Graphene Oxide membranes could reduce paper industry energy costs
(Press-News.org) The U.S. pulp and paper industry uses large quantities of water to produce cellulose pulp from trees. The water leaving the pulping process contains a number of organic byproducts and inorganic chemicals. To reuse the water and the chemicals, paper mills rely on steam-fed evaporators that boil up the water and separate it from the chemicals.
Water separation by evaporators is effective but uses large amounts of energy. That's significant given that the United States currently is the world's second-largest producer of paper and paperboard. The country's approximately 100 paper mills are estimated to use about 0.2 quads (a quad is a quadrillion BTUs) of energy per year for water recycling, making it one of the most energy-intensive chemical processes. All industrial energy consumption in the United States in 2019 totaled 26.4 quads, according to Lawrence Livermore National Laboratory.
An alternative is to deploy energy-efficient filtration membranes to recycle pulping wastewater. But conventional polymer membranes -- commercially available for the past several decades -- cannot withstand operation in the harsh conditions and high chemical concentrations found in pulping wastewater and many other industrial applications.
Georgia Institute of Technology researchers have found a method to engineer membranes made from graphene oxide (GO), a chemically resistant material based on carbon, so they can work effectively in industrial applications.
"GO has remarkable characteristics that allow water to get through it much faster than through conventional membranes," said Sankar Nair, professor, Simmons Faculty Fellow, and associate chair for Industry Outreach in the Georgia Tech School of Chemical and Biomolecular Engineering. "But a longstanding question has been how to make GO membranes work in realistic conditions with high chemical concentrations so that they could become industrially relevant."
Using new fabrication techniques, the researchers can control the microstructure of GO membranes in a way that allows them to continue filtering out water effectively even at higher chemical concentrations.
The research, supported by the U.S. Department of Energy-RAPID Institute, an industrial consortium of forest product companies, and Georgia Tech's Renewable Bioproducts Institute, was reported recently in the journal Nature Sustainability. Many industries that use large amounts of water in their production processes may stand to benefit from using these GO nanofiltration membranes.
Nair, his colleagues Meisha Shofner and Scott Sinquefield, and their research team began this work five years ago. They knew that GO membranes had long been recognized for their great potential in desalination, but only in a lab setting. "No one had credibly demonstrated that these membranes can perform in realistic industrial water streams and operating conditions," Nair said. "New types of GO structures were needed that displayed high filtration performance and mechanical stability while retaining the excellent chemical stability associated with GO materials."
To create such new structures, the team conceived the idea of sandwiching large aromatic dye molecules in between GO sheets. Researchers Zhongzhen Wang, Chen Ma, and Chunyan Xu found that these molecules strongly bound themselves to the GO sheets in multiple ways, including stacking one molecule on another. The result was the creation of "gallery" spaces between the GO sheets, with the dye molecules acting as "pillars." Water molecules easily filter through the narrow spaces between the pillars, while chemicals present in the water are selectively blocked based on their size and shape. The researchers could tune the membrane microstructure vertically and laterally, allowing them to control both the height of the gallery and the amount of space between the pillars.
The team then tested the GO nanofiltration membranes with multiple water streams containing dissolved chemicals and showed the capability of the membranes to reject chemicals by size and shape, even at high concentrations. Ultimately, they scaled up their new GO membranes to sheets that are up to 4 feet in length and demonstrated their operation for more than 750 hours in a real feed stream derived from a paper mill.
Nair expressed excitement for the potential of GO membrane nanofiltration to generate cost savings in paper mill energy usage, which could improve the industry's sustainability. "These membranes can save the paper industry more than 30% in energy costs of water separation," he said.
Georgia Tech continues to work with its industrial partners to apply the GO membrane technology for pulp and paper applications.
This work is supported by the U.S. Department of Energy (DOE) Rapid Advancement in Process Intensification Deployment (RAPID) Institute (#DE-EE007888-5-5), an industrial consortium comprising Georgia-Pacific, International Paper, SAPPI, and WestRock, and the Georgia Tech Renewable Bioproducts Institute. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the sponsoring organizations.
CITATION: Zhongzhen Wang, et al., "Graphene Oxide Nanofiltration Membranes for Desalination under Realistic Conditions." (Nature Sustainability, 2021) https://doi.org/10.1038/s41893-020-00674-3.
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
Large galaxies are known to strip the gas that occupies the space between the stars of smaller satellite galaxies.
In research published today, astronomers have discovered that these small satellite galaxies also contain less 'molecular' gas at their centres.
Molecular gas is found in giant clouds in the centres of galaxies and is the building material for new stars. Large galaxies are therefore stealing the material that their smaller counterparts need to form new stars.
Lead author Dr Adam Stevens is an astrophysicist based at UWA working for the International Centre for Radio Astronomy Research (ICRAR) and affiliated to the ARC Centre of Excellence in All Sky Astrophysics in 3 Dimensions (ASTRO 3D).
Dr Stevens ...
FAYETTEVILLE, Ark. - Cold temperatures, prevalent during glacial periods, had a significant impact on past and modern unglaciated landscapes across much of North America, according to a recent study by University of Arkansas geologist Jill A. Marshall.
Marshall, assistant professor of geosciences, is the first author of the study, published in the journal Geophysical Research Letters.
The findings help shape understanding of the earth's "Critical Zone," the relatively thin layer of the planet that extends from where vegetation meets the atmosphere to the lowermost extent of weathered bedrock. "Climate and ecosystems determine how quickly bedrock ...
DALLAS - Feb. 22, 2021 - Three decades-old antibiotics administered together can block a type of pain triggered by nerve damage in an animal model, UT Southwestern researchers report. The finding, published online today in PNAS, could offer an alternative to opioid-based painkillers, addictive prescription medications that are responsible for an epidemic of abuse in the U.S.
Over 100 million Americans are affected by chronic pain, and a quarter of these experience pain on a daily basis, a burden that costs an estimated $600 billion in lost wages and medical expenses ...
Scientists have identified a way to "rescue" muscle cells that have genetically mutated, paving the way to a possible new treatment for rare childhood illness such as Duchenne Muscular Dystrophy (DMD).
The study, led by the Universities of Exeter and Nottingham, is published in the Proceedings of the National Academies of Sciences, USA. The research used novel drugs being developed at the University of Exeter, which "metabolically reprogram" the cellular energy production centres in muscle cells, by providing them with a fuel source to generate metabolic energy.
DMD is a genetic condition caused by a mutation in a gene called dystrophin which results in progressive irreversible muscular degeneration and weakening. Its symptoms include muscle ...
Things just got hairy at Princeton.
Researchers found they could coat a liquid elastic on the outside of a disc and spin it to form useful, complex patterns. When spun just right, tiny spindles rise from the material as it cures. The spindles grow as the disc accelerates, forming a soft solid that resembles hairs.
Inspired by biological designs and rationalized with mathematical precision, the new method could be used at an industrial scale for production with plastics, glasses, metals and smart materials.
The researchers published their findings ...
(Boston)--Tau is a protein that helps stabilize the internal skeleton of nerve cells (neurons) in the brain. Groups of toxic tau protein, termed tau oligomers, drive disease progression and memory loss in Alzheimer's disease (AD). A new study from Boston University School of Medicine (BUSM) shows how these tau oligomers form, and, correspondingly, how they can be prevented.
AD is a major cause of disease in the elderly and places a huge financial cost on the health care system. Scientists have known for a long time that two proteins (?-amyloid and tau) clump and accumulate in the brains ...
LOGAN, UTAH, USA -- You might not like mosquitoes, but they like you, says Utah State University biologist Norah Saarman. And where you lead, they will follow.
In addition to annoying bites and buzzing, some mosquitoes carry harmful diseases. Aedes aegypti, the so-called Yellow Fever mosquito and the subject of a recent study by Saarman and colleagues, is the primary vector for transmission of viruses causing dengue fever, chikungunya and Zika, as well as yellow fever, in humans.
"Aedes aegypti is an invasive species to North America that's become widespread in the eastern United States," says Saarman, assistant professor in USU's Department of Biology and the USU Ecology Center, whose research focuses ...
Adolescents and teens may be more likely to be bullied by their friends -- and friends-of-friends -- than classmates they don't know as well, according to a new study.
Diane Felmlee, Distinguished Professor of Sociology and Demography at Penn State and researcher on the paper, said the findings give new insight into how and why bullying occurs -- important information for anti-bullying efforts.
"People often assume that bullying occurs between relative strangers, or that it targets those on the fringes of the social network," Felmlee said. "Those do occur, but in our study, we find that the rate of peer aggression is significantly higher between those students who are closely linked. Furthermore, our finding is not due to friends simply spending ...
In a new study out of University of California San Diego School of Medicine, researchers have identified a universal strain of bacteria derived from healthy human skin that can treat the most common type of eczema, also known as atopic dermatitis.
In the paper published Feb. 22, 2021, in Nature Medicine, the research team investigated the safety and mechanisms of this certain bacteria in a first-in-human, Phase I, double-blinded clinical trial looking to treat people living with eczema. Of the 54 participants, two-thirds reported improvements in their ...
The diversity and numbers of wild salmon in Northern B.C. have declined approximately 70 per cent over the past century, according to a new Simon Fraser University study.
Researchers drawing on 100-year-old salmon scales report that recent numbers of wild adult sockeye salmon returning to the Skeena River are 70 per cent lower than 100 years ago. Wild salmon diversity in the Skeena watershed has similarly declined by 70 per cent over the last century.
The research undertaken by Simon Fraser University (SFU) and Fisheries and Oceans Canada was published today in the Journal of Applied Ecology.
The research team applied modern genetic tools to salmon scales collected from commercial ...
LAST 30 PRESS RELEASES:
[Press-News.org] Graphene Oxide membranes could reduce paper industry energy costs