Synthesis of A New Calixarene Derivative and Its Immobilization Onto Magnetic Nanoparticle Surfaces for Excellent Extractants Toward Cr(VI), As(V), and U(VI)

This article describes the synthesis of 5,11,17,23-tetra-tert-butyl-25,27-di(benzhydrazidyhnethoxy)-26,28-dihydroxycalix[4]arene (3) through the treatment of a dialkyl bromide derivative of p-tert-butylcalix[4]arene with benzhydrazide under mild reaction conditions. 5,11,17,23-Tetra-tert-butyl-25,27-di(benzhydrazidylmethoxy)-26,28-dihydroxy-calix[4]arene (3) was characterized by a combination of FTIR, H-1 NMR, and elemental analyses. The macrocyclic building block of the calixarene derivative (3) has been immobilized on silica-based magnetic nanoparticles to receive a new magnetic calixarene derivative (BHCB-MN). 5,11,17,23-Tetra-tert-butyl-25,27-di(benzhydrazidylmethoxy)-26,28-dihydroxy-calix[4]arene immobilized silica-based magnetic nanoparticles (BHCB-MN) were characterized by a combination of Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and thermogravimetric analyses (TGA). Studies regarding the removal of arsenate, dichromate, and uranyl ions from aqueous solutions have also been carried out by using these extractants in both liquid liquid extraction and solid liquid sorption experiments. The extraction results depict that these new calixarene derivatives have good extraction abilities toward dichromate/arsenate and uranyl ions.