INTRODUCTION AND PROJECT BACKGROUND

This document is a summary of the main activities developed in the DYES4EVER LIFE project. The project started during the second semester of 2013, in July, and it came to end on December 2015 after fulfilling the pursued objectives, putting the scientific knowledge at the service of the environment. The project is the result of close cooperation between: La Asociación de Investigación de la Industria Textil, (AITEX, from Spain) acting as coordinator, University of Bari Aldo Moro (UNIBARI, from Italy), Universidad Católica San Antonio de Murcia (UCAM, from Spain) and a representative Spanish SME, COLORPRINT Fashion S.L. The project total budget was 919.740,00 € and it has been co-funded by the European Union for an amount of 459.244, 00 € (50%) through the LIFE PROGRAMME.

In order to clarify the project as a whole, this document goes through basic information starting with the problem definition, continuing with proposed solution and steps followed until getting successful results obtained by following a work planning as foreseen, the dissemination activities, publications and meetings held and finalizing with the conclusions.

ABOUT THE LIFE PROGRAMME

lifeThe LIFE programme is the EU's funding instrument for the environment. The general objective of LIFE is to contribute to the implementation, updating and development of EU environmental policy and legislation by co-financing pilot or demonstration projects with European added value.
LIFE began in 1992 and to date there have been four complete phases of the programme (LIFE I: 1992-1995, LIFE II: 1996-1999, LIFE III: 2000-2006 and LIFE+: 2007-2013). During this period, LIFE has co-financed some 3954 projects across the EU, contributing approximately €3.1 billion to the protection of the environment.
The European Commission (DG Environment and DG Climate Action) manages the LIFE programme. The Commission has delegated the implementation of many components of the LIFE programme to the Executive Agency for Small and Medium-sized Enterprises (EASME). External selection, monitoring and communication teams provide assistance to the Commission and EASME. The European Investment Bank will manage the two new financial instruments (NCFF and PF4EE).
For further information:
0http://ec.europa.eu/environment/life/about/index.htm 

WHAT IS DYES4EVER? PROBLEM TO BE SOLVED AND PROJECT OBJECTIVES

THE PROBLEM

THE PRESENCE OF ORGANIC CONTAMINANTS SUCH AS DYES IN THE HYDROSPHERE IS OF PARTICULAR CONCERN FOR WATER ENVIRONMENTS BECAUSE OF THEIR NONBIODEGRADABILITY AND POTENTIAL CARCINOGENIC NATURE. IN THE OTHER HAND, WATER EFFLUENTS CHARGED WITH DYES, ABSORB SUNLIGHT, THUS IMPEDING THE PHOTOSYNTHETIC ACTIVITY OF AQUATIC PLANTS AND SERIOUSLY THREATENING THE WHOLE ECOSYSTEM. IN THIS SENSE, STRICTER REGULATORY REQUIREMENTS ALONG WITH AN INCREASED PUBLIC DEMAND FOR COLOUR-FREE EFFLUENT, NEEDS THE INCLUSION OF A VERY EFFECTIVE AND EVIRMENTALLY-FRIENDLY DECOLORISATION STAGE IN WASTEWATER TREATMENT PLANTS.

Traditional dyeing processes are not perfect, they are indeed inefficient, because a percentage of the dyes are not fixed into the fabric, literature confirms that between 5% and 50% depending of the family of dye, remaining as contaminant in the wastewater.  In recent years the chemical industry has been working in concentrate the dyes and in increases their efficiency in order to use less quantity of dyes. By other hand the machinery has been improved decreasing the amount of water needed in the dye process producing less contaminated water.  

The size of the problem can be estimated if it is considered that to add colour to one kilogram of fabric, over 100 liters of water may be used. The water coming from finishing and dyeing processes are normally addressed to wastewater treatment plants where water is treated through physical, chemical and biotechnological methods. A water effluent of better characteristics of quality and quantity is achieved, based on certain standard parameters and they are better in some procedures than others.

In Figure. 1 Industrial Wastewater TreatmentPlant and Figure. 2 Industrial wastewater Treatment Plant, real Wastewater Treatment Plants are represented. Very exhaustive and stricter National and European standards control the deposition of this kind of water in public sewage system. The industry must guarantee that deposited water is under the parameters, and it represents an overhead to be reduced by means of reducing the level of contamination or recovering resources that are going to waste.

FIGURA1

Figure. 1 Industrial  WastewaterTreatmentPlant

Figura2

Figure. 2 Industrial wastewater Treatment Plant

The problem is magnified by the ever-changing fashion, in composition (wool, cotton, polyester,…) and colorful. These changes require the existence of a wide range of dyes with different chemical compositions that make it difficult to find an efficient solution for all of them.

Fortunately, not only the fashion changes but also tools, raw materials and procedures, despite finishing processes and technologies launched on the market today are premised on reducing consumption, those now present in the European small and medium industry still consume plenty of water. The transition between the current and emerging technologies will be a long process in time and initiatives as the project DYES4EVER help mitigate adverse effects are vital.

The DYES4EVER project is focused in the encapsulation of the dye unfixed in the waste water of textile dyeing processes of fabrics, natural and synthetic (Cotton and Polyester) to clean the water. The current technologies are focused only in clean water, in fact there are diverse procedures to treat the waste water (flocculation, filtration, coagulation, enzyme…), but all of those methods destroy the dye, not try to recover it. DYES4EVER include the use of a natural element as cyclodextrins and have been conceived since an environmental perspective, once recovered by encapsulation processes, those materials they became in raw materials (including the water) again, so they are ready for dyeing new fabrics, reducing the chemical employed to treat the wastewater.

There is no evidence of other projects achieving what this project proposes using CYCLODEXTRINS. These molecules have been traditionally and mainly applied into pharmaceutical and cosmetics sector as encapsulating agent. The cyclodextrin had been used before in textile industry as a finishing capturing the bad odor of cloths. This use of cyclodextrins in the textile industry is very innovative, and the effects on the nature are the main justification. As remarked before cyclodextrins are an alternative for reducing the use of chemicals as they are product that is always reducing the charge of chemicals without adding more for encapsulate the unfixed dyes.

The solution must be thought justified because of the environmental and economic impact, in consequence should be addressed into two directions, in one hand, into augmenting the quantities of dyes that impregnates into the fabric and in the other hand, creating new technologies that are able to recover the water leaving it applicable to other processes.

THE OBJECTIVE

IN THE LIGHT OF THE EXPOSED PROBLEM, DYES4EVER PROJECT WAS INTENDED TO DEMONSTRATE THE ABILITY OF CYCLODEXTRINS TO ACT AS ENCAPSULATION AGENTS OF DYES, SO THEY CAN BE RECOVERED FROM THE WASTEWATER, LIVING THEM
AVAILABLE FOR NEW DYEING PROCESSES.
THE CORE OBJECTIVE MAY BE SUB-DIVIDED IN THE FOLLOWING,

figura3a

THE SCHEME SHOWN IN Figure. 3 Project Objectives, SUMMARIZING THE OBJECTIVES PURSUED MAY BE EXPLAINED AS FOLLOWS:  FROM WASTES OF TEXTILE DYE PRODUCTS, SUB-PRODUCTS WILL BE OBTAINED: WATER WITHOUT COLOUR AND ENCAPSULATED DYES, THEN DYES AND WATER RECOVERED ARE REUSED AS RAW MATERIALS IN A NEW DYEING PROCESS. 

figura3b

MATERIALS USED

"Cyclodextrins are a group of structurally related natural products formed during bacterial digestion of cellulose. These cyclic oligosaccharides consist of (α-1,4)-linked α-D-glucopyranose units and contain a somewhat lipophilic central cavity and a hydrophilic outer surface. Due to the chair conformation of the glucopyranose units, the cyclodextrins are shaped like a truncated cone rather than perfect cylinders. The hydroxyl functions are orientated to the cone exterior with the primary hydroxyl groups of the sugar residues at the narrow edge of the cone and the secondary hydroxyl groups at the wider edge. The central cavity is lined by the skeletal carbons and ethereal oxygens of the glucose residues, which gives it a lipophilic character. The polarity of the cavity has been estimated to be similar to that of an aqueous ethanolic solution". Figure. 4 Cyclodextrins represented in literature.

About 30 different pharmaceutical products containing cyclodextrins are now on the market worldwide and numerous food products, cosmetics and other commercial products contain cyclodextrins. In these products cyclodextrins are mainly used solubilizing agents to increase water-solubility of lipophilic compounds. However, cyclodextrins can also be used to increase both chemical and physical stability of various compounds, including proteins. To enhance availability of compounds, for example to enhance taste or to enhance bioavailability of drugs. Cyclodextrins can be used to convert liquids to solid powders, to reduce local irritation, to prevent skin absorption of topically applied compounds (e.g. sunscreen agents), and to obtained sustained release of, for example, drugs or fragrances.

figura4

Figure. 4 Cyclodextrins represented in literature

WHAT ARE DIRECT AND DISPERSE DYES?

DIRECT DYES
Direct dye, also called Substantive Dye, any of a class of coloured, water-soluble compounds that have an affinity for cellulosic fibre and are taken up directly, such as the benzidine derivatives. Direct dyes are usually cheap and easily applied, and they can yield bright colours. Washfastness is poor but may be improved by after treatment. Most packaged dyes sold for home use are direct dyes.

DISPERSE DYES
Disperse dyes are the only water-insoluble dyes that dye polyester and acetate fibers. They exist in the dye bath as a suspension or dispersion of microscopic particles, with only a tiny amount in true solution at any time. Disperse dye molecules are the smallest dye molecules among all dyes.

WHAT HAVE WE DONE? PROJECT DESCRIPTION

The Project was structured in the following activities:

• Analysis and characterization of dyes and cyclodextrins.
• Study of the complexation and recovering of the dyes.
• Design and installation of the surface for recovering the dyes encapsulated with cyclodextrins.
• Validation of the recovered dyes in the dyeing process.
• Monitoring of the environmental impact of the project actions.
• Monitoring of the socio-economic impact of the project actions.

The activities carried out in the different phases are described below:

ANALYSIS AND CHARACTERIZATION OF DYES AND CYCLODEXTRINS

The main aim of this action is the selection of dyes widely used in the textile industry. The complexity of demanding consumption in markets is reflected on the need of a great variety of dyes in order to obtain a wider color spectrum to be deposited over synthetic and natural fibres. Finally the dyes selected were direct and disperse dyes.

In order to characterize encapsulation process of dyes by means of cyclodextrins, it was necessary to know the structure and chemical composition of commercial dyes, their molecular weight, their color index classification, etc. After the selection process a complete process of classification and characterization carried out and its result was summarized in a database. 

 amarillo  escarlata  azul
Amarillo Auxiester M-ST (disperse dye)
Database file 
Escarlata Duvaster (disperse dye)
Database file

Azul Turquesa (disperse dye)
Database file

From all the dyes in study the tricomies employed by Colorprint Fashion in each group was selected. The auxiliaries employed were sodium sulfate for direct dyes and acetic acid for disperse dyes.

Due to technical problems in the encapsulation with the cyclodextrins it was necessary to be added two more direct dyes:

 directDyes  DisperseDyes
Direct Dyes  Disperse Dyes 

Direct Dyes Selected:

Five direct dyes were chosen, Direct Yellow, Direct Red, Direct Grey, Direct yellow super HT-2GL and Direct blue Super HT-4GL 200%

Disperse Dyes Selected:

Three disperse dyes were chosen, Orange Auxiester M-ST, Rubi Duvaster 2G 150%, and Blue Duvaster s-BG 200%).

The following table summarizes de direct and disperse dyes used for the study:

tabla1

Table. 1 Disperse and Direct Dyes Selected

The Cyclodextrins are classified by the number of the glucose molecules that form, there are three basic structures:

· α (alpha)-cyclodextrin: 6-membered sugar ring molecule

· β (beta)-cyclodextrin: 7-membered sugar ring molecule

· γ (gamma)-cyclodextrin: 8-membered sugar ring molecule

Their main difference is the size of the diameter of the ring formed and, consequently, its internal volume.

Native Cyclodextrins

The molecular structure of cyclodextrins creates a bucket-like cavity that can complex with molecules or functional groups on molecules to improve solubility of poorly soluble compounds. The same mechanism makes these excipients capable of masking unpleasant taste/odor and stabilizing drugs that are prone to degradation. The number of glucose units in the ring determines the internal diameter of the cavity and its volume, as the height of the cyclodextrin cavity is the same for all the native cyclodextrin grades.[1]

Modified Cyclodextrins

Through modification, the natural cyclodextrins are effective templates for the generation of a range of molecular hosts. This makes it possible to tailor a cyclodextrin host to a particular guest, to meet specific requirements in the host-guest complex, and opens the way to diverse new areas of supramolecular chemistry.

[1] http://www.ashland.com/products/cavamax-native-cyclodextrins

STUDY OF THE COMPLEXATION AND RECOVERING OF THE DYES

 

Cyclodextrin Selected

 

α -CD both native and modified was refuse because some of the dyes cannot be complexed by the small size of the cavity.  The Selected Cyclodextrins were the native β-CD and γ-CD and the modified native HPβ-CD and HPγ-CD with very high binding constant indicating that the complexation happens very efficiently. Selection was made through analysis of spectrophotometric, electrochemical and calorimetric measurements, in order to determine the ability of cyclodextrins, with different cavities and moieties, to interact with same direct and disperse dyes and with same industrial wastewater composed respectively by direct and disperse dyes mixtures.

 figura7

Figure. 7. Beta and Gamma Cyclodextrins Graphic Representation

AN ALTERNATIVE SOLUTION FOR ENCAPSULATION OF DISPERSE DYES

In the case of disperse dyes results were not as successful as direct dyes, and then an alternative process was proposed for the recovery of this kind of dyes.

The project has demonstrated the ability of chitosan films in binding different textile dyes, varying conditions and modifying the procedure to prepare chitosan (CH) films.

The kinetic studies show that the adsorption onto the different typologies CH follows a first order kinetics (Langergren model). The adsorption of dyes onto CH film results to be dependent on various parameters such as aqueous solution pH, contact time and initial dye concentration.

In particular, for CH STD type films, good results have been obtained when the film is neutralized with NaOH, it is immersed in alkaline dye solution and when it is treated with Et OH.

figura8

Figure. 8 DyesRecoverybyUsingChitosan

As seen in pictures shown in Figure. 8 Dyes Recovery by Using Chitosan , very good results were obtained by using the Chitosan, nevertheless release process was not as efficient as expected.

WHAT IS CHITOSAN?

Chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-Acetyl-D-glucosamine (acetylated unit). It is made by treating shrimp and other crustacean shells with the alkali sodium hydroxide.

 

 DESIGN AND INSTALLATION OF THE SURFACE FOR RECOVERING THE DYES ENCAPSULATED WITH CYCLODEXTRINS.

The prototype designed industrial scale has a capacity of processing of 25 l of waste water sample in each recovery process.

image061  image065

Figure. 9 Project Pilot plant


The selected machine to install the prototype was a jigger

image066

Figure. 10 Jigger HT machine.

As shown in Figure. 11 Project Pilot Plants parts, the prototype receives the wastewater through the ① wastewater inlet located on the top, via a hose connected directly to the evacuation system of the Jigger HT machine (Figure. 9 Jigger HT machine.). Cyclodextrins are added to the process through ② Cyclodextrins Inlet, directly from the recipient in which there have been prepared. When the wastewater has filled.

Inside, the agitator blades will dynamically provide sufficient energy to perform their task allowing cyclodextrins encapsulate the maximum number of dyes. After agitation, when time established for cyclodextrins and dyes processed is met, clean water is ready for being released through the ③ Clean Water Emptying Outlet after decantation. The average temperature of the process is 60ºC and it depends of the type of materials used, and that is provided during the dyeing process as no temperature is added during encapsulation process inside the prototype.

Once the process is over, the filter is retired from the ④filter Sluice-gate.

figura11

 

 

After the procedure, when the cyclodextrins are deposited on a paper filter located at the bottom and water has been redirected into other tanks for reuse, the device can be opened to allow removal of the encapsulated dye.

In the case of non-foreseen situations, system may be evacuated through the ④Emergency Emptying Outlet.

The dyes are recovered without a drying process in a solid state as shown in Figure. 12. Operating Prototype and Results.

figura12
Figure12 Operating Prototype and Results

VALIDATION OF THE RECOVERED DYES IN THE DYEING PROCESS.

After the recovering, we have introduced the encapsulated into new dyeing processes and some of the results are shown in the following images:

figura13

Dyeing with encapsulated dyes have been developed in a progressive way, ability of re-dyeing can be used in repetitive opportunities, as shown in Figure. 13 Different stages of dyeing with encapsulated recovered dyes. Until three consecutive dyeing processes have been achieved obtaining successful and satisfactory results.

MONITORING OF THE ENVIRONMENTAL IMPACT OF THE PROJECT ACTIONS

The main objective of this phase is measure qualitative and quantitative of the environmental impact of the project actions.
The project has contributed to the reduction of chemicals and dyestuff used in dyes recovery, has permitted something that never before was possible with traditional methods of recovery, because they have been conceived to reduce the charge of water released into the environment, the reuse of the dyes and water. Main indicators defined and measured are described below in the point WHAT HAVE WE OBTAINED? MAJOR OUTPUTS AND RESULTS.

MONITORING OF THE SOCIO-ECONOMIC IMPACT OF THE PROJECT ACTIONS

It is aimed that the reuse of these chemical compounds recovered by the use of cyclodextrins to be validated increase social awareness and acceptance of the benefits of protecting the environment through the reuse of products giving them an added value and recovering them in an environmental-friendly way and as a way of protect the environment.
Through the launching a series of surveys he projects has demonstrated the degree of acceptation from the European Community on regard to the prevalence of environmental friendly process in spite of they are more expensive. Water is a limited resource and all initiatives that contribute to the reduction on the impact of industry are very welcome and supported by general community.

 

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