Colombian Project Seeks to Prevent Metal Corrosion Using Avocado and Coffee Waste
One of the clearest explanations of what corrosion is has been provided by NASA. It is the degradation of a metal due to a reaction with its environment, involving the deterioration of the material’s physical properties. It can affect materials such as metals, polymers (plastics, rubbers, etc.), ceramics (concrete, bricks, etc.), or composites (mechanical mixtures of two or more materials with different properties). To preserve metallic structures from this process, Colombia is advancing a project to create natural coatings from avocado, coffee, and plantain peels and pruning residues.
Why do metals corrode? NASA continues with its simple explanation: because they are used in environments where they are chemically unstable. Only copper and precious metals (gold, silver, platinum, etc.) are found in nature in their metallic state. All other metals, including iron (the most widely used), are processed from ores or minerals, which are inherently unstable in their environments.
Corrosion is not a minor problem. Every year, the global industry assumes enormous maintenance and repair costs due to the damage it causes. International studies, cited in a bulletin by the News Agency of the National University of Colombia (UNAL), estimate that nearly 4% of the gross domestic product (GDP) of developed countries is spent on replacing or restoring metallic structures deteriorated by this phenomenon.
Traditional inhibitors are extremely toxic
Amid this scenario, the technology being developed in Colombia, which seeks to replace toxic products and extend the service life of some industrial materials by up to twice as long, is promising. Even more so considering that, according to tests carried out, applying this type of inhibitor would allow a metallic structure initially designed to last 50 years to reach up to 100 years of useful life.
For nearly a decade, a group of researchers at UNAL’s Manizales campus has been working on the development of “green corrosion inhibitors,” that is, natural coatings that help slow rust and metal deterioration without using the highly toxic compounds found in many traditional industrial anticorrosive products. The project is being carried out at the Innterfaz Technological Development Center, according to the UNAL News Agency.
“The problem with many traditional inhibitors is that they are extremely toxic and generate significant environmental impacts,” physical engineer Daniel Alejandro Pineda Hernández, an expert in electrochemistry applied to the study of corrosion and head of the Electrochemistry Area at Innterfaz, told that outlet. “That is why, decades ago, the research line on green corrosion inhibitors emerged, seeking to use natural extracts and agro-industrial waste to reduce those impacts.”
Natural anchors allow adhesion
The inhibitors developed use agro-industrial waste generated in the department of Caldas, including avocado, coffee, and plantain pruning residues, as well as plantain peels—materials that contain polyphenols and other phytochemicals with antioxidant properties that help reduce the deterioration of metallic surfaces.
Although the use of natural inhibitors has been studied internationally since the 1970s, one of the main challenges remained achieving adequate adhesion of these compounds to metallic surfaces and providing long-lasting protection. Precisely, the main contribution of the research group was to create a formula capable of improving that adhesion by combining agro-industrial waste and natural components.
“We managed to generate natural anchors that allow the inhibitor to adhere much better to the metal, making it possible to considerably increase the useful life of structures,” Pineda added.
The formulation, called LV-1720, was created during a doctoral dissertation supported by the Electrochemistry Research Seedbed and is currently undergoing industrial protection procedures.
In addition to reducing costs associated with corrosion, green inhibitors seek to be a less polluting alternative to conventional paints and anticorrosive products, many of which are made with toxic compounds.
The development has already surpassed the laboratory testing stage and is currently advancing through market validation and specialized technical trials, including “salt spray chamber tests,” considered an international standard for evaluating anticorrosive materials. The process is being carried out with five private companies from the paint and metalworking sectors, with which product validation exercises have been conducted.