Iron Research Articles

Recovery of Fe Element from Red Mud by Sodium Roasting and Alkaline Leaching

Recovery of Fe Element from Red Mud by Sodium Roasting and Alkaline Leaching

Mitigating Methylglyoxal-Induced Glycation Stress: The Protective Role of Iron, Copper, and Manganese Coordination Compounds in Saccharomyces cerevisiae.

Glycation-induced stress (G-iS) is a physiological phenomenon that leads to the formation of advanced glycation end-products (AGEs), triggering detrimental effects such as oxidative stress, inflammation, and damage to intracellular structures, tissues, and organs. This process is particularly relevant because it has been associated with various human pathologies, including cancer, neurodegenerative diseases, and diabetes. As therapeutic alternatives, coordination compounds with antioxidant activity show promising potential due to their versatility in attenuating oxidative stress and inflammation. Herein, we investigated the antioxidant-related protective potential of a series of complexes: [Cu(II)(BMPA)Cl2] (1), [Fe(III)(BMPA)Cl3] (2), and [Cl(BMPA)MnII-(μ-Cl)2-MnII(BMPA)-(μ-Cl)- MnII(BMPA)(Cl)2]•5H2O (3), all synthesized with the ligand bis-(2-pyridylmethyl)amine (BMPA) in Saccharomyces cerevisiae exposed to G-iS caused by methylglyoxal (MG). Pre- treatment with complexes 1 - 3 proved highly effective, increasing yeast tolerance to G-iS and attenuating mitochondrial dysfunction. This observed phenotype appears to result from a reduction in intracellular oxidation, lipid peroxidation levels, and glycation. Additionally, an increase in the activity of the antioxidant enzymes superoxide dismutase and catalase was observed following treatment with complexes 1 - 3. Notably, although complexes 1 - 3 provided significant protection against oxidative stress induced by H2O2 and menadione, their protective role was more effective against MG-induced glycation stress. Our results indicate that these complexes possess both antiglycation and antioxidant properties, warranting further investigation as potential interventions for mitigating glycation and oxidative stress-related pathologies.

Recovery of Titanium from Red Mud Using Carbothermic Reduction and High Pressure Leaching of the Slag in an Autoclave

Red mud is a by-product of alumina production, which is largely stored in landfills that can endanger the environment. Red mud, or bauxite residue, is a mixture of inorganic compounds of iron, aluminum, sodium, titanium, calcium and silicon mostly, as well as a large number of rare earth elements in small quantities. Although certain methods of using red mud already exist, none of them have been widely implemented on a large scale. This paper proposes a combination of two methods for the utilization of red mud, first by carbothermic reduction and then, by leaching under high pressure in an autoclave in order to extract useful components from it with a focus on titanium. In the first part of the work, the red mud was reduced with carbon at 1600 °C in an electric arc furnace, with the aim of removing as much iron as possible using magnetic separation. After separation, the slag is leached in an autoclave at different parameters in order to obtain the highest possible yield of titanium, aiming for the formation of titanium oxysulfate and avoiding silica gel formation. A maximal leaching efficiency of titanium of 95% was reached at 150 °C using 5 mol/L sulfuric acid with 9 bar oxygen in 2 h. We found that high-pressure conditions enabled avoiding the formation of silica gel during leaching of the slag using 5 mol/L sulfuric acid, which is a big problem at atmospheric pressure. Previously silica gel formation was prevented using the dry digestion process with 12 mol/L sulfuric acid under atmospheric pressure.

Hair and Blood Trace Elements (Cadmium, Zinc, Chrome, Lead, Iron and Copper) Biomonitoring in the Athletic Horse: The Potential Role of Haematological Parameters as Biomarkers

The aim of the present study was the evaluation of the bioaccumulation of cadmium (Cd), Zinc (Zn), Chrome (Cr), Lead (Pb), Iron (Fe) and Copper (Cu), in the blood, serum, tail and mane of horses from the industrialized area of Milazzo (Messina, Sicily), to understand the relationships between haematological parameters: Red Blood Cells (RBCs), White Blood Cells (WBCs), Haemoglobin (Hb), Haematocrit (Hct), Mean Corpuscular Volume (MCV), Mean Corpuscular Haemoglobin (MCH), Mean Corpuscular Haemoglobin Concentration (MCHC), Platelets (PLTs) and the concentrations of trace elements. Blood and hair samples from 20 healthy Italian Saddle horses and water, hay and concentrates samples were obtained to determine the haemogram and mineral concentration using a Thermo Scientific iCAP-Q ICP-MS spectrometer. Descriptive analysis showed a higher concentration of Zn, Cr, Pb, Fe, and Cu in the blood and a higher concentration of Cd in the tail than other substrates. A positive correlation was found for Cr (p < 0.0001) and Zn (p < 0.01) between blood and serum substrates, for Zn (p < 0.001) between mane and tail and for Pb (p < 0.01) between blood and mane, while a negative correlation was observed for Cr (p < 0.01) between blood and tail. Results showed a close relationship between the bioaccumulation of certain trace elements in biological substrates and haematological parameters, which represent useful biomarkers suggesting further studies, given the role of haematological parameters in athletic horses.

Local Crystallographic Texture of Alpha Quartz in Silicified Wood (Late Triassic, Madagascar)

Compositional and anatomical studies of silicified wood have been carried out extensively all around the world. The classification of silicified wood as such deals with all the forms and phases of silica that come under its umbrella. One such class of silicified wood is fossil wood with a high content of quartz, and there are very limited mentions of this category of fossilized wood. The examined wood belongs to gymnosperm and comes from the Upper Triassic deposits of Madagascar. A fresh approach to such samples is adopted by studying the crystallographic texture of the fossil wood to understand the orientation of the crystals replacing the organic matter within the sample. This work focuses on crystallographic texture analysis based on pole figures measured by X-ray diffraction. The intensity of the pole density maxima on the pole figures measured on the heartwood surface part of the analyzed samples is higher than that on the sapwood. This affirms that the crystallographic texture is sharper at the heartwood part compared to the sapwood. The X-ray tomography study, conducted to understand the difference in mineral distribution within the sample, reveals a greater X-ray absorbing phase on the sapwood of both samples. This is due to the concentration of iron compounds, which both replace the remaining conductive structures of the wood and fill the cavities inside them. We believe that this research on silicified wood is the first research work that encompasses crystallographic texture analysis with pole figures, an approach not previously undertaken in similar studies. We hope that our research can be useful in understanding the processes of replacement of organic matter by minerals.

Wear properties of Al6061/SiC + B4C + TiC hybrid composites produced by vacuum infiltration method

Abstract In the study, hybrid metal matrix composite (HMMC) structures were produced by vacuum infiltration method (VIM) using Al6061 alloy and varying amounts of SiC, B4C, and TiC ceramic powder pairs. Age-hardening processes were applied to these HMMCs. After heat treatment, wear behavior was examined under different loads using the pin-on-disc test method. All Al6061 hybrid composites exhibited better wear performance than unreinforced Al6061. In the wear tests of composite samples, the lowest volume loss and therefore the highest wear resistance were obtained in Al6061 3 wt.% B4C + SiC composites under 5 N force. The lowest wear resistance due to the highest volume loss was determined in Al6061/1 wt.% TiC + B4C composites under 15 N force. Abrasive and adhesive wear characteristics were observed in field emission scanning electron microscopy(FESEM) images of worn surfaces. Additionally, wear debris, smearing, and deep grove formations were determined on the surface. In the EDS analysis performed on the worn surface, O and Fe elements were found in addition to the elements that are likely to be in the structure (such as Al, B, C, Ti, Si, and Mg). The wear tests caused the formation of oxide layers on the sample surfaces.

Engineered nanoplatform mediated gas therapy enhanced ferroptosis for tumor therapy in vivo

The high glutathione (GSH) environment poses a significant challenge for inducing ferroptosis in tumor cells, necessitating the development of nanoplatforms that can deplete intracellular GSH. In this study, we developed an engineered nanoplatform (MIL-100@Era/L-Arg-HA) that enhances ferroptosis through gas therapy. First, we confirmed that the Fe element in the nanoplatform undergoes valence changes under the influence of high GSH and H2O2 in tumor cells. Meanwhile, L-Arg generates NO gas in the presence of intracellular H2O2, which reacts with GSH. Additionally, Erastin depletes GSH by inhibiting the cystine/glutamate antiporter system, reducing cystine uptake and impairing GPX4, while also increasing intracellular H2O2 levels by activating NOX4 protein expression. Through these combined GSH-depletion mechanisms, we demonstrated that MIL-100@Era/L-Arg-HA effectively depletes GSH levels, disrupts GPX4 function, and increases intracellular lipid ROS levels in vitro. Furthermore, this nanoplatform significantly inhibited tumor cell growth and extended the survival time of tumor-bearing mice in vivo. This engineered nanoplatform, which enhances ferroptosis through gas therapy, shows significant promise for ferroptosis-based cancer therapy and offers potential strategies for clinical tumor treatment.

Microstructure, Corrosion Resistance and Tensile Properties of Modified Al-0.7Mn Alloy

A modified alloy (Al-0.7Mn) was designed and fabricated with an increased Mn content up to 0.7wt.% and a controlled Fe content of 0.1wt.% and compared with the conventional Al3102 (Al-0.3Mn) alloy using the air-slip casting process. Both alloys were homogenized at 510°C for 10 hours and then air-cooled. The microstructure, corrosion resistance, and mechanical properties of these materials were investigated. In the modified Al-0.7Mn alloy, the Mn/Fe ratios were found to be higher in both the α-Al matrix and the intermetallic compound of Al<sub>6</sub>(Mn, Fe) compared to those of the Al3102 alloy. Additionally, the size and volume fraction of the Al<sub>6</sub>(Mn, Fe) phase were relatively larger and higher in the modified Al-0.7Mn alloy, while the grain size of the α-Al matrix was significantly smaller. The galvanic corrosion test results indicated that the corrosion potential (E<sub>corr</sub>) of the conventional Al3102 alloy was higher than that of the modified Al-0.7Mn alloy (Al-0.7Mn: -682.1mV, Al3102: -652.4mV). In contrast, the corrosion current (I<sub>corr</sub>) and corrosion rate were measured to be 49.86 μA and 0.541 mm/year for the Al-0.7Mn alloy, and 53.91 μA and 0.585 mm/year for the Al3102 alloy, respectively. Thus, it was confirmed that the corrosion rate of the Al-0.7Mn alloy was slower compared to the conventional alloy, indicating better corrosion resistance. Room temperature tensile results showed that the tensile strengths of the modified and conventional alloys were 92.55 MPa and 78.39 MPa, respectively, demonstrating that the modified Al-0.7Mn alloy achieved higher strength without a significant decrease in ductility. This improvement is attributed to the higher Mn/Fe wt.% ratio in the Al<sub>6</sub>(Mn, Fe) phase of the modified Al-0.7Mn alloy, which can reduce the detrimental effect of Fe element and enhance the corrosion resistance. Additionally, the larger size and higher volume fraction of Al<sub>6</sub>(Mn, Fe) in the modified alloy, along with the smaller grain size, may contribute to the higher tensile strength. Based on these results, the corrosion mechanisms and deformation behavior of the modified Al-0.7Mn alloy were also discussed.

ADHESION OF STEEL CORD WITH CU-ZN-FE COATING IN COBALT-FREE COMPOUND

ABSTRACT The adhesion of steel cord with Cu-Zn-Fe coating in a cobalt-free skim compound in hot and humid conditions was investigated and compared with the current adhesion system consisting of brass-coated steel cord in cobalt-containing skim compound. Standard adhesion tests showed that the adhesion retention of Cu-Zn-Fe–coated cord in a cobalt-free compound was significantly improved with respect to current adhesion system. Advanced characterization of adhesion interphases by field emission scanning electron microscopic examination of cord-compound cross sections and X-ray photoelectron spectroscopy depth profiling revealed that incorporating the Fe element into the coating significantly reduces the dezincification of the metallic coating and prevented excessive growth of adhesion interphase. This results in high adhesion retention of Cu-Zn-Fe–coated steel cord in cobalt-free compound. Furthermore, a hypothesis was proposed to explain how the Fe element decreases the dezincification of the metallic coating in hot and humid conditions. Because Cu-Zn-Fe–coated cord eliminates the need for cobalt salts in the compound, using this cord in cobalt-free compounds generates a completely cobalt-free solution to tackle adhesion degradation and health risks of the current adhesion system.

Analysis of Oxide Layer Formation During Oxidation of AISI 4140 Steel at 1000 °C over Exposure Time

The high-temperature shaping of steels is accompanied by the formation of surface scales composed of oxide layers. However, the oxidation kinetics and morphology of these scales remain poorly understood. This study analyses the formation of oxide layers on AISI 4140 steel at varying oxidation times (20, 40 and 60 min) at 1000 °C. The analysis revealed the presence of hematite, magnetite, and transformed wustite in the oxide layers, along with clusters of alloying element oxides, predominantly chromium and iron oxide (FeCr2O4). There was a direct correlation between the duration of the oxidation process and the thickness of the scale and the number of defects observed in the material. The coating layer of alloying element oxides demonstrated insufficient adhesion to the steel substrate. Similarly, the oxides of alloying elements within this layer exhibited low cohesion among themselves. The alloying elements are present in all oxide layers, but in greater quantity in the layer in contact with the steel substrate, where a reduction in their concentrations was observed over time. This indicates that the alloying elements tend to disperse as the thickness of the alloying element oxide layer increases over time.

A Study of the Features of Coating Deposition on a Carbide Substrate Using Preliminary Etching with Glow-Discharge Plasma

The properties of coatings obtained using two surface preparation methods were compared: heating and etching by ion bombardment with plasma generation by arc evaporators and heating and etching by a glow discharge. A Ti-TiN-(Ti,Cr,Al)N coating was deposited. The use of a glow discharge provides better resistance of the coating to destruction during the scratch test and wear resistance of metal-cutting tools when turning steel. As the cutting speed increases, the advantage in wear resistance of the coating deposited using a glow discharge increases. During the process of heating and etching by ion bombardment with metal ions, a nanolayer rich in cobalt and tooling elements (iron, molybdenum) is formed in the area of the interface of the coating and the carbide substrate. When heated and etched by a glow discharge, such a layer does not form. When using both methods, there is identical diffusion of tungsten into the coating and diffusion of chromium and possibly titanium into the substrate. Thus, the glow-discharge heating and etching method can be effectively used in the process of PVD coating deposition.

Nano-priming of Vigna radiata seeds with opuntia stricta-derived γFe2O3 nanoparticles

The experimental investigation aimed to enhance sustainable and biocompatible nano-agriculture by examining the possible effects of biosynthesized nanoparticles (γFe2O3 NPs) on seed growth and growth parameters of Vigna radiata. The outcomes of various characterization procedures such as FTIR, XRD, UV, and Fe-SEM were used to determine the successful generation of γFe2O3 NPs (nanoparticles), which were capped with multiple phytoconstituents contained in the Opuntia stricta extract. γFe2O3 NPs were synthesised, as evidenced by the peak's presence, having a mean crystallite size of 13.9 nm, and were successfully detected using X-ray diffraction (XRD). Crucial Energy Dispersive X-ray Spectroscopy (EDS) testing also yielded unambiguous proof of the element iron's presence. Raman spectroscopy was used to confirm the synthesis of pure maghemite nanoparticles. Wide areas around 350, 500, 670, and 1330 cm-1 values verify the creation of pure maghemite. TGA analysis was performed to check the stability of nanoparticles in which the residual weight was found to be 87.62%. TEM images confirm the spherical shape, and the mean size of the nanoparticles was found to be 12.28 nm. Through a number of tests, the analysis showed that the nanoparticles have a strong antioxidant capacity. This experiment aimed to determine how biogenic γFe2O3 Nanoparticles affected Vigna radiata seed germination. Measurements of shoot and root lengths, seed vigour index, germination rates, mean daily germination, and peak value (PV) were all included of the assessment. There was a total of four distinct γFe2O3 NPs concentrations examined (25, 50, 75, and 100 μg/mL). The penetration of the γFe2O3 NPs affects the germination and growth of the Vigna radiata seeds. When compared to untreated seeds, the germination index values for Vigna radiata seeds that underwent effective treatment with γFe2O3 NPs significantly improved.

Nano-Fe3O4/FeCO3 modified red soil-based biofilter for simultaneous removal of nitrate, phosphate and heavy metals: Optimization, microbial community and possible mechanism

The pollution of nitrogen, phosphorus and heavy metals in surface water is becoming more and more serious, affecting the safety of water quality. In this study, three biofilters were constructed using iron-modified red soil-based filler carriers (RSC, nano-Fe3O4@RSC, and FeCO3@RSC) combined with strain Zoogloea sp. ZP7 to simultaneously remove nitrate (NO3--N), phosphate (PO43--P), copper (Cu2+), and zinc (Zn2+). The long-term operation results showed that the three groups of biofilters could remove 85.0, 90.0, and 89.8% of NO3--N, respectively. Furthermore, the addition of iron compounds enhanced the removal of PO43--P and the resistance to the stress of Cu2+ and Zn2+ in the biofilter. The analysis illustrated that iron modification improved the redox activity and zeta potential of RSC surface. The secondary structure analysis of the protein showed that the microbial secreted proteins were more compact on the surface of the iron-modified RSC, which facilitated the formation of biofilm on the carrier surface. In addition, the iron-modified RSC-based biofilter also showed excellent NO3--N and PO43--P removal efficiency in the treatment of actual surface water. The microbial community analysis results showed that Zoogloea became the dominant species in the biofilter. On the other hand, the presence of iron-reducing bacteria and the expression iron cycle-related genes may contribute to denitrification under low nutrient conditions.

Application of Fenton's Reaction for Removal of Organic Matter from Groundwater.

In this study, the effectiveness of the Fenton process in removing natural organic matter (NOM) from groundwater was investigated. The subject of this study is groundwater characterised by increased content of NOM and iron (II) compounds. In laboratory-scale studies, the influence of the ratio of concentrations of Fe(II) ions, which are naturally occurring in groundwater, to hydrogen peroxide (H2O2) as well as oxidation time and pH on the removal efficiency of organic matter was determined. Indicators such as total organic carbon (TOC), dissolved organic carbon (DOC), UV absorbance at 254 nm (UV254), UV absorbance at 272 nm (UV272), and specific UV absorbance (SUVA254) were used to quantitatively and qualitatively assess the organic substances present in the raw water and after oxidation with Fenton's reagent. Analysis of the results obtained showed that the highest removal efficiency of organic substances in the deep oxidation process using the Fenton reaction was obtained for a concentration ratio of Fe(II) to H2O2 = 1:5. Acidification of the water samples to a pH of about 4 and extending the oxidation time to 30 min significantly increased the removal efficiency of organic substances including mainly dissolved organic substances containing aromatic rings. The organic substances containing aromatic rings, determined at a wavelength of 254 nm, were degraded to other organic intermediates.

Serum Levels of Trace Elements (Magnesium, Iron, Zinc, Selenium, and Strontium) are Differentially Associated with Surrogate Markers of Cardiovascular Disease Risk in Patients with Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is associated with an increased risk of cardiovascular disease (CVD), which is attributed to inflammatory processes that accelerate atherosclerosis. Therefore, the exploration of novel biomarkers association is needed. This study investigated the associations between serum trace elements (Fe, Zn, Mg, Se, and Sr) and surrogate markers of CVD in 219 RA patients and compared them with those with metabolic disorders (MetD, n = 82) and control participants (n = 64). Surrogate markers included carotid intima-media thickness (cIMT), carotid plaque presence (cPP), pulse wave velocity (PWV), distensibility (DIST), and the augmentation index (AIx). RA patients displayed heightened inflammatory markers, increased arterial stiffness and thickness, and elevated CV risk factors. Compared with those in control participants, Se levels in RA patients were lower, regardless of sex. Women and men with RA had lower Sr and Mg levels than those with MetD, respectively. Backward regression models demonstrated inverse associations of Sr and Zn with cIMT in men with RA and those with MetD, respectively. In RA patients, Sr and Zn were predictors of an increased AIx, with sex-specific associations. Increased Fe levels were associated with an increased AIx in women with MetD. Fe and Zn were predictors of increased cIMT in control participants, with sex-specific associations. Serum trace elements are independently associated with surrogate markers of CVD in patients with RA, highlighting their potential role in CV risk assessment. Prospective studies are essential for validating these associations and establishing optimal trace element levels for managing CVD risk in patients with RA.

Upcycling of steel slag to activate persulfate for the degradation of chlortetracycline hydrochloride: Performance and mechanism

ABSTRACT Steel slag has great potential as an Fe-based heterogeneous Fenton-like catalyst because of its high iron content and low cost. However, the iron compounds are often encapsulated by calcium or silicon compounds in the steel slag. Herein, steel slag powder was acid-modified with salicylic acid to remove some Ca–Si compounds and thus expose more iron active sites. The results showed that the calcium content significantly decreased from 36.33 to 20.54% after modification, and more transition metals of Fe and Mn with catalytic activities were exposed simultaneously. During the activation of peroxysulphate, the conversion of Fe(Ⅱ) to Fe(Ⅲ) occurs and large amounts of •OH and 1O2 are produced as the main reactive oxygen species. The removal rates of CTC and TOC are 93.42 and 46.05%, respectively, and a degradation process may also be inhibited by CO32−, H2PO4−, and humic acid (HA). The degradation pathways of CTC mainly include both dechlorination and demethylation. In addition, salicylic acid-modified steel slag shows good repeated usability, and its removal ability is maintained at higher than 80% after four times of recycling. This study provides a new idea for designing an efficient and cheap catalyst to treat organic wastewater.

Selective direct deoxygenation of m-cresol on Heusler alloy catalysts via precise control of electronic structure: An integrated density function theory and microkinetic modeling study

Directional designing a catalyst with high direct deoxygenation selectivity of Phenols during hydrodeoxygenation (HDO), remains a formidable challenge in cost-effectively converting biomass to bio-fuel and chemicals. Herein, we evaluated for the first time the catalytic performance of Heusler alloy surfaces for HDO process of m-cresol at the atomic scale. The direct deoxygenation (DDO) route of m-cresol on the Co2FeGa (110) surface at 573.15 K exhibited relatively low kinetic (1.20 eV) and thermodynamic (−0.04 eV) barriers, leading to high selectivity (near 100 %) for toluene production. The degree of rate control (DRC) analysis revealed that direct dehydroxylation constituted the rate-limiting elementary reaction. Additionally, by tailoring the Ga and Ge ratio on the Co2FeGa1-xGex (110) surface, an almost linear relationship (R2 = 0.95) was discovered between activation energy of C-OH and the d-band center energy of the Fe element in the unit cell. Both the activation energy of C-OH and d-band center energy of the Fe decreased with increasing Ge/Ga substitution ratio. This research unveils for the first time the catalytic performance of Heusler alloy for the selective direct deoxygenation of m-cresol, but also suggest the possibility tuning d-band center of Heusler alloys to precisely tailor the selectivity of DDO during HDO process.

Mineralogical Characteristics and Their Usability as Gemstones of Jaspers in Altered Metavolcanics Belonging to the Topçam Formation, Tokat, Turkiye

The jaspers located in the Topçam Mountain, Tepeyurt region (Tokat, Turkey), were formed at green-colored metavolcanic levels within Permian–Triassic schists. The sizes of the jaspers generally vary from a few cm to 1.5 m, and their colors vary from grayish–reddish–brownish/blackish tones depending on the increase in the amount of Fe and Mn elements they contain. According to thin section and X-ray Diffraction (XRD) analysis examinations, it was determined that the composition of jaspers includes quartz, hematite, calcite, and pyrite. As stated by the Wavelength Dispersive X-ray Fluorescence (WDXRF) analysis results, it was observed that the amount of SiO2 in jaspers was 82.5%, and the amount of Fe2O3 was 15.5%. According to Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) analysis results, Fe and Mn impurities, which are thought to cause the color of jaspers, as well as the amount of Fe (6975.5 ppm–46,893.9 ppm–96,431.1 ppm) and the amount of Mn (935.9–3219.7–6040.4 ppm), caused a darkening in color tones (grayish–reddish–brownish/blackish). Cabochon cutting applications were made of jaspers taken from the study area. As a result of these applications, it has been determined that jaspers can be used as gemstones due to their properties, such as their workability, polish retention, and color and light reflection.

Iron Age Fur Skin Tanning – a Sustainable Practice?

Tanning is among the most polluting industries in the world. Industrial-produced hides and skins are fully or pre-tanned with highly polluting chromium salts. The purpose of the study was to gain new knowledge about Iron Age tanning methods to clarify whether sustainable tanning methods can be developed based on this. Fur skin capes, uncovered in Jutland bogs, from Baunsø Mose (20-220 AD), Borremose I (365-116 BC), Huldremose I (1-174 AD) and Vindum Mose (386-203 BC) were analysed by Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Gas Chromatography-Mass Spectrometry (GC-MS) and morphological assessment of the skin fibres to identify tanning substances and material condition. Analyses were supplemented with source studies of previous visual assessment of the capes and measured shrinkage temperature of leather and skins excavated from bogs. Our results show that only the samples from Baunsø Mose, Borremose I and Huldremose I contain vegetable tannins. Furthermore, Baunsø Mose contains cow fat and Borremose I, Huldremose I and Vindum sheep fat. All contain indications of the presence of aluminum and iron compounds. The samples are decomposed to varying extents. Remnants from conservation were detected on Huldremose I, Baunsø Mose and Vindum Mose.

Synergistic inhibition effect of Chlorella sp. and benzotriazole on the corrosion of Q235 carbon steel in alkaline artificial seawater

The interaction of microalgae on the reinforced concrete with corrosion inhibitor is not well understood. Moreover, the inhibition role of microalgae on corrosion has been reported in recent years. In this study, the corrosion inhibition behavior of Q235 carbon steel (CS) due to the presence of Chlorella sp. and benzotriazole (BTA) in alkaline artificial seawater was investigated by means of weight loss, electrochemical measurements including open circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarization curves, and surface analysis including scanning electron microscopy, energy dispersion spectrometer, and X-ray photoelectron spectroscopy. The results of reduced corrosion rates in the algae-BTA system demonstrated that Chlorella sp. could facilitate the corrosion inhibition efficiency of BTA on the CS specimens. Moreover, polarization measurement showed the algae-BTA system had a mixed-type corrosion inhibition effect. The mechanisms of inhibition were proposed to be the precipitation of iron complexes such as Fe-BTA-EPS and Fe-BTA and iron compounds on the steel surface in the presence of the microalgae and BTA–. This study highlights the application of CS corrosion control by combining biological and chemical approaches that can be used for future research and practice, rather than purely chemical approaches.