Kristina Brix

Fungal contaminations pose a persistent challenge in the fields of healthcare, agriculture, and industry, primarily due to their environmental adaptability and increasing resistance to antifungal agents. In this study Aspergillus niger is utilized as model organism. This work evaluates copper, brass, and steel surfaces functionalized with ultrashort pulsed laser‐induced periodic surface structures (USP‐DLIP) designed as 3 and 9 µm topographies. Fungal spore viability assays show that 9 µm periodicities on copper surfaces achieve a 99% reduction in spore viability, indicating that increased copper ion release is a key factor in enhanced antifungal effectivity. Scanning electron microscopy (SEM) analysis confirm substantial spore damage, linked to the viability testing and the measured copper ion release by inductively coupled plasma triple quadrupole mass spectrometry (ICP‐QQQ) spectrometry. Interestingly, 9 µm structured steel surfaces reveal a trend toward antifungal activity despite their inert nature. Whereas structured brass surfaces do not show significant improvement in antifungal activity. These findings suggest USP‐DLIP structuring on copper and stainless‐steel surfaces have considerable potential for antifungal applications, although interactions between surface structures, released ions, and fungal spores are highly complex. Yet, USP‐DLIP offers promising advantages for developing advanced antifungal materials.

In the context of the safe storage of high-level radioactive waste, the time-dependent retention of a waste cocktail (WC) consisting of Zr(IV), Mo(VI), Ru(III), Pd(II), Cs(I), Sm(III), Eu(III) and U(VI) was studied on the commercially available C-S-H phase Circosil^®. The herein presented results focus on Cs(I), Sm(III), Eu(III) and U(VI). Precipitation and wall adsorption studies in the absence of the solid phase show only a small amount of precipitation for Sm(III) and Eu(III) (34 ± 18%) in the high-saline diluted Gipshut solution (DGS, pH 10.6, I = 2.6 M). For Cs(I) and U(VI), no precipitation was observed. In 0.1 M NaCl (pH 10.9), the measured retention could completely be attributed to wall adsorption for all four elements. The obtained R_d values for the time-dependent retention of Sm(III), Eu(III) and U(VI) on Circosil^® of 10⁵ to 10⁶ L·kg⁻¹ are in good agreement with the literature. For Cs(I) in the strongly saline background electrolytes, slightly higher R_d values of up to 8·10² L·kg⁻¹ were determined for the crystalline Circosil^® compared to the wet chemical C-S-H phases. Overall, the commercial product Circosil^® is suitable as an alternative to synthesised C-S-H phases to observe trends in the retention behaviour of these elements. Comparison between both background electrolytes shows an increase in the amount and velocity of retention for all four elements with decreasing salinity. This confirms adsorption processes as the fastest and initial retention mechanism. Precipitation or incorporation of Eu(III), Sm(III) and U(VI) cannot be ruled out in the long term. Comparing the kinetic of this WC study to single-element studies in the literature, a longer uptake time to reach a steady state of 7 d in 0.1 M NaCl and 28 d in DGS instead of <1 d was observed for Eu(III) and Sm(III). The situation for Cs(I) is similar. This indicates competing effects between the different WC elements for adsorption sites on the C-S-H phases.

With the current global projection of over 130 million electric vehicles (EVs), there soon will be a need for battery waste management. Especially for all‐solid‐state lithium‐ion batteries (lithium ASSBs), aspects of waste management and circular economy have not been addressed so far. Within such ASSBs, the use of solid‐electrolytes like garnet‐type Li_6.5La₃Zr_1.5Ta_0.5O₁₂ (LLZTO) may shift focus on strategies to recover not only the transition metal elements but also elements like La/Zr/Ta. In this work, we present a two‐step recycling approach using citric acid as the leaching agent to separate and recover the individual components of a model cell comprising of Li₄Ti₅O₁₂ (LTO) anode, Li_6.5La₃Zr_1.5Ta_0.5O₁₂ (LLZTO) garnet electrolyte and LiNi_1/3Mn_1/3Co_1/3O₂ (NMC) cathode. We observe that by adjusting the concentration of citric acid, it was possible to separate the materials from each other without strong mixing of individual phases and also to maintain their principle performance characteristics. Thus, the process developed has a potential for upscaling and can guide towards considering separation capability of battery components in the development of lithium ASSBs.

All solid-state lithium-ion batteries (lithium ASSBs) are promising candidates for their use in high energy density applications like electric vehicles (EVs). With the current global projections of over 130 million EVs on road by 2030, there soon will be a need for lithium ASSBs waste management. For lithium ASSBs, various combinations of solid electrolytes and electrode materials could be imagined, e.g., with garnet electrolyte Li6.5La3Zr1.5Ta0.5O12 (LLZTO) and the use of a solid electrolyte might shift focus on recycling strategies. Not only the transition metals of the electrode materials will then be an important target, but also the recovery of La/Zr/Ta. In this work, we present a recycling approach based on a two-step leaching process with citric acid to separate and recover the individual components of a full model cell comprising of Li4Ti5O12 (LTO) anode, Li6.5La3Zr1.5Ta0.5O12 (LLZTO) garnet electrolyte and LiNi1/3Mn1/3Co1/3O2 (NMC) cathode. By treating the complex mixture of LTO/LLZTO/NMC in this process, we manage to separate the materials from each other without strong mixing of elements between the individual phases. We show that the battery components can maintain their principle performance characteristics, demonstrating that the developed process can serve as a basis to recover functional battery materials. Thus, the process developed has a potential for upscaling and can guide towards considering separation capability for battery components in the development of lithium ASSBs.