Tag Archives: Wallenberg Wood Science Center

Remove 80 percent of dye pollutants from wastewater with wood nanocrystals

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They’re usually known as cellulose nanocrystals (CNCs) but the term wood nanocrystals works too. From a March 23, 2023 news item on Nanowerk,

Researchers at Chalmers University of Technology, Sweden, have developed a new method that can easily purify contaminated water using a cellulose-based material. This discovery could have implications for countries with poor water treatment technologies and combat the widespread problem of toxic dye discharge from the textile industry.

Clean water is a prerequisite for our health and living environment, but far from a given for everyone. According to the World Health Organization, WHO, there are currently over two billion people living with limited or no access to clean water.

This global challenge is at the centre of a research group at Chalmers University of Technology, which has developed a method to easily remove pollutants from water. The group, led by Gunnar Westman, Associate Professor of Organic Chemistry focuses on new uses for cellulose and wood-based products and is part of the Wallenberg Wood Science Center.

The researchers have built up solid knowledge about cellulose nanocrystals* – and this is where the key to water purification lies. These tiny nanoparticles have an outstanding adsorption capacity, which the researchers have now found a way to utilise.

“We have taken a unique holistic approach to these cellulose nanocrystals, examining their properties and potential applications. We have now created a biobased material, a form of cellulose powder with excellent purification properties that we can adapt and modify depending on the types of pollutants to be removed,” says Gunnar Westman.

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Caption: Researchers at Chalmers University of Technology, Sweden, have developed a new biobased material, a form of powder based on cellulose nanocrystals to purify water from pollutants, including textile dyes. When the polluted water passes through the filter with cellulose powder, the pollutants are absorbed, and the sunlight entering the treatment system causes them to break down quickly and efficiently. Laboratory tests have shown that at least 80 percent of the dye pollutants are removed with the new method and material, and the researchers see good opportunities to further increase the degree of purification. Credit: Chalmers University of Technology, Sweden | David Ljungberg

A March 23, 2023 Chalmers University of Technology press release (also on EurekAlert), which originated the news item, describes the water treatment in more detail including how it will be tested in field conditions,

Absorbs and breaks down toxins
In a study recently published in the scientific journal Industrial & Engineering Chemistry Research, the researchers show how toxic dyes can be filtered out of wastewater using the method and material developed by the group. The research was conducted in collaboration with the Malaviya National Institute of Technology Jaipur in India, where dye pollutants in textile industry wastewater are a widespread problem.

The treatment requires neither pressure nor heat and uses sunlight to catalyse the process. Gunnar Westman likens the method to pouring raspberry juice into a glass with grains of rice, which soak up the juice to make the water transparent again. 

“Imagine a simple purification system, like a portable box connected to the sewage pipe. As the contaminated water passes through the cellulose powder filter, the pollutants are absorbed and the sunlight entering the treatment system causes them to break down quickly and efficiently. It is a cost-effective and simple system to set up and use, and we see that it could be of great benefit in countries that currently have poor or non-existent water treatment,” he says. 

The method will be tested in India
India is one of the developing countries in Asia with extensive textile production, where large amounts of dyes are released into lakes, rivers and streams every year. The consequences for humans and the environment are serious. Water contaminant contains dyes and heavy metals and can cause skin damage with direct contact and increase the risk of cancer and organ damage when they enter into the food chain. Additionally, nature is affected in several ways, including the impairment of photosynthesis and plant growth.

Conducting field studies in India is an important next step, and the Chalmers researchers are now supporting their Indian colleagues in their efforts to get some of the country’s small-scale industries to test the method in reality. So far, laboratory tests with industrial water have shown that more than 80 percent of the dye pollutants are removed with the new method, and Gunnar Westman sees good opportunities to further increase the degree of purification.

“Going from discharging completely untreated water to removing 80 percent of the pollutants is a huge improvement, and means significantly less destruction of nature and harm to humans. In addition, by optimising the pH and treatment time, we see an opportunity to further improve the process so that we can produce both irrigation and drinking water. It would be fantastic if we can help these industries to get a water treatment system that works, so that people in the surrounding area can use the water without risking their health,” he says.

Can be used against other types of pollutants
Gunnar Westman also sees great opportunities to use cellulose nanocrystals for the treatment of other water pollutants than dyes. In a previous study, the research group has shown that pollutants of toxic hexavalent chromium, which is common in wastewater from mining, leather and metal industries, could be successfully removed with a similar type of cellulose-based material. The group is also exploring how the research area can contribute to the purification of antibiotic residues.

“There is great potential to find good water purification opportunities with this material, and in addition to the basic knowledge we have built up at Chalmers, an important key to success is the collective expertise available at the Wallenberg Wood Science Center,” he says.

More about the scientific article
Read the full article in Industrial & Engineering Chemistry Research: Cellulose nanocrystals derived from microcrystalline cellulose for selective removal of Janus Green Azo Dye. The authors of the article are Gunnar Westman and Amit Kumar Sonker of Chalmers University of Technology, and Ruchi Aggarwal, Anjali Kumari Garg, Deepika Saini, and Sumit Kumar Sonkar of Malaviya National Institute of Technology Jaipur in India. The research is funded by the Wallenberg Wood Science Center, WWSC and the Indian group research is funded by Science and Engineering Research Board under Department of Science and Technology (DST-SERB) Government of India. 

*Nanocrystals 
Nanocrystals are nanoparticles in crystal form that are extremely small: a nanoparticle is between 1 and 100 nanometres in at least one dimension, i.e. along one axis. (one nanometre = one billionth of a metre).

Wallenberg Wood Science Center
•    The Wallenberg Wood Science Center, WWSC, is a research centre that aims to develop new sustainable biobased materials using raw materials from the forest. The WWSC is a multidisciplinary collaboration between Chalmers University of Technology, KTH Royal Institute of Technology and Linköping University, and is based on a donation from the Knut and Alice Wallenberg Foundation.
•    The centre involves about 95 researchers and faculty members and 50 doctoral students. Eight research groups from Chalmers are part of the centre.

About dye pollutants and access to clean water
•    Over two billion people in the world live with limited or no access to clean water. It is estimated that over 3.5 million people die each year from lack of access to clean water and proper sanitation.
•    The global textile industry, which is concentrated in Asia, contributes to widespread water pollution. Production often takes place in low-wage countries, where much of the technology is antiquated and environmental legislation and oversight may be lacking.
•    Emissions contribute to eutrophication and toxic effects in water and soil. There are examples in China and India where groundwater has been contaminated by dye and processing chemicals.
•    Producing one kilogram of new textiles requires between 7,000 and 29,000 litres of water, and between 1.5 and 6.9 kg of chemicals.
•    In 2021, around 327 thousand tonnes of dyes and pigments were produced in India. A large proportion of the country’s dye pollutants is discharged untreated.

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Sources 

Swedish Environmental Protection Agency: https://www.naturvardsverket.se/amnesomraden/textil/dagens-textila-floden-ar-en-global-miljoutmaning/ 

WHO: https://www.who.int/news-room/fact-sheets/detail/drinking-water

A critical review on the treatment of dye-containing wastewater: Ecotoxicological and health concerns of textile dyes and possible remediation approaches for environmental safety. Ecotoxicology and Environmental Safety, February 2022

https://www.sciencedirect.com/science/article/pii/S0147651321012720

Effects of textile dyes on health and the environment and bioremediation potential of living organisms. Biotechnology Research and Innovation, July–December 2019

https://www.sciencedirect.com/science/article/pii/S2452072119300413

Swedish Chemicals Agency: https://www.kemi.se/kemiska-amnen-och-material/nanomaterial

Statista: https://www.statista.com/statistics/726947/india-dyes-and-pigments-production-volume/#:~:text=In%20fiscal%20year%202021%2C%20the,around%20327%20thousand%20metric%20tons

Even though there’s a link to the research in the press release, here’s my link to and citation for the paper, which specifies a particular dye suggesting this is not a universal treatment,

Cellulose Nanocrystals Derived from Microcrystalline Cellulose for Selective Removal of Janus Green Azo Dye by Ruchi Aggarwal, Anjali Kumari Garg, Deepika Saini, Sumit Kumar Sonkar, Amit Kumar Sonker, and Gunnar Westman. Ind. Eng. Chem. Res. 2023, 62, 1, 649–659 DOI: https://doi.org/10.1021/acs.iecr.2c03365 Publication Date: December 26, 2022 Copyright © 2022 American Chemical Society

This paper is behind a paywall.

Nanocellulose at the American Chemical Society’s 243rd annual meeting

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Nanocellulose seems to be one of the major topics at the ACS’s (Americal Chemical Society) 243rd annual meeting themed Chemistry of Life  in San Diego, California, March 25-29, 2012. From the March 25, 2012 news item on Nanowerk,

… almost two dozen reports in the symposium titled, “Cellulose-Based Biomimetic and Biomedical Materials,” that focused on the use of specially processed cellulose in the design and engineering of materials modeled after biological systems. Cellulose consists of long chains of the sugar glucose linked together into a polymer, a natural plastic–like material. Cellulose gives wood its remarkable strength and is the main component of plant stems, leaves and roots. Traditionally, cellulose’s main commercial uses have been in producing paper and textiles –– cotton being a pure form of cellulose. But development of a highly processed form of cellulose, termed nanocellulose, has expanded those applications and sparked intense scientific research. Nanocellulose consists of the fibrils of nanoscale diameters so small that 50,000 would fit across the width of the period at the end of this sentence.

“We are in the middle of a Golden Age, in which a clearer understanding of the forms and functions of cellulose architectures in biological systems is promoting the evolution of advanced materials,” said Harry Brumer, Ph.D., of Michael Smith Laboratories, University of British Columbia, Vancouver. He was a co-organizer of the symposium with J. Vincent Edwards, Ph.D., a research chemist with the Agricultural Research Service, U.S. Department of Agriculture in New Orleans, Louisiana. “This session on cellulose-based biomimetic and biomedical materials is really very timely due to the sustained and growing interest in the use of cellulose, particularly nanoscale cellulose, in biomaterials.”

One of the presenters has a very charming way of describing the nanocellulose product his team is working on (from the news item),

Olli Ikkala, Ph.D., [Aalto University, Finland] described the new buoyant material, engineered to mimic the water strider’s long, thin feet and made from an “aerogel” composed of the tiny nano-fibrils from the cellulose in plants. Aerogels are so light that some of them are denoted as “solid smoke. [emphasis mine]” The nanocellulose aerogels also have remarkable mechanical properties and are flexible.

There were some 20 presentations in this symposium held under the auspices of the ACS annual meeting. Here’s a few of the presentations (some of these folks have been featured on this blog previously), from the news item,

Native cellulose nanofibers: From biomimetic nanocomposites to functionalized gel spun fibers and functional aerogels Olli Ikkala, Professor, PhD, Aalto University, P.O. Box 5100, Espoo, Finland, FIN-02015, Finland , 358-9-470 23154, olli.ikkala@aalto.fi Native cellulose nanofibers and whiskers attract interest even beyond the traditional cellulose community due to their mechanical properties, availability and sustainability. We describe biomimetic nanocomposites with aligned self-assemblies combining nanocellulose with nanoclays, polymers, block copolymer, or graphene, allowing exciting mechanical properties. Functional ductile and even flexible aerogels are presented, combining superhydrophobicity, superoleophobicity, oil-spill absorption, photocatalytics, optically switchable water absorption, sensing, and antimicrobial properties. Finally mechanically excellent fibers are gel-spun and functionalized for electric, magnetic, optical and drug-release properties.

Evaluation of skin tissue repair materials from bacterial cellulose Lina Fu, Miss, Huazhong University of Science & Technology, College of Life Science & Technology, 1037 Luoyu Road, Wuhan, Hubei, 430074, China , 86-18971560696, runa0325@gmail.com Bacterial cellulose (BC) has been reported as the materials in the tissue engineering fields, such as skin, bone, vascular and cartilage tissue engineering. Exploitation of the skin substitutes and modern wound dressing materials by using BC has attracted much attention. A skin tissue repair materials based on BC have been biosynthesized by Gluconacetobacter xylinus. The nano-composites of BC and chitosan form a cohesive gel structure, and the cell toxicity of the composite is excellent. Unlike other groups, which showed more inflammatory behavior, the inflammatory cells of the BC group were mainly polymorph-nuclear and showed few lymphocytes. The BC skin tissue repair material has an obviously curative effect in promoting the healing of epithelial tissue and reducing inflammation. With its superior mechanical properties, and the excellent biocompatibility, these skin tissue repair materials based on BC have great promise and potential for wound healing and very high clinical value.

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New materials from nanocrystalline cellulose Mark MacLachlan [mentioned in my Nov. 18, 2010 posting], University of British Columbia, Department of Chemistry, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada , 604-822-3070, mmaclach@chem.ubc.ca Nanocrystalline cellulose (NCC) is available from the acid-catalyzed degradation of cellulosic materials. NCC is composed of cylindrical crystallites with diameters of ca. 5-10 nm and large aspect ratios. This form of cellulose has intriguing properties, including its ability to form a chiral nematic structure. By using the chiral nematic organization of NCC as a template, we have been able to create highly porous silica films and carbon films with chiral nematic organization.1,2 These materials are iridescent and their structures mimic the shells of jewel beetles. In this paper, I will describe our recent efforts to use NCC to create new materials with interesting optical properties.

Factors influencing chiral nematic pitch and texture of cellulose nanocrystal films Derek G Gray, McGill University, Department of Chemistry, Pulp and Paper Building, 3420 University Street, Montreal, QC, H3A 2A7, Canada , 1-514-398-6182, derek.gray@mcgill.ca Appropriately stabilized cellulose nanocrystal (NCC) suspensions in water form chiral nematic liquid crystalline phases above some critical concentration. In the absence of added electrolye, the chiral nematic pitch of such suspensions is longer than that of visible light. Films prepared by evaporation from the suspensions also often display the characteristic fingerprint patterns characteristic of long-pitch chiral nematic phases, but the pitch values can be shifted into the visible range by adding small quantities of electrolyte to the evaporating suspension. The factors that control the final pitch have been the subject of some confusion. While still not well understood, it is clear that at high nanocrystal concentrations and in solid films, the pitch is not simply a reversible function of nanocrystal concentration. We examine some of the factors that control the pitch and liquid crystal texture during the drying of chiral nematic NCC films.

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Bioprinting of 3D porous nanocellulose scaffolds for tissue engineering and organ regeneration Paul Gatenholm, Professor, [mentioned in my March 19, 2012 posting] Wallenberg Wood Science Center, Chalmers, Department of Chemical and Biological Engineering, Kemigarden 4, Goteborg, V. Gotaland, SE41296, Sweden , 46317723407, paul.gatenholm@chalmers.se Nanocellulose is a promising biocompatible hydrogel like nano-biomaterial with potential uses in tissue engineering and regenerative medicine. Biomaterial scaffolds for tissue engineering require precise control of porosity, pore size, and pore interconnectivity. Control of scaffold architecture is crucial to promote cell migration, cell attachment, cell proliferation and cell differentiation. 3D macroporous nanocellulose scaffolds, produced by unique biofabrication process using porogens incorporated in the cultivation step, have shown ability to attract smooth muscle cells, endothelial cells, chondrocytes of various origins, urethral cells and osteoprogenitor cells. We have developed bioprinter which is able to produce 3D porous nanocellulose scaffolds with large size and unique architecture. Surface modifications have been applied to enhance cell adhesion and cell differentiation. In this study we have focused on use of 3D porous Nanocellulose scaffolds for stem cell differentiation into osteogenic and chondral lineages.

Nanocellulose as scaffolding for nerve cells

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Swedish scientists have announced success with growing nerve cells using nanocellulose as the scaffolding. From the March 19, 2012 news item on Naowerk,

Researchers from Chalmers and the University of Gothenburg have shown that nanocellulose stimulates the formation of neural networks. This is the first step toward creating a three-dimensional model of the brain. Such a model could elevate brain research to totally new levels, with regard to Alzheimer’s disease and Parkinson’s disease, for example.

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“This has been a great challenge,” says Paul Gatenholm, Professor of Biopolymer Technology at Chalmers.?Until recently the cells were dying after a while, since we weren’t able to get them to adhere to the scaffold. But after many experiments we discovered a method to get them to attach to the scaffold by making it more positively charged. Now we have a stable method for cultivating nerve cells on nanocellulose.”

When the nerve cells finally attached to the scaffold they began to develop and generate contacts with one another, so-called synapses. A neural network of hundreds of cells was produced. The researchers can now use electrical impulses and chemical signal substances to generate nerve impulses, that spread through the network in much the same way as they do in the brain. They can also study how nerve cells react with other molecules, such as pharmaceuticals.

I found the original March 19, 2012 press release  and an image on the University of Chalmers website,

Nerve cells growing on a three-dimensional nanocellulose scaffold. One of the applications the research group would like to study is destruction of synapses between nerve cells, which is one of the earliest signs of Alzheimer’s disease. Synapses are the connections between nerve cells. In the image, the functioning synapses are yellow and the red spots show where synapses have been destroyed. Illustration: Philip Krantz, Chalmers

This latest research from Gatenholm and his team will be presented at the American Chemical Society annual meeting in San Diego, March 25, 2012.

The research team from Chalmers University and its partners are working on other applications for nanocellulose including one for artificial ears. From the Chalmers University Jan. 22, 2012 press release,

As the first group in the world, researchers from Chalmers will build up body parts using nanocellulose and the body’s own cells. Funding will be from the European network for nanomedicine, EuroNanoMed.

Professor Paul Gatenholm at Chalmers is leading and co-ordinating this European research programme, which will construct an outer ear using nanocellulose and a mixture of the patient’s own cartilage cells and stem cells.

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Previously, Paul Gatenholm and his colleagues succeeded, in close co-operation with Sahlgrenska University Hospital, in developing artificial blood vessels using nanocellulose, where small bacteria “spin” the cellulose.

In the new programme , the researchers will build up a three-dimensional nanocellulose network that is an exact copy of the patient’s healthy outer ear and construct an exact mirror image of the ear. It will have sufficient mechanical stability for it to be used as a bioreactor, which means that the patient’s own cartilage and stem cells can be cultivated directly inside the body or on the patient, in this case on the head. [Presumably the patient has one ear that is healthy and the researchers are attempting to repair or replace an unhealthy ear on the other side of the head.]

As for the Swedish perspective on nanocellulose (from the 2010 press release),

Cellulose-based material is of strategic significance to Sweden and materials science is one of Chalmers eight areas of advance. Biopolymers are highly interesting as they are renewable and could be of major significance in the development of future materials.

Further research into using the forest as a resource for new materials is continuing at Chalmers within the new research programme that is being built up with different research groups at Chalmers and Swerea – IVF. The programme is part of the Wallenberg Wood Science Center, which is being run jointly by the Royal Institute of Technology in Stockholm and Chalmers under the leadership of Professor Lars Berglund at the Royal Institute of Technology.

The 2012 press release announcing the work on nerve cells had this about nanocellulose,

Nanocellulose is a material that consists of nanosized cellulose fibers. Typical dimensions are widths of 5 to 20 nanometers and lengths of up to 2,000 nanometers. Nanocellulose can be produced by bacteria that spin a close-meshed structure of cellulose fibers. It can also be isolated from wood pulp through processing in a high-pressure homogenizer.

I last wrote about the Swedes and nanocellulose in a Feb. 15, 2012 posting about recovering it (nanocellulose) from wood-based sludge.

As for anyone interested in the Canadian scene, there is an article by David Manly in the Jan.-Feb. 2012 issue of Canadian Biomass Magazine that focuses largely on economic impacts and value-added products as they pertain to nanocellulose manufacturing production in Canada. You can also search this blog as I have covered the nanocellulose story in Canada and elsewhere as extensively as I can.