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Master Thesis : On the Effectiveness of Selected Adsorbents in Reducing Odor of Recycled Polypropylene from Post-Consumer Waste and their Influence on Polymer Stabilization

Sun, 25 Jan 2026 23:00:00 GMT

Title: Master Thesis : On the Effectiveness of Selected Adsorbents in Reducing Odor of Recycled Polypropylene from Post-Consumer Waste and their Influence on Polymer Stabilization Abstract: Degradation of residual impurities in post-consumer recycled polypropylene generates volatile organic compounds that cause malodor, limiting consumer acceptance and high-quality reuse. This master’s thesis evaluates the effectiveness of selected odor scavengers and their influence on polymer stability in post-consumer recycled polypropylene. An increase in oxidative sensibility was linked to the odor scavenger Tego Sorb PY 88 T.Q. and to a lower degree to BYK MAX OR 4207. Both odor scavengers did not significantly decrease the odor intensity. The other odor scavengers Rescofil 1476-400, Rescofil 1476–400 Plus, Zeoflair 100 and a custom surface modified version of Zeoflair 100 did significantly alter the odor profile, with Zeoflair 100 performing as the most efficient odor adsorption additive. Nevertheless, for high requirement applications further increases in odor adsorption efficiency is needed. No negative impact on polymer stabilization was noted. Rather, some rheological measurements indicate a slight support of these odor scavengers for polymer stabilization; possibly by the adsorption of hydro peroxides.

Scale-up production viability of biobased flame-retardant composites

Sun, 07 Sep 2025 22:00:00 GMT

Title: Scale-up production viability of biobased flame-retardant composites Abstract: The polymer industry is in the middle of transitioning from conventional fossil fuel-based materials to more biobased environmentally compatible biopolymers for the sake of a more sustainable future. Most biopolymers are very flammable, and it is a necessity to make them flame retardant for commercial use. Use of conventional flame retardants is increasingly discouraged due to their environmental and health impacts, creating a need for scalable, bio-based solutions. A better alternate is needed to be developed that can be used at large scale to make a completely sustainable bio compatible solution. This study investigates the development and characterization of bio-based flame-retardant polylactic acid (PLA) composites using lignin nanocapsules (LNCs) with ammonium polyphosphate (APP) as the cargo. The performance of this core–shell system was compared to direct incorporation of APP into PLA. To enhance sustainability and scalability, emulsion formulation optimization was performed by reducing waste generation and increasing production. Emulsion preparation and drying processes such as sonication, rotor stator homogenization, microfluidization, freeze drying and spray drying were investigated to potentially determine the best fit processes for scale up. Comprehensive characterization, including Microscale Combustion Calorimetry (MCC), Thermogravimetric Analysis (TGA), Gel Permeation Chromatography (GPC), mechanical testing, UL94, LOI, and SEM-EDX were conducted to select the best loading for the composite sample prepared using twin screw extrusion. Results showed that direct incorporation of APP at 1 wt% modestly improved flame retardance but only achieved a V-2 UL-94 rating, insufficient for commercial standards. PLA composites achieved a V-0 rating at ≥3 wt% APP loading or ≥5 wt% LNC loading. While higher additive concentrations reduced heat release rate (HRR) and increased LOI, they also led to molecular weight reduction and mechanical property loss. SEM-EDX images confirmed improved dispersion of phosphorus in the LNC composites compared to APP based ones. LNC composites were found to retain mechanical properties better than APP ones at higher loadings. The LNC system was found to offer a more sustainable pathway to flame-retardant PLA by utilizing less APP and better conserving the inherent properties of the biopolymer. There is a need to further investigate LNC system to make it more biobased and universally compatible with polymers. Further, validation on the post processing survival of LNC particles is needed. This research highlights LNCs as a promising bio-based flame-retardant system with industrial scalability potential.

Study of lithium separation, concentration and precipitation during the hydrometallurgical process of black mass.

Sun, 07 Sep 2025 22:00:00 GMT

Title: Study of lithium separation, concentration and precipitation during the hydrometallurgical process of black mass. Abstract: The need for efficient recovery of lithium through recycling of lithium-ion batteries has increased in recent time to meet the growing demand of li as well as to mitigate the supply risk of this critical resource. The supply of Li from primary sources is not enough to offset the growing demand which requires Li from secondary sources such as end-of-life lithium-ion batteries to feed and close the loop. The recovery of Ni, Co and Mn have become more established methods, however, the efficient recovery of Li is still lagging behind. In order to obtained a high enough recovery and purity of Li in the form of Li2CO3, this study evaluates the effect of chemical precipitation and CO2 precipitation. In the recovery of Ni, Co and Mn, NH3 in the form of NH4OH is often used in adjusting pH in order to precipitate these metals. This study which focuses on recovering Li from a downstream process of this stuff also focuses on the handling of NH3 that is still present in the Li recovery feed solution. Experimental results demonstrate that it is possible to achieve a Li recovery of 80% and a purity >96.5% through chemical precipitation, under optimised pH, temperature and CO32-:Li+ ratio. At a pH of 9.7, and operating temperature of 80℃, it is possible to reach these results and have a Na content of <0.2%. The results also show that CO2 precipitation of Li2CO3 is feasible with recoveries up to 39% and purity of 85%. The handling of NH3 in the solution is also feasible by scrubbing with water to regenerate NH4OH which can be used in the adjustment of pH in other upstream precipitation processes. This study also confirms the feasibility of having a closed-loop system for managing NH3 and Na impurities which exploring the recovery of Li from LIBs recycling streams.

Contribution to the evaluation of the environmental footprint of stainless steel production: the case of APERAM Belgium

Sun, 07 Sep 2025 22:00:00 GMT

Title: Contribution to the evaluation of the environmental footprint of stainless steel production: the case of APERAM Belgium Abstract: The production of stainless steel has rapidly increased in recent years due to its suitability for a wide range of applications, including construction and automotive industries. However, stainless steel production is a resource and energy-intensive process, which not only increases global warming potential and resource depletion but also contributes to human health damage through emissions and pollutants released during the extraction, processing, and handling of raw materials and ferroalloys. Therefore, as part of the ECWALI project, which is included in the broader Reverse Metallurgy+ portfolio, this thesis focuses on evaluating the prospective environmental burdens associated with key sub-processes in the production of 304L stainless steel at Aperam, Belgium. Through a detailed Life Cycle Assessment (LCA), along with sensitivity and scenario analyses, this research quantifies the environmental impacts associated with each sub-process in 304L stainless steel production. The results indicate that ferroalloys contribute significantly to the impact categories of interest, whereas electricity has a comparatively lower effect. Comparative analysis further reveals that the AOD converter stage has the highest environmental impact due to the larger amount of ferroalloys used compared to the EAF stage. These findings are further confirmed by scenario analysis, which shows that changes in the electricity source have a negligible effect on the overall results, whereas the origin of ferroalloys and the percentage of recycled ferroalloys used in the process substantially influence the outcomes. Ultimately, these findings can guide strategies for reducing the overall environmental burden of stainless steel production by supporting more sustainable practices in the industry.