Acid Corrosion Research Articles

A nonmetal substrate of surface‐enhanced Raman spectroscopy for trace fentanyl detection

AbstractRapid detection and identification of opioids are of great significance and an urgent need in drug regulation and forensic science. Fentanyl is an extremely potent synthetic drug of abuse that unfortunately cannot be accurately detected. Therefore, techniques combining fast, highly sensitive and portable for fentanyl detection need to be developed. Surface‐enhanced Raman spectroscopy (SERS) has emerged as a promising detection technique owing to its high sensitivity and selectivity. Here, we reported a nonmetal SERS substrate used for trace fentanyl detection. The lowest detectable concentration was 10−7 M, and the MoO2 substrate exhibited excellent thermal and chemical stability, which could even ensure high‐temperature heating, laser irradiation, and corrosion of strong acid or alkali.

Synthesis, characterization, efficiency evaluation of some novel triazole derivatives as acid corrosion inhibitors

Synthesis, characterization, efficiency evaluation of some novel triazole derivatives as acid corrosion inhibitors

Deterioration of alkali-activated and Portland cement-based mortars under sulfur oxidizing bacteria corrosion

This study investigated the deterioration behavior of the metakaolin based alkali-activated mortar (MK-M), flay-ash-based alkali-activated mortar (FA-M) and granulated blast furnace slag powder-based alkali-activated mortar (SG-M) under simulated microbial induced acid corrosion (MIAC). For comparison, the MIAC induced corrosion of the Ordinary Portland cement-based mortar (OPC) was also studied. The pH variation of the corrosive solution (sulfur oxidizing bacteria liquid medium), visually observation, and mass loss were monitored to estimate the deterioration. X-ray diffraction (XRD), scanning electron microscope (SEM) and thermogravimetric analysis (TGA) were used to analyze the composition and morphology of different samples. The results revealed that the three alkali-activated cement-based mortars displayed a higher alkalinity compared to the Portland cement-based mortar. MK-M and SG-M exhibited better resistance to MIAC with a smooth surface and without the formation of typical corrosives owing to the stable structure of N-A-(S)–H and the lower content of calcium ion. However, SG-M suffered severe corrosion, which was similar to OPC-M, with the formation of abundant gypsum and ettringite and visually changed morphology for its high content of calcium ion and degenerated structure.

Mechanical properties and damage constitutive model of sandstone after acid corrosion and high temperature treatments

Aiming at the problem of temperature-mechanics-chemical (T-M-C) action encountered by rocks in underground engineering, sandstone was selected as the sample for acid corrosion treatment at pH 1, 3, 5 and 7, the acid corrosion treated samples were then subjected to high-temperature experiments at 25, 300, 600, and 900 °C, and triaxial compression experiments were conducted in the laboratory. The experimental results show that the superposition of chemical damage and thermal damage has a significant impact on the quality, wave velocity, porosity and compression failure characteristics of the rock. Based on the Lemaitre strain equivalent hypothesis theory, the damage degree of rock material was described by introducing damage variables, and the spatial mobilized plane (SMP) criterion was adopted. The damage constitutive model can well reflect the stress-strain characteristics of the rock triaxial compression process, which verified the rationality and reliability of the model parameters. The experiment and constitutive model analyzed the change law of mechanical properties of rock after chemical corrosion and high temperature thermal damage, which had certain practical significance for rock engineering construction.

Application of Biomass Corrosion Inhibitors in Metal Corrosion Control: A Review

Corrosion is the process of damaging materials, and corrosion of metallic materials frequently results in serious consequences. The addition of corrosion inhibitors is the most effective means of preventing metal corrosion. Until now, researchers have made unremitting efforts in the research of high-efficiency green corrosion inhibitors, and research on biomass corrosion inhibitors in a class of environmentally friendly corrosion inhibitors is currently quite promising. This work presents the classification of green biomass corrosion inhibitors in detail, including plant-based corrosion inhibitors, amino acid corrosion inhibitors, and biosurfactant corrosion inhibitors, based on the advantages of easy preparation, environmental friendliness, high corrosion inhibition efficiency, and a wide application range of biomass corrosion inhibitors. This work also introduces the preparation methods of biomass corrosion inhibitors, including hydrolysis, enzymatic digestion, the heating reflux method, and microwave extraction. In addition, the corrosion inhibition mechanisms of green biomass corrosion inhibitors, including physical adsorption, chemisorption, and film-forming adsorption, and evaluation methods of biomass corrosion inhibitors are also explicitly described. This study provides valuable insights into the development of green corrosion inhibitors.

Acidic Corrosion Behaviour of Niobium-Added Welding Overlays Fabricated by Self-Shielded Metal-Cored Wires

Acidic Corrosion Behaviour of Niobium-Added Welding Overlays Fabricated by Self-Shielded Metal-Cored Wires

Influencing Factors of Sulfuric Acid Resistance of Ca-Rich Alkali-Activated Materials

In this paper, we distinguished the degradation of alkali-activated material (AAM) exposed to sulfuric acid as physical (scaling, spalling, cracking, breaking, etc.) and chemical degradation (neutralization), because the mechanisms of these two types of degradation are different. Then, the effects of curing method, raw materials, and their mixing proportions on the two kinds of degradation of AAMs containing GGBFS were investigated in detail, including liquid-filler ratio, component of alkali activator, chemical admixture, inactive filler alternative to fly ash (FA), addition of municipal waste incineration bottom ash (BA), etc. The experimental results show that (a) small liquid-filler ratio, heat-curing, and the use of blended alkali activator solution of sodium silicate and NaOH can reduce both physical and chemical degradation of AAMs; (b) large GGBFS content or AE agent addition decreases the physical degradation, but increases the chemical degradation; (c) using crushed stone powder to replace FA and adding BA or a retarder would increase the physical and chemical degradation; but (d) the use of drying shrinkage reducer composed of polyether derivatives does not affect acid resistance. We also discussed the applicability and limitation of XRD and SEM-EDS in analyzing the chemical compositions of Ca-rich AAMs exposed to sulfuric acid, and found that (e) XRD analysis can identify the gypsum formation, and the gypsum peak intensity is related to the physical degradation of the Ca-rich AAMs; (f) by SEM-EDS analysis, the decalcification and dealkalization of C-A-S-H gels can be judged from the decrease in the average Ca/Si atomic ratio and the average Na atomic percentage in the acid corrosion area, but dealumination can be only determined from the dissimilarity of Al and Si elemental maps; and (g) if the CaO/SO3 molar ratio ranges from 0.8 to 1.0, gypsum formation can be estimated.

Modulating the bactericidal activity and corrosion resistance of Al2O3 porous ceramics through Cu and Fe co-introduction for membrane support application

Ceramic membrane-based filtration is perceived as an energy-saving and chemical-less solution to the wastewater problem. In this work, Cu- and/or Fe-containing Al2O3 porous ceramics were fabricated by powder metallurgy, with Cu and Fe introduction for bactericidal functionalization and Cu stabilization, respectively. The Cu- and Fe-free Al2O3 porous ceramics were composed of irregular α- Al2O3 particles and inter-particle NaAlSiO4 phase. The introduction of Cu resulted in the formation of band-shaped CuO and particle-shaped CuAl2O4 spinel phase in Al2O3 matrix. Further introducing Fe into Cu-containing Al2O3 increased the fraction of particle-shaped CuM2O4 (M=Al/Fe) spinel phase, while decreased that of band-shaped CuO. Without Cu incorporation, Fe reacted with Al2O3 to form Al3Fe5O12 phase. The introduction of Cu resulted in increased linear shrinkage and bending strength, while decreased porosity of Al2O3 porous ceramics. However, the effects of Fe were the opposite. The Cu-containing Al2O3 ceramics exhibited excellent bactericidal activity, but poor acidic corrosion resistance. The co-introduction of Cu and Fe enhanced the acidic corrosion resistance due to Cu stabilization from CuO to spinel phase, while compromised the bactericidal activity to some extent. Together, the results indicate that Cu- and Fe-containing Al2O3 porous ceramics are promising candidate materials for ceramic membrane support application.

Electrochemical corrosion behavior in sulfuric acid solution and dry sliding friction and wear properties of laser-cladded CoCrFeNiNbx high entropy alloy coatings

316 stainless steel (SS) was coated with CoCrFeNiNbx (x: atomic ratio, x = 0, 0.1, 0.2, and 0.3) high entropy alloy coatings (HEACs) by laser cladding (LC). The impacts of Nb content on the phase composition, microstructure, microhardness, wear resistance and corrosion properties of CoCrFeNi based HEACs were examined. Different from the canonical dendritic (DR) - interdendritic (ID) microstructure presented by the other three HEACs, the ID of Nb0.3 HEACs also existed nanoscale Nb-rich Laves phase composed of NbNi and NbCo. The inclusion of Nb significantly reduced the average grain size of CoCrFeNi based HEACs from 59.43 μm to 11.38 μm. It also greatly diminished the formation of high angle grain boundaries (HAGBs), increasing the percentage of low angle grain boundaries (LAGBs) from 31 % to 61 %. The microhardness of Nb-containing HEACs was significantly promoted due to the solid solution strengthening and fine grain strengthening caused by large size Nb atoms. Affected by Laves phase with high coordination number and space filling ratio and higher proportion of LAGBs, the microhardness of Nb0.3 HEAC was even as high as 530 HV. The increase in Nb concentration also strengthened the HEACs' resistance to wear. Nb0, Nb0.1, Nb0.2, and Nb0.3 HEACs had corresponding specific wear rates of 0.36, 0.32, 0.23, and 0.20 mm3/Nm. Unlike 316 SS, Nb0 and Nb0.1 HEACs, which had both adhesive wear and abrasive wear, Nb0.2 and Nb0.3 HEACs were mainly wear by abrasive wear. The corrosion behavior of CoCrFeNiNbx HEACs in 0.5 M H2SO4 solution was similar to 316 SS, but the corrosion resistance was stronger than 316 SS. Nb0.3 HEAC with the Ecorr of −164 mV and Icorr of 6.40 × 10−7 A/cm2 showed the best acid corrosion resistance, which could be attributed to the stable and dense passivation film on its surface. Distinct from the intergranular corrosion of other coatings, the corrosion of Nb0.3 HEAC mainly occurred in DR, because the FCC phase acted as the anode site in it when FCC and Laves phase co-existed.

Quinoxaline Derivatives as Newly Acid Corrosion Inhibitors for Mild Steel: Synthesis, Electrochemical, and Theoretical Investigations

Quinoxaline Derivatives as Newly Acid Corrosion Inhibitors for Mild Steel: Synthesis, Electrochemical, and Theoretical Investigations

Alkali salts of amino acids as alkaline additives for neutralization of acidic corrosion inhibitors

We present alkali salts of amino acids as functional, non-toxic, non-hazardous, non-volatile, chemically stable, and cheap alkaline additives for common acidic corrosion inhibitors. The resulting mixtures have been evaluated for Co, Ni, and Cu leaching and were analyzed by chip filter assay, potentiodynamic polarization measurements, electrochemical impedance measurements, and gravimetry for corrosion protection of iron and steel in aqueous environment at slightly alkaline pH. Leaching of Co and Ni was found to depend on the corresponding complex stabilities. Taurine (Tau) as well as aminohexanoic acid (AHX) leads to low leaching of Co and Ni. Particularly AHX is an attractive low leaching additive leading to lower Co and Ni concentrations in solution than currently used amino alcohols. Glu and Tau were found to synergistically interact with several acidic corrosion inhibitors of the carboxylic acid and the phosphonic acid type. Tau had a particularly positive impact on the protective properties of carboxyphosphonic acids. Glu had also a positive effect on the anti-corrosive properties of several acidic corrosion inhibitors and served as an anti-scalant. Alkali salts of Glu and Tau might thus serve as commercially and ecologically attractive substitutes for current alkaline additives to acidic corrosion inhibitors.

Community structures and biodeterioration processes of epilithic biofilms imply the significance of micro-environments

Epilithic biofilms colonising outdoor stone monuments can intensify the deterioration processes of the stone materials and pose great challenges to their protection. In this study, biodiversity and community structures of the epilithic biofilms colonising the surfaces of five outdoor stone dog sculptures were characterised by high-throughput sequencing. Although they are exposed to the same envrionment in a small yard, the analysis of their biofilm populations revealed high biodiversity and species richness as well as great differences in community compostions. Interestingly, populations responsible for pigment production (e.g., Pseudomonas, Deinococcus, Sphingomonas and Leptolyngbya) and for nitrogen (e.g., Pseudomonas, Bacillus, and Beijerinckia) and sulfur cycling (e.g., Acidiphilium) were the core common taxa in the epilithic biofilms, suggesting the potential biodeterioration processes. Furthermore, significant positive corrolections of metal elements rich in stone with biofilm communities showed that epilithic biofilms could take in minerals of stone. Importantly, geochemical properties of soluble ions (higher concentration of SO42− than NO3−) and slightly acidic micro-environments on the surfaces suggest corrosion of biogenic sulfuric acids as a main mechanism of biodeterioration of the sculptures. Interestingly, relative abundacne of Acidiphilium showed a positive correlation with acidic micro-environments and SO42− concentrations, implying they could be an indicator of sulfuric acid corrosion. Together, our findings support that micro-environments are inportant to community assembly of epilithic biofilms and the biodeterioration processes involved.

Construction and Performance of Superhydrophobic Surfaces for Rusted Iron Artifacts

Ancient iron artifacts need to be protected with a rust layer, often stabilized by tannic acid corrosion inhibition. In humid environments, water vapor could slowly penetrate and trigger galvanic corrosion of metal artefacts. Sealing treatments are generally applied to the artefact surface to isolate water and enhance its corrosion resistance. Superhydrophobic modifications could effectively block the penetration of moisture into the interior of the artefact and provide a nice water barrier. Stearic acid with tannic acid inhibition treatment creates a superhydrophobic protective layer on the surface of rusted iron artifacts and enhances corrosion resistance effectively. Various scientific analyses and testing methods are used in this paper to evaluate the corrosion resistance of rusted surfaces after superhydrophobic modification and investigate the reaction mechanisms. The results indicate that the contact angle of the rusted surface after corrosion inhibition by tannic acid and modified by stearic acid is increased to 152.2°, which means the superhydrophobic protective layer has been successfully constructed. The C/Fe ratio of the rusted surface is increased from 0.21 to 2.10, and the characteristic diffraction peaks of O1s and Fe 2p3/2 shift toward higher binding energy. Stearic acid is combined with the corrosion product layer by chemical bonding. Chelation between rust products, tannic acid, and steric acid is effective, and the chelate is chemically stable. The superhydrophobic surface forms a lamellar wax-like layer as an air barrier to isolate liquid water, resulting in a significant decrease in corrosion current and an increase in Warburg impedance to 217.9 times the original state, with a protection efficiency of 88.3%. Tannic acid corrosion inhibition and stearic acid superhydrophobic modification have an excellent synergistic protective effect on improving the corrosion resistance of iron artifacts, resulting in better corrosion resistance of iron artifact materials. The research provides new ideas and references for the protection of ancient iron artifacts sealing.

Effect of Ni-Fe/CaO-Al2O3 catalysts on products distribution in in-situ and ex-situ catalytic pyrolysis of Chinese herb residue

It is necessary to investigate the differences between in-situ and ex-situ methods of bimetallic supported catalysts for biomass catalytic pyrolysis. In this paper, the Ni–Fe/CaO–Al2O3 catalysts with different Ni/Fe ratios have been synthesized by coprecipitation method, and it was explored that the effect of products distribution about Chinese herb residue(CHR) catalytic pyrolysis by in-situ and ex-situ methods. The results showed that in-situ NiFe-3 group had the highest content of aromatic compounds (59.68%) and the lowest content of aliphatic compounds (17.67%). This was beneficial to the utilization of chemical raw materials extracted from pyrolysis oil. Meanwhile, the CaO in the catalyst effectively reduces the acid content and corrosion of pyrolysis oil. The results showed that higher Ni and CaO content has the synergistic catalytic action in ex-situ catalytic experiments. It could promote water-gas shift reaction, which is conducive to the generation of H2. In-situ catalysis is mainly used for the upgrading of pyrolysis oil, while ex-situ catalysis is mainly used to promote secondary pyrolysis of pyrolysis products and improve the quality of pyrolysis oil. This work provides reference for the difference and high value utilization of biomass pyrolysis by different catalytic methods.

Chitosan derivatives as promising green corrosion inhibitors for carbon steel in acidic environment: Inhibition performance and interfacial adsorption mechanism

Among the biodegradable polysaccharide, chitosan is widely present in the cell membranes of bacteria and algae and in the cell walls of higher plants. As a promising biopolymer, chitosan has great potential as eco-friendly corrosion inhibitor. Herein, two synthetic chitosan derivatives (N-phenylthiourea chitosan (CS-PT), N-phenyl-O-benzylthiourea chitosan (CS-PT-Bn)) were investigated as high-efficient acidic corrosion inhibitors to deal with the corrosion issue of carbon steel. The anti-corrosion property of the chitosan derivatives was explored by electrochemical tests, surface characterization and theoretical calculations. The experimental results indicate that both CS-PT and CS-PT-Bn present high-efficient inhibition performance with the inhibition efficiency of 98.4% and 98.5% at the concentration of 100 mg/L, respectively. Their adsorption mechanism at steel/solution interface is revealed by quantum chemical calculations, molecular dynamics (MD) and GFN-xTB calculations. It is found that CS-PT and CS-PT-Bn adsorb at the steel/solution interface by forming Fe-N and Fe-S bonds. Compared to CS-PT molecule, the introduction of benzyl group endows CS-PT-Bn molecule with stronger electrostatic effect and hydrophobicity, which favors the interfacial adsorption of CS-PT-Bn molecule on carbon steel surface.

Neodecanoic Acid Diamides as Inhibitors of Acid Corrosion of Low-Carbon Steel

Neodecanoic Acid Diamides as Inhibitors of Acid Corrosion of Low-Carbon Steel

Assessing economic feasibility of retrofitting steam dryer and steam-air preheater to existing biomass power plant

Conventionally, the thermal design a biomass power plant is aimed at maximizing the energy efficiency by using extracted steam to increase feed water temperature in feed water heaters and installing heating surface areas of heat exchangers in boiler to recover flue gas energy. The temperature of flue gas at the boiler outlet must not be so low that a risk of acid corrosion is unacceptable. The energy efficiency can also be improved by reducing fuel moisture content in steam dryer and increasing air temperature in steam-air preheater. However, both devices require extracted steam, which is already used for raising feed water temperature in an existing power plant. In this paper, it is hypothesized that retrofitting steam dryer and steam-air preheater to an existing power plant can improve the energy efficiency. Performances of the existing power plant and the retrofitted power plant integrated with steam dryer and steam-air preheater are compared. Simulation results indicate that, despite lower final feed water temperature in the retrofitted power plant, the retrofitted power plant is more energy efficient than the existing power plant. Economic assessment is carried under the condition that both power plants generate the same power output, which means that the retrofitted power plant consumes less fuel than the existing power plant. The payback period for the retrofitting investment is approximately 7 years.

Nitric Acid Corrosion of As-Received and Autoclaved Zircaloy-4 in All Zr-4 Nitric Acid Test Facility

Nitric Acid Corrosion of As-Received and Autoclaved Zircaloy-4 in All Zr-4 Nitric Acid Test Facility

Root cause analysis for 410 S stainless steel structured packing failure in vacuum distillation column (case study)

A root cause analysis was conducted on the premature failure of 410 S stainless steel structured packing material in a vacuum distillation column. The multidisciplinary team identified four potential causal factors that could contribute to the failure, including: low temperature corrosion, high temperature attack, design aspects and operational parameters. For each causal factor, sub-factors were determined and classified as primary contributor, secondary contributor and noncontributor. The analysis revealed that low temperature chloride condensation in the tower top bed led to severe hydrochloric acid corrosion while high temperature coking in the lower beds led to intergranular cracking of the stainless steel. Also, the 0.1 mm packing material thickness used was not sufficient to obtain a 10–15 years design life. Recommendations include changes to the operating parameters to prevent condensation and coking as well as mechanical design modifications to get acceptable lifetimes.

In Situ Embedding Hydrogen‐Bonded Organic Frameworks Nanocrystals in Electrospinning Nanofibers for Ultrastable Broad‐Spectrum Antibacterial Activity

AbstractIn the event of a public health crisis, highly effective and sustainable antimicrobial materials and equipment will be urgently needed. Here, the preparation is reported by electrospinning of broad‐spectrum antibacterial nanofibers embedded in a photoactive hydrogen‐bonded organic framework (HOF) of rod‐like nanocrystals ≈60 nm in length. The resulting HOF@PVDF‐HFP nanofibers maintain excellent tensile and breathability characteristics while shielding HOF nanocrystals against acid and alkali corrosion. A series of nanofibers embedded with different amounts and types of HOF nanocrystals are prepared to optimize their efficiency of singlet oxygen (1O2) generation. The 0.5 wt.% HOF‐101‐F@PVDF‐HFP nanofibers exhibit the most efficient 1O2 generation that is enhanced by a factor of almost 2 when compared with the HOF‐101‐F microcrystalline powder. The HOF@PVDF‐HFP nanofibers are demonstrated to highly effectively kill pathogens, including viruses, bacteria, and fungi in 30 min under ambient light conditions.