The TRANSCEND University Consortium : integrated waste management

TRANSCEND (Transformative Science and Engineering for Nuclear Decommissioning) is a collaborative research consortium comprising 11 universities and 8 industry partners. The £9.4 million research program, funded primarily by the Engineering and Physical Sciences (EPSRC) Research Council of the UK, incorporates >40 projects in total, which will address some of the key challenges within the areas of nuclear decommissioning and waste management; including mobilization, processing, packaging, storage, transport and final disposal. This paper will outline a summary of the current progress and impact of Theme 1 - Integrated Waste Management. This theme focuses on underpinning science and engineering in areas of relevance to hazard reduction and decommissioning, where the three key work package objectives are: (1) New materials and methods for effluent decontamination; (2) Modelling and experiments for understanding pond and silo sludge/slurry behavior; (3) Innovative wasteform materials. In total, this theme has 15 different projects, delivered through both postdoctoral and PhD researchers, all with specific industry supervision from our partners, led by the NNL. The following provides a review of the project summaries to date, and their critical impact

AMİDOKSİM FONSİYONEL GRUBU İÇEREN PAMUK KUMAŞLARIN AŞI POLİMERİZASYONU İLE HAZIRLANMASI

In this thesis, amidoxime group containing nonwoven cotton fabrics were prepared by grafting with acrylonitrile (AN) using plasma-induced graft polymerization method for the recovery of uranium ions in trace amounts from seawater. Different parameters such as power applied and plasma treatment time were studied to determine optimum plasma treatment conditions in order to perform graft polymerization. The experiments were carried out by applying three different plasma powers (60, 80 and 100 watts) and three different treatment periods (3, 5 and 10 min) in the plasma process. The optimum plasma treatment conditions for the grafting of acrylonitrile onto the nonwoven cotton fabrics were determined as 0.2 mbar pressure, 100 watts of power and 10 min of treatment time in Ar-plasma. Grafting of AN onto nonwoven cotton fabrics by using plasma-induced graft polymerization were carried out in emulsion solutions at different reaction temperatures (40, 60 and 70°C) and different concentrations (10% (w/w), 30% (w/w), 50% (w/w) and 70% (w/w)) for 24 h to increase the degree of grafting of AN. Homopolymer formation was observed in 50% and 70% (w/w) AN solutions while the grafting formation was not observed in 10% (w / w) AN emulsion solution within 24 hour. The optimum grafting conditions were determined as 30% (w/w) AN concentration, 0.5% Tween 20, 60 °C reaction temperature and 24 hour reaction time. For the preparation of uranyl ion selective adsorbent, the nitrile groups in the AN grafted nonwoven cotton fabric was converted to amidoxime groups by using hydroxylamine. The AO conversion amount was calculated to be 10.48 mmol/g cotton. AO group containing nonwoven cotton fabric was used fort he adsorption of U(VI) from aqueous solutions by studying the effect of pH, adsorption kinetics and initial concentration U (VI). It was found that the adsorption of U (VI) ion reached to equilibrium at 90 minutes and the amount of adsorption from a 250 ppm U (VI) solution was determined to be 530,46 mg U (VI)/g adsorbent at pH 6.00. Desorption of uranyl ions from nonwoven cotton fabrics was performed by using %3 HNO3 and nearly 100% of U (VI) ions were desorbed. Five adsorption desorption cycles were obtained as a result of reusability studies. The adsorption amount was determined as 0,17 mg (VI)/g adsorbent from 10 mL of seawater for 24 hours. The chemical structures, surface morphology and thermal properties of nonwoven cotton fabric, AN grafted, AO group modified and U (VI) adsorbed nonwoven cotton fabrics were characterized by using FTIR, XPS, SEM, EDX and TGA techniques.ÖZET i ABSTRACT iii TEŞEKKÜR v İÇİNDEKİLER vi ŞEKİLLER DİZİNİ x ÇİZELGELER DİZİNİ xiv KISALTMALAR xv 1. GİRİŞ 1 2. URANYUM 7 2.1 URANYUM GERİ KAZANIM YÖNTEMLERİ 9 2.1.1 Çözücü Ektraksiyonu 9 2.1.2 Elektrokimyasal İndirgeme 9 2.1.3 İyon Değişimi 9 2.1.4 Adsorpsiyon 10 2.1.4.1 Langmuir Adsorpsiyon İzotermleri 11 2.1.4.2 Freundlich Adsorpsiyon İzotermi 11 3. ADSORBENT MALZEMELER 12 3.1 Selüloz 12 3.2 Pamuk 13 3.3 Nanolif 13 3.4 Dokumasız Pamuk Kumaş 14 4. YÜZEY MODİFİKASYON TEKNİKLERİ 15 4.1 Çapraz Bağlama 15 4.2 Harmanlama (Blend) 16 4.3 Kompozit Oluşumu 16 4.4 Aşılama 17 5. AŞILAMA TEKNİKLERİ 18 5.1 Kimyasal Yolla Aşılama 18 5.1.1 Redoks Başlatıcılar 18 5.1.1.1 Fenton Reaktifleri (Fe(II)/H2O2) 18 5.1.1.2 Fe(II) / Persülfat 19 5.1.1.3 Persülfat ve İndirgeyici Ajanı 19 5.1.1.4 Fe(II) ve Hidroperoksit 20 5.1.1.5 Direk Oksidasyon 20 5.2 Fotoışınlama ile Aşılama 20 5.3 Enzimatik Aşılama 21 5.4 Radyasyon ile Aşılama 21 5.4.1 Ön Işınlama ile Aşılama 22 5.4.2 Birlikte Işınlama ile Aşılama 23 5.4.3 Peroksidasyon ile Başlatılan Aşılama 23 5.5 PLAZMA 24 5.5.1 Yüksek Sıcaklık Plazması 24 5.5.2 Düşük Sıcaklık Plazması 24 5.5.3 Plazma ile Yüzey Modifikasyonu 25 5.5.4 Plazma Radyasyonu ile Aşılama 27 5.5.5 Plazma Parametreleri 27 6. KARAKTERİZASYON YÖNTEMLERİ 29 6.1 Fourier Dönüşüm Kızılötesi (FTIR) Spektroskopisi 29 6.2 X-Işını Fotoelektron Spektroskopisi 30 6.3 Termogravimetrik Analiz (TGA) 30 6.4 Taramalı Elektron Mikroskobu (SEM) 31 6.5 Enerji Dağılım X-Işını Spektrometresi (EDX) 32 6.6 İndüktif Eşleşmiş Plazma Kütle Spektrometri (ICP-MS) 33 7. DENEYSEL ÇALIŞMALAR 35 7.1 Kullanılan Kimyasallar 35 7.2 Dokumasız Pamuk Kumaş Yüzeyine Plazma Tekniği ile Akrilonitril Aşılanmış Kumaşların Hazırlanması 37 7.3 Aşılanmış Kumaşların Hidroksilamin Hidroklorür ile Modifikasyonu 38 7.4 Uranyum Örneklerinin Hazırlanması 39 7.5 AO Grubu İçeren Dokumasız Pamuk Kumaşların U(VI) Adsorpsiyonu 39 7.5.1 U (VI) İyonlarının Adsorpsiyonuna pH’ın Etkisi 39 7.5.2 U (VI) İyonlarının Adsorpsiyon Kinetiği 39 7.5.3 U (VI) İyonlarının Adsorpsiyonuna Başlangıç Derişiminin Etkisi 40 7.5.4 U (VI) İyonlarının Desorpsiyon Çalışmaları 40 7.6 ICP-MS ile Uranyum Analizi 40 7.7 Modifiye Edilmiş Dokumasız Pamuk Kumaş Adsorbentin Karakterizasyonu 41 7.7.1 FTIR 41 7.7.2 XPS 41 7.7.3 TGA 41 7.7.4 SEM ve EDX 41 8. DENEYSEL SONUÇLAR ve TARTIŞMA 42 8.1 Dokumasız Pamuk Kumaş Yüzeyine Plazma ile Başlatılan Aşı Polimerizasyonu Kullanılarak AN Aşılanması 42 8.2 AO Grubu İçeren Dokumasız Pamuk Kumaşların Hazırlanması 45 8.3 Amidoksim Grubu içeren Dokumasız Pamuk Kumaşların U(VI) Adsorpsiyonu 46 8.3.1 U(VI) İyonlarının Adsorpsiyonuna pH Etkisi 47 8.3.2 U(VI) İyonlarının Adsorpsiyon Kinetiğinin Belirlenmesi 47 8.3.3 U(VI) İyonlarının Derişim Etkisi 50 8.3.4 U(VI) İyonlarının Adsorpsiyon İzoterminin Belirlenmesi 51 8.3.5 U(VI) İyonlarının Desorpsiyon Çalışması 53 8.3.6 U(VI) İyonu Adsorpsiyonunun Tekrarlanabilirliğinin Tayini 54 8.3.7 Deniz Suyu Uygulaması 54 8.3.8 Çoklu Element Adsorpsiyonu 56 8.4 Karakterizasyon Çalışmaları 58 8.4.1 FTIR Analizleri 58 8.4.2 XPS Analizleri 61 8.4.3 TGA Analizleri 64 8.4.4 SEM Analizleri 69 8.4.5 EDX Analizleri 72 9. SONUÇLAR 76 KAYNAKLAR 78 ÖZGEÇMİŞ 82Bu tez çalışmasında, deniz suyunda eser miktarda bulunan uranyum iyonlarının geri kazanımında kullanılacak, amidoksim grubu içeren aşılanmış dokumasız pamuk kumaşlar, plazma ile başlatılan aşı polimerizasyonu yöntemi kullanılarak akrilonitril (AN) aşılanması ile hazırlanmıştır. Aşı polimerizasyonunu gerçekleştirebilmek amacıyla optimum plazma muamele koşullarının belirlenmesi için uygulanan güç ve plazma muamele süresi gibi farklı parametrelerle çalışılmıştır. Plazma işleminde üç ayrı güç (60, 80 ve 100 watt) ve üç farklı muamele süresi (3, 5 ve 10 dk) uygulanarak deneyler gerçekleştirilmiştir. Dokumasız pamuk kumaşlara akrilonitril aşılamak amacıyla optimum plazma muamele işlem koşulları, 0.2 mbar basınç, 100 watt güç, 10 dk muamele süresi ve Ar-plazma olarak belirlenmiştir. Aşılama derecesini arttırmak için plazma ile muamele edilmiş dokumasız pamuk kumaşların AN ile aşılanması farklı reaksiyon sıcaklıklarında (40, 60 ve 70oC) ve farklı derişimlerde %10(w/w), %30(w/w), %50(w/w) ve %70(w/w), hazırlanan emülsiyon çözeltileri 24 saat aşılama sürelerinde gerçekleştirilmiştir. 24 saat aşılama süresi sonunda elde edilen sonuçlarda, %10 (w/w) derişimde hazırlanan AN emülsiyon çözeltisinden düşük oranda aşılanma gözlemlenirken, %50 ve %70 (w/w) derişimlerde hazırlanan AN çözeltilerinde homopolimer oluşumu gözlemlenmiştir. Yapılan tüm denemeler sonucunda optimum aşılama koşulları %30 (w/w) AN derişimi, %0,5 Tween 20, 60oC reaksiyon sıcaklığı ve 24 saat reaksiyon süresi olarak belirlenmiştir. Uranyum iyonlarına seçici adsorbent malzeme hazırlanması amacı ile, optimum şartlarda elde edilen AN aşılanmış dokumasız pamuk kumaş yapısında bulunan nitril grupları, hidroksilamin ile modifiye edilerek amidoksim gruplarına dönüştürülmüştür. Modifikasyon işlemi sonucu AO dönüşümü 10,48 mmol/g aşılı kumaş olarak hesaplanmıştır. AO grubu içeren modifiye edilmiş dokumasız pamuk kumaş adsorbentin U(VI) iyonları adsorpsiyonu için pH, adsorpsiyon kinetiği ve başlangıç derişimi etkisi çalışılmıştır. Optimum pH 6.00 ortamında U(VI) iyonu adsorpsiyonunun 90 dakikada dengeye geldiğini ve 250 ppm U(VI) çözeltisinden adsorplanan miktarın 530,46 mg U(VI)/g adsorbent olduğu bulunmuştur. Uranil iyonlarını adsorplamış dokumasız pamuk kumaşların desorpsiyon çalışması %3 HNO3 ile gerçekleştirilmiş ve U(VI) iyonlarını yaklaşık %100’ü desorbe edilmiştir. Tekrar kullanılabilirlik çalışmaları sonucunda U(VI) iyonları adsorpsiyonunun beş adsorpsiyon desorpsiyon döngüsü boyunca korunduğu gözlenmiştir. Ayrıca 10 mL deniz suyu ile adsorpsiyon çalışması yapılmış ve 24 saat sonunda adsorpsiyon miktarı 0,17 mg U(VI)/g adsorbent olarak tespit edilmiştir. Dokumasız pamuk kumaş, AN aşılanmış, AO grubu modifiye edilmiş ve U(VI) iyonu adsorplamış dokumasız pamuk kumaşların kimyasal yapıları, yüzey morfolojileri ve termal özellikleri, FTIR, XPS, SEM, EDX ve TGA teknikleri kullanılarak karakterize edilmiştir

Investigation of the Effect of Milling Duration on a Ce-Gd Doped Zirconolite Phase Assemblage Synthesised by Hot Isostatic Pressing

Zirconolite is a candidate ceramic wasteform under consideration for the immobilisation of the UK civil PuO2 inventory. In the present work, a baseline dual-substituted zirconolite with the target composition (Ca0.783Gd0.017Ce0.2)(Zr0.883Gd0.017Ce0.1)(Ti1.6Al0.4)O7 was fabricated by hot isostatic pressing (HIPing). In order to optimise the microstructure properties and improve the obtained yield of the zirconolite phase, a range of planetary ball milling parameters were investigated prior to consolidation by HIP. This included milling the batched oxide precursors at 400 rpm for up to 120 min, the pre-milling of CeO2 (PuO2 surrogate) to reduce the particle size and using a CeO2 source with finer particle size (&lt;5 µm). The HIPed zirconolite product consisted of both zirconolite-2M and zirconolite-3T polytypes in varying proportions; however, an additional perovskite phase was obtained in varying quantities as a secondary phase. Ce L3-edge X-ray absorption spectroscopy was utilised to determine the Ce oxidation state. In this study, the ideal milling parameter for the fabrication of zirconolite waste forms was defined as 60 min at 400 rpm.</p

The Quality of Life in the Patients with Diabetic Foot Ulcers

Introduction: Diabetic foot ulcer (DFU), one of the complications of Diabetes Mellitus (DM), is the most common reason for the hospitalization of diabetic patients and leads to extremity amputations and increase in mortality. DFU brings an additional physical and emotional burden to the patients and affects their quality of life (QoL) negatively. This study was organized with the aim of comparing the anxiety, depression and QoL levels of DFU patients with diabetic patients without DFU due to the limited number of the studies investigating the QoL and mental health of DFU patients. Materials and Methods: One hundred and thirty-three patients followed up in the X University Faculty of Medicine Infectious Diseases and Clinical Microbiology Department and volunteered to participate in this cross-sectional study. Besides sociodemographic information, anxiety and depression levels were assessed by Hospital Anxiety Depression (HAD) Scale and QoL was measured by Short Form 36 (SF-36). Results: Among the 133 DM patients with a median age of 60 years, 83 patients were in the DFU group. Mean age (p= 0.006, t=-2.813) and male prevalence (p= 0.0002, chi(2)= 13.824) were higher in the DFU group. Only physical functioning scores were lower in the DFU group (p= 0.002, Z=-3.04) while comparing SF-36 and HAD scores between the two groups. All SF-36 subscale scores of both diabetic groups were lower than the Turkish normative values (p< 0.0001). Conclusion: Finding worse QoL in the aspect of physical functioning among DFU patients reveals the necessity of interventions that will improve the DFU patients' QoL by increasing their physical functioning, besides medical and surgical treatments for foot ulcers. In our study, it was found that all diabetic patients had lower QoL than the normal population. This finding emphasizes the need for taking steps to improve the QoL of patients with DM and especially DFU

Synthesis and characterisation of HIP Ca_0.80Ce_0.20ZrTi_1.60Cr_0.40O₇ zirconolite and observations of the ceramic–canister interface

Abstract: A sample of zirconolite with nominal composition Ca0.80Ce0.20ZrTi1.60Cr0.40O7 was processed via Hot Isostatic Pressing (HIP), with a dwell temperature and pressure of 1320 °C/100 MPa maintained for 4 h. The produced wasteform was characterised by powder XRD, SEM–EDS, Ce L3 and Cr K-edge XANES. A significant portion of the Ce inventory did not fully partition within the zirconolite phase, instead remaining as CeO2 within the microstructure. Inspection of the stainless steel–ceramic interface detailed the presence of an interaction region dominated by a Cr-rich oxide layer. No significant Cr or Fe migration was observed, although a greater concentration of perovskite was observed at the periphery, relative to the bulk ceramic matrix. The X-ray absorption features of Cr remained analogous with Cr3+ accommodation within TiO6 octahedra in the zirconolite matrix. The absorption edge of Ce was comprised of contributions from zirconolite-2M and unincorporated CeO2, with an average oxidation state of Ce3.9+. As zirconolite-2M accounted for &gt; 92 wt% of the overall phase assemblage, it is clear that the dominant oxidation state of Ce in this phase was Ce4+. Graphic abstract: [Figure not available: see fulltext.]</p

Underpinning the use of indium as a neutron absorbing additive in zirconolite by X-ray absorption spectroscopy

Abstract Indium (In) is a neutron absorbing additive that could feasibly be used to mitigate criticality in ceramic wasteforms containing Pu in the immobilised form, for which zirconolite (nominally CaZrTi2O7) is a candidate host phase. Herein, the solid solutions Ca1-xZr1-xIn2xTi2O7 (0.10 ≤ x ≤ 1.00; air synthesis) and Ca1-xUxZrTi2-2xIn2xO7 (x = 0.05, 0.10; air and argon synthesis) were investigated by conventional solid state sintering at a temperature of 1350 °C maintained for 20 h, with a view to characterise In3+ substitution behaviour in the zirconolite phase across the Ca2+, Zr4+ and Ti4+ sites. When targeting Ca1-xZr1-xIn2xTi2O7, single phase zirconolite-2M was formed at In concentrations of 0.10 ≤ x ≤ 0.20; beyond x ≥ 0.20, a number of secondary In-containing phases were stabilised. Zirconolite-2M remained a constituent of the phase assemblage up to a concentration of x = 0.80, albeit at relatively low concentration beyond x ≥ 0.40. It was not possible to synthesise the In2Ti2O7 end member compound using a solid state route. Analysis of the In K-edge XANES spectra in the single phase zirconolite-2M compounds confirmed that the In inventory was speciated as trivalent In3+, consistent with targeted oxidation state. However, fitting of the EXAFS region using the zirconolite-2M structural model was consistent with In3+ cations accommodated within the Ti4+ site, contrary to the targeted substitution scheme. When deploying U as a surrogate for immobilised Pu in the Ca1-xUxZrTi2-2xIn2xO7 solid solution, it was demonstrated that, for both x = 0.05 and 0.10, In3+ was successfully able to stabilise zirconolite-2M when U was distributed predominantly as both U4+ and average U5+, when synthesised under argon and air, respectively, determined by U L3-edge XANES analysis