The natural form of DNA, which carries genetic information in living organisms, is similar to a standard store-bought Lego set containing specific pieces and colors, each representing a building block.
But what if DNA was made in the laboratory by determining the arrangement and structure of the building blocks (nucleotides) in a way that served a specific function? It will be like someone designing “Lego” pieces in his own workshop, so that he can choose the color, shape and size of each cube, and create his unique collection different from the one in the store, and this is the philosophy of “artificial DNA” that Chinese scientists designed to achieve two desalination functions. Seawater and extracting uranium metal from it.
From “design” to “mineral extraction”
And in the study I published patrol “Science Advances”, the researchers detailed their new method of desalination, with the additional function of extracting uranium metal, through several steps:
- First: sequence design
DNA consists of nucleotides. Each nucleotide consists of a sugar molecule, a phosphate group, and one of four nitrogenous bases: adenine, thymine, cytosine, or guanine. The sequence of these bases is carried along the length of the DNA strand. Genetic information.
In synthetic DNA, researchers can manipulate and engineer these sequences to achieve specific functions, such as binding to certain metals or facilitating certain chemical processes, so the first step in this work was to describe the specific DNA sequence needed for the desired function.
- Second: Chemical synthesis
Using chemical reactions, scientists build DNA chains atom by atom, and using specialized machines and reagents they add nucleotide building blocks in the correct order and following the designed sequence.
- Third: Purification
The synthesized DNA is purified to remove any impurities or unwanted byproducts from the chemical synthesis.
The synthesized DNA is then verified to ensure it matches the intended sequence, using various techniques such as DNA sequencing.
- Fifth: Incorporation into the hydrogel
Once the synthetic DNA is ready, it is incorporated into the hydrogel, becoming part of a hydrogel system designed to efficiently evaporate water when exposed to solar energy.
- Sixth: Reinforcement with graphene oxide
Graphene oxide (a material known for its excellent light-absorbing properties) is introduced into the DNA-enriched hydrogel, and this addition enhances the hydrogel's ability to absorb solar energy, making the water evaporation process more efficient.
- Seventh: Selective mineral extraction
During water evaporation, the DNA hydrogel revealed that by design it was supplied with the uranyl DNA enzyme; High ability to selectively extract metals – such as uranium – from seawater.
Uranyl DNA enzyme is a type of catalytic DNA that shows a specific affinity for uranyl ions, a form of uranium commonly found in seawater. This enzyme plays a crucial role in uranium extraction, because it is designed to have high specificity. It captures uranyl ions, meaning it can selectively bind to them, even in the presence of other ions in seawater. This specificity is essential for efficient uranium extraction without capturing unwanted materials.
Working under solar lighting
The entire system operates under solar lighting, which drives water evaporation and mineral extraction. Simulations and laboratory experiments revealed that the temperature gradient resulting from solar illumination increases ion transport, further enhancing the overall efficiency of desalination and mineral extraction.
The researchers tested the system's performance in natural seawater, and it demonstrated the ability to quickly evaporate water and selectively extract minerals, providing a sustainable solution for seawater desalination.
The system demonstrated a high capture capacity of 5.7 mg per gram for uranium from natural seawater, due to rapid ionic transfer resulting from solar-powered interfacial evaporation and high selectivity.
and say the professor College of Chemistry and Materials Science in China, and the lead researcher of the study, Hanxu Liang, Fei a report Published by the Tech Explore website: Their new system could provide easy-to-use devices suitable for seawater treatment in the future, a solution that should be expanded in implementation due to the increasing scarcity of fresh water, which represents a threat to societies due to rapid population and economic growth.
To facilitate access to fresh water, there is a need to desalinate seawater, which represents up to 97% of the total water content on Earth.
While researchers have developed techniques for desalinating seawater with solar energy as a promising means of producing seawater without additional energy consumption, Liang asserts that their method is promising, because it provides, in addition to desalinating seawater, the extraction of one of the precious metals, which is uranium.
Positive results await from the application challenge
For his part, Khaled Abdel Zaher, professor of water chemistry at the Egyptian University of the South Valley, differentiates between what the study found on a small scale and the challenge of application on a large scale.
He explained in a telephone interview with Al Jazeera Net that the study reveals an innovative experience in desalination that achieves, according to experiments conducted on a small scale, a set of environmental and economic benefits, including:
- Reduce energy consumption:
Engineering DNA hydrogels to efficiently absorb solar energy in the desalination process helps reduce reliance on traditional energy sources, reducing the environmental impact associated with traditional desalination methods that often require large energy inputs.
- Reducing environmental impact:
The selective nature of DNA hydrogels, especially in mineral extraction, may reduce the environmental impact of desalination by reducing the extraction of unwanted materials, and this selectivity could lead to more environmentally friendly processes and reduce potential damage to ecosystems.
- Sustainable use of resources:
The ability to extract precious metals such as uranium from seawater using synthetic DNA may contribute to a more sustainable use of resources, and could reduce the need for traditional mining methods, which can have major environmental consequences.
- Cost effectiveness:
Solar desalination using synthetic DNA could be a cost-effective solution, especially in areas with abundant sunlight.
However, despite Khaled Abdel Zaher’s acknowledgment of these apparent benefits from the results of the experiments included in the study, the important question he raises remains: “Will these benefits continue to exist when applied on a larger scale?”
In this context, he points to a set of challenges that must be resolved to move from the level of experiments to application, which are:
- Firstly: Scalability, ensuring that the method remains cost-effective on larger scales is crucial for practical implementation.
- secondly: Cost of DNA synthesis Synthesis can be expensive, so addressing the economic feasibility of this process on a large scale is important for the commercial viability of this technology.
- Third: Durability and reusability of DNA hydrogel Its longevity and reusability must be studied in the desalination process, as continuous exposure to seawater and sunlight may affect its structural integrity and performance over time.
- Fourthly: Real-world testing: Although the researchers conducted a small field trial, the effectiveness must be verified in large-scale field trials across different regions.