Estimation of oxalic acid by photochemical oxidation with ceric sulphate

1955 ◽  
Vol 145 (6) ◽  
pp. 426-430 ◽  
Author(s):  
G. Gopala Rao ◽  
G. Aravamudan
Keyword(s):  
Oxalic Acid ◽  
Photochemical Oxidation ◽  
Ceric Sulphate

scholarly journals Molecular distributions and stable carbon isotope compositions of oxalic acid and related SOA in Beijing before, during and after the 2014 APEC

2016 ◽  
Author(s):  
Jiayuan Wang ◽  
Gehui Wang ◽  
Jian Gao ◽  
Han Wang ◽  
Yanqin Ren ◽  
...  
Keyword(s):  
Oxalic Acid ◽  
Carbon Isotope ◽  
Isotope Composition ◽  
Stable Carbon Isotope ◽  
Dicarboxylic Acids ◽  
Photochemical Oxidation ◽  
Stable Carbon ◽  
Aerosol Composition ◽  
Air Masses ◽  
Emission Controls

Abstract. To ensure the good air quality for the 2014 APEC, stringent emission controls were implemented in Beijing and its surrounding regions, leading to a significant reduction in PM2.5 loadings. To investigate the impacts of the emission controls on aerosol composition and formation, high-volume PM2.5 samples were collected in Beijing from 08/10/2014 to 24/11/2014 and determined for secondary inorganic ions (SIA, i.e., SO42−, NO3− and NH4+), dicarboxylic acids, keto-carboxylic acid and α-dicarbonyls, as well as stable carbon isotope composition of oxalic acid (C2). Our results showed that SIA in PM2.5 are 52 ± 47, 18 ± 13 and 33 ± 29 μg m−3 before-, during- and after-APEC, accounting for 29 %, 18 % and 20 % of PM2.5, respectively. As the leading dicarboxylic acid, C2 in PM2.5 during the three phases are 502 ± 564, 101 ± 69 and 166 ± 157 ng  m−3, accounting for 46 %, 31 % and 34 % of total detected organic compounds (TDOC, i.e., the sum of dicarboxylic acids, keto-carboxylic acids and α-dicarbonyls). The higher values of concentrations and relative abundances of SIA and C2 before-APEC suggest that PM2.5 aerosols during this period are more enriched with secondary products, mainly due to an enhanced photochemical oxidation under the higher temperature and more humid conditions. SIA, C2 and related SOA in PM2.5 during-APEC were 2–4 times lower than those before-APEC. C2 in the regional air masses, which mostly occurred before-APEC, are abundant and enriched in 13C. On the contrary, C2 in the long-range transport air masses, which mostly occurred during-APEC, is much less abundant but still enriched in 13C. In the local air masses, which mostly occurred after-APEC, C2 concentration is lower than that before-APEC but higher than that during-APEC and enriched in lighter 12C. A comparison on chemical composition of PM2.5 and δ13C values of C2 in two events that are characterized by the highest PM2.5 levels before- and after-APEC, respectively, further showed that after-APEC SIA and TDOC are much less abundant and fine aerosols are enriched with primary organics and relatively fresh, compared with those before-APEC. Such reduction in secondary aerosols after-APEC, along with a similar reduction during-APEC, is largely due to the decreasing temperatures. Our results indicate that the significant reduction in PM2.5 during-APEC is mainly due to the efficient emission controls, but the effect of the decreasing temperatures, which suppressed secondary aerosol production, may also take an important role.

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.

Pilot trials of hemicelluloses extraction prior to thermomechanical pulp production: Part 1

TAPPI Journal ◽  
2011 ◽  
Vol 10 (5) ◽  
pp. 21-28 ◽  
Author(s):  
CARL HOUTMAN ◽  
ERIC HORN
Keyword(s):  
Oxalic Acid ◽  
Energy Savings ◽  
Wood Chip ◽  
Strength Properties ◽  
Thermomechanical Pulp ◽  
Sugar Solution ◽  
Bisulfite Treatment ◽  
Pilot Trials ◽  
Pulp Production ◽  
Production Part

Pilot data indicate that wood chip pretreatment with oxalic acid reduced the specific energy required to make thermomechanical pulp. A combined oxalic acid/bisulfite treatment resulted in 21% refiner energy savings and 13% increase in brightness for aspen. A low level of oxalic acid treatment was effective for spruce. Energy savings of 30% was observed with no significant change in strength properties. Adding bisulfite did not significantly increase the brightness of the spruce pulp. For pine, the optimum treatment was a moderate level of oxalic acid, which resulted in 34% energy savings and an increase in strength properties. For all of these treatments 1–3 w/w % carbohydrates were recovered, which can be fermented to produce ethanol. The extract sugar solution contained significant quantities of arabinose.

Photochemical Oxidation of Poly(dimethylsiloxane) Surface and Subsequent Coating with Biomimetic Phosphorylcholine Polymer

2007 ◽  
Vol 2 (2) ◽  
pp. 245-249 ◽  
Author(s):  
Yoshiteru Hamada ◽  
Takao Ono ◽  
Takanori Akagi ◽  
Kazuhiko Ishihara ◽  
Takanori Ichiki
Keyword(s):  
Photochemical Oxidation

Fabrication and Characterization of PVA Based Cross-linked Film with Oxalic Acid

2020 ◽  
Author(s):  
Madhur Kumar Dubey ◽  
Naman Jain ◽  
Atul Kumar ◽  
Gaurang Deep ◽  
Md Sharib
Keyword(s):  
Oxalic Acid ◽  
Fabrication And Characterization
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