Novel composite sorbents based on carbon fibers decorated with ferric hydroxides – simultaneous removal of antimonate and arsenate from aqueous solutions

The competitive adsorption of antimonate and arsenate on carbon fibers decorated with ferric hydroxide (CF-Fe) has been investigated at different pH and temperatures. Tap and drinking water samples spiked with unitary and binary solutions were subjected to kinetic tests and compared with distilled water media. As the required time for attaining the arsenate concentration permitted by law, the legal limit was found as 3 hours for drinking and tap water systems. It was shown that arsenate can be adsorbed more strongly than antimonate. Such multiple adsorption/desorption cycles showed that the CF-Fe sample had approximately 96% of the first antimonate adsorption at the seventh cycle. X-ray photoelectron spectroscopy (XPS) analyses were performed in order to obtain insight into the adsorption mechanism.