Synthesis of Highly Efficient and Recyclable Bimetallic Co-Fe-MOF for the Synthesis of Xanthan and Removal of Toxic Pb and Cd Ions.

Mono-(Fe) and bimetallic Co-Fe-MOF with different Co and Fe contents was successfully synthesized by the solvothermal method. The structural properties of the prepared samples were characterized by X-ray diffraction, transmission electron microscopy (TEM), Brunauer-Emmett-Teller specific surface area, and Fourier transform infrared spectroscopy. The results revealed the successful formation of mono and mixed Co-Fe-MOF. Also, the results of TEM displayed that the particle structure of Co-Fe-MOF changed to octahedral after the addition of cobalt. The surface acidity results illustrated that the samples showed both Lewis and Brønsted acid sites, and Co-Fe-MOF possessed more surface acidity than Fe-MOF. The catalytic performance of the prepared samples was tested by synthesis of 14-phenyl-14-dibenzo [a, j] xanthene (xanthene), and bimetallic Co-Fe-MOF showed higher activity compared to monometallic Fe-MOF. The sample with Co-Fe-MOF gave the highest yield of xanthene with 90.2%. In addition, the prepared samples were used for removal of Pb and Cd ions from the aqueous solution. The sample with Co-Fe-MOF showed the highest removal efficiency compared with mono- and other bimetallic samples. The results illustrated that the addition of Co to Fe enhanced the structural properties, acidity, and catalytic performance of the prepared samples due to the synergistic effect between Fe and Co ions. According to the obtained results, the prepared samples showed great potentials for the synthesis of pharmacologically active compounds and environmental protection.