New Technology Purifies Seawater Using Metal-Organic Frameworks and Solar Power

Researchers from Monash University in Australia have transformed seawater and brackish water into clean and safe drinking water within 30 minutes with the use of MOFs or metal-organic frameworks and solar power. The research team is composed of scientists from many countries.

The discovery is important because it can make potable drinking water available for millions all over the world. The research team was able to filter out harmful particles from the sea, generating 139.5 liters of clean water for every one MOF kilo per day. The team also did this without the high amounts of energy needed by current methods of desalination. It is an energy-efficient system.

The team published the pioneering research in Nature Sustainability, entitled "A sunlight-responsive metal-organic framework system for sustainable water desalination."

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Standard Quality for Drinking Water

The WHO or World Health Organization determined that drinking water is of good quality if it has less than 600 ppm of TDS (total dissolved solids). The research team attained a TDS of less than 500 ppm within only 30 minutes and regenerated the MOF in just four minutes using sunlight to reuse it.

Monash University Department of Chemical Engineering professor and lead study author Huanting Wang said that their research started a new method of design of materials responsive to stimuli for a sustainable and energy-efficient water purification and desalination.

Existing Desalination Processes

According to Wang, desalination is presently used in addressing the worsening shortage of water worldwide. This is due to the abundance of seawater and brackish water and the careful process of desalinating. The treated water may also be integrated with the existing systems without significant health risks.

However, he adds, thermal desalination through evaporation needs high energy consumption. Besides, technologies like reverse osmosis involve many problems, which similarly include high waste of energy plus the use of chemicals in dechlorination and cleaning the membrane.

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The Innovative Technology

Wang says that sunlight is virtually inexhaustible and is the most renewable energy source available to us. The development of the new adsorbent process of desalination using sunlight to regenerate power is energy-efficient and sustainable.

MOFs are compounds that consist of metal ions which form crystals with the most significant known surface area. They are very porous and can fit a whole football field surface within a teaspoon.

The researchers created a MOF known as PSP-MIL-53. They synthesized it by putting PSP or poly-spiropyran acrylate into the MOF's pores. The research team made PSP-MIL-53 yield 139.5L freshwater per kilo MOF per day with only small energy consumption, desalinating 2,233 ppm of water.

Wang says it is promising as a future solution for clean water due to its efficient and sustainable adsorption.

Wang concluded that sunlight-responsive metal-organic frameworks could be used for mineral extraction using low energy and environmentally friendly methods. It can be applied to sustainable mining and similar industries.

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