Abstract
Bromine and chlorine are almost ubiquitous in waste of electrical and electronic equipment (WEEE) and the knowledge of their content in the plastic fraction is an essential step for proper end of life management. The aim of this study is to compare the following analytical methods: energy dispersive X-ray fluorescence spectroscopy (ED-XRF), ion chromatography (IC), ion-selective electrodes (ISEs), and elemental analysis for the quantitative determination of chlorine and bromine in four real samples taken from different WEEE treatment plants, identifying the best analytical technique for waste management workers. Home-made plastic standard materials with known concentrations of chlorine or bromine have been used for calibration of ED-XRF and to test the techniques before the sample analysis. Results showed that IC and ISEs, based upon dissolution of the products of the sample combustion, have not always achieved a quantitative absorption of the analytes in the basic solutions and that bromine could be underestimated since several oxidation states occur after combustion. Elemental analysis designed for chlorine determination is subjected to strong interference from bromine and required frequent regeneration and recalibration of the measurement cell. The most reliable method seemed to be the non-destructive ED-XRF. Calibration with home-made standards, having a similar plastic matrix of the samples, enabled us to carry out quantitative determinations, which have been revealed to be satisfactorily accurate and precise. In all the analyzed samples a total concentration of chlorine and/or bromine between 0.6 and 4 w/w% was detected, compromising the feasibility of a mechanical recycling and suggesting the exploration of an alternative route for managing these plastic wastes.
Highlights
Electronic scrap is considered a peculiar type of waste, containing many different materials such as various metals, fillers, glass fibers, and flame-retardants (FRs) in addition to plastics
Bromine is generally preferred over chlorine because it requires lower quantities of FRs and minimizes the impact of the additive on the polymer’s performance, even if chlorine is present as polyvinyl chloride (PVC) in the electrical wires
Old electronic equipment (EEE) manufactured before 1 July 2006 could be still in use, as they are long life products and higher concentrations of brominated compounds can be found to date in waste of electrical and electronic equipment (WEEE) plastics Wäger et al [4] have shown in their study on hazardous substances regulated under RoHS that, in the sampling campaigns, no fraction of mixed plastic from WEEE is completely free and that other brominated flame retardants (BFRs), which are not regulated by RoHS, were present as well
Summary
Electronic scrap is considered a peculiar type of waste, containing many different materials such as various metals, fillers, glass fibers, and flame-retardants (FRs) in addition to plastics. Chlorinated and brominated organic compounds or polymers are mixed with the plastics used in electric and electronic equipment (EEE) to prevent fire damage [1]. Old EEE manufactured before 1 July 2006 could be still in use, as they are long life products and higher concentrations of brominated compounds can be found to date in WEEE plastics Wäger et al [4] have shown in their study on hazardous substances regulated under RoHS that, in the sampling campaigns, no fraction of mixed plastic from WEEE is completely free and that other brominated flame retardants (BFRs), which are not regulated by RoHS, were present as well
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