Adsorption of perfluorooctane sulfonate on carbonized poly-melamine-formaldehyde sponge
Ruiming Zhang1, Zhibiao Hu2, Huanhuan Wei3
1College of Chemistry and Materials, Longyan University, Fujian 364012, China; Fujian Provincial Colleges and University Engineering Research Center of Solid Waste Resource Utilization (Longyan University), China; Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ, United States of America.
Abstract:
In this study, we developed a simple carbonized poly-melamine-formaldehyde sponge (CMF) acting as an adsorbent for adsorbing perfluorooctane sulfonate (PFOS) from the waste poly-melamine-formaldehyde (MF) sponge. The PFOS removal by the developed adsorbent was comprehensively investigated using batch adsorption, including kinetics, isotherm, ionic strength and ionic type and pH edge. PFOS adsorption kinetics followed a pseudo-second-order kinetic model, and reached equilibrium within 3 min. The adsorption isotherm was well described by the Freundlich model, as well as by the Langmuir model at a low initial concentration. The adsorption capacity gradually decreased with the increase of pH, and it was up to 216.4 μg/g even at pH 12.1. However, the adsorption capacity increased with the increase in ionic strength. Furthermore, the co-existing ions and small organic acids also promoted the PFOS adsorption on CMF sponge to different extents. Both the hydrophobic interaction and electrostatic attraction played an important role on adsorption, as well as chemical interaction and hydrogen bonding from spectroscopic results.
