Front Cover https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202203929

Singapore scientists have demonstrated that fruit peels can be used to purify water, an innovation that can be employed in remote areas and disaster zones where electricity access is limited. The findings were published in Chemistry A European Journal

Every year, approximately 20,000 tonnes of fruit waste is produced in Singapore, with the majority generated by the fruit juicing industry, which uses 50% of the fruit while discarding the remainder, such as fruit peel, as waste. While others see waste, Dr. Edison sees a source of wealth because wastes are free resources that can be converted into valuable products, in this case MXene. MXene is a class of material with excellent light-to-heat conversion properties that can be used to create solar stills for water purification using renewable solar energy. This solar still can be made portable and easily deployed in remote areas where electricity access is limited.

Using a two-step carbonization method, common fruit wastes such as coconut husks, orange peels and banana peels were used to create MXene materials. These MXene materials were then used to create a solar absorber for use in a solar still for water desalination.

The study demonstrated that MXenes derived from fruit wastes had an excellent light-to-heat conversion efficiency of 90%, which is nearly 30% higher than that of the commercial solar absorber, improving the water production rate by approximately 50% over the existing solar still. Moreover, MXene material was less expensive than commercial alternatives because one of the reactant sources was obtained for free from fruit waste. Lastly, the purified water produced by the homemade solar still prototype met the World Health Organization (WHO) drinking water standard.
Like graphite, MXenes are not only naturally conductive but also have a 2D structure, which makes them useful for storing charges in batteries and could soon be used in the production of batteries. Therefore, the MXene produced from fruit waste has potential applications far beyond water purification.
The main challenge is identifying appropriate materials for an eco-friendly and more efficient solar still. Organic wastes are typically mixed with other impurities, which are not organic in nature. As a result, the use of existing technologies to produce pure materials is limited. Future work is required to sort out the waste material types, such as using artificial intelligence in conjunction with machine learning to improve the quality of the waste management process.