Modified alginate beads as biosensor and biosorbent for simultaneous detection and removal of cobalt ions from aqueous solution

A novel biomaterial was prepared to simultaneously detect and remove cobalt ions from aqueous solution by modifying alginate (AG) polymer with a high selectivity and sensitive indicator for Co 2+ , 4-(5-chloro-2-pyridylazo)-1,3-phenylenediamine (5-Cl-PADAB). The analysis of FT-IR spectra proved that 5-Cl-PADAB was covalently connected to AG. The modified AG beads can effectively adsorb Co 2+ and indicate the presence of Co 2+ in aqueous solution. After adsorption of Co 2+ , the color of the modified AG beads changed from yellow to pink, resulting in a noticeable change, which can be observed by naked eyes. The adsorption of Co 2+ by the modified AG beads can be described by pseudo second-order kinetic model and the Freundlich isotherm model. The AG bead modified with an indicator is a promising biosensor and biosorbent for simultaneous detection and removal of cobalt ions from aqueous solution. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 260–266, 2018