SYNTHESIS AND CHARACTERIZATION OF PES COPOLYMERS WITH CARBOXYL UNITS AS METAL RECOVERING MATERIALS

Aromatic polyethersulfone is one of the most used polymeric material for many technological applications. This material possesses a high hydrophobicity, which leads to biofouling phenomena. In order to prepare materials with an optimal balance of hydrophobic and hydrophilic character, a series of aromatic polyethersulfones containing different percentages of 4,4-Bis(4-hydroxyphenyl) pentanoic acid (DPA) units in the main chains was synthesized1. The structure of these polymers show a random distribution of DPA units along the chains, according to a statistical Bernullian theoretical model. Thermal analysis (DSC) shows that the Tg values of copolymers decrease as the amount of DPA units increase. The thermal degradation of the copolymers occurs at a lower temperature with respect to pure PES2,3 due to the presence of DPA units which decompose by losing CO2. For recovering heavy metals from water medium, membranes of PES-DPA copolymers were prepared by electrospinning from DMF solution (Fig.1). Metals (lead, chromium, zinc, cadmium, copper) were recovered by dipping the membrane in aqueous solutions with a concentration of 50ppm, for each metal, and the solution was analysed by ICP-MS. The results show that membranes are able to recovery up to 85% of lead already after 5 minutes of dipping.