Taking Advantage of an Unlimited Source: The Sun

Camilo Sánchez (ESR8)

Have you ever noticed how some objects change their properties when they are left under the Sun?

For example, when a newspaper is exposed to sunlight for several days, it becomes yellowish. This remarkable process is called photodecomposition, which means that a substance is degraded by exposure to the light.

All the energy that arrives at the Earth from the Sun is coming in the form of radiation.

This radiation is mainly composed of infrared (49%), visible (42%), and ultraviolet (8%) light. The infrared radiation is the least energetic, and it is absorbed by the water and CO2 to become heat, that is why more CO2 emissions increase the temperature on the Earth (Global warming). Visible light is more potent than infrared but less than ultraviolet. It is mainly used by plants in the photosynthesis process (conversion of CO2 to oxygen) as well as it is responsible that we can see everything colourful. Meanwhile, the ultraviolet light is the most energetic one, and it induces photodecomposition of many things, including our skin (sunburns and skin cancer). That is why many objects have UV protection, and it is recommended that we use sunscreen.

The photodecomposition phenomenon is the base of my purification system that I am applying for removing organic micropollutants (OMPs) from water. As other technologies used for purifying air and water based on the decomposition processes, they are usually boosted using some compounds called “catalysts”. They take the ultraviolet light and make the oxidation of the substances (pollutants) present in air and water more efficient and faster. One of this catalyst is titanium dioxide (TiO2). This fantastic compound is used in several industries, such as cosmetics, paints and coatings, solar panels, as well as in air and water treatment, because of its non-toxicity, low cost, and chemical stability. Although TiO2 works very well in the removal of many contaminants that are discharged to the water bodies (rivers, lakes, oceans, etc.), TiO2 receives only ultraviolet radiation and not all radiations mentioned before. Thus, it is necessary to modify the TiO2 to absorb visible light too. In this way, we could take advantage completely of our unlimited source of energy, the Sun.

Mainly, my project focus on a new methodology for the synthesis of a photocatalyst based on TiO2/graphene oxide for the removal of organic micropollutants (OMPs). As my fellow Michele said, graphene could improve communication between microorganisms. In my case, it could enhance the light absorption of my catalyst. Additionally, for the synthesis of the materials, I am applying a microwave oven, like the one we use at home, but with additional features that allow me to control the process more accurately. We believe this new synthesis methodology might produce materials with a higher purity in a shorter time (just minutes), reducing the consumption of production energy significantly.

My research is part of the NOWELTIES project for developing innovative technologies for water treatment. We are working all together, sharing experiences and knowledge, building a great scientific network. From this, we are trying to find out efficient, economically, and environmentally friendly solutions to the problems related to water, that could improve the well-being of society.