High-Efficiency Adsorption of Cr(VI) and Mn(VII) from Wastewater by a Two-Dimensional Copper-Based Metal–Organic Framework

Cr(VI) and Mn(VII)
in industrial wastewater have certain toxicity,
and they pose a threat to the environment and human health and safety.
Metal–organic frameworks (MOFs) usually have rich adsorption
sites and a large specific surface area. They can effectively adsorb
Cr(VI) and Mn(VII) from wastewater. In this paper, a two-dimensional
copper-based metal–organic framework, {[Cu·(4,4′-bpy)2·(H2O)]·2(NO3)·6(H2O)·(CH3OH)}n (1), is synthesized by hydrothermal synthesis. The structure
of 1 is characterized by Fourier transform infrared (IR)
spectroscopy, single-crystal X-ray diffraction, element analysis,
and X-ray photoelectron spectroscopy (XPS). The results showed that 1 had a two-dimensional network structure, and the specific
surface area of the nanostructure was 67.63 m2/g. The nanostructure
of 1 could efficiently adsorb Cr(VI) and Mn(VII) from
wastewater. The adsorption properties of Cr(VI) and Mn (VII) of 1 showed that the optimal concentration of both adsorbents
was 0.2 g/L. It has good adsorption performance in the pH range 4–8.
The adsorption performance is the best when pH is 7, which can reach
145 and 83 mg/g, respectively.