A Novel Approach to Investigate Bromine Content in E-Waste Plastic By Short Wave Infrared Spectroscopy

Brominated Flame Retardants (BFRs) are toxic for the environment and harmful for human health and animals. Those chemical substances are mainly used in plastics for its property to increase fire resistance and delay/avoid flames, especially in Electrical and Electronic Equipment (EEE). In the last decades, have been introduced different prohibitions on production and utilization of some families of BFRs. For these reasons, is of utter importance to develop sustainable correct actions of recycling. Nowadays, Plastics containing BFRs are sorted by dense medium, however plastics containing other kind of additives are lost in underflow by using these traditional methods. Thus, the necessity of using a technology, which is low cost, effective, reliable, sustainable and with a low environmental impact. The aim of this study was to test whether SWIR (Short Wave InfraRed) spectroscopy can be used as a tool for testing the bromine concentration plastics coming from an e-waste stream of CRT (cathode-ray tube) monitors and televisions. In order to achieve this goal, X-Ray Fluorescence (XRF) analysis was performed on plastic scraps and used as reference method. An ASD FieldSpec® 4 Standard-Res portable spectroradiometer working in VIS-SWIR was used for collecting spectra on samples. Chemometric methods were adopted for setting up models able to discriminate bromine content. More in detail, Principal Component Analysis (PCA) was used as exploratory tool. While, Partial Least Squares (PLS) and Locally Weighted Regression (LWR) – based on PLS regressions were used as multivariate regression models for testing the ability of the spectra to predict bromine content.