Designing a Robust Ni-P/CeO2 Superhydrophobic Composite Coating for Synergistically Enhanced Corrosion Protection and Friction Reduction Performance.

Superhydrophobic surfaces have received widespread attention for their unique hydrophobicity in metal corrosion protection. However, the shortcomings of mechanical stability and long-term corrosion resistance limit their practical application. In this work, we designed and fabricated an anticorrosive and friction reducing Ni-P/CeO2 superhydrophobic composite (SC) coating on a copper surface. The fabricated coating shows good superhydrophobicity with a water contact angle of up to 154°. The Ni-P support structure and CeO2 nanoparticles form a multilayer micro/nanostructure by electrodeposition, ensuring excellent mechanical stability of the Ni-P/CeO2 SC coating. Electrochemical tests indicate that the coating has excellent corrosion resistance due to the superhydrophobic air film, Ni-P barrier layer, and CeO2 inhibition. Moreover, the friction coefficient of the coating is only 0.11 under dry friction conditions, showing excellent friction-reducing performance, which is attributed to the cooperation of the low adhesion coefficient of superhydrophobic surfaces, the ball-rolling effect of CeO2 nanoparticles, and the self-healing effect of the Ni-P micro/nanostructure. This work provides a novel strategy for designing a robust superhydrophobic coating with mechanical stability, corrosion protection, and friction reduction abilities to inspire new applications of superhydrophobic surfaces.

Synergistic inhibition effect of ultraviolet irradiation and benzalkonium chloride on the corrosion of 316L stainless steel caused by Aspergillus terreus.

Microbiologically influenced corrosion (MIC) is a key factor that damages engineering materials in marine environments. One of the major concerns in this regard is the corrosion protection of stainless steel (SS) caused against fungal attacks. This study investigated the effect of ultraviolet (UV) irradiation and benzalkonium chloride (BKC) on the corrosion of 316L stainless steel (316L SS) induced by marine Aspergillus terreus in 3.5 wt% NaCl solution. This was accomplished by employing microstructural characterisations and electrochemical analysis to analyse the synergistic inhibition behaviour of the two methods. The results indicated that while UV and BKC demonstrated individual abilities to suppress the biological activity of A. terreus, their inhibitory effects were not significant. The combination of UV light and BKC was found to cause a further decline in the biological activity of A. terreus. The analysis revealed that the combination of BKC and UV significantly decreased the sessile cell counts of A. terreus by more than three orders of magnitude. The fungal corrosion inhibition effect of individual application of UV light or BKC did not yield satisfactory results owing to the low intensity of UV and low concentration of BKC. Furthermore, the corrosion inhibition of UV and BKC occurred mainly during the early stages. The corrosion rate of the 316L SS declined rapidly when the combination of UV light and BKC were used, indicating that UV light and BKC exert a good synergistic inhibitory effect on the corrosion of the 316L SS caused by A. terreus. Therefore, the results suggest that the combination of UV light and BKC can be an effective approach to control the MIC of 316L SS in marine environments.

Corrosion inhibition of deposit-covered X80 pipeline steel in seawater containing Pseudomonas stutzeri.

Under-deposit corrosion, a typical corrosion type, is a major threat to the safe running of pipeline steel in marine environment. Under-deposit corrosion behaviour and mechanism still require further investigation, especially when there is participation of microorganisms. In this work, the inhibition of corrosion of deposit-covered X80 pipeline steel due to the presence of Pseudomonas stutzeri in seawater containing CO2 was investigated using weight loss, electrochemical measurements, a wire beam electrode and surface analysis. The results show that steel corrosion rates decline rapidly due to the covered deposit in the presence or absence P. stutzeri, but corrosion rates were slower in the presence of P. stutzeri. The highest corrosion rates were (0.365 ± 0.021) mm/y and (0.230 ± 0.001) mm/y in abiotic and biotic conditions, respectively. The corrosion inhibition efficiency of P. stutzeri was reduced in the presence of deposits, because the deposits led to a lowered biological activity. The galvanic current density between deposit-covered and bare specimens in seawater was weakened by P. stutzeri, leading to diminshed corrosion, especially pitting corrosion.

Microbiological corrosion acceleration of N80 steel in shale gas field produced water containing Citrobacter amalonaticus at 60 °C.

Microbiologically influenced corrosion (MIC) is one of typical reasons leading to a lot of damage of pipeline steels in the shale gas environments. MIC behavior and mechanism studies are important towards to steel protection. In this work, Citrobacter amalonaticus, a corrosive bacterium, was isolated from a shale gas well of China. And the corrosion behavior of N80 steel caused by C. amalonaticus was studied in simulated shale gas produced water at 60 °C making use of weight loss, surface analysis, electrochemical impedance spectroscopy (EIS), anodic potentiostatic polarization measurements, and potentiodynamic polarization curves. Results demonstrate that C. amalonaticus could accelerate the uniform and localized corrosion rates of N80 steel at 60 °C with values of (0.221 ± 0.016) and (0.557 ± 0.062) mm/y, respectively. Experimental results suggested that the adsorption of an organic inhibitor film on steel surface caused the corrosion rates of abiotic specimens going down. However, the existence of C. amalonaticus inhibited the adsorption of organic inhibitor film. The adhesion and biofilm formation of C. amalonaticus contributed to steel corrosion acceleration. The nucleation and growth of metastable pitting were enhanced by C. amalonaticus, thus causing a severe localized corrosion.

Stable Carbon Isotope Analysis of Hexachlorocyclohexanes by Liquid-Liquid Extraction Gas Chromatography Isotope Ratio Mass Spectrometry: Method Evaluation and Applications.

Compound specific isotope analysis (CSIA) and enantiomer specific isotope analysis (ESIA) are powerful tools for assessing the fate of hexachlorocyclohexanes (HCHs) in the environment. However, there is no systematic study on the CSIA and ESIA analysis test methods of the carbon isotopes of HCHs in water and soil environments, in particular the isotope fractionation in the pre-concentration process. We endeavored to test the compatibility of CSIA and ESIA with the liquid-liquid extraction method of HCHs in water. The results showed that there were negligible changes in the δ13C of HCHs after extraction, indicating that liquid-liquid extraction can be used as a pre-concentration method for the determination of δ13C of HCHs in water. The optimized method was validated and then applied to differentiate three HCHs from different manufacturers, to identify in situ degradation of HCHs of groundwater from a contaminated site and to resolve the carbon isotope fractionation occurring in the α-HCH oxidation by CaO2/Fe(II) Fenton system. The results showed that the same reagents from different manufacturers have different carbon isotope compositions, and different isomers from the same manufacturer also have different isotope compositions, showing useful evidence in identifying the source of HCHs. The more enriched δ13C in the down-gradient wells indicated that HCHs have undergone biodegradation or/and chemical reactions in the groundwater system of the site. Carbon isotopic enrichment factors (εC) of -1.90 ± 0.10‱ were obtained in the oxidation process. Hence, the method validated in this study has great potential as a method for identifying the degradation of HCHs in a water environment.

Early corrosion behavior of X80 pipeline steel in a simulated soil solution containing Desulfovibrio desulfuricans.

Microbiologically influenced corrosion (MIC) is one of the reasons leading to the service failure of pipelines buried in the soil. The effects of sulfate-reducing bacteria (SRB) on steel corrosion without organic carbon are not clear. In this work, SRB cells were enriched in the simulated soil solution, aiming to study SRB corrosion behavior without organic carbon source using weight loss, electrochemical measurements, and surface analysis. Effects of DO on SRB corrosion were also studied. Results indicate that SRB can survive after 14 days of incubation without organic carbon source, but approximately 90% SRB have died. SRB without organic carbon source could inhibit the uniform corrosion but enhance the pitting corrosion compared with the control specimen. The corrosion rate of the control calculated from weight loss is highest with a value of (0.081 ± 0.013) mm/y. The highest localized corrosion rate of (0.306 ± 0.006) mm/y is obtained with an initial SRB count of 107 cells/mL. The presence of DO influences the steel corrosion process. Oxygen corrosion dominates for the specimens in the absence and presence of SRB with an initial count of 103 cells/mL, while SRB MIC is primary for the specimens with high SRB counts.

Association between ADAM33 polymorphisms and asthma risk: a systematic review and meta-analysis.

BACKGROUND: Asthma is a common complex chronic, inflammatory polygenic disease with heterogeneous manifestations, affecting individuals of all age groups and posing an immense burden on healthcare resources. A number of studies have identified the association between a disintegrin and metalloprotease 33 (ADAM33) polymorphisms and asthma risk, however, the results still remain inconclusive. The objective of the present study was to identify the effect of ADAM33 variants in asthma susceptibility. METHODS: Eligible case-control studies published between January 2000 and June 2018 was searched and retrieved from online electronic databases. The odds ratio (OR) with its 95% confidence interval (CI) was employed to calculate the effect. RESULTS: A total of 63 case-control studies were finally screened out, including 13,280 asthma patients and 13,340 controls. Eleven SNPs of ADAM33 gene were identified. Our results detected a significant association between ADAM33 T2, Q1, F + 1 and AA genotype of T + 1 polymorphisms and asthma risk in total population. Subgroup analysis by ethnicities showed that the alleles and genotypes of T2, Q1 and F + 1 polymorphisms were associated with asthma susceptibility among Asian populations, while V4 polymorphism was associated with asthma among Caucasian populations. Subgroup analysis by ages showed that T2, F + 1 and ST + 4 polymorphisms were associated with childhood asthma, while Q1 and V4 polymorphisms were associated with asthma risk in adults. Subgroup analysis by asthma severity showed that only the G allele of ADAM33 T1 polymorphism was associated with the severity of asthma when compared with the controls. In addition, T2, Q1 and F + 1 polymorphisms of ADAM33 were significantly associated with increased the asthma risk in Chinese asthma patients. CONCLUSIONS: Our results found that T2, Q1 and F + 1 polymorphisms of ADAM33 gene might contribute to asthma risk. Future well-designed case-control studies with large population and more ethnicities are still needed to estimate the association.