Organic Green Corrosion Inhibitors Derived from Natural and/or Biological Sources for Conservation of Metals Cultural Heritage

Abstract

In the last decade, there has been an increase in research related to green corrosion inhibitors for conservation of metals cultural heritage to help promote sustainable practices in the field that are safe, environmentally friendly, and ecologically acceptable. The most common are organic substances derived either from natural and/or biological sources: plant extracts and oils, amino acids, microorganisms, and biopolymers. The chapter will provide a review of these substances as corrosion inhibitors for metals conservation, by discussing the state-of-the-art research to date, with a special focus on cysteine. Most of the research has focused on the examination of such inhibitors on metal coupons with or without corrosion products using electrochemical techniques or weight-loss measurements to determine their effectiveness. Some of these studies have also considered the conservation principles for practice, i.e., reversibility of the treatment and the visual aspect of the modification of the treated metal surface. However, before such green inhibitors can be routinely applied by conservators, more research is required on their application to real artefacts/monuments using in situ corrosion measurements. Furthermore, given that the composition of a green inhibitor is highly dependent on its extraction process, research must also involve identifying the specific adsorption models and involved mechanisms to ensure reproducibility of results.

Brewed Robusta Coffee Increases Nickel Ion Release from Dental Alloys: An In Vitro Study

“…Caffeine (C 8 H 10 N 4 O 2 ) is a compound containing an N group which has free electrons. The N group will donate its free electrons to the alloy, thus inhibiting the corrosion rate in the immersion of pure coffee [20]. According to [21], the high concentration of caffeine in a solution will reduce the corrosion rate of an alloy.…”

“…SEM was conducted to determine the surface roughness and porosity of the NiCr alloy. Surface roughness is the irregularity of a surface in the form of curves or scratches [20]. Based on Figure 2 shows that different alloys display different surface roughness, number of pores, and pore sizes.…”

Non-Invasive Evaluation of Polymeric Protective Coatings for Metal Surfaces of Cultural Heritage Objects: Comparison of Optical and Electromagnetic Methods

“…We evaluated two polymer classes, including two acrylic and one cellulose nitrate lacquer. Paraloid ® B-72 (PB-72) (CTS, Vicenza, Italy) is a copolymer of methyl acrylate and ethyl methacrylate widely used in conservation as an adhesive, consolidant, and protective layer [27][28][29][30][31]. Paraloid ® B-44 (PB-44) (CTS, Italy) is the commercial name for methyl methacrylate and ethyl acrylate copolymer, part of the Incralac ® coating formulation [29].…”

Plant wastes as alternative sources of sustainable and green corrosion inhibitors in different environments

“…(i) Pipelines in fertiliser, oil and gases (ii) Pickling process (iii) Boiler cleaner (iv) Reactors (v) Oil well acidising There are several ways of applying corrosion inhibitors, depending on the aim of such applications. Some of the ways are as follows [22]:…”