Use of Graphene in Water Filtration

Access to clean water is a critical objective within the United Nations' sustainable development framework. To meet this global challenge, innovative solutions in water purification are urgently needed. One promising advancement lies in the application of graphene technology. 

Graphene, discovered in 2004, has revolutionized water filtration by enabling membrane-based purification without chemical processes. This material, composed of carbon atoms arranged in a honeycomb structure, exhibits remarkable tensile strength and electrical conductivity, making it highly suitable for various applications, especially in water treatment. This article delves into the utilization of graphene for water purification to make it potable. Discover Nanografi's cutting-edge graphene products now and transform your water purification process!

Introduction

Water is the cornerstone of life, but ensuring its cleanliness and availability is a growing global challenge. As the world's population and environmental pressures grow, traditional water treatment methods are often insufficient to meet demand. Contaminated water sources lead to serious health problems, economic burdens and impeded development, especially in vulnerable communities. In response to this problem, scientific innovation has turned to advanced materials that could revolutionize water treatment processes. Graphene, a material discovered in 2004 with exceptional physical and chemical properties, has emerged as a promising solution.

Understanding Water Scarcity and Contamination

Globally, approximately 700 million people lack access to safe drinking water, leading to severe health and nutritional issues. Contaminated water consumption results in malnutrition, with 50% of child malnutrition cases attributed to repeated diarrhea and intestinal infections caused by poor water quality and inadequate hygiene. Despite significant progress since 1990 by governments and NGOs, supported by the United Nations, over 2 billion people still lack access to clean water, predominantly in rural or remote areas. Climate experts warn that this issue could escalate without unprecedented intervention.

Sustainable Development Goals and Water

In 2015, global leaders adopted the Sustainable Development Goals (SDGs) to eradicate poverty, protect the planet, and ensure prosperity by 2030. These goals, applicable to all countries, encompass various sectors, including climate change and gender inequality. Goal 6 specifically targets clean water and sanitation for all. Water's cross-sectoral importance is crucial for achieving other goals, such as Zero Hunger and Health and Wellness. However, current progress indicates that many countries may not meet Goal 6 by 2030. Enhanced efforts and investments are required, particularly in health and hygiene, through national policy adjustments, resource mobilization, and robust statistical systems to monitor SDG indicators. Advanced solutions, such as graphene filters, are essential for providing clean water universally.

Graphene in Water Treatment

MIT researchers have developed graphene nanoscrolls for efficient and targeted water filtration systems. Graphene's exceptional physical and chemical properties inspired researchers to design purification membranes that remove pollutants both chemically and physically. These nanoscrolls, layered and selectively capturing contaminants, produce pure water without unpleasant tastes or odors.

Graphene Nanoscrolls

Graphene is heralded as a revolutionary material, particularly in the realm of electronics. However, the outstanding properties identified by researchers are challenging and expensive to harness. Addressing the cost issue, researchers from the Massachusetts Institute of Technology (MIT) and Harvard University have turned their attention to graphene oxide. The challenge lies in maintaining graphene's purity and scaling its use for industrial applications, necessitating further research for practical implementation. MIT and Harvard researchers are exploring the oxidized variant, which, though tainted with oxygen and hydrogen atoms, is more affordable than pure graphene. By employing ultrasonic techniques, they have successfully created nanoscrolls of controllable dimensions from graphene oxide. These nanoscrolls exhibit the same mechanical properties as graphene but at a significantly lower cost.

While the concept of utilizing graphene nanoballs is not novel, the technique remains prohibitively expensive for industrial use. Previous attempts to produce graphene oxide nanoscrolls have also been made. The U.S. researchers initially employed a chemical process known as the Hummers' method to generate graphene oxide sheets from graphite chips. Once in solution, these sheets were subjected to two distinct ultrasonic methods, both yielding the spontaneous formation of nanoscrolls.
MIT and Harvard researchers utilized piezoelectric probes, which, when activated and immersed in a solution, generate sound waves at frequencies of approximately 20 Hz or 390 Hz. These waves agitate the solution, creating bubbles that, upon bursting, release enough energy to form conical nanoscrolls from the graphene oxide sheets. Their findings indicate that higher frequencies and shorter treatment durations result in larger nanoscrolls, and vice versa.

Currently, only 10% of the sheets have been converted into nanoscrolls. Nevertheless, MIT and Harvard researchers are confident that their techniques can be refined to achieve higher yields. This advancement could then be integrated into existing industrial processes, such as the production of water filtration membranes.

Seawater Desalination

Similarly, scientists have addressed one of humanity's most pressing issues: purifying seawater to make it suitable for drinking. A recent breakthrough by researchers at the University of Manchester introduced a filtration method that could alleviate the global drinking water shortage, a critical challenge facing humanity.

Currently, 14% of the global population lacks access to potable water, a figure projected by the United Nations Organization to remain unchanged over the next eight years. This issue could potentially be mitigated by the Earth's abundant water bodies, which cover 71% of the planet. However, the high costs associated with desalinating ocean water have rendered such solutions impractical until the advent of graphene oxide.

Scientists have engineered a graphene-based compound through a straightforward oxidation process in the laboratory. This innovation produces large graphene sheets capable of filtering seawater to make it drinkable. But how did researchers ensure that the common salts in seawater did not penetrate the material?

Initially, the structure of graphene oxide permitted small nanoparticles, organic molecules, and large salts to pass through, but failed to block common sea salts due to the inadequate size of the pores in the sheets. This allowed the membranes to swell, letting unwanted substances pass through.

The groundbreaking advancement involved applying a thin resin layer—commonly used in adhesives—on each side of the graphene oxide fabric. This prevented the membrane from expanding and refined the material's properties by controlling the pore size, thereby enhancing desalination. The next step in this scientific progress is to scale up the production of these sheets industrially and cost-effectively.

Recent Research on Water Treatment using Graphene

Australian scientists have engineered a filtration system utilizing a graphene derivative that can purify brackish or contaminated water from pollutants. This method is more energy-efficient than conventional filters and is anticipated to address issues related to global drinking water shortages, aligning with the United Nations’ Sustainable Development Goal 6. Traditional water purification typically involves a complex, multi-stage process, making this innovation potentially transformative for the estimated 2.1 billion people lacking access to potable water worldwide.

The Australian research team aims to enhance access to safe drinking water, crucial for human health. Their newly developed filter can remove 99% of salt from seawater and eliminate most impurities and industrial pollutants. This process employs a specific form of graphene—a two-dimensional carbon crystal with atom-thick hexagonal patterns. Notably, this material is hydrophobic, meaning it repels water. The scientists have devised a method to produce graphene from soybean oil, an affordable and renewable resource. This product, termed GraphAir, manifests as a thin film that, when applied to conventional filtration membranes, purifies any brackish or polluted water in a single pass.

Moreover, this graphene filter is more cost-effective, faster, and environmentally friendly to produce compared to other filters, thanks to its primary component, renewable soybean oil, which also enhances purification efficiency. While oil-based contaminants can eventually affect the filter's properties, necessitating their removal before reuse, tests with Sydney Harbor's highly polluted waters showed no degradation of the device, according to researchers who published their findings in "Nature." Graphene-based filters have the potential to replace the current complex, time-intensive, multi-stage purification processes utilized by individuals and the water industry.

Conclusion

Water pollution and scarcity are pressing global issues, affecting 700 million people without access to clean water. Contaminated water consumption leads to numerous diseases and fatalities. Graphene, with its unique high-permeability structure, offers promising solutions for both desalination and purification of water. The studies highlighted in this article demonstrate that graphene-based water treatment can be conducted more quickly and cost-effectively. MIT's nanoscrolls, along with significant advancements by Australian and British researchers, underscore graphene's potential in addressing global water challenges.

To follow the latest developments and innovations related to graphene and water purification, visit Blografi for up-to-date insights.

References

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World Economic Forum. (2014, November 19). What can nature teach us about solving water shortages? https://www.weforum.org/agenda/2014/11/nature-to-solve-water-shortages/