Characterization of input material, benchmarking of cleaning processes

One of the main tasks of Work Package (WP) 4 of the European project CIRCULAR FoodPack comprises the analytical characterization and monitoring of recyclates’ quality at different stages of the recycling process. This is essential as the quality of the input materials as well as the performed recycling treatments (such as deodorization, water-based de-inking, solvent-based process) are assumed to have a significant impact on the presence of migratable components in the recyclate material produced within the project. For the assessment of quality, the chromatographic fingerprint of the various recyclates as well as of various waste samples was characterized by screening techniques (such as Headspace GCMS, GC-FID/MS with liquid injection, HPLC-HRMS) and (semi-)quantification of residual contents. Furthermore, the content of inorganic components in the material as a marker for the fate of pigment and tracer substances was performed by ICP-MS. In addition to the instrumental analyses, the presence of mutagenic substances in the recyclates must be excluded since mutagenicity is regarded as the most critical toxicological parameter. This was done using AMESbased bioassays. From the analyses performed on three different waste samples as an input material, it could be concluded that the samples contain a high amount of both saturated and unsaturated hydrocarbons as well as a variety of volatile, semi-volatile and non-volatile contaminants. In addition, mutagenicity was observed by bioassays. It was concluded based on the experiments that the quality of the PE waste samples must improve significantly for the use in food contact applications. In the investigated samples of different recycling steps, a range of different contaminants was detected in addition to chemical compounds typically found in laminate structures. The results of these analyses are used to set up a database as reported in Deliverable 4.5. Furthermore, the (semi-)quantification results on substances contained in the recycled material serve as a basis to calculate the theoretical migration into food taking into account the barrier properties of the laminate structure as evaluated within Task 4.5. This is reported in Deliverable 4.6. Using biological assays, mutagenicity was observed in the sample after recycling (100 % Project PCR monofilm from Loop3 Cycle1), which is in line with literature data. Inorganic pigments based on copper and titanium were selected as marker substances for the used printing inks. The removal of these elements was the basis to assess the capability of the investigated CIRCULAR FoodPack treatment steps and technologies to remove printing ink components. By ICP-MS measurements, the obtained data on the reduction efficiencies showed that the investigated treatment steps and technologies are not yet sufficient to achieve the envisaged > 99.5 % ink removal (based on the investigated inorganic elements as representative printing ink components). Note: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 101003806.