Role of Graphene Oxide in Climate Change Adaptation and Mitigation!

Water plays a vital role in the day-to-day life of every living being. In human health, water has an essential duty. 60% of the human body consists of water. So, consuming water daily is very important for us.

Though 71% of the earth’s surface is covered with water, 97% is found as salt water. Saltwater could be healthier for humans, as its ability to be used daily is meager. Only 2.5% of fresh water is available on the earth, but most of that (almost 1.5%) is locked in glaciers as frozen water. So only 1% of water from the earth is available worldwide. Here is more information about the availability of water around the world.

There are more than 8 billion people in the world. One of the primary needs of all of them is fresh water. But the availability of freshwater could be much higher. This is why we must be more aware and careful about water use. We have to manage this limited water resource carefully among people and use it sustainably. 

Water Contaminants and Human Health

Anyhow, even this limited water resource is vulnerable to the effects of different ways. These little, usable freshwater sources are more likely to pollute through contaminants. Surface water sources like rivers and lakes may be contaminated with pesticides, insecticides, agricultural runoff, industrial discharges, and municipal sewage. Most groundwater sources are polluted by improper disposal of hazardous waste, leaking septic tanks or the percolation of contaminants from the surface, leaking underground storage tanks, and leaching from landfills. There are even other natural ways for mixing water contaminants into freshwater sources. Naturally occurring contaminants like arsenic and radon occur naturally in certain geological formations. Water drawn in these areas may naturally contain elevated levels of these substances. Harmful algal blooms also add toxins that contaminate water bodies.

When these contaminant levels become higher or when the level of these contaminants exceeds the safe level, it can harm our health due to their toxic or disease-causing properties. The specific ways contaminants harm health can vary depending on the contaminant type and the exposure level. Ingestion, chemical toxicity, bioaccumulation, and carcinogens are some common mechanisms of how water contaminants can harm human health. These can cause allergic reactions, endocrine disruptors, respiratory issues, neurological effects, etc.

To ensure our safety from water contaminants, there are several measures. Some of them are using safe water sources and avoiding unknown water sources, using proper storage, water conservation, and testing water regularly. If there are contaminated water sources that can be repaired, it is essential to practice improving them instead of avoiding them. These practices are boiling water before consumption and installing water filtration systems.

Water Filtration Systems

Some of the water contaminants can be removed from the water, and there is an ability to make that water healthier than normal fresh water. Water filtration systems are devices or methods used to remove impurities, contaminants, and undesirable substances from water, making it safe and suitable for various purposes such as drinking, cooking, and bathing. Several types of water filtration systems are available, each designed to address specific contaminants or water quality issues.

Active carbon filters, reverse osmosis (RO) systems, UV (ultraviolet) purifiers, water softeners, ceramic filters, ion exchange resins, distillation units, multi-stage filtration systems, whole-house filtration systems, and portable filtration devices are some of the standard water filtration methods.

The choice of a water filtration system depends on the area’s specific contaminants or water quality issues, budget, and water usage needs. 

In most of these filtration methods, graphene oxide has gained significant attention as a material in recent years for its potential applications in water filtration and purification. 

What is Graphene Oxide?

Graphene oxide is an oxidized form of graphene. This unique material has a layered carbon structure with oxygen-containing functional groups. With specific features of graphene, it produces graphene oxide, which consists of many individual components that can be useful for many different needs. Here is more on graphene oxide and its structure, synthesis, and derivatives. 

Graphene oxide has many unique applications. With counting the advantages and importance of graphene oxide derivatives, this application range increases to more.

Generally, graphene oxide is commonly used in conductive transparent coating, flexible electronics, water electrolysis, water filtration and purification, and biological and medicinal applications. Here for more of those uses.

Graphene Oxide in Water Treatment

Graphene oxide has many properties which are very important in water filtration and purification.

1. Ultrafiltration and Nanofiltration: Graphene oxide membranes can be used as ultrafiltration or nanofiltration membranes. Their exceptional mechanical strength, high surface area, and tunable pore sizes allow them to effectively block the passage of large particles, such as bacteria and some viruses while allowing water molecules to pass through. This makes graphene oxide membranes useful for water purification and desalination.
2. Absorption: Graphene oxide has many functional groups on its surface, including hydroxyl and carboxyl groups. These functional groups make it highly effective at absorbing various contaminants, including heavy metals, organic compounds, and dyes from water. This absorption process can significantly improve water quality.
3. Disinfection: Graphene oxide can be functionalized to have antimicrobial properties. When incorporated into water treatment systems, it can help disinfect water by inactivating bacteria, viruses, and other microorganisms. This can be especially useful in water treatment for potable water supply.
4. Selective removal: Graphene oxide can be modified to remove specific contaminants selectively. Researchers have explored its ability to remove various pollutants from water sources, such as pharmaceuticals and endocrine-disrupting compounds.
5. Graphene oxide composites: Graphene oxide can be combined with other materials to enhance its filtration and absorption properties. For example, it can be integrated into composite materials to improve the removal of specific contaminants, making it more versatile for various water treatment applications.

It is important to note that while graphene oxide shows excellent promise for water filtration and purification, there are still challenges to overcome, including the scalability of production, long-term stability of membranes, and cost-effectiveness. Research and development in this field continue to explore ways to harness the unique properties of graphene oxide for more practical and widespread applications in water treatment.

With these characteristics, graphene oxide is used in many filters and purifiers to increase their effectiveness.

1. Membrane filters
2. Absorption filters
3. Disinfection filters
4. Selective filters
5. UV and Light-activated purifiers – When exposed to UV or visible light, graphene oxide can produce reactive oxygen species, breaking down and neutralizing organic pollutants in water.
6. Long-lasting filters – Graphene oxide-based filters have a longer lifespan than traditional filters, as they are less prone to clogging and fouling due to their unique structure.
7. Desalination – In some cases, graphene oxide membranes are used for desalination. They can effectively separate salt and water, making seawater or brackish water potable.
8. Portable water purifiers – Graphene oxide-based portable water purifiers and filters are compact and can be used in emergencies or while traveling, providing access to safe drinking water.

Also, Graphene oxide-based sensors can monitor the water and air quality, aiding in early detection and prevention. This prevents the consumption of low-quality water and breathing low-quality air without knowing they are contaminated. These are a type of environmental sensor.

Prop and Cons of Using Graphene Oxide in Water Filtration and Purification

As mentioned above, using graphene oxide in water purification and filtration offers several advantages. According to their uses and characteristics, high efficiency, antimicrobial properties, longevity, and selective removal are a few main props. Also, the pore sizes in graphene oxide membranes can be controlled, allowing for the customization of filtration to target specific contaminants and water quality requirements. Graphene oxide water filtration methods reduced energy consumption in that process than the others. The low pressure required to push water through graphene oxide membranes can reduce energy consumption, making it more efficient for desalination and water treatment.

When discussing the cons of graphene oxide-related water filtration and purification methods, high production cost affects the most. High-quality graphene oxide is expensive, which can limit its widespread adoption, especially in developing regions. Scaling up the production of graphene oxide membranes and filters to meet the demand of large-scale water treatment facilities remains a challenge.

While graphene oxide-based filters are less prone to fouling, they are not immune to clogging, especially if exposed to high levels of particulate matter. 

Regenerating and maintaining graphene oxide filters can be complex and costly, depending on the specific application and contamination.

The most important thing to be concerned about is the disposal of used graphene oxide membranes.

Also, the effectiveness of graphene oxide-based filtration and purification methods can be influenced by the variability of water sources, which may require adjustments or pre-treatment. 

In summary, graphene oxide has the potential to revolutionize water purification and filtration, offering high efficiency and versatility. However, cost, scalability, and maintenance challenges must be addressed to make it more accessible and practical for various water treatment applications.

How Graphene Oxide Can Help Climate Change Adaptation and Mitigation?

As mentioned above, climate change is a primary reason that affects water quality. Climate change harms water quality in different ways. Climate change increases water temperature, reducing the solubility of oxygen in water, which can stress aquatic ecosystems and lead to lower oxygen levels. Altered precipitation patterns by climate change, including more intense rainfall events and prolonged droughts, can also lead to water quality issues. Heavy rainfall can cause runoff of pollutants from urban and agricultural areas into water bodies, increasing contamination. In contrast, drought can concentrate pollutants in reduced water volumes, leading to higher concentrations. Extreme weather events and high rainfall can cause soil erosion, and pesticides, herbicides, and other chemicals can contaminate the soil.

Also, higher temperatures and increased nutrient runoff from agriculture can promote the growth of toxic algal blooms.

So, mitigation and adaptation for climate change is essential to increase water quality while minimizing contaminants and pollutants. 

Graphene oxide has the potential to play a role in addressing climate change in various ways.

Graphene oxide can be used in carbon capture technologies to capture carbon dioxide emissions from industrial processes or power plants. It can absorb carbon dioxide due to its high surface area and turntable properties, which can help reduce greenhouse gas emissions.

Graphene oxide can be used in advanced energy storage systems, such as supercapacitors and batteries, enabling an efficient and cost-effective process and reducing reliance on fossil fuels. For example, graphene oxide can make solar energy batteries more efficient.

By improving the efficiency of various processes and materials, graphene oxide can help reduce energy consumption, decreasing greenhouse gas emissions.

Environmental and Health Impact of Graphene Oxide

The disposal of graphene oxide membranes should be discussed further due to its impact on environmental and human health. Graphene oxide is safe for long-term occupational exposure, but inhalation of graphene oxide should be avoided, depending on the size of the particles. A study by the University of Trieste, Italy, the University of Castilla-La Mancha, and CIC BiomaGUNE, Spain, showed that graphene and layered materials may reduce pollen vitality in the lab. Still, these effects are less evident in living organisms. Here is more on the environmental and health impact of graphene oxide.

For these reasons, the disposal of graphene oxide membranes and related materials should be carried out carefully to prevent any potential environmental impact and comply with local regulations. Before disposing of graphene oxide membranes, checking local and national regulations regarding hazardous or nanomaterial waste disposal is essential. Whenever possible, graphene oxide membranes should be considered for reuse or recycled. This is the most sustainable option for reducing this waste. Chemical treatment or decontamination of the graphene oxide membrane, if toxic substances are contaminated with the membrane, is essential before disposing of it. Secure packaging and disposal of hazardous waste are other best ways of disposing of them. These practices help to minimize the impact on the external environment from graphene oxide.

On the other hand, graphene oxide is an intelligent choice for water purification and filtration. This has more positive impacts on both the environment and health.

Water quality directly affects human health, and with climate change and other environmental issues, the water is becoming increasingly polluted. So, graphene oxide is a good solution for water scarcity and climate change adaptation plans.

Graphene Oxide in Sri Lanka

Graphene oxide is a recently widely discussed topic in Sri Lanka. Graphite is a common mineral in Sri Lanka, and Sri Lanka has been mining graphene since the Dutch occupation of the country. The largest graphite deposits in the country can be found in the comprehensive northwestern and southern parts of the island.

Sri Lanka produces 9000 to 10000 tons of graphite annually for two underground mines in Kahatagaha and Bogala. In Sri Lanka, graphene oxide is also produced and used in different fields. Here for more details. 

One of the primary users of graphene oxide for research purposes is the Sri Lanka Institute of Nanotechnology (SLINTEC). They have researched graphene on functional coating and surface modifications, multifunctional materials and composites, energy storage, sensors, and water and air purification. According to SLINTEC, there are many projects on graphene oxide running in the institute. But they are still at the research level. They also mentioned that they hope for more grants to conduct these critical projects further.

Recently, SLINTEC and Adelaide University, Australia, have been researching graphene oxide-coated sands for water purification. In this case, their objective is to improve the sand filter medium by surface modification. Here is an old study of similar research. According to research data, the preparation of graphene oxide sand composites is super absorbent for water purification. Here is a research paper related to this.

There is a project of a specific graphene oxide used battery in SLINTEC as well.

As Sri Lanka is a country that has a rich availability of graphene, we can pay more attention to graphene oxide air and water purification methods. Also, most Sri Lankans are suffering from kidney failure and other water-related diseases and respiratory illnesses due to dirty air. This will be a good solution for all those issues. It is essential that these researches and projects would be more than just successful projects but successful practices all over Sri Lanka.

Conclusion

Graphene oxide produces oxidizing graphite and is an expensive but effective agent and very useful for water and air purification and treatment. There is so much research about using graphene oxide more effectively in water and air purification, even in Sri Lanka. Though these are very expensive, Sri Lanka is lucky to have a suitable graphite disposal. So, we have reachable sources for graphene oxide even with all the barriers. Using graphene oxide widely in water and air purification practices in Sri Lanka is essential.