Cleaner Air around Bins Sunlight and a Catalyst in a Trashcan Lid Get Rid of Garbage Stink

A sunlight-activated catalyst fitted to a wheelie bin lid could help reduce odours from rotting food. In outdoor tests, the removable insert broke down odour-causing acetic acid for more than 40 days, using natural sunlight instead of electrical heating.

Garbage left outside starts smelling unpleasant very quickly, especially in warm, humid climates that accelerate food decay. In ACS’ Environmental Science & Technology, researchers report a solar-powered lid insert that fits onto standard wheeled trash bins and helps combat the stench. In tests with real food, the lid insert efficiently breaks down acetic acid, the main culprit released from rotting waste that’s responsible for its odors, and continues working for more than a month.

Household waste is often unwanted food that rapidly degrades in bins on neighborhood curbs, forming strong odors such as acetic acid (vinegar), an astringent-smelling compound often associated with stinky garbage. Placing filters with activated charcoal, also called activated carbon, under the lid can help keep the stink contained, but they don’t work well in hot and humid environments.

Another option is to harness sunlight that hits outdoor garbage bins to remove odor-causing chemicals. “Our motivation was therefore very practical. We wanted to address the odor at its source, inside the bin itself, instead of letting it escape into the street,” says Jinlong Wang, a corresponding author of the study. An inexpensive catalyst like manganese oxide (MnO₂) could help — when activated with sunlight, it both adsorbs volatile organic acids and breaks the chemical bonds of acetic acid. So, Wang and colleagues wanted to develop a MnO₂-based catalyst and integrate it into a lid insert made from a transparent membrane that concentrates sunlight onto the catalyst.

The team ionically bonded lithium to MnO₂ as a sort-of electronic booster, creating a refined catalyst that is more effective at breaking down acetic acid than MnO₂ alone or activated carbon in simulated sunlight conditions in the lab. The catalyst also performed well in humid conditions.

For a real-world test, the team developed a transparent gas-permeable insert containing a lens that concentrated light onto a layer of the catalyst. The removable module fit onto the lid of a standard wheeled trash bin. The catalyst insert continuously and efficiently broke down acetic acid generated by decaying fruit, bread, and wine for more than 40 days in natural sunlight, demonstrating its long-term stability.

“Conventional catalytic odor abatement relies on electrical heating to activate the catalyst, but we use light instead,” says Wang. The authors anticipate their results could someday provide a sustainable solution for odor control in waste management.

The authors acknowledge funding from the Beijing Academy of Science and Technology, the National Natural Science Foundation of China, the Wuhan Municipal Science and Technology Bureau, and the Central China Normal University.

Original Article: Ionic–Covalent Bond-Mediated Electron-Rich Lattice Oxygen for Solar-Driven Acetic Acid Abatement; Environmental Science & Technology; DOI:10.1021/acs.est.6c07573

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