BNL Citric Acid Technology: Pilot Scale Demonstration

Francis, A.J.; Dodge, J. Steven; Gillow, J. B.; Forrester, K.

doi:10.2172/770454

Cited by 4 publications

(4 citation statements)

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“…These literature findings suggest for both grades that a low amount of citrate adsorption at pH 11 and a high adsorption at pH 4.5 may contribute to the observed low amount of released metals at pH 11 and the relatively high amount of released Fe at pH 4.8, Fig. 1 7,26) . The release of Cr was among the investigated alloying constituents most dependent on the pH.…”

Section: Resultsmentioning

confidence: 54%

Influence of Citric Acid on the Metal Release of Stainless Steels

Mazinanian¹,

Wallinder

Hedberg³

2015

Corrosion Science and Technology

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Knowledge of how metal releases from the stainless steels used in food processing applications and cooking utensils is essential within the framework of human health risk assessment. A new European standard test protocol for testing metal release in food contact materials made from metals and alloys has recently been published by the Council of Europe. The major difference from earlier test protocols is the use of citric acid as the worst-case food simulant. The objectives of this study were to assess the effect of citric acid at acidic, neutral, and alkaline solution pH on the extent of metal release for stainless steel grades AISI 304 and 316, commonly used as food contact materials. Both grades released lower amounts of metals than the specific release limits when they were tested according to test guidelines. The released amounts of metals were assessed by means of graphite furnace atomic absorption spectroscopy, and changes in the outermost surface composition were determined using X-ray photoelectron spectroscopy. The results demonstrate that both the pH and the complexation capacity of the solutions affected the extent of metal release from stainless steel and are discussed from a mechanistic perspective. The outermost surface oxide was significantly enriched in chromium upon exposure to citric acid, indicating rapid passivation by the acid. This study elucidates the effect of several possible mechanisms, including complex ion-and ligand-induced metal release, that govern the process of metal release from stainless steel under passive conditions in solutions that contain citric acid.

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Section: Resultsmentioning

confidence: 54%

Influence of Citric Acid on the Metal Release of Stainless Steels

Mazinanian¹,

Wallinder

Hedberg³

2015

Corrosion Science and Technology

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“…Since the mixed cell culture contains two species, it was not possible to distinguish the contribution of each to the reduction of uranium. The mixed cell culture described here, however, does contain a Clostridium sp., and Clostridium is another bacterial genus described as being capable of uranium reduction (5,6,7). However, the fraction of biomass associated with the Clostridium sp.…”

Section: Discussionmentioning

confidence: 99%

Modeling Reduction of Uranium U(VI) under Variable Sulfate Concentrations by Sulfate-Reducing Bacteria

Spear

Figueroa

Honeyman

2000

Appl Environ Microbiol

102

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(20,21,22,23,26,39). Models for the SRB reduction of these metals and radionuclides can be used to develop and design treatment systems employing SRB for bioremediation. For example, bioreduction of soluble hexavalent uranium [U(VI)] to insoluble tetravalent uranium [U(IV)] can be utilized to remove soluble uranium from groundwaters, mine waters, or secondary waste streams.In addition to SRB, a number of bacterial species have been described as capable of reducing U(VI) to U(IV), including Geobacter metallireducens (25) (previously reported as GS-15 [11]), Shewanella putrefaciens (25), and Shewanella alga strain BrY (previously reported as BrY, or Shewanella halotolerans strain BrY [3]). A kinetic study for the reduction of U(VI) has been described for the iron-reducing S. alga strain BrY (40) but not for SRB. Before a biotreatment scheme can be designed and implemented, studies must go beyond the identification of novel processes, to quantifying the kinetics of such a process. Because of the metabolic diversity of the SRB, it is important to identify the species involved in the processes studied. Since sulfate reduction rates depend upon the species used and experimental conditions, it is important to characterize sulfate reduction for the mixed culture used in previous uranium reduction experiments (38) that were performed under repeatable, uniform conditions.The goals of this study were to characterize the mixed SRB culture previously isolated (38) and to develop models to describe sulfate reduction alone and sulfate reduction with concurrent uranium reduction. Utilizing a mixed cell culture was viewed as an advantage in that in an operational biotreatment scheme, purity of culture in treating large volumes of water will be difficult to maintain. Understanding U(VI) reduction by SRB in a consortium is more likely to be relevant for an operational condition. The nature of the mixed SRB culture was examined via 16S ribosomal DNA (rDNA) analysis. Models for separate sulfate reduction and concurrent sulfate and uranium reduction were fit to data generated by both a mixed and a pure culture of SRB. Sulfate and cell concentrations were varied during these experiments, which were conducted at room temperature, 21 Ϯ 3°C. This is at the upper end of temperatures expected in natural waters that could be treated. Sulfate concentration is expected to be a variable in the treatment of uranium-contaminated waters, and cell concentration is an operational variable for treatment design. These kinetic determinations were made under conditions of insignificant growth (in the absence of nutrients other than a lactate carbon source; the sulfate concentrations present could facilitate growth, but experimental time courses were too short), and under anaerobic batch conditions, to isolate the enzymatic reductive processes of both electron acceptors from those of cellular growth processes. Quantification with modeling of the sulfate reduction rate alone and the uranium reduction rate in the presence of sulfate is important for the ...

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“…[35][36][37] Also, it was observed that Fe 3+ ions gave a stable complex with chlorphenamine, having a similar structure to histamine, at pH 6.0 (log b: 3.6 at ratio of 1 : 1). For this purpose, preliminary experiments were carried out with metal ions including Fe(III), Cu(II), and Sn(IV) at isomolar concentrations.…”

Section: Optimization Of the Variables Affecting Complex Formation Anmentioning

confidence: 99%

A new atomic absorption-based method development for indirect determination of histamine in fish samples, dairy products, and alcoholic beverages by flame AAS

2016

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A new and sensitive analytical method for the indirect determination of histamine in fish samples, dairy products, and alcoholic beverages by flame atomic absorption spectrometry (FAAS) was developed. The method was based on the complex formation of histamine with Fe(III) and 2 0 ,4 0 ,5 0 ,7 0tetrabromofluorescein (eosin) at pH 4.5, and then extraction into the micellar phase of polyethylene glycol dodecyl ether (Brij 35). In this study, an ultrasonic assisted cloud point extraction (UA-CPE) procedure was used for the separation/pre-concentration of histamine from the related sample matrices. The optimal conditions were established and a good pre-concentration was achieved using 25 mmol L À1 Fe(III), 5 mmol L À1 eosin, 10 mmol L À1 Brij 35, 0.7% (w/v) Na 2 SO 4 , pH 4.5 citrate buffer, equilibrium temperature of 45 C, incubation time of 20 min and ultrasonication at 40 kHz and 300 W.At optimal conditions, a detection limit of 0.25 mg L À1 with a sensitivity improvement of 143-fold in the linear working range of 0.8-170 mg L À1 was obtained. The proposed method was evaluated for the analysis of some food samples and received a good recovery with the standard addition assay. In addition, the validity of the method was tested by intra-day and inter-day precision studies and recovery experiments, obtaining satisfactory results. To the best of our knowledge, this method was also the first study for indirect determination of histamine in the selected samples using UA-CPE coupled to FAAS.

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BNL Citric Acid Technology: Pilot Scale Demonstration

Cited by 4 publications

References 0 publications

Influence of Citric Acid on the Metal Release of Stainless Steels

Influence of Citric Acid on the Metal Release of Stainless Steels

Modeling Reduction of Uranium U(VI) under Variable Sulfate Concentrations by Sulfate-Reducing Bacteria

A new atomic absorption-based method development for indirect determination of histamine in fish samples, dairy products, and alcoholic beverages by flame AAS

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