Synthetic zeolite materials from recycled glass and aluminium food packaging as potential oenological adjuvant

Glass and aluminium packaging materials were recycled, in the perspective of circular economy, to synthetize potassium and sodium zeolitic materials (Zeo-K and Zeo-Na) through an alkaline hydrothermal treatment. Both materials were then tested as oenological adjuvants for the removal of riboflavin (300 mu g L-1) from a model wine solution, to prevent the light-struck taste defect that can be caused in white and rose ' wines by light exposure during storage or consumption. Suspension tests revealed that Zeo-Na at 1 g L-1 removed 15 % riboflavin in 16 h, similarly to what removed by a commercial bentonite at the same concentration. To reduce the riboflavin concentration below the risk threshold, 50 g L-1 Zeo-Na were required. Effectiveness of Zeo-K was slightly lower compared to Zeo-Na, possibly due to the lower crystallinity, cation exchange capacity and porosity of this zeolitic material. A higher removal efficiency and time saving were obtained by filtration using columns packed with Zeo-Na. Weak bonding and physical entrapment are suggested as potential mechanisms for riboflavin sorption by zeolites.