Cost Of Corrosion Research Articles

Corrosion inhibition performance of expired amlodipine on cupronickel alloy in a neutral chloride environment: electrochemical and surface analysis

Purpose The corrosion of cupronickel and copper alloys in marine and chloride environments presents significant challenges in the chemical and petrochemical industries. This paper aims to investigate the corrosion inhibition of cupronickel alloy (Cu-10Ni) in a sodium chloride medium using expired amlodipine as a corrosion inhibitor. The use of this drug in its expired form could reduce the costs of corrosion and help mitigate the accumulation of pharmaceutical waste. Design/methodology/approach The inhibitory action was evaluated using a weight loss method, potentiodynamic polarization, electrochemical impedance spectroscopy measurements, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The effect of temperature on the inhibition performance was also studied. Findings The results of these experiments demonstrated that the drug amlodipine effectively inhibited the corrosion of cupronickel alloy in chloride solutions. The corrosion rate of cupronickel was found to decrease with increasing inhibitor concentration and to increase with rising temperature. A maximum inhibition efficiency of 91.92 was achieved with an inhibitor concentration of 0.025 g/L at 298 K. Adsorption of the inhibitor followed the Langmuir adsorption isotherm. Polarization studies indicated that the expired drug acted as a mixed inhibitor. SEM and AFM analyses confirmed that the surface morphology of cupronickel specimens was significantly improved in the presence of the inhibitor. Practical implications Amlodipine can be conveniently used to mitigate problems with the corrosion of copper alloys in chloride environments. Originality/value Amlodipine is evaluated as a novel and effective corrosion inhibitor for cupronickel alloy in neutral chloride environments.

A novel corrosion inhibitor for copper in sulfuric acid media: Complexation of iodide ions with Benincasa Hispida leaf extract

In the context of green and low-carbon development, the rapid development of industry brings the problem of metal corrosion costs increase, metal corrosion protection methods are of great concern. Extracts from Benincasa hispida leaves (BHLE), which were obtained through pressurised liquid extraction, were employed as a inhibitor for copper corrosion in 0.5 M H2SO4. Their composition and anti-corrosion properties were subsequently analyzed and evaluated. The electrochemical analysis results indicated that BHLE functions as a cathodic-type corrosion inhibitor. The anti-corrosion performance intensifies with the increase in concentration but diminishes gradually as the temperature rises, when the concentration of BHLE is 400 mg/L, the corrosion inhibition efficiency can reach 91.82 %, when the concentration of added potassium iodide reaches 16 mg/L the slow-release efficiency of the compounded corrosion inhibitor reaches 96.92 %. The addition of I− strengthens the inhibition efficiency through the adsorption form dominated by competitive adsorption. The adsorption of BHLE onto the surface of copper follows the Langmuir monolayer adsorption model.

AHP VIKOR framework for selecting wind turbine materials with a focus on corrosion and efficiency

The research objective in the context of the study relates to the major concern of corrosion affecting the wind turbines in operation to find materials with high durability in relation to environmental conditions of operation, strength, and cost. A method is an integration of the Analytical Hierarchy Process (AHP) and VIKOR Multi-Criteria Decision Making (MCDM) techniques that will assess seven different material options on sixteen criteria that comprise corrosion resistance, mechanical properties, cost, and a negative environmental impact. From this result, the AHP method calculated the weights for the indicators and chose potential materials, and finally, the VIKOR method used these materials and compared and ranked them to obtain a compromise solution. The research novelty integrates the AHP and VIKOR MCDM methods to address corrosion in wind turbines. By evaluating seven materials against challenging sixteen criteria—including corrosion resistance, mechanical properties, cost, and toxicity, AHP ranks and weights the criteria, while VIKOR identifies the optimal material choice. This dual approach enhances the selection process, ensuring the chosen material improves turbine performance and durability, offering a significant advancement in the sustainable development of wind energy technology. In conclusion, by integrating AHP and VIKOR, it comprehensively evaluates multiple material options based on corrosion resistance, mechanical properties, cost, and environmental impact. This methodology effectively identifies materials that enhance wind turbine performance and extend their lifespan, addressing a critical industry challenge. The alternative exhibits a similarity to the positive ideal solution (Si) of 0.3704 and a relative closeness to the ideal solution (Ri) of 0.0750. Additionally, its priority ranking (Qi) is 0.001, placing it in the first rank for Carbon Fiber Reinforced Polymers (CFRP) within the selection methodology.

Advances in ectoine biosynthesis and biochemical characteristics of key enzymes

Compatible solutes are highly water-soluble organic osmolytes produced by microorganisms to adapt to extreme environments, such as high salinity and osmotic pressure. Among these, ectoine plays a crucial role in repairing and protecting nucleic acids, protein, biofilms, and cells. As a result, it has found widespread applications in cosmetics, biological agents, the enzyme industry, medicine, and other fields. Currently, the market value of ectoine is around US$ 1 000/kg, with a global demand reaching 15 000 tons per year. Although halophilic bacteria serve as the natural source of ectoine synthesis, its production in high-salinity media presents challenges such as equipment corrosion and high cost for industrial production. Advancements in functional genomics, systems biology, and synthetic biology have paved the way for the development of high-yielding cell factories through metabolic engineering, leading to significant progress. For example, engineered Escherichia coli achieved a maximum ectoine titer of 131.8 g/L, with a productivity of 1.37 g/(L·h). This review aims to explore the biosynthetic pathway, biochemical characteristics of key enzymes, and the biosynthesis of ectoine, shedding light on current research status and offering insights for industrial-scale ectoine production.

Evaluation of volcanic ash as a low-cost high-temperature thermal energy storage material for concentrated solar power

The integration of renewable energy sources is facilitated by TES because it enables the storage and release of excess clean energy, which improves grid stability. In concentrating solar power plants (CSP), solar molten salt is frequently used since it has some advantages such as good thermal properties. However, certain challenges, such as molten salt corrosion, salt solidification, and high production costs, must be carefully considered. An alternative approach gaining attention involves the use of solid ceramic materials capable of withstanding high temperatures as a potential TES medium without the molten salt drawbacks. Elevating the operating temperature of power conversion processes while concurrently reducing capital costs is a strategic means to enhance the competitiveness of these innovative power plants. This study explores the potential of volcanic ash, a low-cost naturally occurring ceramic material, for TES. The evaluation revealed high-temperature stability up to 750 °C, slight mass gain but stable over time, elevated solar absorption, and excellent thermal and chemical stability, even in the presence of molten salts.

Medium-Entropy Monosilicates Deliver High Corrosion Resistance to Calcium-Magnesium Aluminosilicate Molten Salt.

For decreasing the global cost of corrosion, it is essential to understand the intricate mechanisms of corrosion and enhance the corrosion resistance of materials. However, the ambiguity surrounding the dominant mechanism of calcium-magnesium aluminosilicate (CMAS) molten salt corrosion in extreme environments hinders the mix-and-matching of the key rare earth elements for increasing the resistance of monosilicates against corrosion of CMAS. Herein, an approach based on correlated electron microscopy techniques combined with density functional theory calculations is presented to elucidate the complex interplay of competing mechanisms that control the corrosion of CMAS of monosilicates. These findings reveal a competition between thermodynamics and kinetics that relies on the temperatures and corrosion processes. Innovative medium-entropy monosilicates with exceptional corrosion resistance even at 1500°C are developed. This is achieved by precisely modulating the radii of rare earth ions in monosilicates to strike a delicate balance between the competition in thermodynamics and kinetics. After 50 and 100h of corrosion, the thinnest reactive layers are measured to be only 28.8 and 35.4µm, respectively.

Corrosion behavior of metallic coatings on titanium bipolar plates of proton exchange membrane water electrolysis

The corrosion resistance, conductivity, and cost of the metallic bipolar plates are the main limitations for the Proton Exchange Membrane Water Electrolysis (PEMWE) commercialization. In the present study, Ta, Nb, and Ti non-precious metallic coatings were deposited by closed-field unbalanced magnetron sputtering to increase the corrosion resistance and conductivity of titanium bipolar plates in PEMWE, respectively. The coating samples suffer from corrosion in a simulated extreme anode operating environment of PEMWE (0.5 M H2SO4 + 5 ppm HF, 80 °C, O2). The surface of the Ti coating forms the micropores due to the high dissolution rate in initial formation stage of the passivation film, resulting in a higher current density (1.41 × 10−6 A cm−2). The hydrolysis reaction of Ta coating causes the adsorption of sulfide ions, thereby affecting the density of the passivation film. Despite the Ta coating exhibiting a favorable current density (4.82 × 10−7 A cm−2), ICR (463.11 mΩ cm2) is lamentably poor. The surface of Nb coating has been completely covered by Nb2O5 and NbO2 in the simulated PEMWE environment. The reoxidation process of NbO2 promotes the rate of passivation film formation and provides excellent conductivity. Therefore, Nb coating exhibits the lowest current density and interfacial contact resistance of 2.23 × 10−8 A cm−2 and 119.78 mΩ cm2, respectively, which is very low compared to the bare titanium bipolar plates.

Corrosion and heat-resistant SiCN/C as lightweight fibers for microwave absorption and electromagnetic field shielding in Ku-band

SiCN fibers are usually combined with metals to increase the magnetic loss in electromagnetic field (EMF) shielding, but this results in high weight density, easy corrosion, difficult treatment, and high cost of the material. This study proposes the manufacturing of corrosion and heat-resistant ceramic lightweight fibers containing in-situ synthesized carbon nanostructures (SiCN/C) with excellent EMF shielding in Ku-band (12.4–18 GHz). The samples showed differential trends of EMF shielding effectiveness in terms of reflectance, transmittance, and absorption behavior. Compared to SiCN fibers, the EMF absorption was two times greater when carbon was added to the SiCN matrix. A minimum reflection coefficient (S11) of −12 dB was observed for SiCN/C fibers, meaning a high shielding efficiency with >90 % of the EMF energy shielded. On the other hand, SiCN fibers showed a minimum S11 of −7 dB, resulting in a protection of 80 % against EMF energy. Computational simulations clarified the better features of SiCN/C in electromagnetic shielding compared to SiCN, which was ascribed to enhanced conduction loss derived from conductive free carbon, and dipole and interfacial polarization loss generated by defects. The fibers were resistant to acidic and basic environments and oxidation of up to 600 °C. Moreover, the addition of carbon precursor represented a weight decrease of 17 % for SiCN/C compared to SiCN fibers. This research will afford an alternative solution for the manufacturing of SiCN/C fibers with EMF absorption properties that can be used as lightweight materials in harsh environments.

Double Carbon Networks Reinforce the Thermal Storage and Thermal Transfer Properties of 1-Octadecanol Phase Change Materials.

Using thermal storage materials with excellent thermal properties in the energy utilization system enables efficient use of renewable energy sources. Organic phase change materials (PCMs) have the advantages of high heat storage density, no corrosion, and low cost, but low thermal conductivity and insufficient heat transfer capacity have always been the bottlenecks in their application. In this paper, melamine foam@ reduction graphene oxide (MF@rGO) and carbon foam@ reduction graphene oxide (CF@rGO) composite foams with double carbon networks were prepared by self-assembly method and further employed in 1-octadecinal (OD) PCMs. The microstructure, chemical composition, phase change behavior, thermal conductivity, and photothermal conversion performance of MF@rGO/OD and CF@rGO/OD were studied in detail using SEM, FTIR, Raman DSC, and LFA. The melting and solidification enthalpies of CF@rGO/OD composite PCMs were 208.3 J/g and 191.4 J/g, respectively, its thermal conductivity increased to 1.54 W/m·K, which is 6.42 times that of pure OD. The porous structure and high thermal conductivity of the double carbon network substantially enhance the efficiency of energy storage and release in composite PCMs. CF@rGO/OD composite PCMs have excellent heat storage performance and heat transfer capacity, and a wide range of application prospects in the fields of low-temperature solar heat storage, precision instrument temperature control, and intelligent buildings.

Study On Corrosion Resistance of Magnesium Phosphate Cement-based Coating Modified by Metakaolin

Magnesium ammonium phosphate cement (MAPC) with a ceramic-like structure has good anti-corrosion properties. As an anti-corrosion coating, it can resist steel corrosion and reduces economic losses caused by steel corrosion. To further improve the anticorrosive properties of the coating, this study modified MAPC by partially replacing MgO with metakaolin (MK). Electrochemical tests analyzed the effect of MK on the anticorrosive properties of the coating. The results showed that the incorporation of MK significantly improved the anticorrosive properties of the coating, and the maximum improvement was obtained when the substitution amount was 15%. The compositions and microscopic morphology of the coatings were analyzed by X-ray diffraction (XRD), thermogravimetric analysis (TG-DTG), and scanning electron microscopy (SEM). According to the results, MK addition did not significantly alter the main composition of the coating, but the MK promoted the formation of MgNH4PO4·6H2O(MAP) to some extent. The microscopic morphology of the coating surface showed that the crystals were stacked together in flower-like layers before soaking, and the crystals grew more entirely after soaking. The internal microstructure of the coating is very dense, which helps to resist the erosion of corrosive media. In addition, the changes in coating pores before and after the incorporation of MK were tested by low-field nuclear magnetic resonance (LF-NMR). Based on the results, the doping of MK can optimize the pores of the coating and reduce its porosity. It is feasible to replace part of the MgO with MK to improve the corrosion resistance of magnesium phosphate cement-based coating, and the optimal dosage of MK is 15%. This research is helpful to improve the anti-corrosion performance of the coating and reduce corrosion costs.

Corrosion studies of various salt solutions on metals and alloys

Corrosion studies of various salt solutions on metals and alloys

Novel Low Temperature Galvanic Coatings

A major influence on performance and lifetime of steel-based structures is corrosion. Some such structures include ground support equipment (GSE). GSE plays a vital role in the safety and efficiency of aircrafts and airports worldwide. GSE encompasses all support equipment at airports, necessary for the function and logistical operation of airports, air bases and other aviation facilities. According to the IMPACT study undertaken by the National Association of Corrosion Engineers (NACE) in 2013, the global cost of corrosion was estimated to be US$2.5 trillion, equivalent to 3.4% of the global GDP at the time. The corrosion of GSE can be attributed to a number of factors present including, but not limited to, moisture in air, salt particles in coastal winds and industrial pollutants from fuel. For these reasons, corrosion prevention through means of protective coatings is of utmost importance; as well as a strict programme of corrosion inspection and repair. Traditional means of protection against corrosion centre around Hot-Dipped Galvanising (HDG). This is the process of applying a protective zinc layer to steel in order to prevent corrosion of a component or structure. One of its major issues is cost. This is primarily due to the need to outsource galvanising to external contractors, especially for manufacturers that do not have the capacity or capability to undertake the process in-house. HDG also happens at high temperatures of ~450°C. This requires a great amount of energy and would be impossible to implement in-house for manufacturers. The repair of HDG sections is also a concern. This often sees the protective Zn coating removed and the section welded to repair. In this instance, the steel substrate is left unprotected and susceptible to corrosive attack. The common solution here is Cold Galvanising Coatings (CGCs) or Zn Rich Paint (ZRP). ZRPs are, however, laden with issues; poor adhesion, UV degradation and poor galvanic contact with the substrate. These shortcomings mean the service life of ZRPs and CGCs are limited.The current work focuses on developing a lower-temperature alternative centred around fusible alloys. The aim is to provide a corrosion-resistant coating that can bond with the substrate at lower temperatures, be applied on-site and offer galvanic protection. The fusible alloy is mixed with zinc powder to create a novel corrosion resistant coating. The coating may also be used for repair of galvanised GSE, which often sees welded areas left susceptible to corrosive attack. Microstructural analysis was carried out as a function of Zn loading weight as well as curing time and temperature. A systematic study on curing time and temperature identified the optimal processing parameters for the novel coating. Heating of below 250°C was used to melt the fusible alloy to envelop the zinc. This can be achieved using a conventional oven, while Near Infrared (NIR) heating was explored as a rapid heating option. The resulting optical and scanning electron microscope (SEM) images show that the fusible alloy acts as a matrix, while “islands” of Zn are dispersed therein to offer galvanic protection. The use of a metal matrix in the microstructure allows for superior electrical contact between the sacrificial Zn and the structural steel substrate, unlike that given by most CGCs and ZRPs. Electrochemical studies, such as Zero Resistance Amplitude (ZRA) and Open Circuit Potential (OCP), and accelerated corrosion tests, implementing the Scanning Vibrating Electrode Technique (SVET), have shown that the coating offers excellent galvanic protection to steel in a 1% NaCl electrolyte. ZRA galvanic corrosion tests demonstrated that current flow between components was negligible. This suggests no obvious self-corrosion in the coating, despite the nobility of fusible alloy components. Current OCP results show that adding Zn to the fusible alloy shifts the OCP from -425mV to -970mV in a 24hr test in 1%NaCl. This is comparable to that of Zn which is stable at -1V and shows promise when compared to bare steel at -700mV, meaning the coating offers galvanic protection to the steel. This is reinforced by SVET maps of coated steel samples, confirming that steel remains cathodic to the coating throughout tests, showing that performance improves as a function of Zn content. Adhesion tests, using the 0t method, show the peak performance comes at a known Zn wt% with cracks appearing and propagating as Zn wt% is increased. Overall; peak microstructure, corrosion protection and adhesion are achieved and demonstrated. The resulting product is a robust, protective, and dynamic coating; a step forward in the fight against corrosion of steel and protection of HDG.

Graphene oxide–polyamine preprogrammable nanoreactors with sensing capability for corrosion protection of materials

Corrosion is one of the major issues for sustainable manufacturing globally. The annual global cost of corrosion is US$2.5 trillion (approximately 3.4% of the world's GDP). The traditional ways of corrosion protection (such as barriers or inhibiting) are either not very effective (in the case of barrier protection) or excessively expensive (inhibiting). Here, we demonstrate a concept of nanoreactors, which are able to controllably release or adsorb protons or hydroxides directly on corrosion sites, hence, selectively regulating the corrosion reactions. A single nanoreactor comprises a nanocompartment wrapped around by a pH-sensing membrane represented, respectively, by a halloysite nanotube and a graphene oxide/polyamine envelope. A nanoreactor response is determined by the change of a signaling pH on a given corrosion site. The nanoreactors are self-assembled and suitable for mass-line production. The concept creates sustainable technology for developing smart anticorrosion coatings, which are nontoxic, selective, and inexpensive.

Electromembrane separation coupled with urea electrolysis for energy-saving recovery of quaternary ammonium hydroxide from industrial wastewater

The electrolytic recovery of quaternary ammonium hydroxide (R4NOH) from the wastewater produced in the process of template-synthesizing molecular sieves has considerable economic benefits. The current practices are challenged by the anode corrosion and high operation costs due to harmful chlorine chemicals in wastewater and high energy consumption. This work proposes a promising energy-saving strategy by combining the recovery of quaternary ammonium hydroxides with urea electrolysis technology. This strategy reduces the anodic oxidation potential and achieves low-energy consumption while avoiding the formation of hypochlorite ions. Through the laboratory-scale closed membrane electrolysis system (CMES) cycle test, it was found that when the cathode output concentration of 0.5 M was reached at a current density of 50 mA cm−2, the energy consumption was saved by 64.7% compared with the traditional technology. Along with the achievement of the expected recovery rate, the high value-added R4NOH were recycled. More specifically, the ultra-low voltage of the electrolyze protected the ecosystem by avoiding the corrosion of harmful chlorine chemicals and demonstrated the potential for large-scale applications at the reduced process costs.

Performance, Mechanical Properties and Durability of a New Type of UHPC-Basalt Fiber Reinforced Reactive Powder Concrete: A Review.

The advent of reactive powder concrete (RPC) has brought about the era of ultra-high performance concrete (UHPC), and the incorporation of fiber has brought about more possibilities for its application. Basalt fiber reinforced reactive powder concrete (BFRPC), as the product of the combination of RPC and fiber, has become a new engineering material that has received much attention from scholars in recent years. Compared with traditional UHPC, BFRPC is superior in corrosion resistance, material compatibility, cost performance, environmental protection, and other aspects; therefore, it is destined to have a wide range of applications in the future. In this article, we extensively reviewed the literature on basalt fiber reinforced RPC in the past decade from the perspective of work performance, mechanical properties, and durability. Moreover, we summarized the research progress and achievements on BFRPCs in the following points: (1) The performance of BFRPCs is mainly influenced by three factors: the frictional resistance between fine aggregates, the consistency of the cement slurry, and the three-dimensional random interweaving of basalt fibers; (2) the mechanical properties of BFRPC are mainly influenced by curing conditions, the design of the RPC matrix proportional mix, and the addition of basalt fibers up to a threshold; (3) thanks in part to RPC's density and the filling and bridging of fibers, BFRPC exhibits uniform and good performance in durability indicators. However, there are still some problems in the current development of BFRPC, such as inconsistent test conclusions among different scholars and a lack of scenarios in which to apply BFRPC. This paper also puts forward the prospect from the aspects of theoretical research and practical application, and provides a reference for subsequent related work.

Study on anti-corrosion performance of composite modified magnesium ammonium phosphate cement-based coatings

Corrosion of metals not only fails the overall stability of a building but causes significant economic losses. Spraying anti-corrosion coatings is the simplest and most effective method of corrosion protection. Magnesium phosphate cement-based coatings are attractive due to their fast-setting speed, high strength and durability. This paper aims to improve the corrosion protection properties of magnesium ammonium phosphate cement-based coatings. Zinc oxide and aluminum tripolyphosphate were used as additives at 3% and 4% by mass of magnesium oxide. Meanwhile, metakaolin and aluminum tripolyphosphate at 15% by mass of magnesium oxide was added as admixtures for compound modification. In addition, the electrode potential and current density, impedance spectra, passivation films and phase composition of the materials were investigated using LPR, EIS, SEM and XRD/TG-DTG measurements. Comparing the anodic slope Ba of the polarization curve shows that the Zinc oxide mixed metakaolin specimens(Zn-CSA) have the highest Ba value, indicating that the coating prevents rusting by inhibiting the anodic electrochemical reaction. The EIS impedance spectroscopy results show that sulfate aluminate cement as a compound modifier of the admixture can effectively improve the corrosion protection of the coating. The addition of ATP is effective in inhibiting the transfer process of the coating in the charge. Furthermore, the addition of Zn is to improve the corrosion resistance of the coating by enhancing the shielding properties of the coating. SEM results show that the Zn-CSA surface is very dense, with a lamellar distribution of crystals consisting of tiny crystals closely packed at the bottom and a lamellar distribution at the top. This effectively prevents the erosion of the substrate by corrosive media. The XRD/TG-DTG results show that the composite modified coating consists mainly of incomplete MgO, the main hydration product MAP, Mg2SiO4 and MgCaSiO4. Moreover, Zn-CSA showed the lowest porosity before and after immersion in the coating porosity test. In the salt spray test, the composite-modified coating showed good corrosion resistance, with no bulging, flaking or rusting of the coating surface after 1440 h of salt spray time. This study has important implications for improving corrosion resistance and reducing corrosion costs.

Mathematical Modelling of CO2 corrosion with NORSOK M 506

The consequences of corrosion is catastrophic also costs reached the global economy “$2.5 trillion, or world GDP’s 3.4%”. Despite the magnitude of the corrosion cost, it can be concluded that scientific studies on corrosion prevention are quite limited, with the exception of high-risk sectors such as aviation and the fuel oil industry. It is important to fight against corrosion in order to ensure the safe operation of oil-carrying pipelines under the sea; and to prevent accidents and environmental damage. As a result of developing industry conditions and increasing needs, modelling corrosion is a very effective method in the prevention of corrosion. Industry, research companies and universities have developed many corrosion rates, prediction models. One of them is the NORSOK M 506 model. In this study, the NORSOK M 506 CO2 corrosion prediction model and the experimental results conducted by Nešić, Solvi and Enerhaug in 1995 were compared in terms of CO2 corrosion rate. The results showed that the mathematical corrosion model calculated nearly six times higher than the experimental study within conformity.

Sulfide Removal by Catalitic Oxidation From Rayon Waste

Catalytic oxidation of spent sulfidic caustic consist of SH- ion or NaHS compound by H 2 O2 in neutral or acidic solution to elemental sulphur may provide a convenient and economical method for the control of sulphide wastes and their associated odors at pulp, paper and textile industry. Oxidation of sulfide in rayon waste by hydrogen peroxide was investigated in the presence of ferric sulfate catalyst. Kinetic equations and activation energies of H 2 O2 and SH- ion to total sulphur and sulphate in rayon waste for catalytic oxidation reaction were calculated based on the experimental results. For the removal of sulfide from sulfide solution the most common process involves its catalytic oxidation to a more benign form sulfate. The rate of sulfidic catalytic oxidation was found higher at lower initial sulphide concentration and the rate of sulphide catalytic oxidation was found directly proportional to loading and hydrogen peroxide addition. Optimum total sulphide concentration was achieved when sulphide solutions in the presence of H 2 O 2 in the ratios SH-/H 2 O 2 1:4.2. The potential user of H 2 O 2 determine the optimal conditions for control of odor, corrosion and waste treatment cost due to sulfide consisting of sulphur ion, sulphate ion, etc. The catalytic oxidation of sulphides into sulphates by H 2 O 2 may be applied directly to aqueous wastes containing these odorants

Metabolomic analysis reveals the responses of docosahexaenoic-acid-producing Schizochytrium under hyposalinity conditions

The heterotrophic Schizochytrium sp. has been utilized to produce docosahexaenoic acids commercially in recent years. However, the high salinity required for Schizochytrium growth and docosahexaenoic acid production could result in salt-induced bioreactor corrosion and high downstream water treatment costs. Thus, exploring the physiological and metabolomic changes of Schizochytrium exposed to low-salt condition is beneficial for developing strategies of reducing the salt concentration during fermentation. In this study, Schizochytrium was exposed to 20, 10, 8, or 6 g/L of sea salt and the responses were determined. It was discovered that biomass accumulation was decreased, while starch and fatty acid was increased, especially unsaturated fatty acid accumulation in Schizochytrium, along with the salt concentration decrease. In addition, the metabolomic analysis showed that the intracellular pool sizes of NADPH, CoA, and ADP-GCS were significantly increased, while those of PEP and Ac-CoA were decreased, consistent with the content changes of fatty acid, starch, and biomass under hyposaline stress. The metabolomic analysis combined with further biochemical evidence revealed that fatty acid content elevation involved strengthening pentose phosphate pathway to provide more NADPH content; elevating CoA content to provide more precursors; upregulating inositol content, which was later demonstrated to enhance fatty acid accumulation; and activating the antioxidant system to reduce oxidation of unsaturated fatty acid caused by the reactive oxidative stress level. Finally, decreased content of glycerol, an important osmoregulator, along with enhanced cell wall polysaccharides, were also discovered in Schizochytrium as an adaptation to low-salt growth conditions. Our paper provides important guidelines for engineering Schizochytrium for low-salt cultivation in the future.

Untangling competition between epitaxial strain and growth stress through examination of variations in local oxidation

Understanding corrosion mechanisms is of importance for reducing the global cost of corrosion. While the properties of engineering components are considered at a macroscopic scale, corrosion occurs at micro or nano scale and is influenced by local microstructural variations inherent to engineering alloys. However, studying such complex microstructures that involve multiple length scales requires a multitude of advanced experimental procedures. Here, we present a method using correlated electron microscopy techniques over a range of length scales, combined with crystallographic modelling, to provide understanding of the competing mechanisms that control the waterside corrosion of zirconium alloys. We present evidence for a competition between epitaxial strain and growth stress, which depends on the orientation of the substrate leading to local variations in oxide microstructure and thus protectiveness. This leads to the possibility of tailoring substrate crystallographic textures to promote stress driven, well-oriented protective oxides, and so to improving corrosion performance.