The Reduction of Free Nitric Acid by Means of Ferrous, Stannous, or Titanous Salts

1924 ◽  
Vol 28 (7) ◽  
pp. 744-757 ◽  
Author(s):  
L. H. Milligan ◽  
G. R. Gillette
Keyword(s):  
Nitric Acid ◽  
Free Nitric Acid

A novel method for the determination of uranium and free acidity in nuclear fuel process samples by extraction spectrophotometry

2019 ◽  
Vol 107 (4) ◽  
pp. 327-337
Author(s):  
Raghbendra Thakur ◽  
Pranab K. Tarafder ◽  
Raj Ranjan Jha
Keyword(s):  
Nitric Acid ◽  
Nuclear Fuel ◽  
Molar Absorptivity ◽  
Ion Pair ◽  
Anionic Complex ◽  
Free Acidity ◽  
Free Nitric Acid ◽  
Relative Standard ◽  
Yellowish Orange

Abstract A novel and useful extraction spectrophotometric method for the rapid determination of uranium and free acidity in nuclear fuel process samples using the reagent, 2,3-dihydroxynaphthalene as an extractant as well as color forming agent is described. Uranium at milligram level forms a yellowish- orange anionic complex with the ligand, 2,3-dihydroxynaphthalene over a pH range, 10–12. This anionic complex is easily extracted into ethylacetate as an ion-pair complex with cetyltrimethylammonium cation (CTA+). The absorbance of the ion-pair complex in ethylacetate is measured at 390 nm. The molar absorptivity and Sandell’s sensitivity of the system being 5.0×103 L·mol−1 cm−1 and 0.047 μg cm−2, respectively at 390 nm. This very reagent (2,3-dihydroxynaphthalene) also forms a yellowish-orange nitro product with free nitric acid (HNO3) in the presence of concentrated sulfuric acid. This nitro- product is easily extracted into the same solvent (ethylacetate) and absorbs maximum at 380 nm. The molar absorptivity (ε) and Sandell’s sensitivity of the system being 2.4×103 L·mol−1 cm−1 and 0.027 μg cm−2, respectively. By using the single chromophoric agent (2,3-dihydroxynaphthalene), both uranium and free acidity can be easily and reliably determined separately in the process solution. The relative standard deviations (RSD) are in the range, 0.5–2.0% and 1.5–2.0%, respectively for uranium and free nitric acid determinations. The method has been applied to nuclear fuel process solutions, and the results obtained have been found to be favorably comparable with those obtained from standard methods.

Ectodesmata as Revealed By Freeze-Etch Preparations of Plant Epidermal Cell Walls

1973 ◽  
Vol 31 ◽  
pp. 468-469
Author(s):  
N.C. Lyon ◽  
W. C. Mueller
Keyword(s):  
Electron Microscopy ◽  
Acetic Acid ◽  
Nitric Acid ◽  
Oxalic Acid ◽  
Light Microscopy ◽  
Epidermal Cell ◽  
Cell Walls ◽  
Plant Viruses ◽  
Plant Leaves ◽  
Thin Sections

Schumacher and Halbsguth first demonstrated ectodesmata as pores or channels in the epidermal cell walls in haustoria of Cuscuta odorata L. by light microscopy in tissues fixed in a sublimate fixative (30% ethyl alcohol, 30 ml:glacial acetic acid, 10 ml: 65% nitric acid, 1 ml: 40% formaldehyde, 5 ml: oxalic acid, 2 g: mecuric chloride to saturation 2-3 g). Other workers have published electron micrographs of structures transversing the outer epidermal cell in thin sections of plant leaves that have been interpreted as ectodesmata. Such structures are evident following treatment with Hg++ or Ag+ salts and are only rarely observed by electron microscopy. If ectodesmata exist without such treatment, and are not artefacts, they would afford natural pathways of entry for applied foliar solutions and plant viruses.

The Action of Nitric Acid on Aluminium

1916 ◽  
Vol 82 (2122supp) ◽  
pp. 150-150
Author(s):  
R. Seligman ◽  
P. Williams
Keyword(s):  
Nitric Acid
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