Removal of indomethacin from water using covalent organic polymers

In recent years, the massive use of pharmaceuticals has led to the detection of a large number of relevant residues in water. As emerging contaminants, pharmaceuticals residues in the environment pose a major threat to human health and ecosystems. Covalent organic polymers (COPs) possess high stability, uniform pore size, and easy functionalization, which have attracted great attention in water treatment. In this study, a novel covalent organic polymer was successfully studied by a simple synthesis method, combining p-phenylenediamine (Pd) and isophthalaldehyde (Is) via a Schiff-base (referred to PdIs-COP), which was used as an absorbent for the removal of indomethacin from aqueous solutions. The composite was characterized with scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) specific surface area and thermogravimetric (TGA) analysis. The effect of changes in the pH values and the adsorption time on the adsorption capacity was also investigated. The results of this study indicated that the absorbent had a high adsorption capacity for indomethacin. The adsorption capacity of PdIs-COP for indomethacin is 92.86 mg g−1 at pH of five and a contact time of 2 min. This shows that PdIs-COP is a novel material with good affinity for pharmaceuticals.