Synthesis and evaluation of chromate and arsenate anions extraction ability of a N-methylglucamine derivative of calix[4]arene immobilized onto magnetic nanoparticles

In this study, 5,17-bis-[(N-methylglucamine)methyl]-25,26,27,28-tetrahydroxy-calix[4]arene (3) was synthesized by the treatment of calix[4]arene with a secondary amine N-methylglucamine and formaldehyde. The calixarene derivative (3) was characterized by a combination of FTIR, 1H NMR and elemental analyses. Followingly, using the macrocyclic building block, the compound 3 was immobilized by [3-(2,3-epoxypropoxy)propyl]trimethoxysilane-modified Fe3O4 magnetite nanoparticles (EPPTMS-MN). The prepared calix[4]arene immobilized material was characterized by a combination of Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and thermogravimetric analyses (TGA). Moreover, the studies regarding the removal of arsenate and dichromate ions from the aqueous solutions were also carried out by using the compound in solid-liquid extraction experiments. It was found that the calix[4]arene-based magnetic material has high extraction ability towards dichromate and arsenate anions in 66% (at pH 1.5) and in 86% (at pH 3.5), respectively.