Thursday, September 28, 2017

Filter May Be a Match for Fracking Water

Superhydrophilic Membrane Cleans Fluids for Reuse

Date: September 25, 2017
Source: Rice University
Summary: A superhydrophilic filter has proven able to remove more than 90 percent of contaminants from water used in hydraulic fracturing operations at shale oil and gas wells.


A superhydrophilic filter produced at Rice University can remove more than 90 percent of contaminants from water used in hydraulic fracturing operations. In this image, 'produced' water from a Marcellus shale fracturing site is at left, the retentate (carbon removed from the feed) is at center, and filtered 'permeate' water is at right. The hydrophilic treatment keeps the filter from fouling and restricting flow while rejecting contaminants.
Credit: Barron Research Group/Rice University

A new filter produced by Rice University scientists has proven able to remove more than 90 percent of hydrocarbons, bacteria and particulates from contaminated water produced by hydraulic fracturing (fracking) operations at shale oil and gas wells.

The work by Rice chemist Andrew Barron and his colleagues turns a ceramic membrane with microscale pores into a superhydrophilic filter that "essentially eliminates" the common problem of fouling.

The researchers determined one pass through the membrane should clean contaminated water enough for reuse at a well, significantly cutting the amount that has to be stored or transported.

The work is reported in Nature's open-access Scientific Reports.

The filters keep emulsified hydrocarbons from passing through the material's ionically charged pores, which are about one-fifth of a micron wide, small enough that other contaminants cannot pass through. The charge attracts a thin layer of water that adheres to the entire surface of the filter to repel globules of oil and other hydrocarbons and keep it from clogging.

A hydraulically fractured well uses more than 5 million gallons of water on average, of which only 10 to 15 percent is recovered during the flowback stage. "This makes it very important to be able to re-use this water," Barron said.

Not every type of filter reliably removes every type of contaminant, he said.

Solubilized hydrocarbon molecules slip right through microfilters designed to remove bacteria. Natural organic matter, like sugars from guar gum used to make fracking fluids more viscous, require ultra- or nanofiltration, but those foul easily, especially from hydrocarbons that emulsify into globules. A multistage filter that could remove all the contaminants isn't practical due to cost and the energy it would consume.

"Frac water and produced waters represent a significant challenge on a technical level," Barron said. "If you use a membrane with pores small enough to separate, they foul, and this renders the membrane useless.

"In our case, the superhydrophilic treatment results in an increased flux (flow) of water through the membrane and inhibits any hydrophobic material -- such as oil -- from passing through. The difference in solubility of the contaminants thus works to allow for separation of molecules that should in theory pass through the membrane."

Barron and his colleagues used cysteic acid to modify the surface of an alumina-based ceramic membrane, making it superhydrophilic, or extremely attracted to water. The superhydrophilic surface has a contact angle of 5 degrees. (A contact angle of 0 degrees would be a puddle.)

The acid covered not only the surface but also the inside of the pores, and that kept particulates from sticking to them and fouling the filter.

In tests with fracking flowback or produced water that contained guar gum, the alumna membrane showed a slow initial decrease in flux -- a measure of the flow of mass through a material -- but it stabilized for the duration of lab tests. Untreated membranes showed a dramatic decrease within 18 hours.

The researchers theorized the initial decrease in flow through the ceramics was due to purging of air from the pores, after which the superhydrophilic pores trapped the thin layer of water that prevented fouling.

"This membrane doesn't foul, so it lasts," Barron said. "It requires lower operating pressures, so you need a smaller pump that consumes less electricity. And that's all better for the environment."

Story Source:
Rice University. "Filter may be a match for fracking water: Superhydrophilic membrane cleans fluids for reuse." ScienceDaily. ScienceDaily, 25 September 2017. https://www.sciencedaily.com/releases/2017/09/170925104714.htm.

Monday, September 11, 2017

Diverse Landscapes are More Productive and Adapt Better to Climate Change

Date: September 4, 2017
Source: University of Zurich
Summary: Ecosystems with high biodiversity are more productive and stable towards annual fluctuations in environmental conditions than those with a low diversity of species. They also adapt better to climate-driven environmental changes. These are the key findings environmental scientists made in a study of about 450 landscapes harboring 2,200 plants and animal species.

Ecosystems with high biodiversity are more productive and stable towards annual fluctuations in environmental conditions than those with a low diversity of species. They also adapt better to climate-driven environmental changes. These are the key findings environmental scientists at the University of Zurich made in a study of about 450 landscapes harbouring 2,200 plants and animal species.

The dramatic, worldwide loss of biodiversity is one of today's greatest environmental problems. The loss of species diversity affects important ecosystems on which humans depend. Previous research predominantly addressed short-term effects of biodiversity in small experimental plots planted with few randomly selected plant species. These studies have shown that species-poor plant assemblages function less well and produce less biomass than species rich systems.

Extensive Study with About 2,200 Species in 450 Landscapes

Researchers participating in the University Research Priority Programme "Global Change and Biodiversity" of the University of Zurich now demonstrate similar positive effects of biodiversity in real-world ecosystems in which mechanisms different from the ones in artificial experimental plots are at play. Using 450 different 1-km2 landscapes that spanned the entire area of Switzerland, they investigated the role of the diversity of plant, bird and butterfly species for the production of biomass, which was estimated from satellite data.

Biodiversity is Important for the Functioning of Complex, Natural Ecosystems

"Our results show that biodiversity plays an essential role for the functioning of extensive natural landscapes that consist of different ecosystem types such as forests, meadows or urban areas," study leader Pascal Niklaus from Department of Evolutionary Biology and Environmental Studies says. The analyses showed that landscapes with a greater biodiversity were more productive and that their productivity showed a lower year-to-year variation.

Biodiversity Promoted the Adaptation of Landscapes

The satellite data analysed by the scientists revealed that the annual growing period increased in length throughout the last 16 years, an effect that can be explained by climate warming. The prolongation in growing season was considerably larger in more biodiverse landscapes. These relations were robust and remained important even when a range of other drivers such as temperature, rainfall, solar irradiation, topography, of the specific composition of the landscapes were considered. "This indicates that landscapes with high biodiversity can adapt better and faster to changing environmental conditions," Niklaus concludes.

Story Source:
University of Zurich. "Diverse landscapes are more productive and adapt better to climate change." ScienceDaily. ScienceDaily, 4 September 2017. https://www.sciencedaily.com/releases/2017/09/170904165641.htm

Friday, August 25, 2017

New Microbe Has Potential to Help Rebalance Earth's Nitrogen Cycle

Date: August 23, 2017
Source: University of Alberta
Summary: Microbiologists have now provided unparalleled insight into the Earth's nitrogen cycle, identifying and characterizing the ammonia-oxidizing microbe, Nitrospira inopinata.

New research from University of Alberta and University of Vienna microbiologists provides unparalleled insight into the Earth's nitrogen cycle, identifying and characterizing the ammonia-oxidizing microbe, Nitrospira inopinata. The findings, explained Lisa Stein, co-author and professor of biology, have significant implications for climate change research.

"I consider nitrogen the camouflaged beast in our midst," said Stein.

"Humans are now responsible for adding more fixed nitrogen, in the form of ammonium, to the environment than all natural sources combined. Because of that, the nitrogen cycle has been identified as the most unbalanced biogeochemical cycle on the planet."

The Camouflaged Beast

Earth's nitrogen cycle has been thrown significantly off balance by the process we use to make fertilizer, known as the Haber-Bosch process, which adds massive quantities of fixed nitrogen, or ammonium, to the environment. Downstream effects of excess ammonium has huge environmental implications, from dead zones in our oceans to a greenhouse gas effect 300 times that of carbon dioxide on a molecule to molecule basis.

Isolation and characterization of the Nitrospira inopinata microbe, Stein said, could hold the answers for Earth's nitrogen problem.

Practical Applications

"The Nitrospira inopinata microbe is an ammonium sponge, outcompeting nearly all other bacteria and archaea in its oxidation of ammonium in the environment," explained Stein. "Now that we know how efficient this microbe is, we can explore many practical applications to reduce the amount of ammonium that contributes to environmental problems in our atmosphere, water, and soil."

The applications range from wastewater treatment, with the development of more efficient biofilms, to drinking water and soil purification to climate change research.

"An efficient complete ammonia oxidizer, such as Nitrospira inopinata, may produce less nitrous oxide," explained Kits. "By encouraging our microbe to outgrow other, incomplete oxidizers, we may, in turn, reduce their contribution to the greenhouse gas effect. Further investigation is required."

Story Source:
University of Alberta. "New microbe has potential to help rebalance Earth's nitrogen cycle." ScienceDaily. ScienceDaily, 23 August 2017. www.sciencedaily.com/releases/2017/08/170823142427.htm

Wednesday, August 9, 2017

Antibiotics Come With 'Environmental Side Effects'

Report published in Microchemical Journal wins Elsevier's Atlas award

Date: July 25, 2017
Source: Elsevier
Summary: Researchers are bringing attention to the fact that commonly used antibiotic drugs are making their way out into the environment, where they can harm microbes that are essential to a healthy environment.

Researchers writing in Microchemical Journal are bringing attention to the fact that commonly used antibiotic drugs are making their way out into the environment, where they can harm microbes that are essential to a healthy environment. Their review article has been selected for the Elsevier Atlas Award, which recognizes research that could significantly impact people's lives around the world or has already done so.

"The amount of antibiotics is very, very low -- there are normally nanograms per liter of these molecules found in natural environments," said Dr. Paola Grenni, a microbial ecologist at the National Research Council's Water Research Institute in Italy. "But the antibiotics and also other pharmaceuticals can have an effect even in low concentrations, the so-called environmental side-effects."

When people take antibiotics, their bodies break down and metabolize only a portion of the drugs. The rest is excreted and enters wastewater. Because wastewater treatment plants aren't designed to fully remove antibiotic or other pharmaceutical compounds, many of those compounds reach natural systems where they can accumulate and harm microbes in nature.

That's a big concern, Dr. Grenni said, because many microbial species found in the environment are beneficial, playing important roles in natural cycles of nutrients, primary production and climate regulation. Some microbes also degrade organic contaminants, such as pesticides.

The review paper published by Dr. Grenni along with colleagues Drs. Valeria Ancona and Anna Barra Caracciolo highlights commonly used antibiotic compounds and their active ingredients. Some of those medications are used to treat people. Many others are used in veterinary medicine, especially to treat farm animals including cattle, pigs and poultry.

The release of antibiotics into natural systems is a "real-life experiment" with consequences that aren't yet fully known. Dr. Grenni and her colleagues say there's a need for more specific protections of environmental microbes given their importance to functioning ecosystems.

It's important for nations to work to reduce unnecessary antibiotic use and the release of those antibiotics that are needed into the environment. To that end, efforts should be made to equip wastewater treatment plants for removal of those compounds and to devise methods to improve the degradation of antibiotics once they reach natural environments. Members of the public can help by taking care to use antibiotics only when they are truly needed, and by disposing of expired medications properly.

"There are only a few researchers working in this field, but it's very important," Dr. Grenni said. "We need to know the different molecules we normally use that are in the environment and the effect they have. We need more research in this field."

Story Source: Elsevier. "Antibiotics come with 'environmental side effects': Report published in Microchemical Journal wins Elsevier's Atlas award." ScienceDaily. ScienceDaily, 25 July 2017. https://www.sciencedaily.com/releases/2017/07/170725122046.htm.

Friday, July 28, 2017

Heavy Metals in Water Meet Their Match

Reusable, Carbon Nanotube-Reinforced Filters Clean Toxins from Water, study shows

Date: July 27, 2017
Source: Rice University
Summary: A high school student's project removes more than 99 percent of heavy metal toxins from water. A new article demonstrates its potential for water remediation in developing nations around the world.



Plain quartz fiber, top, gains the ability to remove toxic metals from water when carbon nanotubes are added, bottom. The filters absorbed more than 99 percent of metals from test samples laden with cadmium, cobalt, copper, mercury, nickel and lead. Once saturated, the filters can be washed and reused.
Credit: Barron Research Group/Rice University


Carbon nanotubes immobilized in a tuft of quartz fiber have the power to remove toxic heavy metals from water, according to researchers at Rice University.

Prize-winning filters produced in the lab of Rice chemist Andrew Barron by then-high school student and lead author Perry Alagappan absorb more than 99 percent of metals from samples laden with cadmium, cobalt, copper, mercury, nickel and lead. Once saturated, the filters can be washed with a mild household chemical like vinegar and reused.

The researchers calculated one gram of the material could treat 83,000 liters of contaminated water to meet World Health Organization standards -- enough to supply the daily needs of 11,000 people.

The lab's analysis of the new filters appears this month in Nature's open-access Scientific Reports.

The robust filters consist of carbon nanotubes grown in place on quartz fibers that are then chemically epoxidized. Lab tests showed that scaled-up versions of the "supported-epoxidized carbon nanotube" (SENT) filters proved able to treat 5 liters of water in less than one minute and be renewed in 90 seconds. The material retained nearly 100 percent of its capacity to filter water for up to 70 liters per 100 grams of SENT, after which the metals contained could be extracted for reuse or turned into a solid for safe disposal.

While the quartz substrate gives the filter form and the carbon nanotube sheath makes it tough, the epoxidation via an oxidizing acid appears to be most responsible for adsorbing the metal, they determined.

Alagappan, now an undergraduate student at Stanford University, was inspired to start the project during a trip to India, where he learned about contamination of groundwater from the tons of electronic waste -- phones, computers and the like -- that improperly end up in landfills.

"Perry contacted me wanting to gain experience in laboratory research," Barron said. "Since we had an ongoing project started by Jessica Heimann, an undergraduate who was taking a semester at Jacobs University Bremen, this was a perfect match."

Barron said the raw materials for the filter are inexpensive and pointed out the conversion of acetic acid to vinegar is ubiquitous around the globe, which should simplify the process of recycling the filters for reuse even in remote locations. "Every culture on the planet knows how to make vinegar," he said.

"This would make the biggest social impact on village-scale units that could treat water in remote, developing regions," Barron said. "However, there is also the potential to scale up metal extraction, in particular from mine wastewater."

Alagappan's research won a series of awards while he was still a high school student in Clear Lake, a Houston suburb, as well as a visiting student in Barron's Rice lab. First was the top prize for environmental sciences at the Science and Engineering Fair of Houston in 2014. That qualified him to enter the Intel International Science and Engineering Fair in Los Angeles the next year, where he also took the top environmental award.

He booted that into the top prize at the 2015 Stockholm Junior Water Prize, where the crown princess of Sweden presented him with the honor.

"It's been a tremendous honor to be recognized on an international level for this research, and I am grateful for the opportunity to work on this project alongside such a talented group of individuals," Alagappan said. "I also especially appreciated being able to meet with other young researchers at the Intel International Science Fair and the Stockholm Junior Water Prize, who inspired me with their firm commitment to elevate society through science and technology."

Story Source: Rice University. "Heavy metals in water meet their match: Reusable, carbon nanotube-reinforced filters clean toxins from water, study shows." ScienceDaily. ScienceDaily, 27 July 2017. www.sciencedaily.com/releases/2017/07/170727083159.htm

Thursday, July 13, 2017

Release of Treated Wastewater From Hydraulic Fracturing Contaminates Lake

Date: July 12, 2017
Source: American Chemical Society
Summary: Hydraulic fracturing has enabled a domestic oil and gas boom in the US, but its rapid growth has raised questions about what to do with the billions of gallons of wastewater that result. Researchers now report that treating the wastewater and releasing it into surface waters has led to the contamination of a Pennsylvania watershed with radioactive material and endocrine-disrupting chemicals.


Treating fracking wastewater and releasing it into surface waters has led to the contamination of a Pennsylvania watershed with radioactive material and endocrine-disrupting chemicals, report investigators. (Stock image)
Credit: © John / Fotolia


Hydraulic fracturing has enabled a domestic oil and gas boom in the U.S., but its rapid growth has raised questions about what to do with the billions of gallons of wastewater that result. Researchers now report that treating the wastewater and releasing it into surface waters has led to the contamination of a Pennsylvania watershed with radioactive material and endocrine-disrupting chemicals. The study appears in ACS' journal Environmental Science & Technology.

In 2015, the unconventional oil and gas extraction method known as hydraulic fracturing, or "fracking," accounted for more than one-half of oil production and two-thirds of gas production in America, according to the U.S. Energy Information Administration. The method's market share is likely to increase even further. Although the technique has resulted in a shift away from coal, which could reduce greenhouse gas emissions, it produces large amounts of wastewater containing radioactive material, salts, metals, endocrine-disrupting chemicals and polycyclic aromatic hydrocarbons that could pose risks to the environment and human health. A Pennsylvania report estimates that in 2015, 10,000 unconventional oil and gas wells in the Marcellus Shale produced 1.7 billion gallons of wastewater. The facilities that collect the water provide only limited treatment before releasing it into surface waters. Bill Burgos and colleagues at Penn State, Colorado State and Dartmouth wanted to see what impact this strategy of treating and releasing fracking wastewater might be having.

The researchers sampled sediments and porewaters from a lake downstream from two facilities that treat fracking wastewater in Pennsylvania. Their analysis detected that peak concentrations of radium, alkaline earth metals, salts and organic chemicals all occurred in the same sediment layer. The two major classes of organic contaminants included nonylphenol ethoxylates, which are endocrine-disrupting chemicals, and polycyclic aromatic hydrocarbons, which are carcinogens. The highest concentrations coincided with sediment layers deposited five to 10 years ago during a peak period of fracking wastewater disposal. Elevated levels of radium were also found as far as 12 miles downstream of the treatment plants. The researchers say that the potential risks associated with this contamination are unknown, but they suggest tighter regulations of wastewater disposal could help protect the environment and human health.

Story Source:
American Chemical Society. "Release of treated wastewater from hydraulic fracturing contaminates lake." ScienceDaily. ScienceDaily, 12 July 2017. https://www.sciencedaily.com/releases/2017/07/170712110605.htm

Thursday, June 29, 2017

Bacteria-Coated Nanofiber Electrodes Clean Pollutants in Wastewater

Date: June 28, 2017
Source: Cornell University
Summary: Researchers may have created an innovative, cost-competitive electrode material for cleaning pollutants in wastewater.

Cornell University materials scientists and bioelectrochemical engineers may have created an innovative, cost-competitive electrode material for cleaning pollutants in wastewater.

The researchers created electro-spun carbon nanofiber electrodes and coated them with a conductive polymer, called PEDOT, to compete with carbon cloth electrodes available on the market. When the PEDOT coating is applied, an electrically active layer of bacteria -- Geobacter sulfurreducens -- naturally grows to create electricity and transfer electrons to the novel electrode.

The conducting nanofibers create a favorable surface for this bacteria, which digests pollutants from the wastewater and produces electricity, according to the research.

"Electrodes are expensive to make now, and this material could bring the price of electrodes way down, making it easier to clean up polluted water," said co-lead author Juan Guzman, a doctoral candidate in the field of biological and environmental engineering. Under a microscope, the carbon nanofiber electrode resembles a kitchen scrubber.

The electrode was made by co-lead author Meryem Pehlivaner, currently a doctoral student at Northeastern University, with senior author Margaret Frey, professor of fiber science and an associate dean of the College of Human Ecology. Pehlivaner fabricated the carbon nanofibers via electrospinning and carbonization processes. After a few hours electrospinning, a thick nanofiber sheet -- visible to the naked eye -- emerges.

Pehlivaner reached out to Guzman and senior author Lars Angenent, professor of biological and environmental engineering, for collaboration in applying the carbon nanofiber electrodes to simultaneous wastewater treatment and production of electrical energy.

The customizable carbon nanofiber electrode was used for its high porosity, surface area and biocompatibility with the bacteria. By adhering PEDOT, the material gets an improved function, according to the researchers.

Guzman said wastewater treatment plants do not employ this method -- yet. On a large scale, the bacteria at the electrode could capture and degrade pollutants from the wastewater that flows by it. Such a technology can improve wastewater treatment by allowing systems to take up less land and increase throughput.

Concepts like this happen on campuses where faculty and students want to communicate and collaborate, Angenent said. "This defines radical collaboration," he said. "We have fiber scientists talking to environmental engineers, from two very different Cornell colleges, to create reality from an idea -- that was more or less a hunch -- that will make cleaning wastewater better and a little more inexpensive."

Story Source: Cornell University. "Bacteria-coated nanofiber electrodes clean pollutants in wastewater." ScienceDaily. ScienceDaily, 28 June 2017. www.sciencedaily.com/releases/2017/06/170628144829.htm