Improving Access to Clean Water and the Role of Nanotechnology

Access to clean, safe drinking water is thought to be a basic human right. Yet, according to the World Health Organization (WHO), over 785 million people across the globe are without access to a basic drinking-water source. This has researchers around the world researching and developing a series of water treatment solutions and applications using nanotechnology.

Current WHO statistics are damning, making this an issue that must be addressed urgently as it is thought that around 2 billion people are using a contaminated water supply. In addition, over 485,000 people die each year from diarrhoeal related illnesses and diseases such as polio, typhoid, and cholera are once again being transmitted as a further consequence. Based on current trends and data, it is thought that by 2025 half of the total global population will be living in water-stressed or water-scarce areas.

 

While there are a wide-range of effective water purification methods and techniques including boiling, filtration, oxidation, and distillation, these often require high amounts of energy. Other treatment processes may include the use of chemical agents which is only possible in areas with an infrastructure that is up to par.

The more affordable and portable devices currently available are not always fit for purpose as they cannot guarantee 100% removal of harmful viruses, bacteria, dust, and even microplastics. So, it is thought that nanotechnology could offer affordable and accessible clean water solutions to the world’s most vulnerable populations.

Nanotechnology is a process that involves manipulating and controlling matter on the atomic scale. In the process of water purification, this involves using nanomembranes to soften the water and eradicate biological and chemical contaminants as well as other physical particles and molecules.

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What’s more is that nanotechnology is portable and can be incorporated into existing commercial devices which increases the likelihood that nanotech solutions could become a feasible option for areas of the developing world and places with limited infrastructure.

In recent years scientists have improved on conventional methods that use coagulants by taking their cues from nature, notably the ocean dwelling Actinia organism. Traditional coagulants, such as aluminum sulfate and other metallic salts can pull out larger contaminants by causing them to group together and settle. However, this method is not effective for smaller particles and molecules and often requires additional methods to ensure the water is clean. Thereby increasing the cost and use of energy as several techniques are required to ensure the water is safe.

Using nanocoagulants, scientists were able to synthesize organic and inorganic matter to replicate the structure of the Actina sea anemone. The researchers produced a reversable core-shell that can catch larger particles as well as the smaller ones when it turns inside-out. This is also a one-step process which removes the need for additional technologies and opens up the potential for minimizing water purification costs.

Another viable method of water purification currently in development that makes use of nanotechnology includes utilizing magnetically active nanoparticles to extract chemicals from water. The process enables the removal of toxins from drinking-water contaminants attracting nanoparticles that consist of magnetic phases. This solution would also be low-energy and could provide an economic advantage as well as health and environmental benefits.

Other proposals for nanotech solutions include using nanoparticles to break down microplastics and a rapid nano-filter that can clean dirty water 100 times faster than current methods. Researchers are also aware that most water purification methods require access to a constant electricity supply, but this can be a significant obstacle in places with limited infrastructure or areas damaged by extreme weather conditions.

One such approach is the creation of a self-sustaining biofoam that conducts heat and electricity by combining bacteria-produced cellulose with graphene oxide. The graphene-fused foam draws water up to the surface via the cellulose layer which accelerates evaporation. This results in a layer of freshwater which can be easily collected and is safe to drink. The biofoam is also lightweight and relatively inexpensive to manufacture making it an attractive alternative to conventional methods.

Thus, as the need for clean, safe water is very much still an urgent global issue, nanotech solutions offer new and essential possibilities for the water treatment industry. The next phase of development is the scaling up of nanotechnologies to improve access to clean water. Perhaps then the future can be one that offers a new hope to the expanding global population experiencing water-stressed and water-scarce conditions.

Re-Posted from AZ NAno – David J. Cross MA

NEWT – Mat baits, hooks and destroys pollutants in water: Rice University

Specks of titanium dioxide adhere to polyvinyl fibers in a mat developed at the Rice University-led NEWT Center to capture and destroy pollutants from wastewater or drinking water. After the mat attracts and binds pollutants, the titanium dioxide photocatalyst releases reactive oxygen species that destroy them. Credit: Rice University/NEWT

A polymer mat developed at Rice University has the ability to fish biologically harmful contaminants from water through a strategy known as “bait, hook and destroy.”

Tests with wastewater showed the mat can efficiently remove targeted pollutants, in this case a pair of biologically harmful endocrine disruptors, using a fraction of the energy required by other technology. The technique can also be used to treat drinking water.

The mat was developed by scientists with the Rice-led Nanotechnology-Enabled Water Treatment (NEWT) Center. The research is available online in the American Chemical Society journal Environmental Science and Technology.

The mat depends on the ability of a common material, titanium dioxide, to capture pollutants and, upon exposure to light, degrade them through oxidation into harmless byproducts.

Titanium dioxide is already used in some wastewater treatment systems. It is usually turned into a slurry, combined with wastewater and exposed to ultraviolet light to destroy contaminants. The slurry must then be filtered from the water.

The NEWT mat simplifies the process. The mat is made of spun polyvinyl fibers. The researchers made it highly porous by adding small plastic beads that were later dissolved with chemicals. The pores offer plenty of surface area for titanium oxide particles to inhabit and await their prey.

The mat’s hydrophobic (water-avoiding) fibers naturally attract hydrophobic contaminants like the endocrine disruptors used in the tests. Once bound to the mat, exposure to light activates the photocatalytic titanium dioxide, which produces reactive oxygen species (ROS) that destroy the contaminants.

Established by the National Science Foundation in 2015, NEWT is a national research center that aims to develop compact, mobile, off-grid water-treatment systems that can provide clean water to millions of people who lack it and make U.S. energy production more sustainable and cost-effective.

NEWT researchers said their mat can be cleaned and reused, scaled to any size, and its chemistry can be tuned for various pollutants.

“Current photocatalytic treatment suffers from two limitations,” said Rice environmental engineer and NEWT Center Director Pedro Alvarez. “One is inefficiency because the oxidants produced are scavenged by things that are much more abundant than the target pollutant, so they don’t destroy the pollutant.

The Rice University-led NEWT Center created a nanoparticle-infused polymer mat that both attracts and destroys pollutants in wastewater or drinking water. A mat, top left, is immersed in water with methylene blue as a contaminant. The contaminant is then absorbed at top right by the mat and, in the bottom images, destroyed by exposure to light. The mat is then ready for reuse. Credit: Rice University/NEWT

“Second, it costs a lot of money to retain and separate slurry photocatalysts and prevent them from leaking into the treated water,” he said. “In some cases, the energy cost of filtering that slurry is more than what’s needed to power the UV lights.

“We solved both limitations by immobilizing the catalyst to make it very easy to reuse and retain,” Alvarez said. “We don’t allow it to leach out of the mat and impact the water.”

Alvarez said the porous polymer mat plays an important role because it attracts the target pollutants. “That’s the bait and hook,” he said. “Then the photocatalyst destroys the pollutant by producing hydroxyl radicals.”

“The nanoscale pores are introduced by dissolving a sacrificial polymer on the electrospun fibers,” lead author and former Rice postdoctoral researcher Chang-Gu Lee said. “The pores enhance the contaminants’ access to titanium dioxide.”

The experiments showed dramatic energy reduction compared to wastewater treatment using slurry.

“Not only do we destroy the pollutants faster, but we also significantly decrease our electrical energy per order of reaction,” Alvarez said. “This is a measure of how much energy you need to remove one order of magnitude of the pollutant, how many kilowatt hours you need to remove 90 percent or 99 percent or 99.9 percent.

“We show that for the slurry, as you move from treating distilled water to wastewater treatment plant effluent, the amount of energy required increases 11-fold. But when you do this with our immobilized bait-and-hook photocatalyst, the comparable increase is only two-fold. It’s a significant savings.”

The mat also would allow treatment plants to perform pollutant removal and destruction in two discrete steps, which isn’t possible with the slurry, Alvarez said. “It can be desirable to do that if the water is murky and light penetration is a challenge. You can fish out the contaminants adsorbed by the mat and transfer it to another reactor with clearer water. There, you can destroy the pollutants, clean out the mat and then return it so it can fish for more.”

Tuning the mat would involve changing its hydrophobic or hydrophilic properties to match target pollutants. “That way you could treat more water with a smaller reactor that is more selective, and therefore miniaturize these reactors and reduce their carbon footprints,” he said. “It’s an opportunity not only to reduce energy requirements, but also space requirements for photocatalytic water treatment.”

Alvarez said collaboration by NEWT’s research partners helped the project come together in a matter of months. “NEWT allowed us to do something that separately would have been very difficult to accomplish in this short amount of time,” he said.

“I think the mat will significantly enhance the menu from which we select solutions to our water purification challenges,” Alvarez said.

More information: Chang-Gu Lee et al, Porous electrospun fibers embedding TiO2 for adsorption and photocatalytic degradation of water pollutants, Environmental Science & Technology (2018). DOI: 10.1021/acs.est.7b06508

Provided by Rice University

Explore further:Researchers turn plastic pollution into cleaners

Rice University: NEWT: New One-Step Catalyst Converts Nitrates to Water and Air

Rice University’s indium-palladium nanoparticle catalysts clean nitrates from drinking water by converting the toxic molecules into air and water. Credit Jeff Fitlow/Rice University

A simple, one-step catalyst could help yield cleaner drinking water with less nitrates.

A team from Rice University’s Nanotechnology Enabled Water Treatment (NEWT) Center have discovered that a catalyst made from indium and palladium can clean toxic nitrates from drinking water by converting them into air and water.

“Indium likes to be oxidized,” co-author Kim Heck, a research scientist at Rice, said in a statement. “From our in situ studies, we found that exposing the catalysts to solutions containing nitrate caused the indium to become oxidized.

“But when we added hydrogen-saturated water, the palladium prompted some of that oxygen to bond with the hydrogen and form water, and that resulted in the indium remaining in a reduced state where it’s free to break apart more nitrates,” she added.

In previous research, the researchers discovered that gold-palladium nanoparticles were not good catalysts for breaking apart nitrates. This led to the discovery of indium and palladium as a suitable catalyst.

“Nitrates are molecules that have one nitrogen atom and three oxygen atoms,” Rice chemical engineer Michael Wong, the lead scientist on the study, said in a statement. “Nitrates turn into nitrites if they lose an oxygen, but nitrites are even more toxic than nitrates, so you don’t want to stop with nitrites. Moreover, nitrates are the more prevalent problem.

“Ultimately, the best way to remove nitrates is a catalytic process that breaks them completely apart into nitrogen and oxygen or in our case, nitrogen and water because we add a little hydrogen,” he added. “More than 75 percent of Earth’s atmosphere is gaseous nitrogen, so we’re really turning nitrates into air and water.”

Nitrates, which could also be a carcinogenic, are considered toxic to both infants and pregnant women.

Nitrate pollution is common in agricultural communities, especially in the U.S. Corn Belt and California’s Central Valley, where fertilizers are heavily used. Studies have shown that nitrate pollution is on the rise because of changing land-use patterns. 

The Environmental Protection Agency regulates allowable limits both nitrates and nitrites for safe drinking water. In communities with polluted wells and lakes, that typically means pretreating drinking water with ion-exchange resins that trap and remove nitrates and nitrites without destroying them.

“Nitrates come mainly from agricultural runoff, which affects farming communities all over the world,” Wong said. “Nitrates are both an environmental problem and health problem because they’re toxic.

“There are ion-exchange filters that can remove them from water, but these need to be flushed every few months to reuse them, and when that happens, the flushed water just returns a concentrated dose of nitrates right back into the water supply.”

The researchers will now try to develop a commercially viable water-treatment system.

“That’s where NEWT comes in,” Wong said. “NEWT is all about taking basic science discoveries and getting them deployed in real-world conditions.

“This is going to be an example within NEWT where we have the chemistry figured out, and the next step is to create a flow system to show proof of concept that the technology can be used in the field,” he added.

The study was published in ACS Catalysis.

Army COE Creates New Energy Efficient ‘Graphene Oxide’ Water Filter at Commercial Scale

The Army Corps of Engineers have successfully created a usable prototype of a new type of water filter.

The membranes are made of a mixture of chitosan, a material commonly found in shrimp shells, and a new synthetic chemical known as “graphene oxide”. Graphene oxide is a highly researched chemical worldwide.

  According to the Army Corps, one problem encountered by scientists working with graphene oxide is not being able to synthesize the material on a scale that can be put to use.

“One of the major breakthroughs that we’ve had here is that with our casting process, we’re not limited by size,” explains Luke Gurtowski, a research chemical engineer working on the membranes.

These filters have been found to effectively remove a number of different contaminants commonly found in water.

Dr. Christopher Griggs is the research scientist in charge of overseeing development of the new membranes.

Dr. Griggs told us, “Anybody who’s experienced water shortages or has been concerned about their water quality, or any type of contaminants in the water, this type of technology certainly works to address that.”

Another challenged faced by conventional water filtering methods is maintaining high energy efficiency.

“It requires a lot of energy for the net driving pressure to force the water through the membrane,” Dr. Griggs explains. “…we’re going to have to look to new materials to try to get those efficiency gains, and so graphene oxide is a very promising candidate for that.”

The Engineer Research and Development Center currently has two patents associated with the new filters and hopes to apply them for both civil and military purposes in the near future. 

Rice University (NEWT) / China team use phage-enhanced nanoparticles to kill bacteria that foul water treatment systems

Clusters of nanoparticles with phage viruses attached find and kill Escherichia coli bacteria in a lab test at Rice University. 

Abstract:
Magnetic nanoparticle clusters have the power to punch through biofilms to reach bacteria that can foul water treatment systems, according to scientists at Rice University and the University of Science and Technology of China.
Magnetized viruses attack harmful bacteria: Rice, China team uses phage-enhanced nanoparticles to kill bacteria that foul water treatment systems.

Researchers at Rice and the University of Science and Technology of China have developed a combination of antibacterial phages and magnetic nanoparticle clusters that infect and destroy bacteria that are usually protected by biofilms in water treatment systems. (Credit: Alvarez Group/Rice University)

The nanoclusters developed through Rice’s Nanotechnology-Enabled Water Treatment (NEWT) Engineering Research Center carry bacteriophages – viruses that infect and propagate in bacteria – and deliver them to targets that generally resist chemical disinfection.

Without the pull of a magnetic host, these “phages” disperse in solution, largely fail to penetrate biofilms and allow bacteria to grow in solution and even corrode metal, a costly problem for water distribution systems.

The Rice lab of environmental engineer Pedro Alvarez and colleagues in China developed and tested clusters that immobilize the phages. A weak magnetic field draws them into biofilms to their targets.

The research is detailed in the Royal Society of Chemistry’s Environmental Science: Nano.
“This novel approach, which arises from the convergence of nanotechnology and virology, has a great potential to treat difficult-to-eradicate biofilms in an effective manner that does not generate harmful disinfection byproducts,” Alvarez said.

Biofilms can be beneficial in some wastewater treatment or industrial fermentation reactors owing to their enhanced reaction rates and resistance to exogenous stresses, said Rice graduate student and co-lead author Pingfeng Yu. “However, biofilms can be very harmful in water distribution and storage systems since they can shelter pathogenic microorganisms that pose significant public health concerns and may also contribute to corrosion and associated economic losses,” he said.

The lab used phages that are polyvalent – able to attack more than one type of bacteria – to target lab-grown films that contained strains of Escherichia coli associated with infectious diseases and Pseudomonas aeruginosa, which is prone to antibiotic resistance.

The phages were combined with nanoclusters of carbon, sulfur and iron oxide that were further modified with amino groups. The amino coating prompted the phages to bond with the clusters head-first, which left their infectious tails exposed and able to infect bacteria.

The researchers used a relatively weak magnetic field to push the nanoclusters into the film and disrupt it. Images showed they effectively killed E. coli and P. aeruginosa over around 90 percent of the film in a test 96-well plate versus less than 40 percent in a plate with phages alone.

The researchers noted bacteria may still develop resistance to phages, but the ability to quickly disrupt biofilms would make that more difficult. Alvarez said the lab is working on phage “cocktails” that would combine multiple types of phages and/or antibiotics with the particles to inhibit resistance.

Graduate student Ling-Li Li of the University of Science and Technology of China, Hefei, is co-lead author of the paper. Co-authors are graduate student Sheng-Song Yu and Han-Qing Yu, a professor at the University of Science and Technology of China, and graduate student Xifan Wang and temporary research scientist Jacques Mathieu of Rice.

The National Science Foundation and its Rice-based NEWT Engineering Research Center supported the research.

Researchers develop hybrid nuclear desalination technique with improved efficiency

Associate Professor I.M. Kurchatov and graduate student R.A. Alexandrov work at the research stand of water purification. Credit: National Research Nuclear University

Lack of fresh water requires development of new desalination methods, including advanced nuclear desalination and water treatment and recycling; requirements for drinking water and other uses may be different.

 

To improve environmental safety and desalination technology, it is necessary to solve a global scientific and technological problem—the creation of an integrated water supply system based on the use of new high-efficiency desalination methods such as nuclear membrane desalination or hybrid technologies. These methods should be combined with recycling and treatment of residues to a level that corresponds with environmental requirements.

The majority of modern desalination technologies are based on distillation of thermal energy, including nuclear desalination, or using desalination membranes (reverse osmosis and electrodialysis membranes). In the process of distillation, salt water is boiled, and produced steam leaves the system and is condensed as fresh water. If a nuclear reactor is used as the heat source, the method is called nuclear desalination.

The membrane method of reverse osmosis is based on the filtering of salt water under the influence of differential pressure across a semipermeable membrane allowing water molecules and excluding salts; the pressure differential should be more than the so-called osmotic pressure (~ 30 atm. for seawater). In membrane electrodialysis, ions penetrate through the so-called ion-exchange membranes, and fresh water remains in the channel.

These membrane methods can be used in conjunction with nuclear desalination (hybrid desalination technologies), i.e., they can be added to existing nuclear facilities, where there is a relatively cheap access to thermal energy.

For the normal functioning of desalination plants, quality of the source water must meet certain strict requirements. This entails the need for a pre-treatment system, the cost of which is sometimes two to three times more than the cost of the desalination plant itself.

Scientists from the National Research Nuclear University MEPhI (Russia) have developed a new technology and technological schemes for a pretreatment unit taking into account data on the composition of pollutants, salinity and performance of water treatment systems. It is based on the reagent methods with hydrodynamic activation of the process of pollutant withdrawal in coagulation, flocculation and adsorption, which reduces the unit’s size and cost. Moreover, the majority of the sparingly soluble salts can be removed in the pretreatment unit, which increases the efficiency of the system as a whole.

From the pre-water treatment unit, salt water flows into the desalination unit, a very energy-intensive process. Hybrid desalination schemes are proposed to reduce the energy consumption of the desalination process. These schemes use distillation and membrane methods in combination, to produce both drinking water and process water.

In addition, the project proposes the development of an integrated technological system of water recycling and desalination systems to reduce environmental burdens and improve the energy efficiency of the system as a whole.

The results are intended to be used in complex projects of the State Corporation Rosatom, in particular, in relation to nuclear power plants in Egypt, where it is planned to realize a nuclear desalination technology.

Explore further: Drinking water from the sea using solar energy

Provided by: National Research Nuclear University

 

Reusable carbon nanotubes could be the water filter of the future, says RIT study

 

A new class of carbon nanotubes could be the next-generation clean-up crew for toxic sludge and contaminated water, say researchers at Rochester Institute of Technology.

Enhanced single-walled carbon nanotubes offer a more effective and sustainable approach to water treatment and remediation than the standard industry materials–silicon gels and activated carbon–according to a paper published in the March issue of Environmental Science Water: Research and Technology.

RIT researchers John-David Rocha and Reginald Rogers, authors of the study, demonstrate the potential of this emerging technology to clean polluted water. Their work applies carbon nanotubes to environmental problems in a specific new way that builds on a nearly two decades of nanomaterial research. Nanotubes are more commonly associated with fuel-cell research.

Also Read About: UC BERKELEY: NANOTECHNOLOGY CAN HELP DELIVER AFFORDABLE, CLEAN WATER WITH GRAPHENE MEMBRANE: VIDEO

 

 

“This aspect is new–taking knowledge of carbon nanotubes and their properties and realizing, with new processing and characterization techniques, the advantages nanotubes can provide for removing contaminants for water,” said Rocha, assistant professor in the School of Chemistry and Materials Science in RIT’s College of Science.

Rocha and Rogers are advancing nanotube technology for environmental remediation and water filtration for home use.

“We have shown that we can regenerate these materials,” said Rogers, assistant professor of chemical engineering in RIT’s Kate Gleason College of Engineering. “In the future, when your water filter finally gets saturated, put it in the microwave for about five minutes and the impurities will get evaporated off.”

Carbon nanotubes are storage units measuring about 50,000 times smaller than the width of a human hair. Carbon reduced to the nanoscale defies the rules of physics and operates in a world of quantum mechanics in which small materials become mighty.

“We know carbon as graphite for our pencils, as diamonds, as soot,” Rocha said. “We can transform that soot or graphite into a nanometer-type material known as graphene.”

A single-walled carbon nanotube is created when a sheet of graphene is rolled up. The physical change alters the material’s chemical structure and determines how it behaves. The result is “one of the most heat conductive and electrically conductive materials in the world,” Rocha said. “These are properties that only come into play because they are at the nanometer scale.”

The RIT researchers created new techniques for manipulating the tiny materials. Rocha developed a method for isolating high-quality, single-walled carbon nanotubes and for sorting them according to their semiconductive or metallic properties. Rogers redistributed the pure carbon nanotubes into thin papers akin to carbon-copy paper.

“Once the papers are formed, now we have the adsorbent–what we use to pull the contaminants out of water,” Rogers said.

The filtration process works because “carbon nanotubes dislike water,” he added. Only the organic contaminants in the water stick to the nanotube, not the water molecules.

“This type of application has not been done before,” Rogers said. “Nanotubes used in this respect is new.”

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Co-authors on the paper are Ryan Capasse, RIT chemistry alumnus, and Anthony Dichiara, a former RIT post-doctoral researcher in chemical engineering now at the University of Washington.

Researchers at A*STAR Discover Nano-Structured Coatings Absorb Pollutants from Drinking Water

Low-cost iron hydroxide coatings with unique fin-like shapes can clean heavily contaminated water with a simple dipping procedure.

As one of the primary components of rust, iron hydroxides normally pose corrosive risks to health. A team at Agency for Science, Technology and Research (A*STAR), Singapore, has found a way to turn these compounds into an environmentally friendly coating that repeatedly absorbs large amounts of pollutants, such as dyes, from drinking water at room temperature.

Conventional activated charcoal treatments have trouble removing heavy metals and bulky organic compounds from water. Instead, iron hydroxides are being increasingly used because they can form stable chemical bonds to these unwanted pollutants. Researchers have recently found that turning iron particles into miniscule nanomaterials boosts their active surface areas and enhances chemical absorption processes.

Separating iron hydroxide nanomaterials from water, however, remains difficult. Commercial filtration systems and experimental magnetic treatments introduce significant complexity and cost into treatment plants. Failure to remove these substances may lead to acute or chronic health issues if they are ingested.

To improve handling of the nanosized iron hydroxides, Sing Yang Chiam from A*STAR’s Institute of Materials Research and Engineering and co-workers decided to attach them to a solid, sponge-like support known as nickel foam. This type of material could safely trap and remove contaminants by immersion into dirty water, and then be regenerated with a simple chemical treatment. But immobilizing the nanoparticles also diminishes their valuable high surface areas — a paradox the team had to solve.

“We were not totally convinced that a coating approach could perform as well as traditional powders and particles,” says Chiam. “So we were really pleased when some nice test results came through.”

The A*STAR team found their answer by synthesizing iron hydroxide coatings with a hierarchy of structural features, from nano- to micrometer scales. To do so, they turned to electrodeposition, a green synthesis method that deposits aqueous metal ions on to nickel foam at mild voltages. After optimizing the uniformity and adhesion of their multiscale coatings, they tested their material in water contaminated by a ‘Congo red’ dye pollutant. Within half an hour, the water became almost colorless, with over 90 per cent of the dye attached to the special coating.

 

The Institute of Materials Research and Engineering team. Credit: © 2017 A*STAR Institute of Materials Research and Engineering

 

Close-up views of the coating’s nanostructure using scanning electron microscopy revealed that elongated, fin-like protrusions were key to recovering active surface area for high-performance pollutant removal. “Even though these coatings have some of the highest capacities ever reported, they are only operating at a fraction of their theoretical capacity,” says Chiam. “We are really excited about tapping their potential.”

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Story Source:

Materials provided by The Agency for Science, Technology and Research (A*STAR). Note: Content may be edited for style and length.

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Journal Reference:

1. Junyi Liu, Lai Mun Wong, Gurudayal Gurudayal, Lydia Helena Wong, Sing Yang Chiam, Sam Fong Yau Li, Yi Ren. Immobilization of dye pollutants on iron hydroxide coated substrates: kinetics, efficiency and the adsorption mechanism. J. Mater. Chem. A, 2016; 4 (34): 13280 DOI: 10.1039/C6TA03088B

Technology could make treatment and reuse of oil and gas wastewater simpler, cheaper – University of Colorado + MIT + Rice Universities (NEWT)

Oil and gas operations in the United States produce about 21 billion barrels of wastewater per year. The saltiness of the water and the organic contaminants it contains have traditionally made treatment difficult and expensive.

Engineers at the University of Colorado Boulder have invented a simpler process that can simultaneously remove both salts and organic contaminants from the wastewater, all while producing additional energy. The new technique, which relies on a microbe-powered battery, was recently published in the journal Environmental Science Water Research & Technology as the cover story.

“The beauty of the technology is that it tackles two different problems in one single system,” said Zhiyong Jason Ren, a CU-Boulder associate professor of environmental and sustainability engineering and senior author of the paper. “The problems become mutually beneficial in our system—they complement each other—and the process produces energy rather than just consumes it.”

The new treatment technology, called microbial capacitive desalination, is like a battery in its basic form, said Casey Forrestal, a CU-Boulder postdoctoral researcher who is the lead author of the paper and working to commercialize the technology. “Instead of the traditional battery, which uses chemicals to generate the electrical current, we use microbes to generate an electrical current that can then be used for desalination.” 

This microbial electro-chemical approach takes advantage of the fact that the contaminants found in the wastewater contain energy-rich hydrocarbons, the same compounds that make up oil and natural gas. The microbes used in the treatment process eat the hydrocarbons and release their embedded energy. The energy is then used to create a positively charged electrode on one side of the cell and a negatively charged electrode on the other, essentially setting up a battery.

Because salt dissolves into positively and negatively charged ions in water, the cell is then able to remove the salt in the wastewater by attracting the charged ions onto the high-surface-area electrodes, where they adhere.

Not only does the system allow the salt to be removed from the wastewater, but it also creates additional energy that could be used on site to run equipment, the researchers said.

“Right now oil and gas companies have to spend energy to treat the wastewater,” Ren said. “We are able to treat it without energy consumption; rather we extract energy out of it.”

Some oil and gas wastewater is currently being treated and reused in the field, but that treatment process typically requires multiple steps—sometimes up to a dozen—and an input of energy that may come from diesel generators.

Because of the difficulty and expense, wastewater is often disposed of by injecting it deep underground. The need to dispose of wastewater has increased in recent years as the practice of hydraulic fracturing, or “fracking,” has boomed. Fracking refers to the process of injecting a slurry of water, sand and chemicals into wells to increase the amount of oil and natural gas produced by the well.

Injection wells that handle wastewater from fracking operations can cause earthquakes in the region, according to past research by CU-Boulder scientists and others.

The demand for water for fracking operations also has caused concern among people worried about scarce water resources, especially in arid regions of the country. Finding water to buy for fracking operations in the West, for example, has become increasingly challenging and expensive for oil and gas companies.

Ren and Forrestal’s microbial capacitive desalination cell offers the possibility that water could be more economically treated on site and reused for fracking.

To try to turn the technology into a commercial reality, Ren and Forrestal have co-founded a startup company called BioElectric Inc. In order to determine if the technology offers a viable solution for oil and gas companies, the pair first has to show they can scale up the work they’ve been doing in the lab to a size that would be useful in the field.

The cost to scale up the technology also needs to be competitive with what oil and gas companies are paying now to buy water to use for fracking, Forrestal said. There also is some movement in state legislatures to require oil and gas companies to reuse wastewater, which could make BioElectric’s product more appealing even at a higher price, the researchers said.

MIT – Toward Cheaper Water Treatment for Oil & Gas Operations

MIT spinout makes treating, recycling highly contaminated oilfield water more economical

Also Read: Nanotechnology Enabled Water Treatment or NEWT: Transforming the Economics of Water Treatment: Rice, ASU, Yale, UTEP win $18.5 Million NSF Engineering Research Center

 

 

 

Explore further: New contaminants found in oil and gas wastewater

More information: “Microbial capacitive desalination for integrated organic matter and salt removal and energy production from unconventional natural gas produced water.” Environ. Sci.: Water Res. Technol., 2015,1, 47-55 DOI: 10.1039/C4EW00050A

Provided by: University of Colorado at Boulder

Genesis Nanotechnology ~ “Great Things from Small Things”
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NSF and Stony Brook University: New Nanotechnology to produce sustainable, clean water for developing nations: Video

This technology would enable communities to produce their own water filters using biomass nanofibers, making clean water more accessible and affordable.

The world’s population is projected to increase by 2-3 billion over the next 40 years. Already, more than three quarters of a billion people lack access to clean drinking water and 85 percent live in the driest areas of the planet. Those statistics are inspiring chemist Ben Hsiao and his team at Stony Brook University. With support from the National Science Foundation (NSF), the team is hard at work designing nanometer-scale water filters that could soon make clean drinking water available and affordable for even the poorest of the poor.

Traditional water filters are made of polymer membranes with tiny pores to filter out bacteria and viruses. Hsiao’s filters are made of fibers that are all tangled up, and the pores are the natural gaps between the strands. The team’s first success at making the new nanofilters uses a technique called electrospinning to produce nanofibers under an electrical field.

Hsiao’s team is also looking to cut costs even further by using “biomass” nanofibers extracted from trees, grasses, shrubs — even old paper. Hsiao says it will be a few years yet before the environmentally friendly biomass filters are ready for widespread use in developing countries, but the filters will eliminate the need to build polymer plants in developing areas. Ultimately, those filters could be produced locally with native biomass or biowaste.

The research in this episode was supported by NSF award #1019370, Breakthrough Concepts on Nanofibrous Membranes with Directed Water Channels for Energy-Saving Water Purification.

Watch the Video: New Nanotechnology to Produce Sustainable, Clean Drinking Water for Developing Nations