From Fruit Waste To Water-purifying Material
Solar stills offer an ingenious and uncomplicated method for purifying contaminated or saline water, although their efficiency is relatively slow. However, a recent breakthrough has demonstrated the ability to enhance their effectiveness using a novel material derived from discarded fruit waste.
In its simplest configuration, traditional solar still comprises a container of non-potable water positioned beneath a transparent enclosure. Sunlight heats the water, causing it to evaporate and condense on the interior surface of the enclosure. The resulting condensation, free from impurities, drips down the surface and accumulates in a separate container, providing a source of clean, drinkable water.
The Heating Process
To expedite the heating process of contaminated or saline water, researchers have devised materials that float on the water’s surface and harness sunlight to generate heat. These materials, although derived from various components, often incorporate carbon sourced from coal.
In search of a cost-effective and environmentally friendly substitute, Assistant Professor Edison Ang and his team at Nanyang Technological University in Singapore explored a resource that requires no mining, is abundantly available, and typically ends up as waste – fruit waste. Specifically, the researchers experimented with coconut husks, orange peels, and banana peels as potential materials.
A Straightforward Carbonization
Through a straightforward carbonization procedure consisting of two stages, the fruit waste underwent heating at a temperature of 850 ºC (1,562 ºF) for several hours and was combined with a molybdenum reactant. This process resulted in the formation of two-dimensional molybdenum carbide sheets from the waste material. Molybdenum carbide belongs to a group of metallic compounds called MXenes. Notably, MXenes possess hydrophilic properties, meaning they have an affinity for water, and they exhibit exceptional efficiency in converting light energy into heat.
During experimentation within a compact solar still, square-shaped sheets composed of photothermal molybdenum carbide exhibited remarkable efficacy in converting sunlight into heat. This accelerated the evaporation process of the underlying simulated seawater, surpassing its natural rate. Additionally, the material’s high porosity allowed water vapor droplets to effortlessly permeate through it, subsequently condensing on the inner surface of the solar still’s cover.
Among the different fruit waste materials tested, the one derived from coconut husks demonstrated superior performance, exhibiting an impressive sunlight-to-heat conversion efficiency rate of 94%.
Building upon these promising results, Professor Ang and his team are currently advancing the technology and actively seeking collaboration with industry partners to facilitate its commercialization.
Read the Original Article NewAtlas.
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