Spray Makes Lead Glow Green in the Environment
The lead exposure threat is especially serious for children. Lead is pervasive in materials such as water pipes, paints, glass, electronic components, and ammunition.
Due to activities like mining, coal power plants, or recycling, this heavy metal ends up directly in the environment. It poses a particular threat to small children and can cause lifelong consequences, including neurological disorders, learning difficulties and severe physical illnesses. Fortunately, people can remove this toxin from the environment relatively easily once they know it is present. The challenge lies in detecting its presence, because the process typically requires complex laboratory techniques to separate and enrich the element from samples.
Understanding the Lead Exposure Threat
Detecting dangerous levels of lead in the environment may become significantly easier in the future. A research group led by Willem L. Noorduin has developed a method in which a sample is sprayed with a chemical and then examined with a UV lamp. Using this lamp, researchers can immediately determine if lead is present. As reported in the journal “Environmental Science & Technology,” the method correctly identified the presence of lead in experiments with over 50 samples. It also worked at very low concentrations and with all types of lead compounds. The spray contains methylammonium bromide, a substance that forms a semiconducting mineral with lead. This mineral emits a green glow under UV light.
The discovery revolves around perovskites, a class of materials with versatile properties that many groups and companies are currently studying intensively. Solar cells based on lead-containing semiconducting perovskites achieve over 25 percent efficiency. Noorduin and his team originally developed methylammonium bromide for perovskite production, and the ability to detect lead in the environment emerged as a fortunate discovery for the research group. The chemical reaction that forms the perovskite when the spray contacts lead, even in the presence of water or acid that would typically break down perovskites, remains somewhat mysterious.
