Potentiometric electronic tongue-flow injection analysis system for the monitoring of heavy metal biosorption processes

An automated flow injection potentiometric (FIP) system with electronic tongue detection (ET) is used for the monitoring of biosorption processes of heavy metals on vegetable wastes. Grape stalk wastes are used as biosorbent to remove Cu2+ ions in a fixed-bed column configuration. The ET is formed by a 5-sensor array with Cu2+ and Ca2+-selective electrodes and electrodes with generic response to heavy-metals, plus an artificial neural network response model of the sensorʹs cross-response. The real-time monitoring of both the Cu2+ and the cation exchanged and released (Ca2+) in the effluent solution is performed by using flow-injection potentiometric electronic tongue system. The coupling of the electronic tongue with automation features of the flow-injection system allows us to accurately characterize the Cu2+ ion-biosorption process, through obtaining its breakthrough curves, and the profile of the Ca2+ ion release. In parallel, fractions of the extract solution are analysed by spectroscopic techniques in order to validate the results obtained with the reported methodology. The sorption performance of grape stalks is also evaluated by means of well-established sorption models.