Electrodeposition of zinc-iron coatings from ammonium oxalate baths

2021 ◽  
Vol 29 (2) ◽  
pp. 19-24
Author(s):  
R. F. Shekhanov ◽  
S. N. Gridchin
Keyword(s):  
Ammonium Oxalate ◽  
Iron Coatings

Screening of an Alkaline CMCase-Producing Strain and the Optimization of its Fermentation Condition

2020 ◽  
Vol 21 (13) ◽  
pp. 1304-1315
Author(s):  
Junmei Zhou ◽  
Lianghong Yin ◽  
Chenbin Wu ◽  
Sijia Wu ◽  
Jidong Lu ◽  
...  
Keyword(s):  
Bacterial Isolate ◽  
Ammonium Oxalate ◽  
Fermentation Condition ◽  
Bivalent Cations ◽  
Rdna Sequencing ◽  
Optimum Ph ◽  
Alkaline Conditions ◽  
Fermentation Parameters ◽  
Pulp And Paper Industries ◽  
Central Composite

Objective: Alkaline Carboxymethyl Cellulase (CMCase) is an attractive enzyme for the textile, laundry, pulp, and paper industries; however, commercial preparations with sufficient activity at alkaline conditions are scarce. Methods: High CMCase-producing bacterial isolate, SX9-4, was screened out from soil bacteria, which was identified as Flavobacterium sp. on the basis of 16S rDNA sequencing. Results: The optimum pH and temperature for CMCase reaction were 8.0 and 55°C, respectively. Alkaline CMCase was stable over wide pH (3.0-10.6) and temperature (25-55°C) ranges. Enzyme activity was significantly inhibited by the bivalent cations Mn2+ and Cu2+, and was activated by Fe2+. To improve the alkaline CMCase production of SX9-4, fermentation parameters were selected through onefactor- at-a-time and further carried out by response surface methodologies based on a central composite design. Conclusion: High CMCase production (57.18 U/mL) was achieved under the optimal conditions: 10.53 g/L carboxymethylcellulose sodium, 7.74 g/L glucose, 13.71 g/L peptone, and 5.27 g/L ammonium oxalate.

scholarly journals Optimization of sunflower head pectin extraction by ammonium oxalate and the effect of drying conditions on properties

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xuemei Ma ◽  
Jiayi Yu ◽  
Jing Jing ◽  
Qian Zhao ◽  
Liyong Ren ◽  
...  
Keyword(s):  
High Performance ◽  
Freeze Drying ◽  
Antioxidant Activities ◽  
Structural Characteristics ◽  
Radical Scavenging ◽  
Ammonium Oxalate ◽  
Extraction Process ◽  
Size Exclusion ◽  
Pharmaceutical Industries

AbstractPectin is a kind of natural and complex carbohydrates which is extensively used in food, chemical, cosmetic, and pharmaceutical industries. Fresh sunflower (Helianthus annuus L.) heads were utilized as a novel source of pectin extracted by ammonium oxalate. The conditions of the extraction process were optimized implementing the response surface methodology. Under optimal extraction parameters (extraction time 1.34 h, liquid–solid ratio 15:1 mL/g, ammonium oxalate concentration 0.76% (w/v)), the maximum experimental yield was 7.36%. The effect of spray-drying and freeze-drying on the physiochemical properties, structural characteristics, and antioxidant activities was investigated by FT-IR spectroscopy, high performance size exclusion chromatography, and X-ray diffraction. The results showed freeze-drying lead to decrease in galacturonic acid (GalA) content (76.2%), molecular weight (Mw 316 kDa), and crystallinity. The antioxidant activities of pectin were investigated utilizing the in-vitro DPPH and ABTS radical-scavenging systems. This study provided a novel and efficient extraction method of sunflower pectin, and confirmed that different drying processes had an effect on the structure and properties of pectin.

scholarly journals Protection of Stone Monuments Using a Brushing Treatment with Ammonium Oxalate

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 379
Author(s):  
Domagoj Mudronja ◽  
Frederik Vanmeert ◽  
Stjepko Fazinic ◽  
Koen Janssens ◽  
Darko Tibljas ◽  
...  
Keyword(s):  
Chemical Weathering ◽  
Treatment Time ◽  
Protective Coatings ◽  
Ammonium Oxalate ◽  
Protective Layer ◽  
Thick Layer ◽  
Calcite Dissolution ◽  
X Ray ◽  
Stone Monuments ◽  
Surface Corrosion

Stone monuments and buildings are susceptible to weathering. Carbonate-based stones are especially vulnerable in acidic environments, whereas magmatic acidic stones are more susceptible to chemical weathering in basic environments. To slow down surface corrosion of limestone and marble artworks/buildings, protective coatings which inhibit calcite dissolution have been proposed. In this work, samples from two stone types with different porosity were treated with ammonium oxalate (AmOx) to create a protective layer of calcium oxalate (CaOx) using the previously developed brushing method. Two different synchrotron microscopy experiments were performed to determine its protective capability. X-ray powder diffraction (SR-μ-XRPD) in transmission geometry allowed visualization of the distributions of calcium carbonate and oxalates along the sample depths. In a second step, X-ray fluorescence (SR-μ-XRF) was used to check the efficiency/integrity of the protective surface coating layer. This was done by measuring the sulfur distribution on the stone surface after exposing the protected stones to sulfuric acid. XRPD showed the formation of a protective oxalate layer with a thickness of 5–15 µm on the less porous stone, while a 20–30 µm thick layer formed on the more porous stone. The XRF study showed that the optimal treatment time depends on the stone porosity. Increasing the treatment time from 1 to 3 h resulted in a decreased efficiency of the protective layer for the low porosity stone. We assume that this is due to the formation of vertical channels (cracks) in the protective layer.

Influence of soil organic matter on sulfate retention in two Podzols in Quebec, Canada

1999 ◽  
Vol 79 (1) ◽  
pp. 103-109 ◽  
Author(s):  
F. Courchesne ◽  
J.-F. Laberge ◽  
A. Dufresne
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Ammonium Oxalate ◽  
X Ray Diffraction ◽  
Weighted Mean ◽  
Fine Silt ◽  
Mineral Horizon ◽  
Organic C ◽  
X Ray

The role of soil organic matter (OM) on SO4 retention was investigated by comparing OM content, SO4 retention, and the distribution of Fe, Al and Si compounds in OM-poor (Grands-Jardins, PGJ) and OM-rich (Hermine, HER) Podzols from Québec, Canada. At both sites, four pedons were sampled by horizon; soil pH in H2O, organic C, phosphate-extractable SO4 and, sodium pyrophosphate, acid ammonium oxalate and dithionite-citrate-bicarbonate (DCB) extractable Fe, Al and Si were measured for each mineral horizon. The mineralogy of the clay (<2 µm) and fine silt (2–20 µm) fractions of selected horizons was determined by X-ray diffraction (XRD) and infrared spectroscopy (IR). Weighted mean organic C and pyrophosphate extractable Fe and Al contents were significantly higher in the HER than in the PGJ sola, while the PGJ soils were richer in amorphous inorganic Al. No trends were observed for inorganic Fe compounds. Chemical dissolution and IR allowed the identification of short-range ordered aluminosilicates, probably allophane, in the OM-poor and slightly acidic to neutral PGJ soils. These materials were absent from the OM-rich and acidic HER soils. Phosphate extractions showed that the weighted mean native SO4 content was five times higher in the PGJ than in the HER soil. Finally, native SO4 was strongly related to inorganic Fe, Al and Si (associated with allophane) at PGJ but only to inorganic Fe at HER. These results indicate that OM indirectly affects SO4 sorption through the influence organic substances exerts on the nature and distribution of pedogenic Fe, Al and Si compounds, such as allophane, in Podzolic profiles. Key words: Organic matter, sulfate, imogolite, allophane, silica, Podzol

DETERMINING AMMONIUM OXALATE-EXTRACTABLE Si IN SOILS

1986 ◽  
Vol 66 (4) ◽  
pp. 751-755 ◽  
Author(s):  
C. WANG ◽  
P. A. SCHUPPLI
Keyword(s):  
Atomic Absorption ◽  
Key Words ◽  
Podzolic Soil ◽  
Ammonium Oxalate ◽  
Podzolic Soils ◽  
Significant Difference ◽  
Key Words Oxalate

Determination of oxalate-extractable Si and Al is useful in assessing the degree of accumulation of allophane-like materials in Podzolic soils. Three procedures were tested for determining Si: manual spectrophotometry, automated spectrophotometry and atomic absorption. For concentrations of oxalate-extractable Si above 0.5 g kg−1, there was no significant difference among results by the three procedures. For lower concentrations of Si, results by atomic absorption were higher than those by the spectrophotometric procedures. Determination by Si by autoanalyzer is the preferred procedure as it is convenient, sensitive and reliable. Key words: Oxalate Si, Podzolic soil, autoanalyzer

Accurate Determination of Total Antimony Using ICP-MS and Optimization Its Extraction Efficiency From Reference and Soil Samples

2018 ◽  
Vol 6 (1) ◽  
pp. 48-58
Author(s):  
Sameer Amereih ◽  
Thomas Meisel ◽  
Wolfhard Wegsheider
Keyword(s):  
Citric Acid ◽  
Reference Materials ◽  
Microwave Digestion ◽  
Accurate Determination ◽  
Ammonium Oxalate ◽  
Ammonium Thiocyanate ◽  
Strong Acid ◽  
Disodium Salt ◽  
Icp Ms ◽  
Ammonium Hydrogen

Two independent digestion techniques (microwave acid digestion with HF and HCl, HNO3 and Na2O2 sintering, respectively) were applied to determine the total Sb concentration in a real soil sample and in reference materials: Icelandic Basalt (BIR-1), Cody Shale (SCo-1) and (Soil-7). ICP-MS was used to determine total antimony concentrations in the digested and the extracted solutions using external calibration and isotope dilution technique. The recoveries of Sb using HF in the acids digestion mixture in closed-vessels microwave digestion system were excellent and the concentrations are in very good agreement with certified or reported concentrations of reference materials. Using closed-vessels combined with microwave heating systems probably prevents the loss of volatile Sb compounds. The use of hydrogen fluoride with other strong acid can help dissociating insoluble antimony silicates. Different extraction reagents were tested for their ability to extract antimony using an ultrasonic bath namely: EDTA disodium salt, potassium hydroxide, citric acid monohydrate, pyridine-2,6-dicarboxylic acid, ammonium acetate, ammonium oxalate, ammonium thiocyanate, ammonium persulphate and di-ammonium hydrogen citrate. A 500 mmol L-1 solution of citric acid pH 1.08 proved to be the most efficient extractant. Optimization of the extraction conditions were investigated by studying the effect of pH, concentration, temperature, time of extraction, the ratio of sample mass to the volume of extractant and the number of consecutive extractions. As a result three consecutive extractions for a total time of 45 min at 80 ˚C was the most efficient condition for Sb extraction. Using these extraction conditions 61%, 3.7% RSD and 42%, 2.2% RSD (n=6) of the total antimony in the real soil and Soil-7 samples, respectively could be extracted.

scholarly journals Remaining phosphorus and sodium fluoride pH in soils with different clay contents and clay mineralogies

2004 ◽  
Vol 39 (3) ◽  
pp. 241-246 ◽  
Author(s):  
Marcelo Eduardo Alves ◽  
Arquimedes Lavorenti
Keyword(s):  
Buffer Capacity ◽  
Ammonium Oxalate ◽  
Clay Mineralogy ◽  
Clay Content ◽  
Response Curves ◽  
Solution Ph ◽  
Ph Values ◽  
Soil Clay ◽  
Soil Clay Content ◽  
Discriminatory Capacity

The remaining phosphorus (Prem) has been used for estimating the phosphorus buffer capacity (PBC) of soils of some Brazilian regions. Furthermore, the remaining phosphorus can also be used for estimating P, S and Zn soil critical levels determined with PBC-sensible extractants and for defining P and S levels to be used not only in P and S adsorption studies but also for the establishment of P and S response curves. The objective of this work was to evaluate the effects of soil clay content and clay mineralogy on Prem and its relationship with pH values measured in saturated NaF solution (pH NaF). Ammonium-oxalate-extractable aluminum exerts the major impacts on both Prem and pH NaF, which, in turn, are less dependent on soil clay content. Although Prem and pH NaF have consistent correlation, the former has a soil-PBC discriminatory capacity much greater than pH NaF.

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