Using light to green the environment
Fresh water is a precious commodity that needs to be managed carefully, particularly in rural areas with developing industries that have limited wastewater treatment options. In the agricultural and seafood industries, for example, standard filtration and microbial wastewater treatments do not remove all organic matter from recycled water. The EU-funded project PCATDES (Photocatalytic materials for the destruction of recalcitrant organic industrial waste) set out to use sunlight to remove organic pollutants from wastewater. The researchers targeted the final stage of water treatment to remove residual matter from oil pressings and chemicals from fish and prawn farming. Radiation energy from ultraviolet light is often used to purify water since it destroys pathogens by producing damaging free radicals. This purification process can be boosted by a light-activated material called a photocatalyst, which absorbs light and passes on the increased energy to other molecules. A commonly used photocatalyst is titanium dioxide, which upon light activation reacts with water to generate free radicals that break down organic molecules. To increase the energy of the photocatalytic reaction, PCATDES used commercially available light-emitting diodes (LEDs), which operate in the high-energy violet-blue part of the spectrum. Having evaluated the activity and stability of the improved photocatalysts, the researchers developed standardised LED-illuminated photoreactors. The team then developed the final prototype of the reactor to be 50 cm with an internal reactor diameter of 5 cm. Next, the researchers scaled up the prototype reactor and tested it in the field, where they focused on the palm oil and seafood industries. PCATDES then tested the operation time of the reactors in industry and found that prolonged treatment of samples did not greatly impact the treatment efficiency. These results will provide a cost-effective, energy-efficient, automated, portable photocatalytic reactor for wastewater treatment in remote areas. Apart from generating new knowledge on photocatalytic materials, the results will increase the global population’s access to clean and safe drinking water.
Keywords
Photoreactors, wastewater treatment, PCATDES, organic pollutants, purify water, photocatalyst
