volume 1, issue 3 water technology - uc

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CLEAN WATER IS HIGH TECHNOLOGY! www.aquaplustech.com

WATER&TECHNOLOGY

First Polymer Approved for Potable Water Clarification

polyDADAMC

GENEVA UPDATEWATERThe process of removing aqueous

contaminants with bacteria is effective,

though generates down-stream burdens

in sludge processing, adding cost and

contributing to global warming. Along

with an academic institute in Capetown

AQUA+TECH is identifying which

combination of flocculants and anti-odor

chemicals can best treat sludge while

reducing the local nuisance effect.

TECHNOLOGYAQUA+TECH has a range of

decoloration chemicals. Our Amber

polyamines, polyDADMACs and blends

are appropriate for cotton, polyester

and mixed yarns. They function in a

complimentary manner with our

polyelectrolyte flocculants ideally after

adjusting the pH to be slightly basic.

EHSSieglinde Matos has received training

and certification in employment law.

She has been instrumental in helping

AQUA+TECH develop a new benefit

strategy which includes accelerated

accruing of pension rights.

OUR TEAMSylvie Dilonardo is our Logistics

Coordinator and is responsible for the

outgoing transport. Sylvie studied

commerce followed by international

relations and biology at the University of

Geneva. She has two young children.

Water-soluble charged synthetic

polymers have become indispensable

for numerous industrial sectors

including water treatment, wastewater

processing, pulp and papermaking,

biotechnology, pharmaceutical,

cosmetics, personal care, and even

biomedicine. Among positively

charged polymers (cationic

polyelectrolytes), quaternary

ammonium polymers are the most

important and extensively used.

The first quaternary ammonium

polymer of technical interest was

synthesized from

diallydimethylammonium chloride

(DADMAC) in the 1950s. Since then,

the interest in polyDADMAC (CAS

no: 26062-79-3) has not diminished.

On the contrary, the practical

application is still expanding. The

interest in polyDADMAC relies on

the unique chemical structure and on

the versatile applicability.

The polymer backbone of

polyDADMAC consists of cyclic units

resulting from the cyclopolymerization

(ring formation) of DADMAC.

PolyDADMAC can be produced by

radical polymerization in aqueous

solution or in inverse emulsion. The

hydrophilic permanently charged

quaternary ammonium groups make

the polymer highly water-soluble. The

solution properties of polyDADMAC

correspond to those of a strong

polyelectrolyte, with a charge density

being constant over a wide range of

pH, about 2-9. PolyDADMAC in

solution is a very rigid molecule, more

similar to polysaccharides in this

regards then flexible acrylamides.

PolyDADMAC was the first polymer

approved by the U.S. Food and Drug

Administration (FDA) for the use in

potable water treatment.

PolyDADMAC was also discovered

for other emerging applications such

as are described subsequently.

Furthermore, novel materials have

been designed and successfully

applied, based on the electrostatic

interaction of polyDADMAC with

oppositely charged molecules.

Examples are membranes for

microcapsules, which are

permselective and even used as

immune-barriers in transplantations,

or films for surface treatment.

PolyDADMAC is preferably supplied

as colorless to light yellow viscous

aqueous solution with solid contents of

20-40 wt%, but also as emulsion or

powder. (Continued on Page 2)

VOLUME 1, ISSUE 3! SUMMER 2010

Coagulants from Waste Wood Kinga Grenda, M.Sc. University of Coimbra, Portugal

Sources of Cellulose

Cellulose is one of the most important skeletal components in a plant. It is considered as a virtually inexhaustible raw material with fascinating structures and properties. This homopolymer, a polysaccharide, is formed by repeated connections of D-glucose building blocks, linear stiff-chains, with biodegradable properties, is promising as a feedstock for the production of chemicals and their applications in various industries.1

The annual production of cellulose is estimated to be 1011-1012 Tons. It occurs mainly in two forms, partially pure, for example seed hairs of the cotton plant (90-99% pure), as well as a mixture with hemicelluloses in the cell wall of woody plants.2 Cellulose can be obtain from a variety of sources such as wood, annual plants, microbes, and animals. These include seed fibres (cotton), wood fibres (hardwoods and softwoods), bast fibres (flax, hemp, jute, and ramie), grasses (bagasse, bamboo), algae, and bacteria. Increased interest has emerged in the alternative sources of cellulose. Global environmental issues such as deforestation and ecological balance of the plant world are concomitant with the growth of industrial demand. In order to address these, the production of cellulose by alternative sources is being developed. One approach to reduce the demand of cellulose from plants is reusing cellulose “wastes”, another approach uses several bacteria and fungi that are able to synthesize this valuable compound.3

Applications

The importance of cellulose in human life likely began with the Egyptian papyri. Therefore, for thousands of years this “sugar of the plant cell wall”, has been present in various cultures. At the outset cellulose was used in three main forms: wood, cotton, and other plant fibres, with the main applications as writing materials (paper), as an energy source, building material (lumber), or for clothing (cotton, flax, and ramie).1

UPDATES

WATER Satellite mapping is being used to quantify the water inlets in aquifers as well as evaporation. Specifically the imaging can be used to determine the inputs (e.g. rainfall) as well as extraction of water, including those based on pumping for agricultural applications. A case study on the Incomati river basin spanning Mozambique, South Africa and Swaziland has recently been published by the International Water Management Institute (Sri Lanka), the UNESCO Institute for Water Education (The Netherlands) and various academic partners: Agriculture, Ecosystems and Environment, 200, 126 (2015).

TECHNOLOGY Quebracho is a South American hardwood tree. One use is to boil chips and extract a tannin for the leather industry. Some scientists are investigating using tannins as a non-fouling coating to replace synthetic paints. aquaTECH has investigated obtaining wood-based wasted from sources around the world, evaluating tannins from Africa, Oceania, Asia, Europe and South America. By extracting these molecules, either in an aqueous process or with a reducing agent, one can obtain an insoluble by product. By reacting these particles, in suspension, one can produce a coagulant which has a concentration of approximately 20% in solids and which is as efficient as some metal based coagulants. One advantage of the aquaTECH process is that it permits the biodegradable wood-based material to be blended with polyaluminum chloride. These “tannin flocs” have been tested in municipal water, in decoloring as well as in the treatment of waste from paper mills, with positive results.

EHS An emerging trend has been the requirement to train and certify Environmental Health Practitioners. California, the World’s 8th largest economy, is leading the way in educating future generations of policy makers.

VOLUME 4, ISSUE 1 WINTER 2013 VOLUME 6, ISSUE 1 WINTER 2015

http://www.aquaplustech.com


Over the millennia cellulose has been the most abounded composite, as a chemical compound and potential material for several other more valuable applications, in the scientific community. The 19th century was powered by coal, while the industrial material of 20th century was oil, and to a lesser extent, uranium. However, the growing importance of protecting the environment, on the one hand, the inexhaustibility and the feasibility of reducing the cost of production efficiency, on the other, make cellulose as non-petroleum, non-nuclear, based polymer feedstock, promising material of the 21st century.1

Cellulose is, therefore, experiencing a renaissance. Its biodegradability and lack of toxicity to mammalian tissues are thickener reasons for extensive commercial interest in the use of cellulose and its derivatives. These applications include cosmetic and pharmaceutical sector emulsifiers, dispersing, gelling or moistening (humectanting) agents. Moreover, it can be also used as binders in the granulation process as well as a bulking agent. These properties permit it to be applied as a coating of solid pharmaceuticals or used as a filler in solid dosage forms like tablets and capsules, as well as a detergent, or in skin or hair care products. In an industrial scale, manmade cellulose derivatives are used for coatings, painting, laminates, optical films and sorption media, as well as for property-determining additives in building materials and foodstuffs. This multifunctional material, depending on the way and type of modification, can be applied as stabilizer, thickener, filler or even as a taste masking agent.4

Cellulose offers an economically and environmentally viable source for the production of “green” chemicals. Moreover, it can be converted to other types of sugars (e.g. glucose) and other bio-based products to obtain biofuels or bioplastics. Numerous new cellulose applications take advantage of its accessibility of forming cellulose composites with synthetic polymers and biopolymers to obtain even more valuable, environmental friendly, biodegradable compounds.

Cellulose absorbs high amounts of water, has a high viscosity in aqueous solutions and provides strength to materials. These properties render it suitable for a wide range of applications. The specific pore structure of cellulose is used in consumer goods, such as non-woven textiles with excellent absorption properties, in highly specialized membrane, dialysis tubes and in analytical applications where they are employed as aids, excipients and column fillers among other applications. The surface modification of cellulose expanded wildly the use to such novel fields as: microwave technologies as metal-coated and magnetically active materials, in electronic and optoelectronic devices as conducting and photo-luminescent materials and reinforcing elements in macromolecular composite materials. This polysaccharide can also replace glass fibres or be used as pollutant traps for organic molecules in a water medium.1,4

Cellulose in Water Treatment

There is a growing interest in replacing metal or oil-based coagulants with more sustainable alternatives. The water-soluble (hydrophilic) modified cellulose plays a very important role as a potential replacement. Some cellulose derivatives were already successfully tested in order to remove suspended solids and plankton. There is also strong focus on developing low-cost biomass (cellulosic) absorbents for treating dye-contaminated waste water (colour removing) from various types of wastewater (agricultural, industrial, municipal wastes).

The driving forces related to the use of cellulose fibres in these new fields of applications resides additionally in the ease with which they can be recycled at the end of their life cycle, whether through their actual re-employment, or through combustion (energy recovery). With the appropriate process cellulose can be used directly to obtain many valuable products or broken down into useable chemical fragments- other chemical components, using it simply as an energy source seems to not exploit the full potential of the molecule during its life cycle.4

Structure and Properties of Unmodified Cellulose

In principle, the properties of cellulose strongly depend on their origin and molecular structure. Cellulose, from a chemical point of view, is a carbohydrate and a natural based polymer, created from covalently linked repeating units of glucose. This results in the polymeric extensive structure, with linear-chains that contain large numbers of hydroxyl groups (three per unit). The structure leads to the properties of cellulose such as hydrophilicity, chirality or degradability. The multiple highly reactive hydroxy (OH) groups of cellulose molecules impart in broad chemical variability. A linear structure with widespread hydrogen bond networks makes the cellulose molecule enable to create a multitude of partially crystalline, semi-crystalline, amorphous fibre structures and morphologies. This hydrogen bond network between neighbouring long molecules is also responsible for cellulose insolubility and difficulties while dissolving in water and in most organic solvents. The long structure of cellulose fibres and their special, unique criss-cross mesh orientation gives strength and shape to the cell wall. This natural polysaccharide is also considered as a structural material since it gives strength and toughness to a plants leaves, roots, and stems.1,4

The ability of plants, bacteria and algae to use photosyntheses simple compounds (carbon dioxide and water) in presence of light to obtain higher value products such as glucose (monomer) is crucial in the production of cellulose fibres. The length of the molecule depends on its origin with wood pulp yielding the smallest chains, cotton intermediate in size and algae the largest.

WATER&TECHNOLOGY

VOLUME 6, ISSUE 1 WINTER 2015



Particles with very small size or chain length resulting from the breakdown of cellulose are typically soluble in water and organic solvents. Increasing chain length, furthermore, tends to decrease chain mobility, and increase toughness. The long-chain cellulose molecules in plants gives the strength and shape to the cell wall. In aqueous solution it presents difficulty of dissolution and poor ability to absorb water, due to its long chains, high molecular weight and crystalline structure.5

Figure 1. Photomicrograph of cellulose fibres: Left 5000 times magnification, Right 250 times magnification.6

The properties of the cellulose are the results of its specific structure that strongly depend on the origin and the way of chemical pre-treatment in order to isolate it from the mother source. Cellulose is a relatively stiff material, and in plants this carbohydrate polymer is used to add stability, strength and toughness. It is like a skeleton that supports and creates plant parts, but can be also soft and fuzzy–cotton like. The reason for this dual behaviour is the way molecules are organized in the cell walls, with specific orientation of microfibrils. Cotton fibres have a lower degree of orientation which corresponds to smaller elasticity modules and higher elongation at breakage. Moreover, the hardwood cellulose fibres, have a much higher microfibril orientation and in the same fibre strength. As a structural molecule, cellulose is also lightweight but strong, and that is what makes it very attractive for future applications.7

Cellulose as a Foodstuff

Despite the fact that cellulose is made up of glucose it cannot be used as an energy source in most animals, as is passes through the digestive tract and is not digested. Cellulose fibres are, however, essential in their diet, as they have help to clean the intestines. Although many fungi are able to break down cellulose to glucose,

only a few types of bacteria have this ability. For example, some species such as termites, cows, sheep, and goats live in symbiosis with bacteria (two different types) in their digestive tract, which produce the enzyme that breaks down cellulose.

This natural plant fibre is very attractive as a component, polymer and molecule for several potential industrial applications. The presence of numerous valuable properties such as non-toxicity, biodegradability, being odourless and tasteless, combined with relatively low price make the cellulose competitive in the market.1,4

Modification for Water Treatment

The majority of coagulants applied in water treatment are waste metals (iron or aluminum) reacted with used acids (hydrochloric or sulphuric). These produce compounds such as ferric chloride or aluminum sulphate. These can both sediment impurities from the water and also lower phosphorous levels. One disadvantage of metal based coagulants is that they generate sludge. For each Ton of carbon you remove from water you generate about half a Ton of sludge. As the dewatering of sludge is not very efficient (cells retain water tenaciously) the transport of this solid waste from the water treatment plant, is a very significant cost. One of the objectives is to produce coagulants which can be eaten by the bacteria in water treatment plants so that they clean the water and then can be consumed (converted to carbon dioxide and water). This would reduce the cost and environmental impact of water treatment.8 Therefore, the aim is to use wood waste instead of metal wastes and this section of the article will discuss some of the advances and challenges in applying cellulose for water treatment.

In recent years, the physical and chemical structure modification of cellulose has been the main focus in the research community. The demand continues to increase, on the environmental friendly materials in treating water and wastewater. These types of effluents from various industries usually contain suspended or dissolved solids, organic or inorganic particles, metals, dyes or other impurities. One way of separation is to extend the mass of the previously small particles and create from dispersed particles, aggregates or agglomerates to form larger particles (flocs) that are easy to settle and then to remove. Due to biodegradability, easy availability, land and an interest in an alternative that minimizes life cycle cost, cellulose, and other wood based resources, are becoming attractive as a potential industrial effluent treatment agent (flocculant) in water clarification.8

In wastewater most of the suspended particles carry a negative charge. In conventional wastewater treatment inorganic metal salts are employed in conjunction with anionic flocculants.

WATER&TECHNOLOGY

VOLUME 6, ISSUE 1 WINTER 2016

also considered as a structural material since it gives strength and toughness to a

plants leaves, roots, and stems.

The ability of plants, bacteria and algae to use photosyntheses simple compounds

(carbon dioxide and water) in presence of light to obtain higher value products as

glucose (monomer) is crucial in the production of cellulose fibers. The length of the

molecule depends on its origin with wood pulp yielding the smallest chains, cotton in-

termediate in size and algae the largest. Particles with very small size or chain length

resulting from the breakdown of cellulose are typically soluble in water and organic

s o l v e n t s . Increasing chain

length furthermore tends to de-

crease chain mobility, and in-

crease toughness. The long-

chain cellulose molecules in

plants gives the strength and

shape to the cell wall. In

aqueous solution it presents dif-

ficulty of dissolution and poor

ability to absorb water, due to

its long chains, high molecular weight and crystalline structure.5

Figure 1. Photomicrograph of cellulose fibers.6

The properties of the cellulose are the results of its specific structure that strongly

depend of the origin and the way of chemical pre-treatment in order to isolate it from

the mother source. Cellulose is a relatively stiff material, and in plants this

carbohydrate polymer is used to add stability, strength and toughness. It is like a

skeleton that supports and creates plant parts, but can be also soft and fuzzy–cotton

like. The reason for this dual behaviour is the way molecules are organized in the cell

walls, with specific orientation of microfibrils. Cotton fibers have a lower degree of

orientation which corresponds to smaller elasticity modules and higher elongation at

breakage. Moreover, the hardwood cellulose fibers, have a much higher microfibril

orientation and in the same fiber strength. As a structural molecule, cellulose is also

lightweight but strong, and that is what makes it very attractive for future application. 7




WATER&TECHNOLOGY


polyDADAMC













































synthesized from


















































VOLUME 1, ISSUE 3! SUMMER 2010

In this system the coagulants will create the cationic species, which are absorbed by negatively charged colloidal particles, resulting in the formation of flocs, followed by sedimentation and filtration stages. In order to proceed, the direct flocculation medium charge density, cationic polymers with high molecular weights are used. This represents dual functions: to neutralize the negative charge and to bridge the aggregated particles together. Cellulose is often hard to manipulate because of its crystallinity and the bonds between the molecules. Treatments such as milling, ultrasound, the application of temperature and chemical treatments such as exposure to caustic or metal salts are used to render the material more amorphous (soft).9 The hydroxyl (OH) groups present in the cellulose chain (three per sugar unit) are highly reactive and very attractive for future investigation (several synthesis). This makes it possible to obtain wide ranges of new cellulose derivatives, with interesting, different properties. Substitution of ionic groups onto cellulose backbones allows us to obtain positively or negatively charged polyelectrolytes that can be apply as a flocculant in wastewater treatment. Not all charged cellulosic derivatives are appropriate for this type of application. First of all the charged cellulose substance needs to exhibit solubility in the medium that is going to be used. The density and size of the substituted group is also very important. Low density of substitution as well as long carbon chains of the substituted group will not improve the solubility in water.8,9 One of the promising ways to modify water soluble cellulose is by adding charged quaternary ammonium groups. This type of novel biopolymeric flocculation agent was already successfully studied in the laboratory scale and it showed a very good potential.10 Another approach is to combine cellulose with synthetic polymers using grafting techniques. This basically means one takes the cellulose chain and sticks on it another chain to produce a molecule like a hand with fingers coming off. These side chains may have a charge on them, and help in adsorption on molecules, and hence water treatment. Due to low efficiencies of natural eco-flocculants and thus higher concentration or higher dosages are needed to be used, this approach is more attractive. Grafting synthetic polymers onto the backbone of natural polymers was already synthesized and tested as a potential effective flocculant. In order to increase the efficiency in pollutants, removal with lower dosage, it has been found that to be easily approachable to contaminants the grafted copolymer has to have fewer longer dangling polymer chains with high molecular weight and high branched structure. It is also observed, while increasing the amount of grafted synthetic polymer, the biodegradability decreases. While this method is interesting, thus far grafting has not resulted in commercial polymers despite the fact that they work over a larger range of concentrations compared to synthetic polymers.1,8,9

Figure 2 shows an example of water coagulated with a natural based coagulants prepared from cactus (Opuntia ficus indica, NC1) and bean peals (NC2).11 The water sample was collected from the surface water source: Kukkarahalli Lake, Mysore. Cellulose is also present in those tested samples. This allows us to conclude that cellulose-based coagulants will work.9 The question is what is the balance of environmental impacts and costs for any given plant. The further the plant is from ultimate disposal of the sludge, the more expensive the use of metal based coagulants and the higher the burden of transport. One has to consider, however, not only the use of the water treatment chemicals but also their production to determine which molecules are the most suitable for a given application.

Figure 2. Raw sample, Clarified lake water by Natural Coagulant I (Opuntia ficus indica, a species of the

cactus) and II peels of Hyacinth Bean.11

In short, cellulose is one of the natural polysaccharides that is promising in the application as a flocculation agent for water and waste water treatment. Many natural flocculants were successfully applied in removing pollutants from effluent in laboratory scale. There is still a need to improve flocculant removal effectiveness, find simple environmental friendly and economically viable processes in order to obtain well defined materials, before upscaling and application in industry.8,9

INVESTOR NEWSLETTER ISSUE N°3 FALL 2009 VOLUME 6, ISSUE 1 WINTER 2015

Another approach is to combine cellulose with synthetic polymers using grafting

techniques. This basically means one takes the cellulose chain and sticks on it another

chain to produce a molecule like a hand with fingers coming off. These side chains

may have charge on them, and help in adsorption on molecules, and hence water

treatment. Due to low efficiencies of natural eco-flocculants and thus higher

concentration or higher dosages are needed to be used, this approach is more

attractive. Grafting synthetic polymers onto the backbone of natural polymers was

already synthesised and tested as a potential effective flocculant. In order to increase

the efficiency in pollutants, removal with lower dosage, it has been found that to be

easily approachable to contaminants the grafted copolymer has to have fewer longer

dangling polymer chains with high molecular weight and high branched structure. It is

also observed, while increasing the amount of grafted synthetic polymer, the

biodegradability decreases. While this method is interesting, thus far grafting has not

resulted in commercial polymers despite the fact that they work over a larger range of

concentrations compared to synthetic polymers..Error: Reference source not found

Figure 2 shows an example of water coagulated (water sample collected from the

surface water source (Kukkarahalli Lake, Mysore) with a natural based coagulants

prepared from cactus (Opuntia ficus indica) (NC1) and bean peals (NC2).12 Cellulose

is also present in those tested samples. This allows us to conclude that cellulose-based

coagulants will work. The question is what is the balance of environmental impacts

and costs for any given plant. The further the plant is from ultimate disposal of the

sludge, the more expensive the use of metal based coagulants and the higher the

burden of transport. One has to consider, however, not only the use of the water

treatment chemicals but also their production to determine which molecules are the

most suitable for a given application.



References

1. D. Klemm, B. Heblein, H. P. Fink, A. Bohn, Cellulose: fascinating biopolymer and sustainable raw material, Angew. Chem. Int. Ed., 2005, 44, 3358-3393.

2. D. L. Kaplan, Biopolymers from Renewable Resources, (Ed.: D. L. Kaplan), Springer, Berlin, 1998, 1- 29.

3. A. Mathur, P. Sharma, N. Goswami, A. Shai, A. Dua, A. R. Das, H. Kaur, S. Kukal, M. S. Dayal, S. Arora, P. Mishra, V. Jain, G. Mathur, Comparative studies on production of bacterial cellulose from Acetobacter sp. And application as carrier for cell culturing, In.: A. Mendez- Vilas, Medical and Environmental Applications of Microorganisms, Netherlands, 2014, 404-407.

4. M. N. Belgacem, A. Gandini, Monomers, Polymers and composites from renewable resources, Elsevier, Great Britain, 2008, 343-418.

5. O. Biermann, E. Hadicke, S. Koltzenburg, F. Muller-Plathe, Hydrophilicity and lipophilicity of cellulose crystal surfaces, Angew. Chem. Int. Ed, 2001, 40, 3822–3825.

6. Y. Wang, W. Shi, Y. Yu, X. Chen, Synthesis characterization and properties of quaternary ammonium cationic cellulose, College of Urban Construction University of Shanghai for Science and Technology.

7. P. Fratzl, Biophysik: Von Knochen, Holz und Zähnen, (Biophysics: from bone, wood and teeth), Phys. J., 2002, 1, 49-55.

8. B. R. Sharma, N. C. Dhuldhoya, U. C. Merchant, Flocculants—an Ecofriendly Approach, Int. J. Chem. Environ. Eng., 2006, 14, 195-202.

9. C. S. Lee, J. Robinson, M. F. Chong, A review on application of flocculants in wastewater treatment, Process Safety and Environmental Protection, 2014, 92, 489-508.

10. J. Sirvio, A. Honka, H. Liimatainen, J. Niinimaki, O. Hormi, Synthesis of highly cationic water-soluble cellulose derivatives and its potential as novel biopolymeric flocculation agent, Carbohydr. Polym., 2011, 86, 266-270.

11. B. S. Shilpa, Akanksha, Kavita, P. Girish, Evaluation of cactus and hyacinth bean peels as natural coagulants, Int. J. Chem. Environ. Eng., 2012, 3, 187-191.


WATER&TECHNOLOGY


polyDADAMC













































synthesized from


















































VOLUME 1, ISSUE 3! SUMMER 2010INVESTOR NEWSLETTER ISSUE N°3 FALL 2009 VOLUME 6, ISSUE 1 WINTER 2015

KINGA GRENDA

Kinga Grenda is doing her PhD in Chemical Engineering at the University of Coimbra, Portugal, She is financed by a European Project which requires the candidate to spend half their time at an SME in another country. Kinga, therefore, works on developing coagulants based on natural materials with aquaTECH. She has a Bachelor of Science in Chemistry from Lodz University of Technology in Poland and a Masters specializing in Polymer Technology. She has also been an Erasmus student at Aveiro University. In her spare time Kinga enjoys travelling, the theatre, dancing and staying up to date with global news.

FORTHCOMING ISSUES

Updates related to the technology, business and impact of water will be discussed including:

• Encapsulation • Advances in Papermaking• Labelling of Chemical Products• Assessing Sustainability• Wind and Water


volume 1, issue 3 water technology - uc

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