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Yao, Jennifer

Publications and source records attributed to Yao, Jennifer.

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DOE OSTI2024

Hanford Waste Treatment Plant Low Activity Waste Facility Stack Effluent Monitoring: Sampling Probe Location Qualification Evaluation (Rev.1)

The Hanford Tank Waste Treatment and Immobilization Plant Low Activity Waste (LAW) facility stack monitor locations were qualified using scale model stacks to mitigate the risk of discovering that sampling locations do not meet the qualification criteria on the full-scale stacks. As required by the American National Standards Institute/Health Physics Society (ANSI/HPS) N13.1-1999 standard, the scale model and its sampling location were geometrically similar to the actual stack and the Reynolds numbers for both the actual and model stacks were >10,000. An additional criterion is that the product of the hydraulic diameter and mean velocity (DV) of the full-scale stack must be between 1/6 DV and 6 DV of the scale model stack tests. Verification tests of the LAW stacks were performed at normal operating conditions. The minimum 1/6 DV value, along with the maximum 6 DV value from the scale model testing, determines the range of stack flow rates for which the full-scale stack may be operated and remain in compliance with the stack verification criterion. For this analysis, the range of qualified flow rates listed is conservatively based on the average DV through 6 DV for LV-S1, LV-S2, and LV-C2, and 1/3 DV to 3 DV for LV-S3. Table S1 lists the operating flow rates along with the conservative lower and upper qualified stack flow rates for each of the LAW facility stacks. For each stack, the operating flow is below the upper qualified stack.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2024

In-house synthesized poly(ether ether ketone) ionenes. I. ToF-SIMS spectra in the positive ion mode

Static time-of-flight secondary ion mass spectrometry (ToF-SIMS) was performed for acquiring the high-resolution surface spectra of four types of synthesized imidazolium ionene membranes. These novel membranes have aromatic ether–ketone–ether linkages inspired by poly(ether ether ketone) (PEEK). The PEEK-ionenes synthesized for this study have imidazolium cations placed in the polymeric backbone with bistriflimide [Tf 2 N]- counterions. The attention given to synthetically modified PEEK derivatives, such as PEEK-ionenes, is considerable due to their ability to selectively capture CO 2 molecules and other light gases. Therefore, it is important to characterize the surface of these synthesized novel PEEK-ionenes. In this work, characteristic and unique peaks were identified in the positive spectra of each sample. The differences in mass spectra among the samples provide insights for optimizing or fine-tuning the PEEK-ionenes synthesis to achieve a high-performance CO 2 separation membrane with enhanced permeability, selectivity, and mechanical stability. The SIMS spectra and identified characteristic peaks of these synthesized ionenes will serve as a reference in the positive mode, complementing the corresponding spectra reported in the negative ion mode (Paper II).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

In-house synthesized poly(ether ether ketone) ionenes. II. ToF-SIMS spectra in the negative ion mode

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used to analyze poly(ether ether ketone) (PEEK) based membranes. PEEK membranes have been shown to be effective in the separation of CO 2 from flue gases (post-combustion technique). The PEEK membranes were synthesized using novel aromatic ether-ketone linkages inspired by PEEK with polymeric backbone bistriflimide [Tf2N]− counterions. One of the keys to advancing this technology is developing membranes that are selective and permeable toward CO 2 , in which PEEK based membranes have been shown to be. Furthermore, the compatibility between various water lean solvents also needs to be investigated. Surface analytical techniques such as x-ray photoelectron spectroscopy and ToF-SIMS are useful for investigating chemical changes between membranes. Herein, we present ToF-SIMS data obtained in the negative ion mode for four different PEEK membranes designed for use in CO 2 capture systems. Positive ion mode spectra are reported in Paper I.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗