By analyzing the corrosion of phosphate completion fluid on the P110 steel at 170 °C, the high-temperature corrosion mechanism of phosphate completion fluid was revealed, and a corrosion inhibition method by memb...By analyzing the corrosion of phosphate completion fluid on the P110 steel at 170 °C, the high-temperature corrosion mechanism of phosphate completion fluid was revealed, and a corrosion inhibition method by membrane transformation was proposed and an efficient membrane-forming agent was selected. Scanning electron microscope (SEM) images, X-ray energy spectrum and X-ray diffraction results were used to characterize the microscopic morphology, elemental composition and phase composition of the precipitation membrane on the surface of the test piece. The effect and mechanism of corrosion inhibition by membrane transformation were clarified. The phosphate completion fluid eroded the test piece by high-temperature water vapor and its hydrolyzed products to form a membrane of iron phosphate corrosion product. By changing the corrosion reaction path, the Zn2+ membrane-forming agent could generate KZnPO4 precipitation membrane with high temperature resistance, uniform thickness and tight crystal packing on the surface of the test piece, which could inhibit the corrosion of the test piece, with efficiency up to 69.63%. The Cu2+ membrane-forming agent electrochemically reacted with Fe to precipitate trace elemental Cu on the surface of the test piece, thus forming a protective membrane, which could inhibit metal corrosion, with efficiency up to 96.64%, but the wear resistance was poor. After combining 0.05% Cu2+ and 0.25% Zn2+, a composite protective membrane of KZnPO4 crystal and elemental Cu was formed on the surface of the test piece. The corrosion inhibition efficiency reached 93.03%, which ensured the high corrosion inhibition efficiency and generated a precipitation membrane resistant to temperature and wear.展开更多
Air nanobubbles(A-NBs)were used to inhibit the brass corrosion in circulating cooling water for the first time in the study.The results of mass loss method and electrochemical method showed that A-NBs had the obvious ...Air nanobubbles(A-NBs)were used to inhibit the brass corrosion in circulating cooling water for the first time in the study.The results of mass loss method and electrochemical method showed that A-NBs had the obvious corrosion inhibition effect.The inhibition rate reached 52%at 35℃.The impedance and surface characterization results of corrosion samples indicated that the corrosion inhibition mechanisms of A-NBs mainly included adsorption of corrosion ions,promoting the formation of the passivation film on metal surface and the formation of the bubble layer and scale film on metal surface.A-NBs are potential excellent corrosion inhibitors.展开更多
It is a longstanding and challenging task to develop sustainable environment-friendly and cost-effective corrosion-protection technologies for Mg alloys, especially under marine conditions in which corrosion can norma...It is a longstanding and challenging task to develop sustainable environment-friendly and cost-effective corrosion-protection technologies for Mg alloys, especially under marine conditions in which corrosion can normally be significantly accelerated by bacterial activity. However,this paper reports on the corrosion of highly active Mg interestingly inhibited by an algal-symbiotic bacterium Bacillus altitudinis. The corrosion of Mg in the presence of the bacterium drastically reduced by one order of magnitude after 14 days of immersion. This means that the algal-symbiotic bacterium widely available in natural ocean environments may be employed as a green and sustainable inhibitor in the marine industry. Based on electrochemical measurements, surface analyses and microbe experiments, a combined inhibition mechanism is proposed in the paper to interpret the interesting corrosion behavior of Mg.展开更多
In the process of exploration and development of oil and gas fields, the acidic environment of oil reservoir, production and transport processes cause corrosion of pipelines and equipment, resulting in huge economic l...In the process of exploration and development of oil and gas fields, the acidic environment of oil reservoir, production and transport processes cause corrosion of pipelines and equipment, resulting in huge economic losses and production safety risks. Corrosion inhibitors were widely used in oil industry because of simple operation process and economical. In this study, three environmentally friendly corrosion inhibitors were synthesized based on the natural polysaccharide chitosan. Corrosion inhibition of three dendritic chitosan derivatives (We name them BH, CH and DH) on mild steel in 1 mol/L HCl solution with natural ventilation system was evaluated by weight loss experiment, electrochemical analysis and surface morphology characterization. The experimental results showed that when the three dendritic chitosan derivatives added in the corrosive medium were 500 mg L^(−1), the corrosion inhibition efficiencies were all more than 80%. Based on quantum chemical calculation, inhibition mechanisms of three dendritic chitosan derivatives were investigated according to molecular structures. The results showed that the benzene ring, Schiff base and N atom contained in the molecule were the active centers of electron exchange, which were more likely to form a film on the carbon steel surface, thereby slowing or inhibiting corrosion. The results also predicted the corrosion inhibition effect BH > DH > CH, which was consistent with the experimental conclusion.展开更多
The corrosion inhibition of a green scale inhibitor, polyepoxysuccinic acid (PESA) was studied based on dynamic tests. It is found that when PESA is used alone, it had good corrosion inhibition. So, PESA should be inc...The corrosion inhibition of a green scale inhibitor, polyepoxysuccinic acid (PESA) was studied based on dynamic tests. It is found that when PESA is used alone, it had good corrosion inhibition. So, PESA should be included in the category of corrosion inhibitors. It is not only a kind of green scale inhibitor, but also a green corrosion inhibitor. The synergistic effect between PESA and Zn2+ or sodium gluconate is poor. However, the synergistic effect among PESA, Zn2+ and sodium gluconate is excellent, and the corrosion inhibition efficiency for carbon steel is higher than 99%. Further study of corrosion inhibition mechanism reveals that corrosion inhibition of PESA is not affected by carboxyl group, but by the oxygen atom inserted. The existence of oxygen atom in PESA molecular structure makes it easy to form stable chelate with pentacyclic structure.展开更多
The corrosion inhibition for carbon steel in circulating cooling water by modified lignosulphonate has been investigated using electrochemical impedance spectroscopy technique. Results show that the inhibition efficie...The corrosion inhibition for carbon steel in circulating cooling water by modified lignosulphonate has been investigated using electrochemical impedance spectroscopy technique. Results show that the inhibition efficiency of modified lignosulphonate GCL2 is a great improvement on that of lignosulphonate. The maximum inhibition efficiency of GCL2 reaches 99.21% at the concentration of 400mg·L^-1 at 303K. The corrosion inhibition of GCL2 is attributed to forming adsorption film on the metal surface for the electrochemical impedance spectroscopy in GCL2 solution shows more than one time-constant.Moreover,results also indicate that it is more efficient in stirring solution than in still solution for GCL2 because the constant of adsorption in stirring solution is much larger than that in still solution. The adsorption of inhibitor GCL2 follows Langmuir's adsorption isotherm.展开更多
The effects of La 3+ ion and chelate reagent 8 hydroxyquinoline on the corrosion rate of zinc in hydrochloric acid were investigated by using weight loss method and electrochemical method. It is found that in a ...The effects of La 3+ ion and chelate reagent 8 hydroxyquinoline on the corrosion rate of zinc in hydrochloric acid were investigated by using weight loss method and electrochemical method. It is found that in a specific concentration range of La 3+ ion and 8 hydroxyquinoline, the obvious corrosion inhibition synergism is obtained. The mechanism of corrosion inhibition synergism was discussed on basis of adsorption theory.展开更多
The kinetics of dissolved O_2 reduction and hydrogen evolution reactions on copper surface was studied in naturally aerated and air and O_2-saturated 0.50 mol/L H_2SO_4 solutions using polarization measurements combin...The kinetics of dissolved O_2 reduction and hydrogen evolution reactions on copper surface was studied in naturally aerated and air and O_2-saturated 0.50 mol/L H_2SO_4 solutions using polarization measurements combined with the rotating disc electrode (RDE).The Koutecky-Levich plot indicated that the dissolved O_2 reduction at the copper electrode was an apparent four-electron process.A correlation between the presence of dissolved O_2 and the formation of Cu_2O,confirmed from XRD,was discussed. Ascorbic a...展开更多
The corrosion inhibition performance of co-immobilized lysozyme and lipase was investigated in a recirculating cooling water system. Four methods were carried out in co-immobilization, and the operating parameters wer...The corrosion inhibition performance of co-immobilized lysozyme and lipase was investigated in a recirculating cooling water system. Four methods were carried out in co-immobilization, and the operating parameters were optimized by using the respond surface methodology(RSM). The corrosion inhibition performance of co-immobilized lipase and lysozyme was evaluated by weight loss measurements and electrochemical measurements. The results revealed that the optimal co-immobilization method should be the sequential immobilization of lysozyme and then lipase. The inhibition efficiency was 86.10% under the optimal co-immobilized conditions. Electrochemical data showed that co-immobilized lysozyme and lipase was a mixed-type inhibitor and the corrosion inhibition efficiency was 81%.展开更多
Layered double hydroxide(LDH),a kind of 2D layered materials,has been recognized as the promising anticorrosion materials for metal and its alloy.The microstructure,physical/chemical properties,usage in corrosion inhi...Layered double hydroxide(LDH),a kind of 2D layered materials,has been recognized as the promising anticorrosion materials for metal and its alloy.The microstructure,physical/chemical properties,usage in corrosion inhibition and inhibition performance of LDH have been studied separately in open literature.However,there is a lack of a complete review to summarize the status of LDH technology and the potential R&D opportunities in the field of corrosion inhibition.In addition,the challenges for LDH in corrosion inhibition of metal-based system have not been summarized systematically.Herein,we review recent advances in the rational design of LDH for corrosion inhibition of metal-based system(i.e.Mg alloy,Al alloy,steel and concrete)and high-throughput anticorrosion materials development.By evaluating the physical/chemical properties,usage in metal-based system and the corrosion inhibition mechanism of LDH,we highlight several important factors of LDH for anticorrosion performance and common features of LDH in applying different metal alloys.Finally,we provide our perspective and recommendation in this field,including high-throughput techiniques for combinatorial compositional design and rapid synthesis of anticorrosion alloys,with the goal of accelerating the development and application of LDH in corrosion inhibition of metal-based system.展开更多
The dissolution of carbon steel in 5% HCl in the temperature range of 30~90℃ was inhibited by two organic compounds having the general formula: ClR NH2(CH2)n NH2 RCl where R is a benzyl group. The behaviour of these ...The dissolution of carbon steel in 5% HCl in the temperature range of 30~90℃ was inhibited by two organic compounds having the general formula: ClR NH2(CH2)n NH2 RCl where R is a benzyl group. The behaviour of these inhibitors in acidic medium were investigated using weight loss method, open circuit potential and linear polarization technique. These inhibitors provided satisfactory corrosion inhibition for carbon steel in hydrochloric acid solutions even at higher temperature and acid concentration (10%). The electrochemical results showed that the polarization resistance (Rp) values increased with increasing inhibitor concentration, also the corrosion current decreased and a higher inhibition efficiency was obtained. The protective properties of these two organic inhibitors were attributed to the chemisorption mechanism展开更多
The inhibition of copper corrosion by acid extract of Gnetum africana was studied using weight loss method of monitoring corrosion rate. The inhibition of Gnetum africana on copper corrosion was optimized by applicati...The inhibition of copper corrosion by acid extract of Gnetum africana was studied using weight loss method of monitoring corrosion rate. The inhibition of Gnetum africana on copper corrosion was optimized by application of 23 factorial design. While the interactive effects of temperature, inhibition concentration and reaction time were investigated, the input factors and output response were also optimized. Optimum conditions for inhibition of Gnetum africana on copper corrosion were recorded at temperature of 303 K, reaction time of 24 h and inhibition concentration of 0.003 g/L. It could be concluded that factorial design was adequately applicable in the optimization of process variables and that Gnetuma africana sufficiently inhibited the corrosion of copper at the conditions of the experiment.展开更多
Inhibition performance of norepinephrine was investigated as corrosion inhibitors by Gravimetric technique and carried out with mild steel samples in 1 M hydrochloric acid solution at room temperature. Norepinephrine ...Inhibition performance of norepinephrine was investigated as corrosion inhibitors by Gravimetric technique and carried out with mild steel samples in 1 M hydrochloric acid solution at room temperature. Norepinephrine exhibited maximum efficiency of 79% at 500 mg/L. The results of Gravimetric studies revealed that the investigated compound acted as good corrosion inhibitor and the inhibition efficiencies increased with increase in the concentrations of the inhibitor IC. The experimental data complied with the Langmuir adsorption isotherm. Thermodynamic parameters, such as ΔGo, ΔHo, and ΔSo, were calculated using adsorption equilibrium constant obtained from the Langmuir isotherm. Results suggested that the norepinephrine adsorption on mild steel surface was a spontaneous and exothermic process. Scanning electron microscopy was used to investigate the mild steel surface at the highest corrosion inhibition studied concentration.展开更多
The action between imidazolinyl-quaternary-ammonium-salt(IQAS) molecule and Fe atom was studied, and the influence of the alkyl group connected with N atom of imidazoline ring on corrosion inhibition efficiency was ex...The action between imidazolinyl-quaternary-ammonium-salt(IQAS) molecule and Fe atom was studied, and the influence of the alkyl group connected with N atom of imidazoline ring on corrosion inhibition efficiency was explored. Quantum chemical methods, HF/6-31 G and HF/Lan L2 dz, were applied successively to calculate the parameters such as front molecular orbit energy of IQASⅠ-Ⅳ and chemical adsorption for IQASⅠ-Ⅳ and Fe atom. The corrosion inhibition efficiency was measured with the weight loss method of carbon steel samples in acidic solution and oil field sewage. Based on the theoretical analyses and experimental results, it is concluded that N-Fe coordination bond is formed between IQAS molecule and Fe atom, corrosion inhibition efficiency is decreased in the following order(from large to small): IQAS Ⅳ, IQAS Ⅲ, IQAS Ⅱ, IQASⅠ.展开更多
Mesoporous SiO_2 microspheres were synthesized using the sol-gel method and were characterized by TEM, FT-IR and BET techniques. The diameter of the microspheres is about 100—150 nm, and the average mesopore diameter...Mesoporous SiO_2 microspheres were synthesized using the sol-gel method and were characterized by TEM, FT-IR and BET techniques. The diameter of the microspheres is about 100—150 nm, and the average mesopore diameter is 2.55 nm, while the specific surface area is 1 088.9 m2/g. Mesoporous SiO_2 microspheres adsorb glutaraldehyde and immobilize laccase by means of the aldehyde group in glutaral which can react with the amidogen of laccase. The immobilization conditions were optimized at a glutaraldehyde concentration of 0.75%, a crosslinking time of 8 h, a laccase concentration of 0.04 L/L and an immobilization time of 10 h. When diesel leakage concentration was 80 mg/L, the highest corrosion inhibition efficiency of immobilized laccase reached 49.23%, which was slightly lower than the corrosion inhibition efficiency of free laccase(59%). The diesel degradation ratio could reach up to 45%. It has been proved that the immobilized laccase could degrade diesel to inhibit corrosion.展开更多
The compound(4-chlorophenyl)-N-(4-methylphenyl)nitrone(4CPNMPN)has been selected as one of the new nitrone derivative for our study.The molecular structure of the compound was investigated based on frontier orbital an...The compound(4-chlorophenyl)-N-(4-methylphenyl)nitrone(4CPNMPN)has been selected as one of the new nitrone derivative for our study.The molecular structure of the compound was investigated based on frontier orbital analysis and natural bond orbital(NBO)theory.The present work also focuses on the inhibition efficiency of the compound.It is an attempt to find the correlation between the molecular structure of the compound and possible behaviour like corrosion inhibitors.The NBO analysis and the values of electric dipole moment(μ)of the investigated molecule were computed using DFT calculations.The molecule orbital contributions were studied by using the total(TDOS)density of states.The strong evidences that the compound can be used as an efficient nonlinear optical(NLO)of 4CPNMPN were demonstrated by considerable polarizability and hyperpolarizability values obtained at DFT levels.展开更多
Corrosion monitoring techniques were performed on X7O steel in saline solution saturated with CO2 with and without thiourea additives within the concentration range 5-25 mg/L. It was found that when the concentration ...Corrosion monitoring techniques were performed on X7O steel in saline solution saturated with CO2 with and without thiourea additives within the concentration range 5-25 mg/L. It was found that when the concentration of the inhibitors were increased, the inhibitor efficiencies(IE) of thiourea varied with solution temperature and immersion time. The results indicated that thiourea had the highest inhibition efficiency. The potentiondynamic polarization studies revealed that thiourea are mixed-type inhibitor that mainly restrains the anodic process.展开更多
Anodic dissolution behaviour of Ni in mono-, di- and trichloroacetic acids has been investigated by measuring current densities of Ni electrode (versus SCE) at different potentials. Effects of acid concentration, pH, ...Anodic dissolution behaviour of Ni in mono-, di- and trichloroacetic acids has been investigated by measuring current densities of Ni electrode (versus SCE) at different potentials. Effects of acid concentration, pH, scan rate and additive inhibitor on the potential were studied and they revealed that there is a considerable shift of potential. Potentiodynamic polarization measurements show that the corrosion rate of Ni in chloroacetic acid solutions increases by increasing the previous factors. However, by adding inhibitor, it decreases.展开更多
Polyaniline (PANI) film was electrosynthesized on 304 stainless steel by cyclic voltammetry using aqueous oxalic acid as supporting electrolyte. The potential sweep rates were changed to achieve the PANI film with dif...Polyaniline (PANI) film was electrosynthesized on 304 stainless steel by cyclic voltammetry using aqueous oxalic acid as supporting electrolyte. The potential sweep rates were changed to achieve the PANI film with different thickness and structures. Protective properties of the PANI film for corrosion of stainless steel in 3% NaCl aqueous solution were investigated by monitoring potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). The results showed that the PANI film which was formed with lower sweep rate led to more positive shift of corrosion potential and greater charge transfer resistance, reflecting higher inhibition for corrosion of the stainless steel.展开更多
The synergistic effect of tetrabutylammonium canon(TBA+)or N-hexadecylpyridinium cation(HDP+)and SCN-or I-in 0. 5 mol. L-1 H2SO4 solution on the corrosion inhibition or Armco iron was investigated by potentiodynamic ...The synergistic effect of tetrabutylammonium canon(TBA+)or N-hexadecylpyridinium cation(HDP+)and SCN-or I-in 0. 5 mol. L-1 H2SO4 solution on the corrosion inhibition or Armco iron was investigated by potentiodynamic polarization and polarization resistance measurements. The results show that the synergistic effect of HDP+ containing v-electron and anion is stronger than that of TBA+ and anion.The Joint adsorption models of canon and anion at electrode-solution interface are related to the structure and property of both ions by analyzing the desorption behaviours of both ions when the electrode is polarized anodically.展开更多
基金Supported by the National Natural Science Foundation of China(5215000105)Huo Yingdong Education Foundation(171043).
文摘By analyzing the corrosion of phosphate completion fluid on the P110 steel at 170 °C, the high-temperature corrosion mechanism of phosphate completion fluid was revealed, and a corrosion inhibition method by membrane transformation was proposed and an efficient membrane-forming agent was selected. Scanning electron microscope (SEM) images, X-ray energy spectrum and X-ray diffraction results were used to characterize the microscopic morphology, elemental composition and phase composition of the precipitation membrane on the surface of the test piece. The effect and mechanism of corrosion inhibition by membrane transformation were clarified. The phosphate completion fluid eroded the test piece by high-temperature water vapor and its hydrolyzed products to form a membrane of iron phosphate corrosion product. By changing the corrosion reaction path, the Zn2+ membrane-forming agent could generate KZnPO4 precipitation membrane with high temperature resistance, uniform thickness and tight crystal packing on the surface of the test piece, which could inhibit the corrosion of the test piece, with efficiency up to 69.63%. The Cu2+ membrane-forming agent electrochemically reacted with Fe to precipitate trace elemental Cu on the surface of the test piece, thus forming a protective membrane, which could inhibit metal corrosion, with efficiency up to 96.64%, but the wear resistance was poor. After combining 0.05% Cu2+ and 0.25% Zn2+, a composite protective membrane of KZnPO4 crystal and elemental Cu was formed on the surface of the test piece. The corrosion inhibition efficiency reached 93.03%, which ensured the high corrosion inhibition efficiency and generated a precipitation membrane resistant to temperature and wear.
基金supported by National Natural Science Foundation of China(52170074).
文摘Air nanobubbles(A-NBs)were used to inhibit the brass corrosion in circulating cooling water for the first time in the study.The results of mass loss method and electrochemical method showed that A-NBs had the obvious corrosion inhibition effect.The inhibition rate reached 52%at 35℃.The impedance and surface characterization results of corrosion samples indicated that the corrosion inhibition mechanisms of A-NBs mainly included adsorption of corrosion ions,promoting the formation of the passivation film on metal surface and the formation of the bubble layer and scale film on metal surface.A-NBs are potential excellent corrosion inhibitors.
基金the National Natural Science Foundation of China (Nos.51731008,52250710159,51671163,51901198)the National Key Research and Development Program of China (No.2017YFB0702100)。
文摘It is a longstanding and challenging task to develop sustainable environment-friendly and cost-effective corrosion-protection technologies for Mg alloys, especially under marine conditions in which corrosion can normally be significantly accelerated by bacterial activity. However,this paper reports on the corrosion of highly active Mg interestingly inhibited by an algal-symbiotic bacterium Bacillus altitudinis. The corrosion of Mg in the presence of the bacterium drastically reduced by one order of magnitude after 14 days of immersion. This means that the algal-symbiotic bacterium widely available in natural ocean environments may be employed as a green and sustainable inhibitor in the marine industry. Based on electrochemical measurements, surface analyses and microbe experiments, a combined inhibition mechanism is proposed in the paper to interpret the interesting corrosion behavior of Mg.
文摘In the process of exploration and development of oil and gas fields, the acidic environment of oil reservoir, production and transport processes cause corrosion of pipelines and equipment, resulting in huge economic losses and production safety risks. Corrosion inhibitors were widely used in oil industry because of simple operation process and economical. In this study, three environmentally friendly corrosion inhibitors were synthesized based on the natural polysaccharide chitosan. Corrosion inhibition of three dendritic chitosan derivatives (We name them BH, CH and DH) on mild steel in 1 mol/L HCl solution with natural ventilation system was evaluated by weight loss experiment, electrochemical analysis and surface morphology characterization. The experimental results showed that when the three dendritic chitosan derivatives added in the corrosive medium were 500 mg L^(−1), the corrosion inhibition efficiencies were all more than 80%. Based on quantum chemical calculation, inhibition mechanisms of three dendritic chitosan derivatives were investigated according to molecular structures. The results showed that the benzene ring, Schiff base and N atom contained in the molecule were the active centers of electron exchange, which were more likely to form a film on the carbon steel surface, thereby slowing or inhibiting corrosion. The results also predicted the corrosion inhibition effect BH > DH > CH, which was consistent with the experimental conclusion.
文摘The corrosion inhibition of a green scale inhibitor, polyepoxysuccinic acid (PESA) was studied based on dynamic tests. It is found that when PESA is used alone, it had good corrosion inhibition. So, PESA should be included in the category of corrosion inhibitors. It is not only a kind of green scale inhibitor, but also a green corrosion inhibitor. The synergistic effect between PESA and Zn2+ or sodium gluconate is poor. However, the synergistic effect among PESA, Zn2+ and sodium gluconate is excellent, and the corrosion inhibition efficiency for carbon steel is higher than 99%. Further study of corrosion inhibition mechanism reveals that corrosion inhibition of PESA is not affected by carboxyl group, but by the oxygen atom inserted. The existence of oxygen atom in PESA molecular structure makes it easy to form stable chelate with pentacyclic structure.
基金supported by the National Natural Science Foundation of China(No.20276024)the Guangdong Provincial Laboratory of Green Chemical Technology
文摘The corrosion inhibition for carbon steel in circulating cooling water by modified lignosulphonate has been investigated using electrochemical impedance spectroscopy technique. Results show that the inhibition efficiency of modified lignosulphonate GCL2 is a great improvement on that of lignosulphonate. The maximum inhibition efficiency of GCL2 reaches 99.21% at the concentration of 400mg·L^-1 at 303K. The corrosion inhibition of GCL2 is attributed to forming adsorption film on the metal surface for the electrochemical impedance spectroscopy in GCL2 solution shows more than one time-constant.Moreover,results also indicate that it is more efficient in stirring solution than in still solution for GCL2 because the constant of adsorption in stirring solution is much larger than that in still solution. The adsorption of inhibitor GCL2 follows Langmuir's adsorption isotherm.
文摘The effects of La 3+ ion and chelate reagent 8 hydroxyquinoline on the corrosion rate of zinc in hydrochloric acid were investigated by using weight loss method and electrochemical method. It is found that in a specific concentration range of La 3+ ion and 8 hydroxyquinoline, the obvious corrosion inhibition synergism is obtained. The mechanism of corrosion inhibition synergism was discussed on basis of adsorption theory.
文摘The kinetics of dissolved O_2 reduction and hydrogen evolution reactions on copper surface was studied in naturally aerated and air and O_2-saturated 0.50 mol/L H_2SO_4 solutions using polarization measurements combined with the rotating disc electrode (RDE).The Koutecky-Levich plot indicated that the dissolved O_2 reduction at the copper electrode was an apparent four-electron process.A correlation between the presence of dissolved O_2 and the formation of Cu_2O,confirmed from XRD,was discussed. Ascorbic a...
基金financially supported by the National Natural Science Foundation of China (project 21077133)the Natural Foundation of Shandong Province and the Top Talent Project of China University of Petroleum (16RC17040003)
文摘The corrosion inhibition performance of co-immobilized lysozyme and lipase was investigated in a recirculating cooling water system. Four methods were carried out in co-immobilization, and the operating parameters were optimized by using the respond surface methodology(RSM). The corrosion inhibition performance of co-immobilized lipase and lysozyme was evaluated by weight loss measurements and electrochemical measurements. The results revealed that the optimal co-immobilization method should be the sequential immobilization of lysozyme and then lipase. The inhibition efficiency was 86.10% under the optimal co-immobilized conditions. Electrochemical data showed that co-immobilized lysozyme and lipase was a mixed-type inhibitor and the corrosion inhibition efficiency was 81%.
基金the Graduate Research and innovation of Chongqing,China(Grant No.CYB20005)the project of Technological Innovation and Application Development in Chongqing(cstc2019jscxmsxm0378)+8 种基金the National Natural Science Foundation of China(Grant Nos.51908092)the Joint Funds of the National Natural Science Foundation of China-Guangdong(Grant No.U1801254)the project funded by Chongqing Special Postdoctoral Science Foundation(XmT2018043)Natural Science Foundation Project of Chongqing for Post-doctor(cstc2019jcyjbsh0079)Technological projects of Chongqing Municipal Education Commission(KJZDK201800801)Projects(No.2020CDJXZ001,2020CDCGJ006 and 2020CDCGCL004)the Fundamental Research Funds for the Central Universitiesthe Innovative Research Team of Chongqing(CXTDG201602014)the Innovative technology of New materials and metallurgy(2019CDXYCL0031).
文摘Layered double hydroxide(LDH),a kind of 2D layered materials,has been recognized as the promising anticorrosion materials for metal and its alloy.The microstructure,physical/chemical properties,usage in corrosion inhibition and inhibition performance of LDH have been studied separately in open literature.However,there is a lack of a complete review to summarize the status of LDH technology and the potential R&D opportunities in the field of corrosion inhibition.In addition,the challenges for LDH in corrosion inhibition of metal-based system have not been summarized systematically.Herein,we review recent advances in the rational design of LDH for corrosion inhibition of metal-based system(i.e.Mg alloy,Al alloy,steel and concrete)and high-throughput anticorrosion materials development.By evaluating the physical/chemical properties,usage in metal-based system and the corrosion inhibition mechanism of LDH,we highlight several important factors of LDH for anticorrosion performance and common features of LDH in applying different metal alloys.Finally,we provide our perspective and recommendation in this field,including high-throughput techiniques for combinatorial compositional design and rapid synthesis of anticorrosion alloys,with the goal of accelerating the development and application of LDH in corrosion inhibition of metal-based system.
文摘The dissolution of carbon steel in 5% HCl in the temperature range of 30~90℃ was inhibited by two organic compounds having the general formula: ClR NH2(CH2)n NH2 RCl where R is a benzyl group. The behaviour of these inhibitors in acidic medium were investigated using weight loss method, open circuit potential and linear polarization technique. These inhibitors provided satisfactory corrosion inhibition for carbon steel in hydrochloric acid solutions even at higher temperature and acid concentration (10%). The electrochemical results showed that the polarization resistance (Rp) values increased with increasing inhibitor concentration, also the corrosion current decreased and a higher inhibition efficiency was obtained. The protective properties of these two organic inhibitors were attributed to the chemisorption mechanism
文摘The inhibition of copper corrosion by acid extract of Gnetum africana was studied using weight loss method of monitoring corrosion rate. The inhibition of Gnetum africana on copper corrosion was optimized by application of 23 factorial design. While the interactive effects of temperature, inhibition concentration and reaction time were investigated, the input factors and output response were also optimized. Optimum conditions for inhibition of Gnetum africana on copper corrosion were recorded at temperature of 303 K, reaction time of 24 h and inhibition concentration of 0.003 g/L. It could be concluded that factorial design was adequately applicable in the optimization of process variables and that Gnetuma africana sufficiently inhibited the corrosion of copper at the conditions of the experiment.
文摘Inhibition performance of norepinephrine was investigated as corrosion inhibitors by Gravimetric technique and carried out with mild steel samples in 1 M hydrochloric acid solution at room temperature. Norepinephrine exhibited maximum efficiency of 79% at 500 mg/L. The results of Gravimetric studies revealed that the investigated compound acted as good corrosion inhibitor and the inhibition efficiencies increased with increase in the concentrations of the inhibitor IC. The experimental data complied with the Langmuir adsorption isotherm. Thermodynamic parameters, such as ΔGo, ΔHo, and ΔSo, were calculated using adsorption equilibrium constant obtained from the Langmuir isotherm. Results suggested that the norepinephrine adsorption on mild steel surface was a spontaneous and exothermic process. Scanning electron microscopy was used to investigate the mild steel surface at the highest corrosion inhibition studied concentration.
基金Project (05A002) supported by Scientific Research Fundation of Hunan Provincial Education Depart ment project(04JJY40010) supported by the Natural Science Foundation of Hunan Province
文摘The action between imidazolinyl-quaternary-ammonium-salt(IQAS) molecule and Fe atom was studied, and the influence of the alkyl group connected with N atom of imidazoline ring on corrosion inhibition efficiency was explored. Quantum chemical methods, HF/6-31 G and HF/Lan L2 dz, were applied successively to calculate the parameters such as front molecular orbit energy of IQASⅠ-Ⅳ and chemical adsorption for IQASⅠ-Ⅳ and Fe atom. The corrosion inhibition efficiency was measured with the weight loss method of carbon steel samples in acidic solution and oil field sewage. Based on the theoretical analyses and experimental results, it is concluded that N-Fe coordination bond is formed between IQAS molecule and Fe atom, corrosion inhibition efficiency is decreased in the following order(from large to small): IQAS Ⅳ, IQAS Ⅲ, IQAS Ⅱ, IQASⅠ.
基金supported by the Foundation for Top Talents Program of China University of Petroleum
文摘Mesoporous SiO_2 microspheres were synthesized using the sol-gel method and were characterized by TEM, FT-IR and BET techniques. The diameter of the microspheres is about 100—150 nm, and the average mesopore diameter is 2.55 nm, while the specific surface area is 1 088.9 m2/g. Mesoporous SiO_2 microspheres adsorb glutaraldehyde and immobilize laccase by means of the aldehyde group in glutaral which can react with the amidogen of laccase. The immobilization conditions were optimized at a glutaraldehyde concentration of 0.75%, a crosslinking time of 8 h, a laccase concentration of 0.04 L/L and an immobilization time of 10 h. When diesel leakage concentration was 80 mg/L, the highest corrosion inhibition efficiency of immobilized laccase reached 49.23%, which was slightly lower than the corrosion inhibition efficiency of free laccase(59%). The diesel degradation ratio could reach up to 45%. It has been proved that the immobilized laccase could degrade diesel to inhibit corrosion.
文摘The compound(4-chlorophenyl)-N-(4-methylphenyl)nitrone(4CPNMPN)has been selected as one of the new nitrone derivative for our study.The molecular structure of the compound was investigated based on frontier orbital analysis and natural bond orbital(NBO)theory.The present work also focuses on the inhibition efficiency of the compound.It is an attempt to find the correlation between the molecular structure of the compound and possible behaviour like corrosion inhibitors.The NBO analysis and the values of electric dipole moment(μ)of the investigated molecule were computed using DFT calculations.The molecule orbital contributions were studied by using the total(TDOS)density of states.The strong evidences that the compound can be used as an efficient nonlinear optical(NLO)of 4CPNMPN were demonstrated by considerable polarizability and hyperpolarizability values obtained at DFT levels.
文摘Corrosion monitoring techniques were performed on X7O steel in saline solution saturated with CO2 with and without thiourea additives within the concentration range 5-25 mg/L. It was found that when the concentration of the inhibitors were increased, the inhibitor efficiencies(IE) of thiourea varied with solution temperature and immersion time. The results indicated that thiourea had the highest inhibition efficiency. The potentiondynamic polarization studies revealed that thiourea are mixed-type inhibitor that mainly restrains the anodic process.
文摘Anodic dissolution behaviour of Ni in mono-, di- and trichloroacetic acids has been investigated by measuring current densities of Ni electrode (versus SCE) at different potentials. Effects of acid concentration, pH, scan rate and additive inhibitor on the potential were studied and they revealed that there is a considerable shift of potential. Potentiodynamic polarization measurements show that the corrosion rate of Ni in chloroacetic acid solutions increases by increasing the previous factors. However, by adding inhibitor, it decreases.
文摘Polyaniline (PANI) film was electrosynthesized on 304 stainless steel by cyclic voltammetry using aqueous oxalic acid as supporting electrolyte. The potential sweep rates were changed to achieve the PANI film with different thickness and structures. Protective properties of the PANI film for corrosion of stainless steel in 3% NaCl aqueous solution were investigated by monitoring potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). The results showed that the PANI film which was formed with lower sweep rate led to more positive shift of corrosion potential and greater charge transfer resistance, reflecting higher inhibition for corrosion of the stainless steel.
文摘The synergistic effect of tetrabutylammonium canon(TBA+)or N-hexadecylpyridinium cation(HDP+)and SCN-or I-in 0. 5 mol. L-1 H2SO4 solution on the corrosion inhibition or Armco iron was investigated by potentiodynamic polarization and polarization resistance measurements. The results show that the synergistic effect of HDP+ containing v-electron and anion is stronger than that of TBA+ and anion.The Joint adsorption models of canon and anion at electrode-solution interface are related to the structure and property of both ions by analyzing the desorption behaviours of both ions when the electrode is polarized anodically.