Esta tesis estudia el impacto que tienen los COV presentes en los plásticos reciclados para la economía circular. Actualmente, la industria del reciclaje actual no puede cubrir la creciente demanda de plásticos reciclados de alta calidad en los últimos años. Hasta ahora, el reciclaje mecánico es la solución más utilizada a nivel mundial, y su eficacia y fiabilidad han sido demostradas para el tratamiento del residuo plástico post-industrial. Sin embargo, el mismo reciclaje mecánico aplicado a los residuos plásticos post-consumo da lugar a un material reciclado de menor calidad que solamente es apto para aplicaciones de bajo valor añadido, como son las tuberías de riego o cubos de basura. Por ello, esta tesis evalúa la influencia que tienen las sustancias orgánicas que aparecen en los plásticos reciclados post-consumo dentro el sector del plástico. / Investigación cofinanciada por el Vicerrectorado de Investigación y Transferencia de Conocimiento para el fomento de la I+D+i de la Universidad de Alicante y Cadel Deinking, S.L.

This study focuses on techniques that can be used to fuel next generation reactors. The first two studies are new techniques for recycling used nuclear fuel (UNF) and the third is a method of separating uranium (U) from lithium fluoride (LiF) and thorium fluoride (ThF4) salt also known as FLiTh for a thorium (Th) fuel cycle. The first technique proposed for UNF recycling was to use the cladding as an anode to oxidize the zircaloy and dissolve it into a LiF, sodium fluoride (NaF), zirconium fluoride (ZrF4) salt. Zirconium (Zr) was also reduced and deposited on a tungsten (W) cathode at the same time transporting the Zr through the salt. As commercial zircaloy would be contaminated with UNF oxides, and the oxides will not oxidize as part of the electrochemical process, they would be left at the anode as the Zr is dissolved away. This means the deposited Zr, on the cathode, can be disposed of as low-level waste (LLW) or recycled back into the nuclear industry instead of being stored as high-level waste (HLW). The next technique was fluorination of UNF oxides using ZrF4. Using the same LiF-NaF-ZrF4 salt, uranium oxide (UO2), lanthanum oxide (La2O3), and yttrium oxide (Y2O3) were fluorinated into uranium fluoride (UF4), lanthanum fluoride (LaF3), and yttrium fluoride (YF3). By sampling and recording the change in concentration over time, the reaction rate of all three oxides was determined and a temperature dependent reaction rate was reported from 500°C to 650°C. A zirconium oxide (ZrO2) product layer developed on UO2, but it only slowed down the fluorination process but did not stop it. UO2 and Y2O3 fluorinated entirely but La2O3 did not. The solubility limit of LaF3 in the salt was determined to be the reason the reaction did not go to completion. The last technique was the electrochemical separation of U from FLiTh, to simulate irradiated Th that decays to protactinium (Pa). A constant, albeit small current, was used to deposit U on a W electrode without Th depositing with it. A liquid metal bismuth (Bi) electrode was used as well, and a constant current resulted in Th depositing with the U. To get just U to deposit, the current needed to be applied for a time and then no current applied for a time so the system could reach equilibrium. By cycling these two steps it was possible to get U to deposit in Bi without Th. / Doctor of Philosophy / This study focused on techniques useful to the fabrication of next generation reactor fuels. The first focus was on new techniques for recycling used nuclear fuel (UNF). Nuclear waste currently needs to be stored for hundreds of thousands of years to reach background radiotoxicity levels. If plutonium (Pu) is removed from the waste this time is limited to ten thousand years and if the other transuranics (TRU) are removed the waste only needs to be stored for 300 years to reach background radiotoxicity levels. As recycling UNF can make such a drastic difference, developing techniques for this are of utmost importance. The first technique studied was to show that the zirconium (Zr) in zircaloy cladding could be oxidized and transported through salt. This was done by applying a current between a zircaloy anode and tungsten (W) cathode, dissolving the cladding into the salt. The salt used was lithium fluoride (LiF), sodium fluoride (NaF), and zirconium fluoride (ZrF4) salt called FLiNaZr. This transported Zr through the salt and then deposited it on W. If this process was done with zircaloy contaminated with used nuclear fuel (UNF) oxides, the oxides would not dissolve into the salt as part of the process and would be left behind at the anode as Zr is transported through the salt, effectively separating the two. This alone leads to a 25% reduction in the weight of the UNF that needs to be stored. The next technique studied was converting the UNF oxides into fluorides. This was done by having it react with ZrF4 to make zirconium oxide (ZrO2) and UNF fluorides. The oxides studied here were uranium oxide (UO2), yttrium oxide (Y2O3), and lanthanum oxide (La2O3). UO2 and Y2O3 reacted until no material was left but La2O3 did not. This was due to lanthanum fluoride (LaF3) having a solubility limit in the salt that made it impossible for more to be made and stopping the reacting. The reaction rate for each oxide was found and the order of the reaction rates was Y2O3>UO2>La2O3. This process was a success and should be studied more to ensure it will work with all oxides found in UNF. The last technique studied was electrochemically separating uranium (U) from lithium fluoride and thorium fluoride (ThF4) salt. Thorium (Th) is another nuclear material, and while it cannot fission in a reactor it can be turned into an isotope of U, U-233, that can. To do this Th must be irradiated so it turns into protactinium (Pa) which can then be separated from the salt. In this study U was a surrogate for Pa as it is too radioactive to handle in this lab. First, an inert W electrode was used to deposit U metal, and once it was successful a liquid metal bismuth (Bi) electrode was used. A small constant current was able to deposit U on W without co-deposition of Th. For a Bi electrode, an alternating time of applying current and then letting the system rest was needed to deposit U without co-deposition of Th.

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Recent advances in activated sludge facilities operations utilize sludge recycle flow rate control to minimize adverse effects on the clarifier during peak solids loading situations. Although this control action is directed at the thickening function, there has been speculation that the elevated recycle rates may be responsible for an increased effluent solids concentration. To evaluate the significance of recycle rate to the steady-state effluent suspended solids concentration, identical side-by-side settling columns were operated with recycle rates spanning the range of normal practice. The studies were conducted so that each side-by-side unit received identical activated sludge feed slurries. Replicate experimental units operating at identical recycle rates and receiving identical feed slurries were used to determine experimental error. The experimental design facilitated a statistical determination of the significance of the effect of recycle flow rate. An analysis of variance procedure was pursued, with the conclusion that recycle rate does, in fact, influence suspended solids removal. Ramifications for facilities design and operation is also reviewed.

The ability of spores to germinate, vegetatively multiply and produce new spores and toxin in the larval cadaver is known as recycling. The ability to recycle is an important characteristic since it may enhance effectiveness and persistence of the microbial insecticides in the larval habitat. The ability of Bacillus sphaericus to recycle has only been examined in the low toxicity strain SSII-1 and in the two highly toxic strains 2362 and 1593, both belonging to serotype 5a5ab. This study was expanded and the ability to germinate and recycle of several B. sphaericus strains was investigated. Strains tested represented different serological and DNA homology groups, and expressed either or both toxins (the binary toxin, proteins of 51 and 42 kDa or the 100-kDa toxin). Nontoxic strains were also tested as recombinants expressing the toxin genes or with soluble binary toxin. Results of this study showed that only spores of the highly toxic B. sphaericus strains, which normally produce both, the binary toxin and the 100-Kda toxins, were able to germinate in high percentage and to recycle. The ability of conjugal transfer of plasmids from B. sphaericus to other bacteria was also investigated. The most likely place for conjugation to occur is in the larval cadaver. where spores of B. sphaericus germinate and grow vegetatively and interact with bacteria present in the larval cadaver. Bacillus sphaericus 2362 carrying the broad host range plasmid pAM8&1, was used as donor in filter mating experiments with other B. sphaericus strains, a restrictionless B. subtilis strain and bacteria isolated from field collected larvae. Conjugal transfer of pAMB1 was observed with strains of the same serotype as the donor and two other serotypes. The possibility that the large cryptic plasmid present in B. sphaericus 2362 (180 kb), could promote its own transfer and mobilize the small nonconjugative plasmids pUB110 to other 8B. sphaericus strains was also tested. No transfer was detected. Conjugation experiments in vivo (the larval cadaver) were done by feeding Culex quinquefasciatus larvae the spores of donor 2362 (pAM81) along with spores of the recipient strains, 2362a or 1593-P51. No transconjugants were detected in cadavers 72 hours after feeding the spores. / Ph. D.

Yes / Recycling of polymers is a necessity in our intensively consuming polymer world but the nature of polymers is such that they are prone to thermal degradation when re-extruded and this poses technical challenges to recycling. This article describes research that seeks to rebuild the structure of degraded PA6. We present data from controlled experiments with pristine pPA6 extruded to form a base recycle rPA6 to which we added two chain extenders, separately: one with anhydride multifunctionality (ANHY), highly reactive with amide groups and one with epoxy multifunctionality (EPOX), less reactive. We found from rheological data carried out in the linear viscoelastic region (so as to study structural changes) a striking difference in the ability of the chain extenders to rebuild structure: 306% increase in the complex viscosity of rPA6/ANHY compared to 25% in that of rPA6/EPOX of the base rPA6. Mechanical and thermal (DSC and TGA) tests confirmed the superior efficacy of the multifunctional anhydride chain extender. Beside the practical benefit that ensues from this research, it also provides a strategic platform to develop chain extenders for other degrading polymers on the basis of understanding the degradation chemical reaction and targeting the most reactive end group of the split chains.

Im Zeitalter der Hochtechnologie und der industriellen Innovationen sind die effiziente Verarbeitung und das Recycling von Materialien für den Leichtbau ein zentrales Anliegen. Aluminium ist aufgrund seiner herausragenden Eigenschaften wie geringe Dichte, Korrosionsbeständigkeit und hohe Festigkeit eines der wichtigsten Metalle in der modernen Industrie. Trotz dieser positiven Eigenschaften ist die Primärproduktion von Aluminium sehr energieintensiv und mit erheblichen Umweltbelastungen verbunden. Das Recycling von Aluminium gewinnt daher zunehmend an Bedeutung, da es nicht nur den Energieverbrauch senkt, sondern auch die Treibhausgasemissionen reduziert. Zusätzlich wird durch das Recycling die Abhängigkeit der Industrie und Gesellschaft von Rohstofflieferanten reduziert. Herkömmliche Recyclingmethoden, insbesondere das Umschmelzen von Aluminiumschrotten, sind jedoch mit Problemen wie Materialverlust, Qualitätseinbußen und geringer Energieeffizienz verbunden. Eine vielversprechende Alternative ist das direkte Recycling von Aluminiumrezyklaten durch Strangpressen. Dieses Verfahren ermöglicht die Herstellung hochwertiger Aluminiumprofile direkt aus dem Rezyklatmaterial ohne den Zwischenschritt des Wiedereinschmelzens (im Englischen als Solid-State Recycling bezeichnet). Dadurch können Materialverluste durch Abbrand minimiert und die Ressourceneffizienz deutlich gesteigert werden. Der Werkstoff Aluminium profitiert zudem vom Einsatz neuartiger Technologien wie etwa additiver Fertigungsverfahren, die das Potenzial besitzen, die Effizienz in der Produktion deutlich zu steigern und dabei gleichzeitig den Ressourceneinsatz zu reduzieren. Additive Fertigungsverfahren ermöglichen die Herstellung komplexer Bauteile direkt aus einem virtuellen CAD-Modell, ähnlich dem Druck auf Papier, nur eben dreidimensional. Besonders vielversprechend für Bauteile aus Aluminium ist das Laserauftragschweißen. Mit dieser Technologie können große Bauteile effizient hergestellt werden, indem Zusatzwerkstoff schichtweise aufgetragen und aufgeschmolzen wird. Aktuelle Forschungsansätze konzentrieren sich auf die Optimierung der Prozessparameter, die Entwicklung prädiktiver Simulationsmodelle zur Qualitätssicherung sowie den Einsatz fortschrittlicher Sensortechnologien zur Prozessüberwachung und -regelung. Diese Entwicklungen sind entscheidend für die industrielle Anwendung und tragen zur Weiterentwicklung und Anwendung des Laserauftragschweißens insbesondere im Hinblick auf Zuverlässigkeit, Effizienz und Nachhaltigkeit in der Produktion bei. Neben den Leichtmetallen werden im Leichtbau häufig verstärkte Kunststoffe eingesetzt, da diese ein sehr günstiges Eigenschaftsprofil aufweisen. Unter der Vielfalt der Verfahren zur Kunststoffverarbeitung hebt sich das Spritzgießen durch sein Potenzial zur effizienten Fertigung von komplexen Formteilen in großen Stückzahlen hervor. Darüber hinaus eignet sich der Spritzguss hervorragend zur Funktionalisierung von metallischen Strukturen, bspw. aus Aluminium. Diese Hybridstrukturen kombinieren dabei die Eigenschaften der einzelnen Materialklassen auf vorteilhafte Weise. Neuartige spritzgegossene Hybridstrukturen kombinieren thermoplastische Formmassen auch mit flächigen Verstärkungsstrukturen wie Organoblechen. Diese Technologie reduziert Montageschritte, ermöglicht Gewichts- und Kosteneinsparungen und wird im Automobilbau bereits in Großserie eingesetzt. Für die Zukunft eröffnet die Kombination aus traditionellem Spritzgießen, Digitalisierung und Hybridtechnologien neue Horizonte für die effiziente und nachhaltige Herstellung hochwertiger kunststoffbasierter Bauteile.:Inhalt 1 Einleitung 1 Aluminium-Strangpressen 3 Laserauftragschweißen 19 Spritzgießen 25 Executive Summary 30 Handlungsempfehlung 32 Literatur 34

Angesichts der globalen Erwärmung bei gleichzeitig weltweit steigendem Bedarf an Konsumgütern ist die Entwicklung von Technologien und Materialien, die eine geschlossene Kreislaufführung bei minimalem Ressourcenverbrauch erlauben, essentiell. Ein Material mit steigender Nachfrage ist das Leichtbaumaterial Aluminium. Die primäre Gewinnung von Aluminium ist jedoch energieintensiv und mit großen Umweltbelastungen verbunden. In diesem Whitepaper werden Handlungsempfehlungen für die nachhaltige, legierungskonforme Kreislaufführung von Aluminium vorgestellt. Diese beinhalten die Untersuchung von Kennzeichnungssystemen zur Verbesserung der Informationsbereitstellung zur Planung adaptiver Recyclingrouten und Führung der Stoffströme. Zudem wird ein Einblick in Aufbereitungstechnologien zur Erzeugung von spezifikationsgerechten Zwischenprodukten in Form von „Aluminiumchips“ als Ausgangsbasis für die Herstellung neuer Aluminiumprofile ohne schmelzmetallurgischen Reinigungsschritt gegeben. Hierdurch kann weitere Energie in der Recyclingroute eingespart werden. In diesem Beitrag wird zudem auf die abfallrechtlichen Rahmenbedingungen für die Umsetzung eingegangen. Digitale Hilfsmittel wie Mixed-Reality-Anwendungen können dabei unterstützend für die Wartung und Schulung von Recyclingprozessen genutzt werden. Exemplarisch wird hierzu auf die Einsatzmöglichkeiten der Datenbrille „HoloLens“ eingegangen.:Einleitung 1 Status Quo des Aluminiumrecyclings 3 Direktrecycling von Aluminium – Koresil 16 Handlungsempfehlungen zur Steigerung der Recyclingquoten 33 Mixed Reality Anwendungen für Schulungszwecke und Fernwartung 38 LITERATUR 52