Corrosion Mitigation of Chitosan Schiff Base for Q235 Steel in 1.0 M HCl

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.

Zwitterion modified chitosan as a high-performance corrosion inhibitor for mild steel in hydrochloric acid solution

Herein, a novel chitosan Schiff base (CS-FGA) as a sustainable corrosion inhibitor has been successfully synthesized via a simple amidation reaction by using an imidazolium zwitterion and chitosan (CS). The corrosion inhibition property of CS-FGA for mild steel (MS) in a 1.0 M HCl solution was studied by various electrochemical tests and physical characterization methods. The findings indicate that the maximum inhibition efficiency of CS-FGA as a mixed-type inhibitor for MS in 1.0 M HCl solution with 400 mg L-1 reaches 97.6 %, much much higher than the CS and the recently reported chitosan-based inhibitors. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and water contact angle (WCA) results reveal that the CS-FGA molecules firmly adsorb on the MS surface to form a protective layer. The adsorption of CS-FGA on the MS surface belongs to the Langmuir adsorption isotherm containing both the physisorption and chemisorption. According to the X-ray photoelectron spectroscopy (XPS) and UV-vis spectrum, FeN bonds presented on the MS surface further prove the chemisorption between CS-FGA and Fe to generate the stable protective layer. Additionally, theoretical calculations from quantum chemical calculation (DFT) and molecular simulations (MD) were performed to reveal the inhibition mechanism of CS-FGA.

Respiration-Triggered Release of Cinnamaldehyde from a Biomolecular Schiff Base Composite for Preservation of Perishable Food

One-third of the food produced worldwide is wasted annually and never consumed, of which ≈ 40-50% are perishable vegetables and fruits (VFs). Although various methods are proposed to reduce this loss, high manufacturing costs and food safety concerns pose significant challenges for the preservation of VFs. Herein, a respiration-triggered, self-saving strategy for the preservation of perishable products based on a biomolecular Schiff base composite fabricated by imidization of chitosan and cinnamaldehyde (CS-Cin) is reported. Ripening of VFs produces acid moisture and triggers a Schiff base reaction in CS-Cin, permitting the release of volatile Cin into the storage space. This enables versatile preservation by placing CS-Cin on the side without the need to touch the food, like the desiccant packet in a food packaging bag, while the rotting of VFs is retarded in a self-saving manner. As a result, the lifetimes of broccoli and strawberries are extended from 2 to 8 days. Furthermore, CS-Cin with restored preservative properties can be repeatedly recycled from used CS via imidization with Cin. Compared with conventional techniques, the preservatives are easy to use, versatile, and cost-effective, and the respiration-responsive release of Cin empowers a self-saving approach toward the smart preservation of perishable food.

Construction novel polybenzoxazine coatings exhibiting corrosion protection of mild steel at different concentrations in a seawater solution

In this work, a new and effective polymeric coating is used to improve mild steel's corrosion resistance. The coating incorporates a Schiff base moiety into a benzoxazine (BZ) precursor, resulting in improved protection against corrosion. The SF-Tol-BZ polymerization behavior and thermal properties were studied using differential scanning calorimetry (DSC) and thermalgravimetric analysis (TGA), respectively, at different curing temperatures. The poly(SF-Tol-BZ) cured at 240 °C had a Td10 value of 604 °C and a Tg of 225 °C. The efficacy of poly(SF-Tol-BZ) coatings in protecting mild steel (MS) from corrosion in a NaCl (3.5%) solution at room temperature was evaluated using various corrosion measurements, including open circuit potential (OCP), and electrochemical impedance spectroscopy (EIS). The results showed that increasing the poly(SF-Tol-BZ) concentration led to a corresponding increase in its protective efficiency, reaching a maximum of 92% at a concentration of 300 g/L. The coatings also exhibited a 24-fold increase in Rct values and a one-order-of-magnitude reduction in CPE compared to the bare mild steel. Finally, the poly(SF-Tol-BZ) precursors demonstrated a CO2 uptake of 23 mg g-1 (measured at 298 K).

Heteropolysaccharides in sustainable corrosion inhibition: 4E (Energy, Economy, Ecology, and Effectivity) dimensions

Carbohydrate polymers (polysaccharides) and their derivatives are widely utilized in sustainable corrosion inhibition (SCI) because of their various fascinating properties including multiple adsorption sites, high solubility and high efficiency. Contrary to traditional synthetic polymer-based corrosion inhibitors, polysaccharides are related to the 4E dimension, which stands for Energy, Economy, Ecology, and Effectivity. Furthermore, they are relatively more environmentally benign, biodegradable, and non-bioaccumulative. The current review describes the SCI features of various heteropolysaccharides, including gum Arabic (GA), glycosaminoglycans (chondroitin-4-sulfate (CS), hyaluronic acid (HA), heparin, etc.), pectin, alginates, and agar for the first time. They demonstrate impressive anticorrosive activity for different metals and alloys in a variety of corrosive electrolytes. Through their adsorption at the metal/electrolyte interface, heteropolysaccharides function by producing a corrosion-protective film. In general, their adsorption follows the Langmuir isotherm model. In their molecular structures, heteropolysaccharides contain several polar functional groups like -OH, -NH₂, -COCH₃, -CH₂OH, cyclic and bridging O, -CH₂SO₃H, -SO₃OH, -COOH, -NHCOCH₃, -OHOR, etc. that serve as adsorption centers when they bind to metallic surfaces.

Rapid adsorption of some heavy metals using extracted chitosan anchored with new aldehyde to form a schiff base

A new aldehyde 2,2’-[propane-1,3-diylbis(oxy)] dibenzaldehyde was synthesized from refluxing 2-hydroxy acetophenone and 2-hydroxy 1,3-dichloropropanean in an alcoholic medium. The compositions and properties of the new aldehyde compound were characterized by elemental analysis, FTIR, and nuclear magnetic resonance spectroscopy studies. The extracted chitosan was made to react with a new aldehyde to form a Schiff base by a suitable method. The effects of initial concentration of metal ions, exposure time, imine weight, and pH on the adsorption of Cu(II), Cr(III), and Zn(II) metal ions were examined. An adsorption batch experiment was conducted. The adsorption process followed a second-order reaction and Langmuir model with qe 25 mg/g, 121 mg/g, and 26.31 mg/g for Cu(II), Zn(II), and Cr(III) respectively. The Gibbs free energy showed a negative value and the adsorption/desorption tests provided a high value 5 times.

Na2SnO3 functions as outstanding magnesium alloy passivator by synergistic effect with trace carboxymethyl chitosan for Mg–air batteries for standby protection

Coordination of Na2SnO3 with trace carboxymethyl chitosan contributes to standby protection and high utilization efficiency of the AZ61 anode.

Corrosion inhibition potential of chitosan based Schiff bases: Design, performance and applications

Chemically, chitosan is a linear polysaccharide constituted of arbitrarily distributed D-glucosamine and N-acetyl-D-glucosamine constituents combined together via β-1,4-glycosidic linkage. Because of increasing ecological awareness and strict environmental regulations, species of natural and biological origin such as chitosan can be identified as ideal environmental sustainable alternative to replace traditional heterocyclic (toxic) corrosion inhibitors. Although, chitosan contains numerous electron rich sites however chitosan itself is not highly effective aqueous phase corrosion inhibitors. Aqueous phase application of chitosan is limited because of its limited solubility. However, chemically modified chitosan derivatives, such as chitosan based Schiff bases (CSBs) exhibit remarkable solubility in such electrolytes. Therefore, recently various reports dealing with the anticorrosion potential of CSBs have been reported. Present review article describes the collections on CSBs as aqueous phase corrosion inhibitors. Nature of CSBs adsorption through chelation (coordination) has also been discussed based on literature outcomes.

Polyaniline/chitosan as a corrosion inhibitor for mild steel in acidic medium

The inhibition performance of polyaniline (PANI)/chitosan (CTS) on metal corrosion in 0.5 M HCl was studied using electrochemical measurements, quantum chemical calculations and morphological observations. Potentiodynamic polarization measurements show that PANI/CTS acts essentially as a mixed-type inhibitor. The inhibition efficiency increases and corrosion rates decrease with increasing concentrations of PANI/CTS. The relationship between experimental inhibition efficiency and quantum chemical calculations that were developed to describe the corrosion inhibition process are discussed.