Different Concentrations Of HCl Research Articles

Viability and life cycle assessment of Fuller's Earth as a low-cost adsorbent for zinc removal from aqueous solutions: Operating parameters, removal mechanisms and environmental impacts

Zinc is a heavy metal that has several health risks and must be removed from wastewater effluents before discharge to water bodies or reuse. Fuller's earth is a sedimentary clay and characterized by its low cost and availability. In this research, Fuller's earth (FE) was investigated as an adsorbent for the Zinc (Zn) removal from aqueous solutions to understand its performance, the mechanism of removal, and the potential environmental impacts. Life cycle assessment (LCA) was conducted using ReCiPe 2016 midpoint method. Zn adsorption studies on FE were conducted at various pH (2.5–9), temperatures (10°C, 25°C, and 40°C), initial concentrations of Zn (25, - 150 mg/L) and adsorbent doses of (0.25–4 g/ 50 ml). The Zn removal efficiency reached 99% at pH = 9 at an initial Zn concentration = 100 mg/L and the adsorbent dose = 0.25 g/ 50 ml. The experimental data fit into the Temkin isotherm, while kinetics were best expressed by pseudo-second order. The controlling step of the adsorption process was the film diffusion according to Boyd model. Thermodynamic experiments showed that adsorption is endothermic with an accompanying rise in randomness in the system. The adsorption capacity was 3.56 mg/g. Images by SEM confirmed the occurrence of adsorption. The desorption was successful at different concentrations of HCl. LCA results showed that the maximum negative and positive environmental impacts were associated with mineral resource scarcity (7.5*10–5 kg Cu eq) and human non-carcinogenic toxicity (−0.821 kg 1,4-DCB), respectively.

Acidity’s Impact on Yield, Morphological Structure, and Surface Functionalities of Polyaniline Synthesised via Oxidative Polymerisation

This research aimed to examine how varying the acidity levels during the chemical oxidative polymerisation (COP) of aniline affects the colour, yield, morphology, and surface functionalities of polyaniline (PANI). In the COP method, aniline monomer was first dissolved in hydrochloric acid (HCl) medium; the solution was then drop added with ammonium persulfate to initiate the polymerisation process. To answer the research objective, the medium acidity was manipulated using different concentrations of HCl (i.e., 0 M, 0.01 M, 0.1 M, 1 M and 10 M). The as-synthesised PANIs were then purified and characterised for their physicochemical properties. The findings revealed that reducing the medium pH from 2.35 (in distilled water) to 0.80 (in 10 M HCl) resulted in a colour change from light brownish to dark green, indicating the formation of emeraldine PANI. Furthermore, it was observed that the amount of PANI yield is inversely related to the medium pH. A decrease in medium pH from 2.35 to 0.80 remarkably increased the PANI yield by 3.2 times. Regarding morphological structure, higher medium acidity produced PANI with well-defined globule shapes, while lower HCl concentrations resulted in a mixed morphology including globules, tubes, and plate-like structures. In addition, it was found that the diameter of globule-like PANI has increased from ~266.67 nm to ~508.33 nm, when the HCl concentration was changed from 0 M to 10 M. Apparently, increasing the acidity of the COP medium promotes enlargement of the PANI size. Despite that, there is not much change in the surface functional groups of the formed PANI. Overall, this study offers insights into manipulating PANI properties by adjusting the medium acidity during the COP process. While the impacts of medium acidity on yield, morphology, and functionalities of PANI were revealed, further investigation is required to evaluate the effect on electrical properties.

The corrosion behavior of multicomponent porous MAX phase (Ti0.25Zr0.25Nb0.25Ta0.25)2AlC in hydrochloric acid

Multicomponent porous MAX phase (Ti0.25Zr0.25Nb0.25Ta0.25)2AlC was fabricated through powder metallurgy. The corrosion behavior in different concentrations of HCl was studied through electrochemical and immersion tests, and porous Ti, 316 L stainless steel, Ta2AlC and Ti2AlC were taken as the comparisons. The corroded samples' phase composition, microstructure, and passive film have been characterized using XRD, SEM, TEM, EDS, and other analyses, from which the corrosion mechanism is summarized. The results reveal that (Ti0.25Zr0.25Nb0.25Ta0.25)2AlC exhibits great corrosion resistance in 6 M HCl, with the lowest mass loss rate, corrosion current density, and the highest polarization resistance compared with other materials. The excellent performance of (Ti0.25Zr0.25Nb0.25Ta0.25)2AlC in HCl is considered to be the result of the combined action of four elements in the M position. This work is expected to provide ideas for the research in the corrosion field of MAX phases.

Migration and Conversion of Phosphorus in Hydrothermal Carbonization of Municipal Sludge with Hydrochloric Acid

Phosphate ore is a non-renewable resource, so finding a replacement is necessary. Municipal sludge has significant recycling potential because of its high phosphorus content and large discharge characteristics. The migration and transformation of phosphorus in municipal sludge treated with different concentrations of HCl were studied using the standards, measurements, and testing phosphorus extraction protocol from two aspects: phosphorus complexation and mineral form. After the hydrothermal carbonization treatment without HCl, the hydrochar retained 99.7% of phosphorus in the sludge, and the organophosphorus percentage was about 30%. In the hydrothermal carbonization treatment with the addition of 0.5–2.5% HCl, the phosphorus content in the hydrochar decreased gradually from 99.5% (46.18 mg/g) to 91.8% (64.17 mg/g) that of the original sludge, and the proportion of non-apatite inorganic phosphorus increased from 34% to 94%. Hydrochloric acid provides a low-pH environment and promotes the dissolution of calcium-related phosphorus precipitates and enhances the dehydration reaction. This study provides technical support for the recovery of phosphorus resources from municipal sludge.

Field-scale remediation of cadmium-contaminated farmland soil by Cichorium intybus L.: Planting density, repeated harvests, and safe use of its Cd-enriched biomass for protein feed

Chicory ( Cichorium intybus L.) is a perennial herb cultivated worldwide that has a wide range of industrial uses, produces large yields, and also has strong cadmium (Cd) accumulation ability. In field experiments in two farmlands with acidic soils, chicory potential to remove Cd from contaminated soils was evaluated at different planting densities and with repeated harvesting. To determine whether Cd-contaminated biomass could be used as a feed ingredient, efficacy of detoxification was measured with successive extractions using different concentrations of HCl. Biomass per plant decreased with an increase in planting density, and maximum biomass per plant in the two experimental fields was 17.11 and 13.89 g·plant −1 . However, the increase in plant numbers at high planting density increased total biomass per hectare, and maximum accumulated biomass at the highest planting density in the two experimental fields was 14,226 and 22,020 kg·ha −1 . The highest Cd concentrations were at the first harvest and were 27.68 and 19.27 mg·kg −1 Cd in the two fields, resulting in bioconcentration factors (BCFs) of 24.94 and 24.39, respectively. With the increase in number of harvests, aboveground Cd concentrations and BCFs decreased. Planting density had no consistent effect on aboveground Cd concentrations at the first two harvests, whereas Cd concentration decreased gradually with the increase in density at the last three harvests. Collectively, after five repeated harvests, total Cd uptake was highest at the highest planting density, reaching 237.55 g·ha −1 (field 2), and the corresponding phytoextraction efficiency was 11.57%. Two consecutive extractions with 0.5% HCl removed 96.30% of Cd in leaf meal, which reduced Cd concentration below the threshold for feed safety while retaining most of the crude protein, there remained a substantial crude protein content with 173.1 g·kg −1 . Thus, biomass of forage crops used for phytoremediation may also provide economic gain. • Phytoextraction efficiency of chicory was not inferior to that of hyperaccumulators. • High planting density and repeated harvesting promote Cd phytoextraction. • Two consecutive extractions with 0.5% HCl removes 96.30% of Cd in biomass. • Protein from leaf after Cd extraction can be a potential source of feed protein.

In Vitro and In Vivo Investigation on the Effectiveness of Alginate-Based Gastric Mucosal Protective Gel.

Objective To investigate the feasibility and effectiveness of an alginate-based gastric mucosal protective gel on the gastric ulcer. Methods (1) In the physical protection model, after GES-1 cell attachment add the gel to transwell chamber, add different concentrations of HCl to the gel. Absorbance was measured to assess proliferation and images of the cells migrating into the wound were taken; then the migration rate of the cells was quantified by comparing images. (2) In the gastric ulcer model, excise the gastric mucosal of SD rats; the gel and fixative were applied on the artificial ulcer immediately. Dissect rats after 10 days, and calculate the wound healing rate and analyzed histology changes. Results The effect of hydrochloric acid on cells in the lower layer was significantly reduced after the use of gastric mucosal protection gel. The protective gel had an isolation effect on different concentrations of acid. A number of GES-1 were significantly higher than those in the control group at 24 h to 72 h (P < 0.01). The migration was observed compared with the control group. The average healing rate of ulcer in the gel group was about 50%, and the control group was about 30%. Inflammation occurred in all wound regions after ten days. In the gel group, inflammatory infiltration depth was lower than that of the control, and part of SD rats' new muscle layer appeared without inflammatory infiltration. The connective tissue proliferation promoted tissue repair. In the control group, necrosis marginal, mucosal hyperplasia, marginal lymphocyte aggregation, and bleeding were observed. Conclusion This novel gel mainly has an isolating and shielding effect to prevent the wound from being exposed to gastric acid for a long time, and it can reduce the inflammatory reaction on the wounds to promote the healing of the ulcer. The gastric mucosal protective gel cannot only promote the speed of wound healing but also improve the quality of wound healing.

Acid Isolation Techniques for Silica isolation from Rice Husk and Determination of Its Physicochemical Properties

Previous research showed that rice husk has a high silica content so it becomes an alternative for processing rice waste. The acid leaching method is a technique to isolate silica by adding an acid solution. The research aim is to obtain the optimum silica yield and determine the chemical ash content of rice husks (rice IR-64,). Rice husks were first calcined at two various temperatures and times. The average yields obtained were 19.54% (500oC / 1 hr), 18.42% (500oC / 2 hrs), 25.03% (700oC /1 hr), and 22.4% (700oC/2 hrs). The physical appearance of ash was grains and white (700 oC/1hr), that were rinsed with 1 M HCl solution to remove impurities. Added 1 M NaOH was to form sodium silicate. The last step was to isolate silica using different concentrations of HCl and HNO3 (3 M, 2 M, and 1 M). The highest result was 99.87% of silica under HNO3 1 M solution. An infrared study supports that the isolated product was silica, with the presence of prominent peaks at 1102 cm-1 (stretching Si-O) and 471 cm-1 (bending Si-O). A unique peak at 958 cm-1 for Si-O-Ca present at the isolated silica using HCl 3 M, gives information on inosilicate type structure. X-ray diffraction analysis with QualX application showed that silica had cristobalite and wollastonite peaks, and the value of crystallinity index was about 63.91%.

Study on viscosification law of OAPB self-diverting acid by acid concentration and inorganic salt in coal

In order to improve the diverting performance of self-diverting acid in underground coal mine, the effects of different concentrations of HCl and inorganic salt on steady state viscosity, micellar length and entangling density of oleylamidopropyl betaine (OAPB) self-diverting acid were studied by rheological measurement, dynamic light scattering and infrared spectroscopy. The results show that with the increase of HCl concentration, the steady-state viscosity and micellar length of the self-diverting acid all show a regulation of “increase first and then decrease”, and reach the highest value of 9.42 pa.s and 63 nm at 5% HCl concentration. With the increase of inorganic salt content, the micellar length of self-diverting acid gradually increases. When the content of CaCl2 and FeCl3 in self-diverting acid is 20 g, the micellar length reaches 141 nm and 287 nm, respectively. The steady state viscosity shows a trend of “increase first and then decrease” with the increase of inorganic salt concentration. The highest values are 18.34 pa.s and 24.18 pa.s when the content of CaCl2 and FeCl3 are 15 g and 10 g, respectively. The relative contribution of acid concentration, CaCl2 and FeCl3 to the diverting performance of self-diverting acid is 38.96%, 75.85% and 100%, respectively. Finally, some targeted opinions were put forward according to the application conditions of self-diverting acid in coal mine.

THE DISMUTATION OF TOLUENE TO BENZENE AND XYLENES OVER H-MORDENITE ZEOLITE

Synthetic and natural mordenite zeolites were decationized (DC) and dealuminized (DA) with different concentrations of HCl, and the catalyst samples were subjected to X-ray phase analysis. Over the samples of the catalyst was carried out the dismutation of toluene to benzene and xylene in the temperature range of 300-380 °C. It has been established that H-mordenite catalysts in the range SiO2/Al2O3 = 17-20 are more active and selective in the reaction under study conditions. It has been shown that synthetic mordenite zeolite has a higher activity than natural mordenite zeolite.

Induction of cellulase production in Trichoderma reesei by a glucose-sophorose mixture as an inducer prepared using stevioside.

Sophorose is currently the most effective inducer of cellulase production by Trichoderma reesei; however, the use of byproduct sophorose from the stevioside acid hydrolysis process has not been developed. In this study, stevioside was hydrolysed with different concentrations of HCl to obtain isosteviol and a mixture of glucose and sophorose (MGS). Isosteviol showed good inhibitory effects on the growth of Aspergillus niger, Saccharomyces cerevisiae and Escherichia coli after separation. At the same time, MGS, as a byproduct, was evaluated for cellulase production to determine the feasibility of this approach. MGS was compared with common soluble inducers, such as lactose, cellobiose, and a mixture of glucose and β-disaccharide (MGD), and induced higher cellulase production than the other inducers. The cellulase activity induced by MGS was 1.64- and 5.26-fold higher than that induced by lactose and cellobiose, respectively, and was not significantly different from that induced by MGD. The crude enzyme using MGS as an inducer with commercial β-glucosidase was further tested by hydrolyzing NaOH-pretreated corn stover with 5% solid loading, and 33.4 g L−1 glucose was released with a glucose yield of 96.04%. The strategy developed in this work will be beneficial for reducing inducer production cost through a simple stevia glycoside hydrolysis reaction and will contribute to studies aimed at improving cellulase production using soluble inducers for easier operation in industrial-scale cellulase production.

Evaluation of Percentage corrosion inhibition efficiency of mild steel with derivatives of Oxazolone

Carbon Steel is one of the most widely used material in the transportation pipelines of Oil and Gas industry. However, they are prone to corrosion in acidic environment. As preventive measure various mitigation techniques are employed to bring a stag to its corrosion, one of which is the use of inhibitors. In the paper, the study of the inhibitive properties of two oxazolone derivatives have been reported. The compounds were synthesized at ease and in high yield. The corrosion studies were performed on carbon steel in three different concentrations of HCl (1N, 1.5N and 2.0N) solutions using weight loss coupon (gravimetric) method. 1N HCl solution was found to have the most effective inhibition property for the oxazolone derivatives. % Inhibition efficiency was found to be maximum with 100 ppm of inhibitor concentration. The results revealed oxazolone derivatives as promising effective corrosion inhibitors.

Selective separation of no carrier added Sc-47 from reactor irradiated Ca using zirconium vanadate gel for nuclear medical applications

The distribution coefficient values (Kd) of 47Sc(III) ions and 47Ca(II) ions have been determined using different concentrations of HCl or HNO3 solutions on the zirconium vanadate ion exchanger (ZrV) by batch technique and the results refer to the loading of 47Sc from 0.001M HNO3 or 0.01M HCl solution onto the ZrV matrix. Different ratios of acetone solution in different HCl concentrations solutions have been investigated for the suitable elution of the adsorbed Sc-47 on ZrV . Column technique was used for separation of Sc-47 from irradiated Ca target. The elution yield of 47Sc was obtained and found to be 88 ± 4.2% using 60 % acetone-0.2M HCl mixture solution as an eluent for 47Sc with an acceptable purity of radionuclidic and radiochemical (> 99.98±0.001and 99.9±0.09 %, respectively). The Ca2+ ions level in the eluted 47Sc solution was determined and confirmed its validity for the application in labeling of pharmaceutical compounds.

Visualizing thermal distribution through hydrogel confined ionic system

SummaryEffective thermal regulation has shown great impacts on tremendous aspects of our life and manufacture. However, the invisible nature of thermal field brings us inconvenience or even security hazard. Herein, we present a method to visualize thermal distribution with the aid of a thermally active material. An ionic liquid with lower critical solution temperature is mixed within hydrogel to demonstrate a hydrogel confined ionic system (HCIS). This particular system turns turbid as the temperature exceeds an established temperature threshold, which is adjustable through applying different concentrations of HCl or NaCl. The system offers straightforward images of the spatial thermal distribution whether simple or sophisticated, which is fully in line with computational simulation. The system is further demonstrated with great promise for the application in fire warning to lower the threat induced by electrical failure. The HCIS opens a practical avenue to visualize thermal distribution and improve our thermal regulation efficiency.

Computer Simulation of Electrochemical Studies of Al6061-Al2O3 Metal Matrix Composite: Effect of Heat Treatment

The aim of this work is to investigate the corrosion Studies of Aluminum Oxide (Al2O3) reinforced Aluminum 6061 metal matrix composites in Different Concentrations of HCl & NaCl solutions using weight loss method, Potentio-dynamic & EIS Technique. The composites have been prepared by Die- casting method. Aluminum 6061 / Al2O3 MMCs containing different sizes such as 40, 60, and 100 microns and 0, 4, and 8 weight percentages of Al2O3 particulates are casted. The corrosion characteristics of Aluminum 6061 / Al2O3 composite and the unreinforced alloy were experimentally assessed. The results indicated that corrosion rate of metal matrix composites is lower than that of matrix material Al 6061 under the corrosive atmosphere irrespective of exposure time and concentration of corrodent. Aluminum 6061 / Al2O3 composite become more corrosion resistant as the Al2O3 content is increased. This is because of the formation of stable oxide layer over the specimens. Scanning Electron Microscopy (SEM) shows the degree of attack of HCl & NaCl solution on the surface of the investigated material.

Abstract 4993: Label-free metabolic imaging of T cell response to the tumor microenvironment

Abstract Numerous factors including low pH, low glucose, and high lactic acid levels in tumors create an immunosuppressive tumor microenvironment. This immunosuppression is partially due to the metabolic requirements of T cell activation, which are difficult to meet in the tumor microenvironment. The goal of this study is to use label-free optical metabolic imaging (OMI) of the metabolic co-factors NAD(P)H and FAD in CD3-conjugated (activated) and control T cells to monitor metabolic changes of T cells within tumor micro environmental conditions. Single-cell measurements include the optical redox ratio (fluorescence intensity of NAD(P)H divided by FAD), which measures the oxidation-reduction state of the cell, and the mean fluorescence lifetimes (τm) of NAD(P)H and FAD, which measure enzyme-binding activity in the cell. Jurkat T cells were conjugated with CD3 antibody over a two-day incubation period to achieve activation. Control and CD3-conjugated cells were exposed to environments with increasing concentrations of lactic acid (0-20 mM), hydrochloric acid (HCl; pH 6.4- 7.4), and glucose deprivation to mimic the tumor microenvironment. OMI monitored metabolic changes on a single-cell level without confounding factors associated with cell surface marker labeling. Treatment with lactic acid resulted in a significant dose-dependent decrease in the FAD τm and optical redox ratio (p&amp;lt;0.005). Along with changes in metabolism, OMI also resolved impaired mobility of the T cells with increasing lactic acid concentrations. Lactic acid affects both pH and metabolism, so cells were separately exposed to different concentrations of HCl (pH 6.4 - pH 7.4) to monitor pH effects alone. In control cells, the optical redox ratio decreased with decreasing pH (p&amp;lt;0.005). Conversely, in the presence of CD3, the optical redox ratio increased with decreasing pH (p&amp;lt;0.005). CD3 conjugation in glucose deprived environments also resulted in increases in both optical redox ratio and NAD(P)H τm. Cellular viability assays indicate apoptosis only in the lowest pH environment (pH 6.4, p&amp;lt;0.005). These studies indicate that OMI is a promising label-free approach to investigate the effects of the tumor microenvironment on T cell metabolism, activation, and drug response. Citation Format: Ava VanDommelen, Amani Gillette, Manish S. Patankar, Melissa Skala. Label-free metabolic imaging of T cell response to the tumor microenvironment [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4993.

Preparation and characterization of highly surface area activated carbons followed type IV from marine red alga (Pterocladia capillacea) by zinc chloride activation

Activated carbon materials with high specific surface area have been produced from red alga Pterocladia capillacea using zinc chloride as an activating agent at impregnation ratio 0.5 and carbonization temperature that ranged from 500 to 900 °C. The effects of activation temperatures, activation holding time, and soaking in different concentrations of HCl on the specific surface area, pore morphology, and activated carbon yield were tested. A high specific surface area for activated carbon was achieved under the optimized conditions of activation temperature 600 °C, holding time 30 min, and 1 M HCl soaked. The obtained Brunauer–Emmett–Teller surface area, total pore volume, and mean pore diameter were 1202.70 m2/g, 0.5797 cm3/g, and 1.93 nm, respectively. The prepared activated carbon surface area analysis showed mainly type IV shape. Examination of the morphology of produced activated by scanning electron microscopy and transmission electron microscope revealed a honeycomb morphology and proved the presence of micropores. The adsorption properties toward iodine removal were 86.54% with 0.25 g, and the maximum capacity of methylene blue was 185.23 mg/g indicating a higher surface area and the presence of largely micro- and mesoporous structures.

Otimização da extração de compostos antioxidantes da guapeva (pouteria gardneriana radlk) através da análise de superfície de resposta

Uma vasta reserva natural de bioma do cerrado apresenta espécies frutíferas exóticas e pouco usadas, como a guapeva (Pouteria gardneriana Radlk),de grande valor biológico e nutritivo. Objetivo: otimizar o processo de extração de compostos antioxidantes do guapeva, com variáveis de ácido clorídrico em diferentes tempos de contato, usando o método de análise por superfície de resposta (ASR). Para extração de antioxidantes, use solventes acetona / metanol, HCl (0,2 mol / l, 0,3 mol / l, 0,4 mol / l 0,5 mol / l 0,6 mol / l) e tempo de contato em minutos (15, 30, 60, 90 e 105) utilizando 4 pontos centrais. Uma atividade antioxidante total do DPPH, foi determinada pelo método de Rufino et al., (2009) e determinação de fenólicos totais por Waterhouse (2002). Como leituras foram realizadas no espectrofotômetro a 515 nm. Utilize o software STATISTICA 8.0. para uma análise estatística da Análise de Variância, Análise de Regressão e Superfície de Resposta. Com um ASR constante, que uma faixa ótima de trabalho para otimização de extração de SRL na polpa foi uma concentração de HCl de 0,50 mol / L, não é relevante uma variável tempo de contato. Na casca, uma faixa ótima ficou acima de 0,50 mol / L de HCL, com tempo de contato inferior a 30 minutos. Já para fenólicos totais, como partes do fruto, obtenha uma faixa ótima de 0,40 mol / L de HCL em 60 minutos de contato. O experimento mostrou ser um método importante para otimizar e criar modelos preditivos, com acidificação por HCl variando ou tempo de contato. Já para fenólicos totais, como partes do fruto, obtenha uma faixa ótima de 0,40 mol / L de HCL em 60 minutos de contato. O experimento mostrou ser um método importante para otimizar e criar modelos preditivos, com acidificação por HCl variando ou tempo de contato. Já para fenólicos totais, como partes do fruto, obtenha uma faixa ótima de 0,40 mol / L de HCL em 60 minutos de contato. O experimento mostrou ser um método importante para otimizar e criar modelos preditivos, com acidificação por HCl variando ou tempo de contato.

Determination of Nano-Collagen Quality from Sea Cucumber Holothuria scabra

Sea cucumber contains high collagen protein and potential to be used in cosmetics and health. The aim of this study are to determine the quality of sea cucumber collagen using hydrochloric acid with different concentrations and the quality of nano-collagen using stirrer magnetic in different stirring times. This study was conducted by an experimental method using stages of the collagen extraction process and manufacture of nano-collagen. Process of extracting sea cucumber meat collagen using different concentrations of HCl (4%, 5%, and 6%), and process of making nano-collagen using 96% ethanol solution with different stirring times (one, two, three hours). Sea cucumber collagen with the 6% HCl extraction process obtained optimally results with collagen yield of 20.76%, white degree 73.97%, moisture level 10.99%, protein 98.3%, ash 0.86%, fat 0.59%, and collagen pH 3.92. The functional groups in collagen in accordance with the standard collagen compounds. The nano-collagen obtained was in the form of a creamy white powder (79.25% white degree), moisture 9.11%, ash 0.68%, fat 0.51%, protein 98.9%, pH 3.98, and particle size 285 nm.

Corrosion and Oxidation Behavior of a Fe-Al-Mn-C Duplex Alloy.

The low-density steels represent a topic of great interest within the scientific world because of the great demand from the steel market of increasingly lighter materials, also featured by an optimal mix of the mechanical properties. In this work, the corrosion and hot oxidation resistance of a Fe-15%Mn-9.5%Al-6.5%Ni-1%Cr-0.43%C were analyzed and related to the microstructural features. The material behavior was analyzed both in the as-cast and in the heat-treated state. For the corrosion test, the experimental plan was fulfilled using four different concentrations of HCl and four temperatures. In the case of hot oxidation resistance, the exposure time and the temperature effects were evaluated. The corrosion resistance in HCl was comparable to the stainless steel, and the iso-corrosion curves showed excellent resistance of the 1300 °C solution-treated material, especially at low temperatures, but it is also good at high temperatures due to the hot oxidation.

Evaluation of Shazab extract as eco-friendly green corrosion inhibitor for 420 stainless steel in hydrochloric acid

The effect of dried Shazab leaf extract (DSLE) as a green, eco-friendly corrosion inhibitor for 420 stainless steel (420 SS) in 0.5 M HCl was evaluated using electrochemical impedance spectroscopy (EIS) and potentiodynamic Tafel polarisation (PTP). Four types of isotherm models were applied to calculate the equilibrium adsorption constant (Kads), and based on the value of the correlation coefficient (R2), the Langmuir isotherm was found to be the best in this study. Moreover, based on the different thermodynamic parameters such as Gads, Hads, and Ea, the adsorption of DSLE on 420 SS was considered to be a physisorption process, and the adsorption was proved using FTIR and UV-vis spectroscopy. The degree of pitting that appeared on the metal surface was investigated in different concentrations of HCl and examined using microscopic photographs. Finally, the inhibition mechanism was studied.