TY - THES

T1 - Development of analytical methods to quantify technology-critical metals in e-waste for recycling assessments

AU - Feiner, Laura

N1 - embargoed until 27-09-2026

PY - 2024

Y1 - 2024

N2 - The aim of optimising the European circular economy and recycling efficiency to reduce the environmental impact goes alongside increasing the recycling rates of electrical and electronic waste and developing efficient recycling technologies. This will further prevent future supply risks and promote Europe's autonomy. The global monitoring of mass flows of WEEE, the creation of an official database and the determination of material compositions are fundamental requirements for the development of sustainable management solutions. Standardized and harmonized analysis methods and certified reference materials should be established to ensure the comparability of measurement results. The master¿s thesis was conducted as part of the EU project MetroCycleEU, which was founded with the aim of developing strategies for sampling and sample preparation of e-wastes as well as developing harmonized multi-element methods for measuring technology-critical elements in urban wastes. As part of this project certified reference materials for lithium-ion-batteries, light-emitting diodes and printed circuit boards were developed and characterised during an interlaboratory comparison. In order to investigate the reliability of selected analysis methods, as well as possible sources of bias in the preceding sample preparation all three types of WEEE were characterized in the course of this master's thesis. As measurement techniques inductively coupled plasma tandem mass spectrometry (ICP-MS/MS), microwave plasma atomic emission spectrometry (MP-AES) and both XRF-techniques energy-dispersive (EDX) and wavelength-dispersive X-ray fluorescence analysis were used. As a sample preparation step to dissolve solid samples a microwave digestion (aqua regia, HBF4) was selected. For the major components (Co, Cu, Ni) accurate results were obtained with all measurement methods. However, the best recoveries of 90 % to 105 % were achieved with ICP-MS/MS. Concerning the characterisation of minor components (Ag, Dy, Ga, Ge, Gd, La, Nd, Pd and Pr) MP-AES, pXRF and WD-XRF show clear limitations in terms of detection and quantification limits (LOD, LOQ). The element titanium shows a recovery of 0 % for the ICP-MS/MS measurement method, while both XRF-techniques show recoveries of 97 % (WD-XRF) and 89 % (pXRF). The significant underdetermination by ICP-MS/MS can be attributed to problems in sample preparation due to incomplete microwave digestion. This illustrates the advantage pXRF and WD-XRF in enabling the characterisation of solid samples.

AB - The aim of optimising the European circular economy and recycling efficiency to reduce the environmental impact goes alongside increasing the recycling rates of electrical and electronic waste and developing efficient recycling technologies. This will further prevent future supply risks and promote Europe's autonomy. The global monitoring of mass flows of WEEE, the creation of an official database and the determination of material compositions are fundamental requirements for the development of sustainable management solutions. Standardized and harmonized analysis methods and certified reference materials should be established to ensure the comparability of measurement results. The master¿s thesis was conducted as part of the EU project MetroCycleEU, which was founded with the aim of developing strategies for sampling and sample preparation of e-wastes as well as developing harmonized multi-element methods for measuring technology-critical elements in urban wastes. As part of this project certified reference materials for lithium-ion-batteries, light-emitting diodes and printed circuit boards were developed and characterised during an interlaboratory comparison. In order to investigate the reliability of selected analysis methods, as well as possible sources of bias in the preceding sample preparation all three types of WEEE were characterized in the course of this master's thesis. As measurement techniques inductively coupled plasma tandem mass spectrometry (ICP-MS/MS), microwave plasma atomic emission spectrometry (MP-AES) and both XRF-techniques energy-dispersive (EDX) and wavelength-dispersive X-ray fluorescence analysis were used. As a sample preparation step to dissolve solid samples a microwave digestion (aqua regia, HBF4) was selected. For the major components (Co, Cu, Ni) accurate results were obtained with all measurement methods. However, the best recoveries of 90 % to 105 % were achieved with ICP-MS/MS. Concerning the characterisation of minor components (Ag, Dy, Ga, Ge, Gd, La, Nd, Pd and Pr) MP-AES, pXRF and WD-XRF show clear limitations in terms of detection and quantification limits (LOD, LOQ). The element titanium shows a recovery of 0 % for the ICP-MS/MS measurement method, while both XRF-techniques show recoveries of 97 % (WD-XRF) and 89 % (pXRF). The significant underdetermination by ICP-MS/MS can be attributed to problems in sample preparation due to incomplete microwave digestion. This illustrates the advantage pXRF and WD-XRF in enabling the characterisation of solid samples.

KW - RFA

KW - ICP-MS/MS

KW - MP-AES

KW - WEEE

KW - CRM

KW - Leiterplatten

KW - Lithium-Ionen-Batterien

KW - LED

KW - zertifizierte Referenzmaterialien

KW - XRF

KW - WEEE

KW - certified reference materials

KW - CRM

KW - PCB

KW - lithium-ion-batteries

KW - LED

KW - ICP-MS/MS

KW - MP-AES

M3 - Master's Thesis

ER -