Fructan from Polygonatum cyrtonema Hua as an eco-friendly corrosion inhibitor for mild steel in HCl media

Research progress on chitosan and its derivatives in the fields of corrosion inhibition and antimicrobial activity

Chitosan stands out as the only known polysaccharide of its kind, second only to cellulose. As the second-largest biopolymer globally, chitosan and its derivatives are extensively used in diverse areas such as metal anti-corrosion prevention, food production, and medical fields. Its benefits include environmental friendliness, non-toxicity, cost-effectiveness, and biodegradability. Notably, the use of chitosan and its derivatives has gained substantial attention and has been extensively researched in the fields of metal anti-corrosion prevention and antibacterial applications. By means of chemical modification or synergistic action, the inherent limitations of chitosan can be substantially improved, thereby enhancing its biological and physicochemical properties to meet a wider range of applications and more demanding application requirements. This article offers a comprehensive review of chitosan and its modified composite materials, focusing on the enhancement of their anticorrosion and antibacterial properties, as well as the mechanisms by which they serve as anticorrosion and antibacterial agents. Additionally, it summarizes the synthesis routes of various modification methods of chitosan and their applications in different fields, aiming to contribute to the interdisciplinary development and potential applications of chitosan in various areas.

Corrosion inhibition activity of a natural polysaccharide from Dysosma versipellis using tailor-made deep eutectic solvents

In this work, a total of 18 types of choline chloride, betaine, and L-proline-based deep eutectic solvents (DESs) were synthesized to determine the extraction yield of a natural polysaccharide (PSA) from Dysosma versipellis using an ultrasound-assisted extraction method. Results indicate that the choline-oxalic acid-based DES has the best extraction yield for PSA due to the proper physical-chemical properties between PSA and DES. To evaluate the optimal extraction conditions, a response surface methodology was carried out. Under the optimal conditions, the extraction yield of PSA reaches 10.37 % (± 0.03 %), higher than the conventional extraction methods. Findings from FT-IR and NMR suggest that the extracted PSA belongs to a neutral polysaccharide with (1 → 6)-linked α-d-glucopyranose in the main chain. Interestingly, results from various electrochemical measurements show the extracted PSA exhibits excellent corrosion inhibition performance for mild steel (MS) in a 0.5 M HCl solution, with 90.8 % of maximum corrosion inhibition efficiency at 210 mg L-1. SEM and XPS measurements reveal the formation of a protective layer on the MS surface. The adsorption behaviour of extracted PSA well obeys the Langmuir adsorption isotherm containing the chemisorption and physisorption. Additionally, theoretical calculations validate the experimental findings.

Synthesis of phytic acid-modified chitosan and the research of the corrosion inhibition and antibacterial properties

In this study, chitosan (CS) and phytic acid (PA) were employed as raw materials to synthesize a range of chitosan-phytic acid complexes (CP) with different ratios (CS:PA = 12:1, 9:1, 6:1, 3:1, 1:1). The structures and elemental compositions of the compounds were characterized using Fourier-Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy (SEM-EDS). The thermal stability of the synthesized materials was analyzed using a Thermogravimetric Analyzer (TG). Electrochemical testing was conducted to explore the corrosion inhibition effect of the modified inhibitors with varying ratios on Q235 steel in 3.5 wt% NaCl solution. Additionally, Scanning Electron Microscopy (SEM) was utilized to investigate the surface morphology of the immersed samples. When the CS:PA ratio was 3:1, CP exhibited an impressive corrosion inhibition efficiency of 94.9 %. Furthermore, the antimicrobial properties of CP were evaluated using the colony plate counting method. At a CS:PA ratio of 1:1, CP demonstrated the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) at 0.1250 % and 0.5000 %, respectively. This research introduces a novel green corrosion inhibitor capable of simultaneously reducing the electrochemical corrosion of Q235 while inhibiting biocorrosion, avoiding the antagonistic effects arising from the simultaneous use of biocides and corrosion inhibitors in the system.

Chitosan/tannic acid phenamine networks-hollow mesoporous silica capsules with reversible pH response: Controlled-releasing amino acid derivatives as "green" corrosion inhibitor

A novel amino acid derivative (SM) was synthesized through Schiff base reaction between syringaldehyde (SA) and methionine (MTI), and loaded to obtain a reversible pH-responsive releasing corrosion inhibitor silica capsule (CS/TA@SM@HMSs) with chitosan/tannic acid phenamine networks on the surface. The corrosion inhibition effect of SM and CS/TA@SM@HMSs on Q235 was studied using electrochemical techniques and surface analysis. The results showed the maximum inhibition efficiency of SM reached to 93.2 % at 200ppm by immersing Q235 in 3.5 wt% NaCl solution. The theoretically calculated electron parameter (the energy gap ΔE = 4.492 eV) indicated that SM molecules were more susceptible to electron transfer with iron surfaces therefore allowing better adsorption on carbon steel surfaces to prevent corrosion. Meanwhile, UV-visible measurements showed that the chitosan/tannic acid phenamine network on the capsule surface responded to changes in pH. The reversible pH-responsive corrosion inhibitor capsule can be switched on and off several times to release SM, demonstrating reversible release and efficient corrosion protection. This study proposes a novel class of "green" amino acid derivative corrosion inhibitors, and establishes a controllable, efficient and reversible pH-responsive release system. A new approach is provided to stimulating the release of corrosion inhibitors in response to long-term corrosion protection of metals.

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.

Inhibition performance of halogen-substituted benzaldehyde thiosemicarbazones as corrosion inhibitors for mild steel in hydrochloric acid solution

Halogen-substituted benzaldehyde thiosemicarbazone derivatives were synthesized and their inhibition performance for mild steel in hydrochloric acid solution were investigated systematically using weight loss measurements, electrochemical techniques, scanning electron microscopy and quantum chemical calculations. Results of weight loss measurements indicated that all these compounds exhibited excellent inhibition performance and the inhibition efficiency increased with increasing inhibitor concentrations. Polarization results revealed that the synthesized benzaldehyde thiosemicarbazone derivatives were mixed-type inhibitors. Adsorption of these compounds onto a mild steel surface was mainly chemisorption and complied with the Langmuir adsorption isotherms. Both theoretical calculations and experimental measurements suggested that the inhibition efficiency of these compounds followed the order of Br-BT > Cl-BT > F-BT > H-BT.

Unraveling the Phytochemistry, Traditional Uses, and Biological and Pharmacological Activities of Thymus algeriensis Boiss. & Reut

Growing concern for public health has increased the need to change the paradigm towards a healthcare system that advocates holistic practices while reducing adverse effects. Herbal therapy is becoming an integral part of the therapeutic arsenal, and several successful plant-derived compounds/molecules are being introduced into the market. The medicinal plants belonging to the genus Thymus are among the most important species within the Lamiaceae family. One of them is Thymus algeriensis which is mainly distributed in the Mediterranean region. For a long time, this species has been used in traditional medicine to treat several disorders and diseases including inflammation, diabetes, rheumatism, digestive, and respiratory affections. This review describes the traditional uses, phytochemical composition, and biological and pharmacological activities of T. algeriensis extracts. Data were obtained using electronic databases such as SciFindern, ScienceDirect, Scopus, and Web of Science. Several plant-based extracts and a broad spectrum of identified secondary metabolites were highlighted and discussed with respective activities and modes of action. T. algeriensis represents a promising natural resource for the pharmaceutical industry mainly for antioxidant, anti-inflammatory, antimicrobial, and anticancer activities. Considering these findings, more research is needed to transmute the conventional uses of T. algeriensis into scientifically sound information. Moreover, extensive preclinical, clinical, toxicological, and pharmacokinetic trials on this species and its derivatives compounds are required to underpin the mechanisms of action and ensure its biosafety and efficiency. This comprehensive review provides a scientific basis for future investigations on the use of T. algeriensis and derived compounds in health maintenance and promotion and disease prevention.

Role of Organic and Eco-Friendly Inhibitors on the Corrosion Mitigation of Steel in Acidic Environments-A State-of-Art Review

Steel has versatile application in chemical, structure and construction industries owing to its mechanical properties. However, it is susceptible to corrosion in acid environments. Thus, it requires to protect the steel from corrosion. Different types of corrosion resistance steel, coatings and inhibitors are developed to mitigate the corrosion, but, inhibitor is the best remedies to control the corrosion of steel in acid condition. Moreover, organic and green inhibitors used in acid condition for descaling, acid pickling, pipelines, boiler tubes and oil-wells. Organic inhibitors reduce the dissolution of steel in acid but, it is hazardous, expensive and needs expertise to synthesize the inhibitor. Therefore, there is utmost required to study and compile the latest research about the eco-friendly corrosion inhibitors, which showed more than 90% corrosion inhibition efficiency. In the present study, I have reviewed the state-of-arts, and compile the latest development in organic and eco-friendly corrosion inhibitor used in acid environment as well as suggested about the future scope and role of green inhibitor for sustainable society, which is economical, less hazardous and readily available from the natural sources.

Inhibition of mild steel corrosion in 1 M HCl by chondroitin sulfate and its synergistic effect with sodium alginate

The development of effective and environment-friendly corrosion inhibitors is of great significance for the protection of mild steel in hydrochloric acid media. Accordingly, a natural polysaccharide mixture inhibitor composed of chondroitin sulfate derived from pig cartilage (CS-PC) and sodium alginate (SA) is developed here, and the synergistic effect of the two polysaccharides towards adsorption on mild steel in 1 M HCl is studied. The inhibition performance has been studied using weight loss test, electrochemical investigations, SEM, SECM and UV methods. The results indicate that the mixtures of CS-PC and SA strongly inhibit the corrosion of mild steel compared to individual inhibitors (i.e., 95.18 % versus 72.78 %), and show a synergistic inhibition effect. The structure-activity relationship between the molecular structure of the CS-PC + SA mixture and its corrosion inhibition performance has been discussed by using the quantum chemistry calculation and molecular dynamics simulations. It is believed that these results have certain guiding significance for the rational design of efficient corrosion inhibitor.

Adlay seed hull polysaccharide as a green corrosion inhibitor for mild steel in acid solution: surface analyses and theoretical calculations

Adlay seed hull polysaccharide was developed here as a green corrosion inhibitor for mild steel in 1 M HCl solution, and its inhibition effect was studied with electrochemical experiments, theoretical calculations, etc.

Plant Extracts as Green Corrosion Inhibitors for Different Metal Surfaces and Corrosive Media: A Review

Natural extracts have been widely used to protect metal materials from corrosion. The efficiency of these extracts as corrosion inhibitors is commonly evaluated through electrochemical tests, which include techniques such as potentiodynamic polarization, electrochemical impedance spectroscopy, and weight loss measurement. The inhibition efficiency of different extract concentrations is a valuable indicator to obtain a clear outlook to choose an extract for a particular purpose. A complementary vision of the effectiveness of green extracts to inhibit the corrosion of metals is obtained by means of surface characterizations; atomic force microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy analysis are experimental techniques widely used for this purpose. Moreover, theoretical studies are usually addressed to elucidate the nature of the corrosion inhibitor—metal surface interactions. In addition, calculations have been employed to predict how other organic substances behave on metal surfaces and to provide experimental work with fresh proposals. This work reports a broad overview of the current state of the art research on the study of new extracts as corrosion inhibitors on metal surfaces in corrosive media. Most constituents obtained from plant extracts are adsorbed on the metal, following the Langmuir adsorption model. Electron-rich regions and heteroatoms have been found to be responsible for chemisorption on the metal surface, whereas physisorption is due to the polar regions of the inhibitor molecules. The plant extracts compiled in this work obtained corrosion inhibition efficiencies above 60%, most of them around 80–90%. The effect of concentration, extraction solvent, temperature, and immersion time were studied as well. Additional studies regarding plant extracts as corrosion inhibitors on metals are needed to produce solutions for industrial purposes.