scholarly journals Comparation of the analytical and experimental models of 304SS corrosion rate in 0.5 m H2SS4 with bee wax propolis extract

2018 ◽  
Vol 38 (2) ◽  
pp. 182-188 ◽  
Author(s):  
Wahyono Suprapto ◽  
Rudy Soenoko ◽  
Femiana Gapsari
Keyword(s):  
Sulfuric Acid ◽  
Corrosion Rate ◽  
Theoretical Calculations ◽  
Reduction Reaction ◽  
Experimental Models ◽  
Propolis Extract ◽  
Data Prediction ◽  
Disaster Data ◽  
Steel Tank ◽  
Transport Vessel

Corrosion in the reservoir and transport vessel often causes a leak that leads to disaster. Data prediction and experimental corrosion in storage technology is very important to prevent damage and reduce maintenance costs. Theoretically, steel tank corrosion by sulfuric acid working medium can be minimized with the formation of sediments oxide by oxidation-reduction reaction. Behavioral inhibition of bee wax propolis on the 304SS in 0.5 M sulfuric acid was carried by potentiodynamic polarization. Based on the polarization testing the corrosion rate of the 304SS in a solution of 0.5 M H2SO4 is at 0.349 g/m2d with the missing mass amounted 5.21 x10 -9 g/s. In experiments, the inhibitor causing less mass loss is equal to 2.28 x 10 -11 g/s. Mass lost without and with inhibitor in this study is also known by theoretical calculations. The mass losses can be used to determine the inhibition efficiency. The calculation of the efficiency theoretically and experimentally gives the same result.

Electrolyte Based Modeling of Corrosion Processes in Sulfuric Acid Mixtures – Part 1: Non-Oxidizing Conditions

CORROSION ◽  
10.5006/3872 ◽  
2021 ◽  
Author(s):  
Narasi Sridhar ◽  
Andrzej Anderko
Keyword(s):  
Sulfuric Acid ◽  
Corrosion Rate ◽  
Weight Percent ◽  
Reaction Rates ◽  
Reduction Reaction ◽  
Proton Reduction ◽  
Mole Percent ◽  
Active Dissolution ◽  
Experimental Values ◽  
Electrochemical Model

The corrosion behavior of stainless steels and Ni-base alloys in non-oxidizing sulfuric acid mixtures at concentrations below approximately 30 moles/Kg H2O is modeled. The redox potential in sulfuric acid across a broad concentration range, from 0 to 80 mole percent (0 to 95.6 weight percent), is determined by the proton reduction reaction. Thus, in the absence of other oxidizing species, sulfuric acid behaves as a non-oxidizing (reducing) acid. The calculated corrosion rate, using an electrochemical model up to about 30 moles/Kg H2O (about 75 weight percent) is in agreement with experimental values. The predicted polarization curves of anodic and cathodic processes showed that the alloys in these environments are in active dissolution regime, consistent with experimental data. The model predictions of corrosion rates in H2SO4+HCl, H2SO4+HF, and H2SO4+HCl+HF mixtures are in agreement with weight-loss corrosion data. The corrosion rate of alloys in the non-oxidizing sulfuric acid mixtures correlated to an equivalent alloy composition given by (Ni0.7-Cr0.1+Mo+0.5W). The effect of alloying elements under these conditions may be related to their beneficial effect on active dissolution and proton reduction reaction rates.

scholarly journals Efficient electrocatalytic nitrogen reduction to ammonia with aqueous silver nanodots

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Wenyi Li ◽  
Ke Li ◽  
Yixing Ye ◽  
Shengbo Zhang ◽  
Yanyan Liu ◽  
...  
Keyword(s):  
Active Sites ◽  
Theoretical Calculations ◽  
Current Collector ◽  
Electrochemical Reactor ◽  
Reduction Reaction ◽  
Solution Ph ◽  
Faradaic Efficiency ◽  
Yield Rate ◽  
Silver Nanodots ◽  
Ti Mesh

AbstractThe electrocatalytic nitrogen (N2) reduction reaction (NRR) relies on the development of highly efficient electrocatalysts and electrocatalysis systems. Herein, we report a non-loading electrocatalysis system, where the electrocatalysts are dispersed in aqueous solution rather than loading them on electrode substrates. The system consists of aqueous Ag nanodots (AgNDs) as the catalyst and metallic titanium (Ti) mesh as the current collector for electrocatalytic NRR. The as-synthesized AgNDs, homogeneously dispersed in 0.1 M Na2SO4 solution (pH = 10.5), can achieve an NH3 yield rate of 600.4 ± 23.0 μg h−1 mgAg−1 with a faradaic efficiency (FE) of 10.1 ± 0.7% at −0.25 V (vs. RHE). The FE can be further improved to be 20.1 ± 0.9% at the same potential by using Ti mesh modified with oxygen vacancy-rich TiO2 nanosheets as the current collector. Utilizing the aqueous AgNDs catalyst, a Ti plate based two-electrode configured flow-type electrochemical reactor was developed to achieve an NH3 yield rate of 804.5 ± 30.6 μg h−1 mgAg−1 with a FE of 8.2 ± 0.5% at a voltage of −1.8 V. The designed non-loading electrocatalysis system takes full advantage of the AgNDs’ active sites for N2 adsorption and activation, following an alternative hydrogenation mechanism revealed by theoretical calculations.

Wallach rearrangement of azoxypyridines and azoxypyridine N-oxides — Charge distributions and dramatic reactivity differences

2008 ◽  
Vol 86 (4) ◽  
pp. 298-304 ◽  
Author(s):  
Erwin Buncel ◽  
Sam-Rok Keum ◽  
Srinivasan Rajagopal ◽  
Eric Kiepek ◽  
Robin A Cox
Keyword(s):  
Sulfuric Acid ◽  
Positive Charge ◽  
Theoretical Calculations ◽  
Medium Effect ◽  
Mulliken Charge ◽  
Reaction Intermediates ◽  
Charge Distributions ◽  
First Time ◽  
Acid Region

Extension of our studies of the generic Wallach rearrangement (of azoxybenzene to 4-hydroxyazobenzene) to the heteroaromatic series (azoxypyridines and axoxypyridine N-oxides) has revealed some dramatic reactivity differences, particularly for the α and β compounds. We have studied the 3-isomers and the 4-isomers in each series, each with α and β forms, eight compounds in all, in the 100 wt% sulfuric acid region of acidity. In those cases in which a product could be observed, the α and β isomers both give the same one, the corresponding 4′-hydroxyazo compounds. All the compounds react much more slowly than does azoxybenzene itself, presumably because of the extra positive charge present in the substrates, but the β isomers have half-lives of seconds and the α isomers half-lives of hundreds of hours in the 100 wt% H2SO4 acidity region. The α compounds have measurable pKBH+ values, but the β compounds do not, exhibiting only a medium effect in the acidity region in which the α compounds protonate. This means that for the β compounds, the protonated intermediates must be much less stable and the postulated reaction intermediates must be much more stable than for the α compounds. To clarify this, we have obtained Mulliken charge distributions for the various species concerned, calculating the charge carried by each half of the molecule, larger charge separations being taken to indicate lesser stability. As far as we can establish, this is the first time that this technique has been used to indicate the stabilities of carbocationic species.Key words: azoxypyridines, azoxypyridine N-oxides, Wallach rearrangement, excess acidity, basicities, theoretical calculations, charge distributions, reactivities.

scholarly journals Effect of Heat Treatment and Sulfuric Acid Anodization on Corrosion Resistance of Aluminum Alloy (AA7075)

2021 ◽  
Vol 40 (1) ◽  
pp. 56-62
Author(s):  
M. Abdullahi ◽  
L.S. Kuburi ◽  
P.T. Zubairu ◽  
U. Jabo ◽  
A.A. Yahaya ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Sulfuric Acid ◽  
Corrosion Rate ◽  
Polarization Resistance ◽  
Testing Machine ◽  
Palm Kernel ◽  
Engine Oil ◽  
Micro Hardness

This paper, studied the effect of heat treatment and anodization on corrosion resistance of aluminum alloy 7075 (AA7075), with a view to improving its corrosion resistance. Microstructure and micro hardness of the anodic film of the samples were studied with the aid of optical metallurgical microscope and automated micro hardness testing machine. Linear polarization methods were used to assess the corrosion behaviour of the alloy in 0.5M HCl. The microstructure of the annealed sample showed formation of dendrites while precipitation hardened samples in palm kernel oil and SAE 40 engine oil showed precipitates of MgZn2. The SEMS result showed pores and micro cracks on the surfaces of the anodized samples, with the as cast and anodized sample in sulfuric acid exhibiting most compact with few pores. The as cast and sulfuric acid anodized sample shows highest micro hardness value of 205.33 HV, while the least value of 150.67 HV was recorded in sample precipitation hardened in SAE 40 engine oil and anodized in sulfuric acid. Analysis of the potentiodynamic polarization data and curves showed a linear relationship (decrease in icorr, decreases the corrosion rate) between current density and the corrosion rate in all the samples. Higher polarization resistance of 15.093 Ω/cm2 was recorded by the as cast and Sulfuric acid (SA) anodized sample while the precipitation treated in SAE 40 engine oil plus SA anodized sample recorded lowest polarization resistance of 5.2311 Ω/cm2. Heat treatment alone improves corrosion resistance of AA 7075 in 0.5 M HCl solution but heat treatment plus SA anodization does not improve corrosion resistance in the same environment.

Experiment Study on Corrosion Rate of Concrete Specimens Immersed in Sulfuric Acid

2012 ◽  
Vol 446-449 ◽  
pp. 3652-3658
Author(s):  
Zhi Gang Song ◽  
Hong Guang Min ◽  
Xue Song Zhang
Keyword(s):  
Sulfuric Acid ◽  
Corrosion Rate ◽  
Experiment Study

Anodic Passivation of Steel In 100 Percent Sulfuric Acid

CORROSION ◽  
1963 ◽  
Vol 19 (2) ◽  
pp. 37t-44t ◽  
Author(s):  
A. O. FISHER ◽  
J. F. BRADY
Keyword(s):  
Sulfuric Acid ◽  
Corrosion Rate ◽  
Laboratory Testing ◽  
Storage Tank ◽  
Substantial Decrease ◽  
Corrosion Resistant ◽  
Equipment Replacement ◽  
Iron Contamination ◽  
Anodic Protection ◽  
Plant Test

Abstract The feasibility of anodic protection for decreasing iron contamination of 100 percent sulfuric acid in an 18,000-gallon steel storage tank was investigated. Since adequate coatings for steel in this service are not available, this approach was taken as an alternative to costly equipment replacement with corrosion resistant alloys. Preliminary laboratory testing indicated that the corrosion rate of steel in 100 percent sulfuric acid could be reduced from 27 mpy to 1 mpy by anodically passivating. As this represented a substantial decrease in terms of iron contamination of the acid, a plant test was run using anodic protection on the storage tank. Passivation of the tank resulted in lowering the iron pickup from 114 ppm down to 9 ppm with trouble-free operation of equipment over a seven-month period. It was concluded that anodic protection offered significant economic advantages compared to the use of more resistant materials of construction.

Nitrogen-doped carbon-based dots prepared by dehydrating EDTA with hot sulfuric acid and their electrocatalysis for oxygen reduction reaction

RSC Advances ◽  
2014 ◽  
Vol 4 (62) ◽  
pp. 32791-32795 ◽  
Author(s):  
Yongqiang Dong ◽  
Hongchang Pang ◽  
Hongbin Yang ◽  
Jian Jiang ◽  
Yuwu Chi ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Ethylenediaminetetraacetic Acid ◽  
Reduction Reaction ◽  
Nitrogen Doped ◽  
Nitrogen Doped Carbon ◽  
Carbon Based

Nitrogen doped carbon-based dots were synthesized by dehydrating ethylenediaminetetraacetic acid, and were used for electro-catalyzing oxygen reduction.

Synergistic Effect of Thiourea and Surfactants on Corrosion Inhibition of Stainless Steel-410 in Presence of Sulfuric Acid

2014 ◽  
Vol 699 ◽  
pp. 186-191 ◽  
Author(s):  
Sami Ullah ◽  
Mohd Shariff Azmi ◽  
Muhammad Nadeem ◽  
Mohammad Azmi Bustam ◽  
Shaukat Ali Shahid ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Sulfuric Acid ◽  
Corrosion Rate ◽  
Corrosion Inhibition ◽  
Sodium Dodecyl ◽  
Ammonium Bromide ◽  
Inhibitor Concentration ◽  
Corrosion Rates ◽  
Inhibition Performance ◽  
Triton X

The inhibition of corrosion of stainless steel (SS)-410 in sulfuric acid using thiourea and three different surfactants, cetyle trimethyl ammonium bromide (CTAB), sodium dodecyl sulfate (SDS) and X-Triton was studied. Corrosion rates were determined by using corrosion coupons. The corrosion rate was found to be decreased with increase in inhibitor concentration. It was observed that the maximum corrosion inhibition occurred in the post micellar concentration of the surfactants. By optimizing the corrosion inhibition performance of different blends of surfactants and thiourea in 3 M H2SO4,the corrosion inhibition order was found as: Triton X-100 + thiourea > CTAB + thiourea > SDS + thiourea. The best results obtained by the addition of 200 ppm thiourea in 500 ppm of Triton X-100 in 3 M H2SO4acid solution. This blend decreased the corrosion rate of SS-410 to 657.66 mpy.

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