Electrohydraulic Fragmentation of Aluminum and Polymer Fractions from Waste Pharmaceutical Blisters

Abstract

Recently, awareness has been raised concerning the need to decrease the total environmental footprint throughout the life cycle of a medicine, including the packaging materials. Aluminum, a highly energy-intensive metal, is widely used in blister packages together with polymers. However, these blister packages suffer from poor recyclability, with the clear majority of waste blister packages (WBPs) disposed of in municipal solid waste, therefore often being incinerated. In the current study, the separation of aluminum from the polymer in WPBs was investigated to make Al available for direct recycling at a secondary Al facility. The characterization of WPBs (ICP-OES, SEM-EDS, and TGA) showed that the investigated fractions consisted of approximately 10-12 wt % of aluminum, with the clear majority of waste blister mass in the polymer fractions, which consisted of two overlapping layers. Moreover, the polymer layer also gave indications of the presence of Cl. WPBs were subjected to electrohydraulic fragmentation, where the effects of the gap between electrodes (10-40 mm), the amount of pulses (50-500 pulses), pulse frequency (2-5 Hz), and discharge voltage (100-180 kV) on the separation process were systematically investigated. It was shown that at optimal conditions (electrode gap of 40 mm, 300 pulses, frequency of 3 Hz, 130 kV of discharge voltage, and 40 g of initial WPB mass), up to 88% of Al (≥99.4% purity) and polymers were recovered from the investigated waste blister samples. The current study contributes toward improving the circular economy of aluminum as well as the reduction in energy consumption by a new application of electrohydraulic fragmentation for pharmaceutical blister packages.