Study on cleaning solvents using activated alumina in PUREX process

Abstract The PUREX process is used to extract uranium and plutonium from dissolved solutions (spent nuclear fuel liquor). The extractant is 30% tributyl phosphate in n-dodecane, which is known to be degradable by radiation and nitric acid. Tributyl phosphate degradation products can generally be washed in alkali solutions like sodium carbonate solution; however, it is more difficult to remove n-dodecane degradation products using this method. A method of cleaning solvents using activated alumina is discussed in this study. A degradation sample of 30% TBP/n-dodecane was prepared by irradiating (1.6 MGy) with a 60Co gamma-source. The degradation products were then qualitatively analyzed using a gas chromatography-mass spectrometer (GC-MS). After being irradiated the solvents were cleaned with activated alumina, and a phase separation test with performed in evaluating the cleaned solvent. This resulted in the discovery of a procedure for the removal of n-dodecane degradation products of dodecanol and dodecanone, with about 70% of the degradation products, and the phase separation performance could be clearly improved through use of activated alumina.

Download Full-text

Designing of a novel polyvinylidene fluoride/TiO2/UiO-66-NH2 membrane with photocatalytic antifouling properties using modified zirconium-based metal-organic framework

Water Science & Technology ◽

10.2166/wst.2021.381 ◽

2021 ◽

Author(s):

Yi-Jing Li ◽

Gui-E Chen ◽

Lian-Jing Liu ◽

Zhen-Liang Xu ◽

Sun-Jie Xu ◽

...

Keyword(s):

Phase Separation ◽

Bovine Serum Albumin ◽

Polyvinylidene Fluoride ◽

Metal Organic Framework ◽

Rejection Rate ◽

Separation Performance ◽

Recovery Ratio ◽

Quantitative Measurements ◽

Metal Organic ◽

Bsa Rejection

Abstract Novel polyvinylidene fluoride/TiO2/UiO-66-NH2 (PVDF/TiUN) membranes were produced by the delay phase separation method via introducing the TiO2/UiO-66-NH2 (TiUN) nanocomposite into PVDF casting solution. Interconnection of TiO2 and UiO-66-NH2 improved photocatalysis capacity and endowed PVDF/TiUN membranes with self-cleaning capability. Quantitative measurements showed that, firstly, PVDF/TiUN membranes exhibited improved photodegradation kinetics and efficiency (up to 88.1%) to Rhodamine B (RhB). Secondly, the performances of bovine serum albumin (BSA) rejection and permeation of PVDF/TiUN membranes outperformed those of other check samples, indicating enhanced hydrophilicity. Thirdly, rejection rate of BSA reached to breathtaking 98.14% and flux recovery ratio (FRR) of BSA reached breathtaking 95.37%. Thus, given their excellent anti-contamination property and separation performance, the PVDF/TiUN membrane is very likely to be a novel water treatment membrane.

Download Full-text

Phase separation of multiphase droplets in a digital microfluidic device

Micro and Nano Systems Letters ◽

10.1186/s40486-019-0099-0 ◽

2019 ◽

Vol 7 (1) ◽

Cited By ~ 1

Author(s):

Mun Mun Nahar ◽

Hyejin Moon

Keyword(s):

Phase Separation ◽

Capillary Number ◽

Digital Microfluidics ◽

Separation Performance ◽

Comprehensive Investigation ◽

Electrowetting On Dielectric ◽

Splitting Technique ◽

Droplet Splitting ◽

Two Phases ◽

Digital Microfluidic

Abstract This study reports the first comprehensive investigation of separation of the immiscible phases of multiphase droplets in digital microfluidics (DMF) platform. Electrowetting-on-dielectric (EWOD) actuation has been used to mechanically separate the phases. Phase separation performance in terms of percentage residue of one phase into another phase has been quantified. It was conceived that the residue formation can be controlled by controlling the deformation of the phases. The larger capillary number of the neck forming phase is associated with the larger amount of deformation as well as more residue. In this study, we propose two different ways to control the deformation of the phases. In the first method, we applied different EWOD operation voltages on two phases to maintain equal capillary numbers during phase separation. In the second method, while keeping the applied voltages same on both sides, we tested the phase separation performance by varying the actuation schemes. Less than 2% of residue was achieved by both methods, which is almost 90% improvement compared to the phase separation by the conventional droplet splitting technique in EWOD DMF platform, where the residue percentage can go up to 20%.

Download Full-text

A Novel Anion Exchange Membrane for Bisulfite Anion Separation by Grafting a Quaternized Moiety through BPPO via Thermal-Induced Phase Separation

International Journal of Molecular Sciences ◽

10.3390/ijms21165782 ◽

2020 ◽

Vol 21 (16) ◽

pp. 5782

Author(s):

Md Mofasserul Alam ◽

Yaoming Wang ◽

Chenxiao Jiang ◽

Tingting Xu ◽

Yahua Liu ◽

...

Keyword(s):

Phase Separation ◽

Anion Exchange ◽

Membrane Surface ◽

Separation Performance ◽

Anion Exchange Membranes ◽

Transmission Electron ◽

Alkali Medium ◽

Core Elements ◽

Anion Separation ◽

Exchange Membrane

Ion-exchange membranes are the core elements for an electrodialysis (ED) separation process. Phase inversion is an effective method, particularly for commercial membrane production. It introduces two different mechanisms, i.e., thermal induced phase separation (TIPS) and diffusion induced phase separation (DIPS). In this study, anion exchange membranes (AEMs) were prepared by grafting a quaternized moiety (QM,2-[dimethylaminomethyl]naphthalen-1-ol) through brominated poly (2,6-dimethyl-1,4-phenylene oxide) (BPPO) via the TIPS method. Those membranes were applied for selective bisulfite (HSO3−) anion separation using ED. The membrane surface morphology was characterized by SEM, and the compositions were magnified using a high-resolution transmission electron microscope (HRTEM). Notably, the membranes showed excellent substance stability in an alkali medium and in grafting tests performed in a QM-soluble solvent. The ED experiment indicated that the as-prepared membrane exhibited better HSO3− separation performance than the state-of-the-art commercial Neosepta AMX (ASTOM, Japan) membrane.

Download Full-text

Ceramic Immobilization Options for Technetium

MRS Advances ◽

10.1557/adv.2017.268 ◽

2017 ◽

Vol 2 (13) ◽

pp. 753-758 ◽

Cited By ~ 2

Author(s):

Martin C. Stennett ◽

Tae-Hyuk Lee ◽

Daniel J. Bailey ◽

Erik V. Johnstone ◽

Jong Heo ◽

...

Keyword(s):

Spent Nuclear Fuel ◽

Thermo Gravimetric Analysis ◽

Fission Products ◽

High Mobility ◽

Biologically Active ◽

Purex Process ◽

Gravimetric Analysis ◽

X Ray Diffraction ◽

Exchange Processes ◽

High Concentrations

ABSTRACTLong half-life biologically active fission products, such as technetium-99, present particular problems for the disposal of spent nuclear fuel (SNF). Technetium is present in relatively high concentrations in fuel (approx. 1kg tonne-1 SNF) and has very high mobility in oxidizing environments. Technetium is therefore generally removed from SNF either by solvent extraction and reduction, during the PUREX process, or by sorption via ion exchange processes. Historically technetium has been disposed of via dilution and dispersion in the sea but stringent regulations now mean that the preferred long term option is immobilization in a highly stable and durable matrix. In this contribution we have looked at the synthesis of fluorite derivative crystalline host phases based on the zirconolite structure. Samples have been characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), thermo-gravimetric analysis (TG), and mass spectroscopy (MS). We have used Mo as an inactive surrogate for Tc.

Download Full-text

Initial Investigation Into the Vitrification of High Molybdenum Solids in Borosilicate Glass

MRS Proceedings ◽

10.1557/proc-1193-291 ◽

2009 ◽

Vol 1193 ◽

Cited By ~ 2

Author(s):

Barbara F. Dunnett ◽

Nick R. Gribble ◽

Andrew D. Riley ◽

Carl J. Steele

Keyword(s):

Phase Separation ◽

Borosilicate Glass ◽

Spent Nuclear Fuel ◽

Storage Tanks ◽

Waste Storage ◽

Waste Vitrification ◽

Durability Testing ◽

Glass Formulation ◽

Selection Of ◽

Scanning Electron

AbstractSellafield Ltd operates a Waste Vitrification Plant (WVP) to immobilise the arisings from the reprocessing of spent nuclear fuel. Washout of solids from the base of waste storage tanks in preparation for decommissioning is likely to produce feeds enriched in molybdenum to the WVP. Vitrification of such feeds in the borosilicate glass formulation currently used by the WVP for vitrification of reprocessing waste has been investigated to determine the maximum achievable loading of MoO3.The vitrification of molybdenum in the absence and presence of reprocessing waste was studied. A number of glasses were manufactured in the laboratory containing various waste loadings. The resultant glasses were examined both visually and under the scanning electron microscope for the presence of any phase separation. Additional aluminium was added to the glasses manufactured in the absence of reprocessing waste to improve the durability of the glass. In borosilicate glass containing 3.5 wt% Al2O3 the onset of a molybdenum phase separation was observed in glasses containing 2.6 wt% MoO3. In the presence of Magnox reprocessing waste, phase separation was observed when the product contained >3.8 wt% MoO3. Soxhlet durability testing of a selection of the glasses manufactured was carried out. The Soxhlet durability of glasses in the absence of phase separation was good.

Download Full-text

Effect of geometric parameters of liquid-gas separator units on phase separation performance

Korean Journal of Chemical Engineering ◽

10.1007/s11814-014-0353-3 ◽

2015 ◽

Vol 32 (7) ◽

pp. 1243-1248 ◽

Cited By ~ 4

Author(s):

Songping Mo ◽

Xueqing Chen ◽

Ying Chen ◽

Zhen Yang

Keyword(s):

Phase Separation ◽

Geometric Parameters ◽

Separation Performance ◽

Gas Separator

Download Full-text

Integrated Clarification and Purification of Monoclonal Antibodies by Membrane Based Separation of Aqueous Two-Phase Systems

Antibodies ◽

10.3390/antib8030040 ◽

2019 ◽

Vol 8 (3) ◽

pp. 40 ◽

Cited By ~ 7

Author(s):

Thomas Kruse ◽

Axel Schmidt ◽

Markus Kampmann ◽

Jochen Strube

Keyword(s):

Monoclonal Antibodies ◽

Phase Separation ◽

Chinese Hamster ◽

Contact Angles ◽

Cell Protein ◽

Phase System ◽

Separation Performance ◽

Downstream Process ◽

Two Phase ◽

Cultivation Broth

Therapeutic monoclonal antibodies (mAb) are used for the treatment of numerous serious diseases, which have led to an increasing demand over the last decades. Increased cell density and mAb titer of the cultivation broth lead to great challenges for the subsequent clarification and capture operations in the downstream process. As an alternative approach to the conventional downstream process, a selective mAb extraction via an aqueous two-phase system (ATPS) directly from the cultivation broth of a mAb producing industrial relevant chinese hamster ovary (CHO) cell line was investigated. An efficient purification of the mAb was accomplished by the ATPS composition. The phase separation was realized by a newly developed membrane based phase separator. Moreover, a complete cell removal was integrated into this process by the used membrane. A selectivity between both phases was achieved by membrane modification. Yields up to 93% in the light phase and removal of process related impurities were obtained after aqueous two-phase extraction (ATPE). Phase separation performance as well as contact angles on the membrane were characterized for different ATPS. ATPE directly from the cultivation broth in combination with the new membrane based phase separation led to a mAb yield of 78% with a simultaneous reduction of deoxyribonucleic acid (DNA) and host cell protein (HCP) load.

Download Full-text