Influence of Acetic Acid on the Integrity and Protectiveness by an Iron Carbonate (FeCO3) Corrosion Product Layer

CORROSION ◽  
10.5006/3659 ◽  
2020 ◽  
Author(s):  
Vanessa Fajardo ◽  
Maryam Eslami ◽  
Yoon-Seok Choi ◽  
Bruce Brown ◽  
Srdjan Nesic
Keyword(s):  
Acetic Acid ◽  
Electrochemical Quartz Crystal Microbalance ◽  
Product Layer ◽  
Sudden Increase ◽  
Ph Change ◽  
Iron Carbonate ◽  
X65 Steel ◽  
Immersion Experiment ◽  
Steel Substrates ◽  
Over Time

ABSTRACT The effect of undissociated acetic acid on the integrity of iron carbonate (FeCO3) layer formed on platinum and X65 steel substrates is investigated. Experiments were conducted using buffered solutions with 0.8 - 5 mM undissociated acetic acid. For the platinum substrates, changes in the FeCO3 layer were monitored via in-situ electrochemical quartz crystal microbalance (EQCM) measurements. This investigation was supported by performing electrochemical experiments, under comparable conditions, on the X65 steel specimens, linking the integrity of FeCO3 layer to its corrosion protection effect. The EQCM measurements revealed that the addition of acetic acid, at all concentrations tested here, caused partial dissolution of the FeCO3 layer. The dissolution occurred selectively, with the outer layer dissolving first, leaving behind an inner FeCO3 layer at the end of the immersion experiment. The electrochemical results revealed that introducing the acetic acid caused a sudden increase in the corrosion rate, which over time returned to a lower value similar in magnitude to that seen before addition of the acetic acid. This was attributed to the protection provided by the inner FeCO3 layer, which was only mildly affected by the addition of acetic acid and was able to repair over time. It was proven that the dissolution of the protective FeCO3 layer in the presence of acetic acid was not due to a small pH change but rather due to the formation of ferrous acetate complexes and changes in ionic strength, which decreases the FeCO3 saturation values.

scholarly journals Pyrite (FeS2)-supported ultrafiltration system for removal of mercury (II) from water

2021 ◽  
Author(s):  
Dong Suk Han ◽  
Kawsher M. D. Solayman ◽  
Ho Kyong Shon ◽  
Ahmed Abdel-Wahab
Keyword(s):  
Membrane Filter ◽  
Pyrite Surface ◽  
Ph Change ◽  
Filtration Process ◽  
Sem Images ◽  
Flux Decline ◽  
Cake Layer ◽  
Water Effects ◽  
Almost All ◽  
Over Time

AbstractThis study investigated the Hg(II) removal efficiencies of the reactive adsorbent membrane (RAM) hybrid filtration process, a removal process that produces stable final residuals. The reaction mechanism between Hg(II) and pyrite and the rejection of the solids over time were characterized with respect to flux decline, pH change, and Hg and Fe concentration in permeate water. Effects of the presence of anions (Cl−, SO42−, NO3−) or humic acid (HA) on the rejection of the Hg(II)-contacted pyrite were studied. The presence of both HA and Hg(II) increased the rate of flux decline due to the formation of irreversible gel-like compact cake layers as shown in the experimental data and modeling related to the flux decline and the SEM images. Stability experiments of the final residuals retained on the membrane using a thiosulfate solution (Na2S2O3) show that the Hg(II)-laden solids were very stable due to little or no detection of Hg(II) in the permeate water. Experiment on the possibility of continuously removing Hg(II) by reusing the Hg/pyrite-laden membrane shows that almost all Hg(II) was adsorbed onto the pyrite surface regardless of the presence of salts or HA, and the Hg(II)-contacted pyrite residuals were completely rejected by the DE/UF system. Therefore, a membrane filter containing pyrite-Hg(II) could provide another reactive cake layer capable of further removal of Hg(II) without post-chemical treatment for reuse.

scholarly journals Silicate fertilization of tropical soils: silicon availability and recovery index of sugarcane

2013 ◽  
Vol 37 (5) ◽  
pp. 1267-1275 ◽  
Author(s):  
Mônica Sartori de Camargo ◽  
Gabriela Rocha ◽  
Gaspar Henrique Korndörfer
Keyword(s):  
Acetic Acid ◽  
Residual Effect ◽  
Tropical Soils ◽  
Soil Types ◽  
Silicon Source ◽  
Recovery Index ◽  
Over Time

Sugarcane is considered a Si-accumulating plant, but in Brazil, where several soil types are used for cultivation, there is little information about silicon (Si) fertilization. The objectives of this study were to evaluate the silicon availability, uptake and recovery index of Si from the applied silicate on tropical soils with and without silicate fertilization, in three crops. The experiments in pots (100 L) were performed with specific Si rates (0, 185, 370 and 555 kg ha-1 Si), three soils (Quartzipsamment-Q, 6 % clay; Rhodic Hapludox-RH, 22 % clay; and Rhodic Acrudox-RA, 68 % clay), with four replications. The silicon source was Ca-Mg silicate. The same Ca and Mg quantities were applied to all pots, with lime and/or MgCl2, when necessary. Sugarcane was harvested in the plant cane and first- and second-ratoon crops. The silicon rates increased soil Si availability and Si uptake by sugarcane and had a strong residual effect. The contents of soluble Si were reduced by harvesting and increased with silicate application in the following decreasing order: Q>RH>RA. The silicate rates promoted an increase in soluble Si-acetic acid at harvest for all crops and in all soils, except RA. The amounts of Si-CaCl2 were not influenced by silicate in the ratoon crops. The plant Si uptake increased according to the Si rates and was highest in RA at all harvests. The recovery index of applied Si (RI) of sugarcane increased over time, and was highest in RA.

Time course of exchanges between red cells and extracellular fluid during CO2 uptake

1975 ◽  
Vol 38 (4) ◽  
pp. 710-718 ◽  
Author(s):  
R. E. Forster ◽  
E. D. Crandall
Keyword(s):  
Carbonic Anhydrase ◽  
Time Course ◽  
Extracellular Fluid ◽  
Extracellular Ph ◽  
Co2 Uptake ◽  
Sudden Increase ◽  
Red Cell ◽  
Ph Change ◽  
Red Cell Membrane

A stopped-flow rapid-reaction apparatus was used to follow the time course of extracellular pH in a human red cell suspension following a sudden increase in PCO2. The extracellular pH change was slow (t1/2 similar to 3.5 s) considering the presence of carbonic anhydrase in the cells. When carbonic anhydrase was added to the extracellular fluid, the half-time was reduced to less than 20 ms. The explanation for these phenomena is that the equilibration of H+ across the red cell membrane is rate-limited by the uncatalyzed reaction CO2 plus H2O formed from H2CO3 outside the cells. A theoretical model was developed which successfully reproduced the experimental results. When the model was used to simulate CO2 exchange in vivo, it was determined that blood PCO2 and pH require long times (greater than 50 s) to approach equilibrium between cells and plasma after leaving an exchange capillary. We conclude that cell-plasma equilibrium may never be reached in vivo, and that in vitro measurements of these quantities may not represent their true values at the site of sampling.

scholarly journals 86 Impact of steeping corn DDGS over 72 hours without or with fiber degrading enzymes and protease alone or in combination on concentration of sugars and organic acids and pH in the liquid medium

2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 49-50
Author(s):  
Youngji Rho ◽  
Rob Patterson ◽  
Elijah Kiarie
Keyword(s):  
Acetic Acid ◽  
Lactic Acid ◽  
Liquid Medium ◽  
Ph Measurements ◽  
Degrading Enzymes ◽  
Sterile Plastic ◽  
And Control ◽  
The Impact ◽  
Over Time ◽  
Corn Ddgs

Abstract We investigated the impact of steeping corn DDGS over 72 h with or without fiber degrading enzymes (FDE) and protease (PRO) on concentration of sugar, acetic and lactic acid, and pH. The concentration of crude fat, CP, NDF and ADF in DDGS sample was 8.6, 30.8, 36.1, 12.2% DM, respectively. Treatments were: 1) DDGS steeped without enzymes (Control), 2) DDGS steeped with FDE (FDE), 3) DDGS steeped with protease (PRO), 4) DDGS steeped with combination (FDEPRO). Enzymes were added at 1% of DDGS. Briefly, 50g of DDGS was mixed with 500-mL water with or without enzymes in sterile plastic bottles and steeped for 0, 12, 24, 48 and 72-h at 37℃ with continuous agitation. Samples were aliquoted to individual bottle for each timepoint. At each time point, bottles were pulled out from the incubator for pH measurements and liquid medium supernatant for sugars and acids. Highest arabinose, xylose and glucose was observed at 12 and 24 h, followed by decrease at 48 and 72 h. At 12 h, arabinose was higher (P < 0.05) for FDE and FDEPRO than control. The highest xylose and glucose was seen at 12 h for PRO, FDE and FDEPRO while control was highest at 24 h. Acetic acid and lactic acid increased over time. At 72 h, FEDPRO had highest acetic acid compared to control and PRO, while lactic acid was highest for FDE and FDPRO compared with (P < 0.0001) control and PRO. The pH decreased (P < 0.05) over time for all treatments. At 72 h, FDE had lowest pH followed by FDEPRO, PRO and control (P < .0001). Overall, arabinose, xylose and glucose increased to a certain timepoint and decreased, while lactic and acetic acid increased over time, subsequently leading to lowest pH at 72 h. In conclusion, FDE increased concentration of sugars and acids in steeped DDGS whereas PRO had no effect.

AN INVESTIGATION ON EFFECTS OF TiO2 NANO-PARTICLES INCORPORATED IN ELECTROLESS NiP COATINGS' PROPERTIES

2012 ◽  
Vol 05 ◽  
pp. 833-840
Author(s):  
S.R. Allahkaram ◽  
S. Salmi ◽  
E. Tohidlou
Keyword(s):  
Corrosion Resistance ◽  
Composite Coatings ◽  
Amorphous Structure ◽  
Nano Particles ◽  
Acid Electrolyte ◽  
Sulfuric Acid Electrolyte ◽  
X65 Steel ◽  
Electroless Coatings ◽  
Api 5L X65 Steel ◽  
Steel Substrates

Electroless composite coatings have been vastly used in various industries during last decades due to their good properties, such as corrosion and wear resistance, hardness and uniform thickness. In this paper, co-deposition of TiO 2 nano-particles with Nickel-Phosphorus electroless coatings on API-5L-X65 steel substrates was investigated. Surface morphology and composition of coatings were studied via SEM and EDX, respectively. XRD analyses showed that these coatings had amorphous structure with TiO 2 crystalline particles. TiO 2 nano-particles increased microhardness of coatings. Corrosion resistance of these coatings was tested using linear polarization in 0.5M sulfuric acid electrolyte. Results showed that NiP - TiO 2 electroless composite coatings increased corrosion resistance of substrates.

scholarly journals Validation of a Fertilizer Potential Acidity Model to Predict the Effects of Water-soluble Fertilizer on Substrate pH

HortScience ◽  
2014 ◽  
Vol 49 (8) ◽  
pp. 1061-1066 ◽  
Author(s):  
Paul R. Fisher ◽  
William R. Argo ◽  
John A. Biernbaum
Keyword(s):  
Calcium Carbonate ◽  
Plant Species ◽  
Ammonium Nitrogen ◽  
Water Soluble ◽  
Ph Change ◽  
Bedding Plant ◽  
Stable Substrate ◽  
Soluble Fertilizer ◽  
Substrate Ph ◽  
Over Time

Two experiments were run to validate a “Nitrogen Calcium Carbonate Equivalence (CCE)” model that predicts potential fertilizer basicity or acidity based on nitrogen (N) form and concentration for floriculture crops grown with water-soluble fertilizer in containers with minimal leaching. In one experiment, nine bedding plant species were grown for 28 days in a peat-based substrate using one of three nutrient solutions (FS) composed of three commercially available water-soluble fertilizers that varied in ammonium to nitrate (NH4+:NO3–) ratio (40:60, 25:75, or 4:96) mixed with well water with 130 mg·L−1 calcium carbonate (CaCO3) alkalinity. Both the ammonium-nitrogen (NH4-N) content of the FS and plant species affected substrate pH. Predicted acidity or basicity of the FS for Impatiens walleriana Hook.f. (impatiens), Petunia ×hybrida E. Vilm. (petunia), and Pelargonium hortorum L.H. Bailey (pelargonium) from the Nitrogen CCE model was similar to observed pH change with an adjusted R2 of 0.849. In a second experiment, water alkalinity (0 or 135.5 mg·L−1 CaCO3), NH4+:NO3– ratio (75:25 or 3:97), and N concentration (50, 100, or 200 mg·L−1 N) in the FS were varied with impatiens. As predicted by the N CCE model, substrate pH decreased as NH4+ concentration increased and alkalinity decreased with an adjusted R2 of 0.763. Results provide confidence in the N CCE model as a tool for fertilizer selection to maintain stable substrate pH over time. The limited scope of these experiments emphasizes the need for more research on plant species effects on substrate pH and interactions with other factors such as residual limestone and substrate components to predict pH dynamics of containerized plants over time.

scholarly journals Effect of environmental and cultural conditions in medium pH and plant growth performance of Douglas-fir (Pseudotsuga menziesii) shoot culture

F1000Research ◽  
2014 ◽  
Vol 3 ◽  
pp. 298
Author(s):  
Chien-Chih Chen ◽  
Rick Bates ◽  
John Carlson
Keyword(s):  
Growth Performance ◽  
Growth Parameters ◽  
Shoot Culture ◽  
Storage Conditions ◽  
Douglas Fir ◽  
Individual Species ◽  
Ph Change ◽  
Medium Ph ◽  
Ph Level ◽  
Over Time

The medium pH level of plant tissue culture has been shown to be essential to many aspects of explant development and growth. Sensitivity or tolerance of medium pH changein vitrovaries accordingly to specific requirements of individual species. The objectives of this study are to 1) determine medium pH change over time in storage conditions and with presence of explants, 2) evaluate the effects of medium pH change and explant growth performance and 3) assess the effects of adding a pH stabilizer, 2-(N-morpholino)ethanesulfonic acid (MES) to Douglas-fir micropropagation medium. Spring buds, collected before breaking dormancy from juvenile and mature donor trees were utilized for these evaluations. Medium with or without MES, each at five medium pH levels was pre-adjusted before adding MES, agar and autoclaving. Medium pH changes and explant growth parameters were measured at eight different incubation times. In general, medium with MES provided a more stable medium pH compared to pre-adjusted pH values under two storage conditions as well as with presence of explants over time. A general trend of decreasing medium pH over time was found comparing explants from juvenile and mature donor genotypes. Explant height and weight growth increased over time, but differ among explants from juvenile and mature donor genotypes. MES may help to maintain stable medium pH for bulk medium preparation. Our findings suggested a 21-day subculture practice may facilitate to sustain medium freshness, medium pH level and desirable explant growth.

scholarly journals Application of the Shrinking-Core Models for Determination of Dissolution Kinetics of Mn and Zn from Spent Zinc–Carbon Battery Powder in Organic Acid Solution

2019 ◽  
Vol 27 (1) ◽  
pp. 99-109 ◽  
Author(s):  
Tevfik Agacayak ◽  
Hasan Ali Taner
Keyword(s):  
Acetic Acid ◽  
Acid Solution ◽  
Acetic Acid Solution ◽  
Dissolution Kinetics ◽  
Kinetic Studies ◽  
Product Layer ◽  
Different Temperatures ◽  
Shrinking Core ◽  
Kinetics Of Dissolution ◽  
Kinetics Of

Abstract In this study, dissolution kinetics of manganese and zinc from spent zinc–carbon batteries in acetic acid solution was investigated. To determine the kinetics of dissolution of manganese and zinc, shrinking core model was applied to dissolution recoveries obtained at different temperatures. As a result of kinetic studies, it was determined that manganese and zinc were dissolved in acetic acid solution by diffusion from product layer and then activation energies (Ea) were calculated.

scholarly journals Crime Is Down and so Is Fear? Analyzing Resident Perceptions of Neighborhood Unsafety in Rotterdam, the Netherlands

2021 ◽  
Author(s):  
Iris Glas
Keyword(s):  
The Netherlands ◽  
Residential Mobility ◽  
Economic Status ◽  
Crime Rates ◽  
Sudden Increase ◽  
Ethnic Heterogeneity ◽  
Resident Perceptions ◽  
Status Level ◽  
Over Time ◽  
Dutch City

AbstractThere is little research on how resident perceptions of neighborhood unsafety develop over time and how changes in these perceptions relate to decreasing crime rates. The present study analyzes and explains trends in perceived neighborhood unsafety within the Dutch city of Rotterdam, based on survey and register data collected in the years 2003–2017 (N = 148.344, 62 neighborhoods). In addition to crime, we also assess to what extent (changes in) the economic status, level of ethnic heterogeneity, degree of residential mobility, and amount of disorder in the neighborhood play a role in how safe or unsafe inhabitants have felt in a 15-year period. We find that unsafety levels steadily declined in the years up to 2007. This decrease was best explained by changes regarding the economic status, victimization rates and disorder level of neighborhoods. After a sudden increase in feelings of unsafety between 2007 and 2008, explained by the shift towards using more self-administrated questionnaires, fear levels stabilized during the remaining years (2008–2017) although recorded crime levels continued to decrease in this period.

scholarly journals Impact of containment type on Covid-19 propagation in Morocco using the SIR model.

2020 ◽  
Author(s):  
Nada Lebkiri ◽  
Zakaria Abidli ◽  
Sara Jadda ◽  
Abdelrhani Mokhtari ◽  
Abdelmajid Soulaymani
Keyword(s):  
Epidemiological Study ◽  
Total Population ◽  
Medical Science ◽  
Sir Model ◽  
Current Situation ◽  
Epidemiological Model ◽  
Sudden Increase ◽  
Risk Of Infection ◽  
First Case ◽  
Over Time

Objective and mehtods: Our objective is to determine the containment effect on the spread of Covid 19 in Morocco. The methodology is based on an epidemiological study whose objective is to take stock of the current situation and to estimate the future spread of Covid-19 over time in Morocco. Several conditions were considered using the SIR epidemiological model for a better reliability of the results. During the study period from the appearance of the first case until 19 June 2020, Morocco reported 9074 cases of infections, 213 deaths with a lethality of 2.35% and a mortality of 6.04 per million inhabitants. Results and Conclusion: The results of the SIR model show a sudden increase in infections. The peak would be 4.4 million inhabitants or 12% of the total population under confined conditions. Selon ces résultats,Containment is one of the most effective methods of reducing the risk of infection. Bangladesh Journal of Medical Science Vol.19(0) 2020 p. S 58-S 65

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