology of MIL-101(Cr)-CS synthesized from chromium-containing sludge as chromium source is similar to that of MIL-101(Cr)–HF prepared from analytical pure Cr(III). High specific surface area (2412 ​m2/g), large pore volume (1.83 ​m3/g). Furthermore, adsorption experiments show that MIL-101(Cr)-CS has a higher adsorption capacity for CO, CO2, and gaseous water, which makes it a potential candidate for some dehumidification devices and flue gas treatment. This work provides a new idea for the high-value utilization of “chromium resources” in chromium-containing wastes.