Dataset Information

Evaluating Solid Sorbents for Recycling Wash Waters Containing Strontium and Calcium.

ABSTRACT: A system for rapid reduction of radioactive contamination and recycle of contaminated waters is called the Integrated Wash-Aid, Treatment, and Emergency Reuse System (IWATERS). First developed for cesium contaminations, IWATERS prescribes the use of salt and surfactant additives to decontaminate radionuclides from urban surfaces. The water is collected and recycled after passing through reactive filtration beds containing selective sorbents. To adapt the IWATERS for strontium contaminations, potential additives to enhance its decontamination from urban surfaces are identified. One possible additive is calcium (Ca2+). However, its concentration can have a very strong detrimental effect on the ability of selective sorbents to remove strontium from spent wash water. We recognized that studies on off-the-shelf sorbents that include Ca2+ concentrations at relevant levels (greater than millimolar) are absent in the literature. To understand better the effect of Ca2+, we completed a literature review, batch tests, and surface complexation modeling to reveal few sorbent options. Only silico-titanate sorbents exhibited high K d values in the presence of Ca2+, but have significant drawbacks in cost and availability. Given the state of the art, it is imperative that alternatives to alkaline earth ions in the IWATERS be identified to permit in situ recycle of the wash waters.

SUBMITTER: Oster C

PROVIDER: S-EPMC6755671 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Evaluating Solid Sorbents for Recycling Wash Waters Containing Strontium and Calcium.

Oster Christopher C Kaminski Michael M Jerden James J Franchini Yvonne Y Magnuson Matthew M

Journal of hazardous, toxic and radioactive waste 20190101 1

A system for rapid reduction of radioactive contamination and recycle of contaminated waters is called the Integrated Wash-Aid, Treatment, and Emergency Reuse System (IWATERS). First developed for cesium contaminations, IWATERS prescribes the use of salt and surfactant additives to decontaminate radionuclides from urban surfaces. The water is collected and recycled after passing through reactive filtration beds containing selective sorbents. To adapt the IWATERS for strontium contaminations, pot ...[more]

PMID: 31548914

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Project description:Foodborne contamination and associated illness in the United States is responsible for an estimated 48 million cases per year. Increased food demand, global commerce of perishable foods, and the growing threat of antibiotic resistance are driving factors elevating concern for food safety. Foodborne illness is often associated with fresh-cut, ready-to-eat produce commodities due to the perishable nature of the product and relatively minimal processing from farm to the consumer. The research presented here optimizes and evaluates the utility of microfluidic droplets, also termed ultra-miniaturized bioreactors, for rapid detection of viable Salmonella enterica ser. Typhimurium in a shredded lettuce wash water acquired from a major Mid-Atlantic produce processing facility (denoted as Producer) in the U.S. Using a fluorescently-labeled anti-S. Typhimurium antibody and relative fluorescence intensities, paired with in-droplet incubation, S. Typhimurium was detected and identified with 100% specificity in less than 5 h. In initial optimization experiments using S. Typhimurium-spiked sterile water, the relative fluorescence intensity of S. Typhimurium was approximately two times that of the observed relative intensities of five non-S. Typhimurium negative controls at 4-h incubation in droplets containing Rappaport-Vasiliadis (RV) broth at 37°C: relative fluorescence intensity for S. Typhimurium = 2.36 (95% CI: 2.15-2.58), Enterobacter aerogens 1.12 (95% CI: 1.09-1.16), Escherichia coli 700609 = 1.13 (95% CI: 1.09-1.17), E. coli 13706 1.13 (95% CI: 1.07-1.19), E. coli 700891 1.05 (95% CI: 1.03-1.07) and Citrobacter freundii 1.04 (95% CI: 1.03-1.05). S. Typhimurium- and E. aerogens-spiked shredded lettuce wash waters acquired from the Producer were then incubated 4 h in-droplet at 37°C with RV broth. The observed relative fluorescence of S. Typhimurium was significantly higher than that of E. aerogens, 1.56 (95% CI: 1.42-1.71) and 1.10 (95% CI: 1.08-1.12), respectively. While further optimization focusing on compatible concentration methodologies for highly-dilute produce water samples is needed, this application of droplet microfluidics shows great promise in dramatically shortening the time necessary-from days to hours-to confirm viable bacterial contamination in ready-to-eat produce wash waters used throughout the domestic and international food industry.

Project description:PurposeThis study developed light cured dental composites with added monocalcium phosphate monohydrate (MCPM), tristrontium phosphate (TSrP) and antimicrobial polylysine (PLS). The aim was to produce composites that have enhanced water sorption induced expansion, can promote apatite precipitation and release polylysine.Materials and methodsExperimental composite formulations consisted of light activated dimethacrylate monomers combined with 80 wt% powder. The powder phase contained a dental glass with and without PLS (2.5 wt%) and/or reactive phosphate fillers (15 wt% TSrP and 10 wt% MCPM). The commercial composite, Z250, was used as a control. Monomer conversion and calculated polymerization shrinkage were assessed using FTIR. Subsequent mass or volume changes in water versus simulated body fluid (SBF) were quantified using gravimetric studies. These were used, along with Raman and SEM, to assess apatite precipitation on the composite surface. PLS release was determined using UV spectroscopy. Furthermore, biaxial flexural strengths after 24 hours of SBF immersion were obtained.ResultsMonomer conversion of the composites decreased upon the addition of phosphate fillers (from 76 to 64%) but was always higher than that of Z250 (54%). Phosphate addition increased water sorption induced expansion from 2 to 4% helping to balance the calculated polymerization shrinkage of ~ 3.4%. Phosphate addition promoted apatite precipitation from SBF. Polylysine increased the apatite layer thickness from ~ 10 to 20 μm after 4 weeks. The novel composites showed a burst release of PLS (3.7%) followed by diffusion-controlled release irrespective of phosphate addition. PLS and phosphates decreased strength from 154 MPa on average by 17% and 18%, respectively. All formulations, however, had greater strength than the ISO 4049 requirement of > 80 MPa.ConclusionThe addition of MCPM with TSrP promoted hygroscopic expansion, and apatite formation. These properties are expected to help compensate polymerization shrinkage and help remineralize demineralized dentin. Polylysine can be released from the composites at early time. This may kill residual bacteria.

Dataset Information

Evaluating Solid Sorbents for Recycling Wash Waters Containing Strontium and Calcium.

Publications

Evaluating Solid Sorbents for Recycling Wash Waters Containing Strontium and Calcium.

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