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- Herausgeber: John Wiley & Sons
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
The increasing environmental and health concerns owing to the use of large quantities of water and hazardous chemicals in conventional textile finishing processes has lead to the design and development of new dyeing strategies and technologies. Sustainable Practices in the Textile Industry comprises 13 chapters from various research areas dealing with the application of different sustainable technologies for enhancing the dyeing and comfort properties of textile materials with substantial reduction in wastewater problems. Chapters focus on the sophisticated methods for improving dye extraction and dyeing properties which will minimize the use of bioresource products. This book also brings out the innovative ways of wet chemical processing to alleviate the environmental impacts arising from this sector. This book also discusses innovations in eco-friendly methods for textile wet processes and applications of enzymes in textiles in addition to the advancements in the use of nanotechnology for wastewater remediation.
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Veröffentlichungsjahr: 2021
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Table of Contents
Cover
Title page
Copyright
Preface
Part 1: SUSTAINABLE DYE EXTRACTION AND DYEING TECHNIQUES
1 Extraction and Application of Natural Dyes
1.1 Introduction
1.2 What are Natural Dyes?
1.3 Why Natural Dyes?
1.4 What are Synthetic Dyes?
1.5 Sources of Natural Dyes
1.6 Types of Natural Dyes
1.7 Natural Dyes Need Fixing Agent (Mordants) for Bonding
1.8 Fibers/Fabrics Used for Natural Dyeing
1.9 Extraction of Natural Dyes
1.10 Dyeing Process
1.11 Evaluation of the Dyed Fabric
1.12 Some Special Characteristics of Naturally Dyed Fabric
1.13 Conclusion
Acknowledgement
References
2 Recent Advances in Non-Aqueous Dyeing Systems
2.1 Introduction
2.2 Supercritical Fluid Dyeing System
2.3 Reverse Micelle Systems
2.4 Solvent Dyeing
2.5 Silicone Non-Aqueous Dyeing
2.6 Conclusion
References
3 Structural Coloration of Textile Materials
3.1 Introduction
3.2 Thin-Film Interference
References
4 Enzymatic Wet Processing
4.1 Introduction
4.2 Enzymes
4.3 Function of Enzymes
4.4 Classification of Enzymes
4.5 Αn-Amylase Enzyme for Desizing
4.6 Pectinase Enzyme for Scouring
4.7 Protease Enzyme for Wool Anti-Felting
4.8 Cellulase Enzyme for Biopolishing and Biostoning
4.9 Hairiness Removal Mechanism
4.10 Enzyme Decolorization of Textile Effluent
4.11 Enzymes for Increasing Dyeability of Different Fibers
4.12 Conclusion
References
Part 2: SUSTAINABLE FUNCTIONAL FINISHING OF VARIOUS TEXTILE MATERIALS
5 Coating Textiles: Towards Sustainable Processes
5.1 Introduction
5.2 Most Used Polymers for Coating Textiles
5.3 Traditional Coating Methods
5.4 Environmental Friendly Polymers
5.5 Sustainable Coating Technologies
5.6 Conclusion
References
6 A Review on Hydrophobicity and Fabricating Hydrophobic Surfaces on the Textiles
6.1 Introduction
6.2 Self-Cleaning Surfaces
6.3 Applications of Hydrophobic Surfaces
6.4 Basic Theories: Modeling of Contact Angle
6.5 Techniques to Make Super-Hydrophobic Surfaces
6.6 Methods of Applying Hydrophobic Coating on Textiles
6.7 Contact Angles (CA) Measurement
6.8 Research Records on Hydrophobic Surface Production
6.9 Conclusion
References
7 UV Protection: Historical Perspectives and State-of-the-Art Achievements
7.1 Introduction
7.2 Fundamentals Regarding UV Protection of Textile Fabrics
7.3 UV Stabilizers Beginnings and Initial Development
7.4 Conclusion
References
8 Synthetic and Natural UV Protective Agents for Textile Finishing
8.1 Introduction
8.2 Ultraviolet Radiation (UVR)
8.3 Importance of Ultraviolet Protective Finish
8.4 Methods of Blocking Ultraviolet Rays
8.5 Ultraviolet Protection Factor Measurement System
8.6 Clothing Factors Affecting Ultraviolet Protection Factor
8.7 Mechanisms of UV Protection
8.8 Types of Ultraviolet Absorbers
8.9 Commercial Ultraviolet Protective Clothing
8.10 Nanoparticle Coatings for Ultraviolet Protective Textiles
8.11 Durability of Ultraviolet Protective Finish
8.12 Conclusion
References
9 Sustainable Orientation of Textile Companies
9.1 Introduction
9.2 Textile Industry—Environmental, Social and Economic Issues
9.3 Circular Economy
9.4 Sustainability Circles
9.5 Circularity in the Supply Chain
9.6 Consumer Behavior of Sustainable Textile Products
9.7 Decision to Purchase Sustainable Textile Products
9.8 Policies and Strategies Used in the Sustainable Textile Industry
9.9 Conclusions
References
Part 3: SUSTAINABLE WASTEWATER REMEDIATION
10 Sustainable Application of Ionic Flocculation Method for Textile Effluent Treatment
10.1 Introduction
10.2 Conventional Methods for Degradation of Textile Effluents
10.3 Surfactants
10.4 Adsorptive Micellar Flocculation (AMF)
10.5 Mechanism
10.6 Choice of Flocculant
10.7 Analysis and Calculations
10.8 Optimization of Conditions for Better Removal of Dye Using AMF
10.9 Potential Advantages of AMF
10.10 Application to Wastewaters
10.11 Conclusion
10.12 Future Prospective
References
11 Remediation of Textile Wastewater by Ozonation
11.1 Introduction
11.2 Sources of Wastewater
11.3 Ozonation Remediation for Textile Water
11.4 Impact of Various Techniques in Combination Ozonation Process for Treatment of Textile Wastewater
11.5 Degradation of Dyes via Ozonation
11.6 Conclusion
References
12 Design of a New Cold Atmospheric Plasma Reactor Based on Dielelectric Barrier Discharge for the Treatment and Recovery of Textile Dyeing Wastewater: Profoks/CAP Reactor
12.1 Introduction
12.2 Advanced Oxidation Processes (AOP) in Wastewater Treatment
12.3 Profoks/CAP Wastewater Treatment and Water Recovery System
12.4 Conclusion
References
13 Nanotechnology and its Application in Wastewater Treatment
13.1 Introduction
13.2 Nanotechnology
13.3 Conclusion
References
Index
Also of Interest
End User License Agreement
List of Illustrations
Chapter 1
Figure 1.1 Schematic representation of applications of natural dyes.
Figure 1.2 Sources of natural dyes.
Figure 1.3 Classification of natural dyes.
Chapter 2
Figure 2.1 Schematic diagram of the supercritical CO
2
apparatus equipped.
Figure 2.2 SEM photographs, (a): undyed fabric, (b & c): cotton fabric dyed with...
Figure 2.3 The mechanism of the reaction between reactive disperse dyes and cell...
Figure 2.4 Reaction of disperse reactive dyes with textile amino groups, for vin...
Figure 2.5 Diagram of (a): the micelle, (b): reverse micelle formation.
Figure 2.6 TEM images of reverse micelle-encapsulated Levafix-CA dye [63].
Figure 2.7 SEM photographs of the surface of cotton fiber, (a): before dyeing; (...
Figure 2.8 Diagram of reactive dye in D5 medium.
Figure 2.9 Color strength (K/S) values and fixation (%) of dichlorotriazine dye ...
Figure 2.10 Interaction between dye and surfactant in D5 medium and D5 reverse m...
Figure 2.11 Confocal fluorescence images of distribution of water (a, b, e, f) a...
Figure 2.12 Adsorption of reactive dyes at isothermal conditions (20 °C), (a & b...
Figure 2.13 The dyeing pilot plant of 25 kg [84].
Figure 2.14 EDX Spectrum and SEM images of samples dyed in water medium (a), (b)...
Chapter 3
Figure 3.1 Examples of structural color by interference on a soap bubble (a), gr...
Figure 3.2 Various ways and methods of structural coloration on textiles.
Figure 3.3 Schematic diagram of single thin-film interference.
Figure 3.4 Schematic diagram of multilayer interference.
Figure 3.5 Schematic illustration of the process of colloidal electrospinning an...
Figure 3.6 Schematic diagram of co-sedimentation self-assembly of binary colloid...
Figure 3.7 Photonic crystal patterns fabricated by P(St-BA-MAA)@disperse dye mic...
Chapter 4
Figure 4.1 Beer manufacturing in ancient Egypt using enzymes reprinted from [2] ...
Figure 4.2 The course of an enzyme reaction [6].
Figure 4.3 Classification of enzymes reprinted from [7] with permission from Els...
Figure 4.4 β-elimination mechanism for α-1,4-polygalacturonic acid cleavage [18]...
Figure 4.5 Wool fiber under Scanning electron microscopy reprinted from [19] wit...
Figure 4.6 Cellulases catalyze three types of reactions: i) endocellulase, ii) e...
Figure 4.7 Left: original (raw) indigo dyed denim, right: Bio-stone washed denim...
Figure 4.8 Microscopic images of: (a) cotton fabric; (b) same cotton fabric afte...
Figure 4.9 Illustrative demonstration of cellulase treatment showing intensifica...
Figure 4.10 Bio hydrolysis of nylon 6.6 fibers after mixed-enzyme treatment [76]...
Figure 4.11 Protease treatment showing hydrolysis of nylon 6 [73].
Chapter 5
Figure 5.1 Chemical structure of tetrafluoroethylene (TFE) and polytetrafluoroet...
Figure 5.2 Vinyl acetate (VA) and polyvinyl acetate (PVAc) chemical formulas [12...
Figure 5.3 Twostep process for PVA synthesis [17, 18].
Figure 5.4 Polyurethanes (PUs) synthesis [12, 24–28].
Figure 5.5 Structural formulas of vinyl chloride (VC), polyvinyl chloride (PVC),...
Figure 5.6 Chemical formulas of silicon and polysiloxanes [34–36].
Figure 5.7 Acrylic polymers; synthesis and chemical structures [12, 40, 41].
Figure 5.8 Polyphosphazenes and polyphosphoesters chemical structures [45, 46].
Figure 5.9 Traditional coating methods [6–8, 12, 13, 28, 47–49].
Figure 5.10 Cyclodextrins chemical structures [54–58].
Figure 5.11 Cyclodextrins dimensions (pm) [56, 58].
Figure 5.12 Chemical structure of chitin before and after a partial deacetylatio...
Figure 5.13 Chair structure of alginic (a) acid and (b) sodium alginate [70–72].
Figure 5.14 Polyethylene glycol (PEG) chemical structure [80].
Figure 5.15 Cis-1,4-polyisoprene (Natural rubber (NR)) [87].
Figure 5.16 Chemical structures of polyvinyl acetate and polyvinyl alcohol [18, ...
Figure 5.17 Chemical structure of polyamidoamine (PAMAM- G0) [102, 103].
Figure 5.18 Silk sericin (SS) chemical structure [113].
Figure 5.19 Chemical structures of polyphenols subclasses [118, 119].
Figure 5.20 Sol–gel process with silicon alkoxides as precursors [134, 136–141].
Figure 5.21 Plasmas classification [7, 145, 148–150].
Figure 5.22 Supercritical fluid phase diagram (CO
2
as an example) [160, 163, 164...
Chapter 6
Figure 6.1 Hydrophilic, hydrophobic, and ultra-hydrophobic surfaces [2, 7].
Figure 6.2 SEM images of lotus leaves [5, 9].
Figure 6.3 Schematic of the connection between roughening and self-cleaning [12]...
Figure 6.4 Surface tensions of solid/liquid/vapor phases in Young’s model [11].
Figure 6.5 Wenzel model for static contact angle [21].
Figure 6.6 The relationship between the contact angle and roughness factor [21].
Figure 6.7 Wenzel model for static contact angle [5].
Figure 6.8 Schematic of the spray-coating of the solution [28].
Figure 6.9 Schematic of advancing and receding angles [32].
Figure 6.10 Schematic representation of the goniometer [32].
Figure 6.11 SEM images of hydrophobic cotton fabric [33].
Figure 6.12 Schematic of cotton modification with TDI [34].
Figure 6.13 SEM images of (a) cotton fiber, (b) treated with nano-silica [10].
Figure 6.14 Chemical structure of hexamethyldisiloxane [29].
Figure 6.15 Production of hydrophobic fabrics using middle frequency (MF) plasma...
Figure 6.16 The effects of BTCA concentration on the carboxyl content [35].
Figure 6.17 The effects of reaction time on the contact angle in BTCA–TBT–OA-tre...
Figure 6.18 The effects of OA curing time and temperature on water contact angle...
Figure 6.19 Schematic of the preparation of hydrophobic fabrics [24].
Figure 6.20 The SEM images of (a) cotton fabric, (b) Fe(III)/TA-treated fabric, ...
Figure 6.21 The effects of laundry cycles on contact angle [27].
Figure 6.22 The effects of the citric acid concentration on contact angle [33].
Chapter 7
Figure 7.1 UV-transmittance behavior of a textile material.
Figure 7.2 UPF for fabrics with different density [32].
Figure 7.3 Chemical arrangements of UV shields for textile supports.
Figure 7.4 Synthesis of nanoparticles for UV shielded textiles.
Chapter 8
Figure 8.1 How clothing blocks UV radiation [20].
Figure 8.2 Radiation in contact with a textile surface reprinted from [3] under ...
Figure 8.3 Interaction of radiation with fabrics of varying cover factors reprin...
Figure 8.4 Typical spectrum of transmission for a titanium dioxide nanoparticle ...
Figure 8.5 An ultraviolet-absorbent finish effects on absorption at different wa...
Figure 8.6 TiO2 nanoparticles’ photocatalytic mechanism under the radiation of U...
Chapter 10
Figure 10.1 Flowsheet diagram for the classification of surfactants.
Figure 10.2 Applications of surfactants in different industries.
Figure 10.3 Pictorial representation of removal of dyes by adsorptive micellar f...
Chapter 11
Figure 11.1 Degradation of a dye by ozonation.
Chapter 12
Figure 12.1 ROS formation during energy and electron reactions [25].
Figure 12.2 Time scale of basic processes taking place in a cold atmospheric pla...
Figure 12.3 Profoks/CAP remote discharge reactor.
Figure 12.4 Pilot scale Profoks/CAP treatment system.
Figure 12.5 Membrane [45].
Figure 12.6 Appearances of raw and treated process water.
List of Tables
Chapter 2
Table 2.1. Dyeing conditions and fastness properties of wool, cotton and silk fa...
Chapter 4
Table 4.1. Industrial applications of hydrolase enzymes [8].
Table 4.2. Biotransformation reactions and application of α-amylase [3].
Table 4.3. Application of cellulases in textile finishing [31].
Table 4.4. Bleaching process conditions [40].
Chapter 5
Table 5.1. Sericin content of amino acids [109, 112].
Chapter 6
Table 6.1. Hydrophobicity of treated fabrics with plasma [30].
Chapter 7
Table 7.1. Protection series of some polymeric supports according to ASTMD6603 a...
Table 7.2. UpdatedTable with the most applied textile UV textile finishing.
Chapter 8
Table 8.1. Range and effects of ultraviolet radiation (UVR) [8].
Table 8.2. Common UPF ratings [21].
Table 8.3. Clothing factors impact on UPF of textiles [36].
Table 8.4. Porosity and maximum theoretical UPF [35].
Table 8.5. Different dyes and different substrates impact on UPF [36].
Table 8.6. UPF values of cotton fabric dyed with natural colorants [21].
Table 8.7. UV protection factors (UPF) of undyed fabrics [21].
Table 8.8. Measurements of UPF for a T-shirt made of cotton (437W) and mercerize...
Table 8.9. Measurements of UPF for a T-shirt made of cotton (437W) and mercerize...
Table 8.10. Measurements of UPF for a T-shirt made of cotton (437W) and merceriz...
Chapter 12
Table 12.1. Wastewater characterization of textile wastewater before and after t...
Table 12.2. Profox/CAP wastewater treatment and water recovery plant design inle...
Table 12.3. Profoks/CAP wastewater treatment and water recovery facility investm...
Guide
Cover
Table of Contents
Title page
Copyright
Preface
Begin Reading
Index
Also of Interest
End User License Agreement
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Scrivener Publishing
100 Cummings Center, Suite 541J
Beverly, MA 01915-6106
Publishers at Scrivener
Martin Scrivener ([email protected])
Phillip Carmical ([email protected])
Sustainable Practices in the Textile Industry
Edited by
Luqman Jameel Rather
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, P.R. China
Mohd Shabbir
School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, Hubei, P.R. China
and
Aminoddin Haji
Textile Engineering Department, Yazd University, Yazd, Iran
This edition first published 2021 by John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA and Scrivener Publishing LLC, 100 Cummings Center, Suite 541J, Beverly, MA 01915, USA
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Preface
In recent years, the textile industry has been the focus of rising interest in global markets due to varied and changing world market conditions. Increasing environmental and health concerns owing to the use of large quantities of water and hazardous chemicals in conventional textile finishing processes, has led to the design and development of new dyeing strategies and technologies. Effluents produced from the textile wet processing industry are very diverse in chemical composition, ranging from inorganic finishing agents, surfactants, chlorine compounds, salts and total phosphate to polymers and organic products. This has forced Western countries to exploit their high technical skills for the advancement of textile materials with high quality technical performances, and the development of cleaner production technologies for cost-effective and value-added textile materials. Sustainable Practices in the Textile Industry is a collection of the current sophisticated ways used to minimize the use of bioresource products to improve dye extraction and dyeing properties. Highlighted in this book are the innovative ways in which wet chemical processing methods are used to alleviate the environmental impacts arising from this sector. The major challenge in the textiles and fashion sector is that it requires massive sustainable innovation in terms of material and end-use products to mitigate the huge environmental impacts arising from chemical processing. Therefore, this book also contains innovations in eco-friendly methods for textile wet processes and applications of enzymes in textiles in addition to advancements in the use of nanotechnology for wastewater remediation.
The book is compiled of 13 chapters from various research areas dealing with the application of different sustainable technologies for enhancing the dyeing and comfort properties of textile materials with substantial reduction in wastewater problems. Chapter 1 deals with the sustainable extraction of natural dyes from plant sources and their subsequent applications in the textile industry. Chapter 2 deals with the advancements in non-aqueous dyeing systems. Chapter 3 gives a brief account of structural coloration of different textiles achieved as a result of scientific observations of nature. Chapter 4 deals with the use of enzymes for enhancing dyeing properties of different textiles. Chapter 5 deals with the use of sustainable processes for textile coating. Chapters 6 through 8 give a detailed account of the functional finishing properties achieved on different textiles using different dyeing methods with natural and synthetic functional finishing agents. Chapter 9 provides up-to-date information regarding sustainable development for brands and manufacturers in the textile industry. Finally, the remaining Chapters 10 through 13 deal with the advanced techniques used for wastewater remediation.
The authors who contributed to this book are specialists in fields involved in using different dyeing systems other than aqueous solvent, employing enzymes in dyeing procedures, surface modifications, sustainable developments for textile manufactures, functional finishing and different advanced techniques for wastewater remediation. Thus, the editors hope that students, researchers and academicians of various fields, such as textile dyeing, chemical engineering, environmental science, materials science among others, will find this book of great interest and useful in their curriculum. We expect it will definitely be helpful for engendering new ideas in textiles research, leading to interdisciplinary research collaborations.
Now the time has come to thank those who supported this book in any way. We acknowledge the great efforts of the eminent authors without whom this book would have been unimaginable. We also appreciate the interest shown and the support given by the publisher, which allowed us to compile this reference book.
Luqman Jameel Rather
Aminoddin Haji
Mohd Shabbir
Part 1SUSTAINABLE DYE EXTRACTION AND DYEING TECHNIQUES
1Extraction and Application of Natural Dyes
Sanjeeda Iqbal and Taiyaba Nimra Ansari*
Department of Botany, Govt. Holkar Science College, Indore, India
Abstract
Environmental pollution and population explosion are becoming the world’s biggest issues. Eco friendly products and practices are popularizing day by day due to present national and international awareness on environmental situations. Textile industries are one of the reasons of environmental pollution and affect all forms of life adversely. Textile dyeing process generally uses chemical dyes and synthetic mordants. Chemicals in the dyeing process began with the discovery of “Mauve” by WH Perkin in 1856. These synthetic dyes are manufactured from coal tar, petrochemicals and many other chemicals, which cause allergies such as contact dermatitis, respiratory diseases, skin irritation and cancer etc. Naturally dyed textile materials are in demand globally because of harmful effects of chemical dyeing and continuous efforts of researchers in this field. Natural dyes can be obtained from natural resources like plants, minerals, insects and fungi but most of the dyes are taken from plant parts i.e. leaves, barks, flowers, fruits and roots. Natural dyes have some special properties like soothing color, biodegradable, non-hazardous, non-carcinogenic and antimicrobial resistance etc. Natural dye extraction process requires plant parts and sometimes their by-products as a raw material. Natural dyeing practices enhance the cultivation of flowering crops, which provides an extra source of income to farmers. Thus, large scale production of naturally dyed fabric in future will solve the problem of human as well as environmental health.
Keywords: Natural dyes, source, fiber, mordant, dyeing, fastness, antibacterial, UV-protection
1.1 Introduction
In the present scenario people are more inclined to be nature-friendly, health conscious and become aware about the environment. The meticulous environmental standards are being imposed by many countries in response to the toxic and allergic reactions associated with synthetic dyes. It has created a revolution in research and development in eco-friendly and non-toxic colorant. Environmental considerations are now becoming vital factors during the selection of consumer goods including textile as well as in cosmetic, pharmaceutical and food industry all over the world. Coloring agent or dyes play an important role in all these industries during manufacturing and other production process. Both qualitative and quantitative research investigations have been undertaken all over the world on safe coloring substance. Natural dyes are widely used in following application (Figure 1.1):
Figure 1.1 Schematic representation of applications of natural dyes.
a. Textile Coloration
Coloring of textile material is called dyeing. Dyeing is a process to enhance the beauty of fiber or fabric by coloring them. The coloring compounds can be synthetic or natural and capable of being fixed to fabric defined as dye. India is a diverse country of region and culture. Dyeing practices varied immensely due to availability of local dye-yielding plants and minerals, the natural sources. Until year 1856, these natural sources were used in coloring but with the discovery of chemical dyes, the use of natural dyes decreased. The side effects of the continuous use of chemical dyes gradually began toappear as health problems and skin diseases that resulted by wearing synthetic dyed fabric for decades. Hazardous chemicals were used in the manufacture of dyes in large scale for rapid growth of textile industries. All those synthetic, hazardous chemicals disposed of in nature after dye preparation, coloring and printing, which ultimately created various pollution problems in the environment. Keeping this situation in mind, many experiments are being done by scientists and researchers for the development of new sources and techniques of natural colors, so that it can be adopted by textile industries on a large scale. There is an increasing awareness among humans about their health and nature, due to which the demand for eco-friendly clothes is also increasing. Natural clothes can be obtained at a higher price from some small scale industries and handlooms, but they are not able to meet the demand of all people. In the past few years, many research works related to natural dye have been done. In this chapter, an attempt has been made to exhibit how natural dyes are used on clothes and their significance for human health and nature.
b. Food Coloration
Human appetizer and choice of food are influenced by color. Food colors are used in processed food, drinks and condiments. They are often added to maintain and improve the appearance of the food. The addition of saffron, turmeric and other spices are reported from ancient times. Commercially available colors are made of chemicals that can be harmful to human and environment. Therefore, natural food colors are in demand again. Most commonly used natural food dyes are saffron, turmeric, annatto, beetroot and carrot etc.
c. pH Indicator
pH is measure of relative amount of free hydrogen and hydroxyl ions in water. The range of pH is in between 0 and 14, where 7 is considered neutral. pH greater than 7 indicates the base, whereas pH less than 7 indicates acidity. A pH indicator is a compound that changes color in solution over a narrow range of pH value. Small amount of indicator compound is sufficient to produce a visible color change. There are many colors of indicators in nature thus, influenced by change in pH range. Some of the natural dyes show color changes with variation of pH. Red cabbage dye is very good example of natural pH indicator [1].
d. Histology Staining
Study of the microanatomy of cells, tissue and organs is called histology. Observations of cells are performed with the help of a microscope. Staining is the technique to highlight and differentiate the structure of tissue. Stain and dyes are applied in staining on tissue and cells. Dyes also can be used to color cells, tissue, organelles as well as microorganism such as bacteria and fungi [2]. Saffron, a natural dye extracted from Saffron crocus was the first stain in histology used by Antonie van Leeuwenhoek, the father of microbiology [3]. Hematoxylin stain is a naturally occurring dye found in Logwood tree widely used in histological study. Researchers also found Punica granatum, Curcuma longa, Syzygium cumini and Sorghum bicolor effective in staining [4–7].
e. Cosmetics and Pharmaceutical
Cosmetic products are used to clear, improve or change the complexion, skin, hair and nails. Colors or dyes are the most important ingredient in production of cosmetics. Henna is traditionally used for coloring hands and hair. Saffron and turmeric also examples of natural dyes utilized in cosmetics. In pharmaceutical field colors of medicine are used to differentiate the dosage. Imparting color to drugs helps in their distinctive appearance. The colorant employed in pharmaceuticals is considered safe such as beet root, paprika and annatto.
f. Dye-Sensitized Solar Cells
Dye-sensitized solar cell is third generation photovoltaic (solar) cell that converts any visible light into electrical energy. It is low-cost solar cell belonging to the group of thin film solar cells. Performances of dye sensitized solar cells are mainly based on dye used as a sensitizer [8]. Godibo et al., attempted the preparation of Dye Sensitized Solar Cells using flowers of Amaranthus caudatus, Bougainvillea spectabilis, Delonix regia, Nerium oleander, Spathodea companulata and a mixture of the extracts [9].
In addition to the above mentioned applications, there is a growing interest for using natural dyes to dye leather, stain wood, pulp, some plastics [10–14]. This chapter intends to discuss the application of natural dyes in textile.
1.2 What are Natural Dyes?
Natural dyes can be derived from natural sources such as plants, animals and minerals. A large number of herbs, shrubs, trees, insects, animals, microbes and minerals have been identified for extraction of coloring compounds [15]. Red, yellow, brown, blue, black, green and orange color can be obtained from natural dyes.
1.3 Why Natural Dyes?
Natural dyes are recommended to be applied on textile materials. Following points support the use of natural dyes on a large scale.
Eco-friendly: Natural dyes are extracted from natural sources therefore they are environment safe.
Biodegradable: These dyes are capable of being decomposed by microorganisms.
Renewable: Replaced by the new material obtained from nature.
No health hazard/Non-toxic: Natural origin of these dyes makes them harmless.
Variety of shades: Varieties of color, shades and hues present in nature itself.
Soothing, soft and lustrous color: Natural dyes are soft and relaxing.
Utilization of waste material: Many agriculture waste products can be used in the dyeing process.
Antibacterial/UV Protective: Naturally dyed fabrics get special properties like antibacterial and UV protection.
As there are many advantages in using natural dyes but they also have some drawbacks:
Expensive: Natural dyes are expensive due to being limited in source.
Faded easily: Sometimes their poor attachment on fabric makes them fade easily.
Difficult to produce/collect: Collection is somewhat difficult in large amounts.
Time consuming: The complete process like collection of dye takes long time.
Reproducibility of shades is difficult to control: Natural dyes produced by secondary metabolic activities of plants or by very special processes in other animals, which depend on climate conditions, age and seasonal variations. Thus, one particular shade cannot be achieved again and again by a single dye.
1.4 What are Synthetic Dyes?
Synthetic dyes are made by organic molecules. They are derived from coal tar hence also known as coal tar dyes. William H Perkin synthesized “Mauve” the first synthetic dye in 1856 in the United Kingdom. Then, a significant number of dyes were discovered and industries quickly adopted them to grow, mainly in the United Kingdom, Switzerland and Germany [16].
The Sudan I (Solvent Yellow 14) is one of the members of azo-dyes widely used in textile industry [17]. It is enzymatically transformed, through the action of the intestinal flora, into carcinogenic aromatic amines, when present in the bodies of animals or humans [18]. In the case of azo-dyes, especially, carcinogenicity can be produced by both the dye itself and its own converted compounds [19]. The study of National Toxicology Program confirmed the neoplastic liver nodules in rats by the presence of Sudan I dye [20]. The Basic Red 9 dye, used in the textile, leather, paper and ink industries [21], develops carcinogenic potential in humans [22], and high toxicity to environment [23]. Under anaerobic conditions, it breaks down into carcinogenic aromatic amines, and when disposed in water bodies can cause allergic dermatitis, skin irritation, and cancer [24]. According to the in vivo tests on rats, it causes local sarcomas and tumors in the liver, bladder [25], mammary glands and hematopoietic system [26].
The Crystal Violet dye, shows an intense color [27], and is a member of the cationic triphenyl methane group, and is responsible for mitotic poisoning and abnormal accumulation of metaphases [28] as well as the in vitro clastogenic effects observed in Chinese hamster ovules [29], which induce chromosomal damage too [30]. According to Bharagava et al., this powerful carcinogenic agent promotes fish tumors [28, 31] and hepatocarcinoma, reticular cell sarcoma in various organs, such as the vagina, uterus, ovary and bladder [32] as well as hardened gland adenoma and ovarian atrophy in rats. In humans, it is capable of generating respiratory and renal failure, chemical cystitis, skin irritation and digestive tract disorder [28].
Advantages/Merits of Synthetic dyes
Easy preparation.
Available in large numbers and quantities.
Quality of fast colors
Cost effective.
Disadvantages/Demerits of Synthetic dyes
Production on high temperature
Carcinogenic
Hazardous to human health.
Problem of environmental pollution.
1.5 Sources of Natural Dyes
Natural dyes can be classified in following groups on the basis of sources (Figure 1.2) [33]:
Figure 1.2 Sources of natural dyes.
Plants:
Roots, leaves, fruits, flowers and barks can be used as a source of natural dyes. Different colors can be obtained from each part such as Sappan-wood tree pods give red, barks give brown and root gives yellow color. Many by-products of plants can also be used to form dyes.
Animals:
Dyes can be obtained from dried body of insects for example, Lac, Cochineal and Kermes. Cochineal is a brilliant red dye produced from insects living on Cactus plants. Carmine and Tyrian purple dye derived from cochineal, shellfish (
Murex
spp.) respectively.
Minerals:
Mineral dyes include iron buff, iron black, manganese bistre, chrome yellow, and Prussian blue.
Microorganisms:
Natural colorant can be extracted from fungi, bacteria and algae that are fast growing and have the potential of being standardized commercially [34].
Chitosan
,
Serratia
spp.,
Trichoderma virens
and
Alternaria alternata
were used to obtained dyes [35]. Natural Red color is produced by
Monascus anka
and also from fungus
Echinodontium tinctorium
. Phycocyanin is blue pigment extracted from
Spirulina plarensis
algae.
1.6 Types of Natural Dyes
Natural dyes were classified in many ways at different time periods by researchers on the basis of chemical constitution and method of application [36].
1.6.1 Classification on the Basis of Their Chemical Constitution
Indigoid dyes:
This group includes Indigo and Tyrian purple dye. Indigo is extracted from
Indigofera tinctoria
and considered the most primitive dye. Woad plant (
Isatis tinctoria
) also has indigo as the chief blue dyeing component.
Anthraquinone dyes:
Most of the red natural dyes from both plant and mineral origin are based on the anthraquinoid structure. Madder, Lacs, Cochineal are some examples of this group. Alizarin and purpurin are the main chromophores in
Rubia tinctorum
.
Alpha naphthoquinones:
Lawsone (henna) is a most important member of this class. Another dye is juglone, isolated from the shells of unripe walnuts.
Flavonoids:
Yellow dyes obtained from this group and can be classified under flavones, isoflavones, aurones and chalcones. These yellows are found in a variety of plants, including Persian berries (
Rhamnus
spp.), young fustic (
Cotinus coggygria
), old fustic (
Chlorophora tinctoria
) and yellow wood (
Solidago virgaurea
).
Di-hydropyrans:
In chemical structure, di-hydropyrans are similar to the flavones. These natural dyes give dark shades on cotton, wool and silk. Logwood and Sappan-wood are the most common examples.
Anthocyanidins:
Orange dye carajurin obtained from leaves of
Bignonia chica
. Carajurin is a chemical member of this class.
Carotenoids:
The class name carotene is derived from the orange pigment found in carrots. In these, the color is due to the presence of long conjugated double bonds. Usually, red, orange and yellow colors come in this category and can be obtained from different plants, e.g. yellow, orange color in sunflower [37, 38].
1.6.2 Classification Based on Method of Application/Preparation
Direct Dyes:
Direct dye soluble in water can be taken up directly by the material. Direct dye also called substantive dyes because of their excellent substantivity for cellulosic material like cotton and viscose rayon. Turmeric,
Chebulic myrobalan
and Annatto used in direct dyes.
Vat Dyes:
As the name suggests that the dye is prepared in a large container for storing and mixing liquids or wooden vessels commonly known as ‘Vat’. This is a primitive method of dye preparation.
Mordant Dyes:
Mordant dyes are attached to textile fibers by a fixing agent “mordant” which can be organic or inorganic substance. Since chromium is used extensively hence, mordant dyes are sometimes called chrome dyes.
Acid Dyes:
These dyes performed in acidic medium. Sulfonic or Carboxylic groups of dye molecules can form electrovalent bonds with amino groups of wool and silk.
Basic Dyes:
These dyes form an electrovalent bond with the carboxylic group of wool and silk. Berberine has been classified as basic dye.
Disperse Dye:
Disperse dye have low aqueous solubility and low molecular weight. These dyes require post mordanting treatment with chromium, copper or tin salt (
Figure 1.3
) [36].
Figure 1.3 Classification of natural dyes.
1.7 Natural Dyes Need Fixing Agent (Mordants) for Bonding
Mordants (from the Latin verb “modere” meaning “to bite”) are natural salts that can form a stable molecular coordination complex with both dye and fiber. Natural dyes and their use in dyeing is the most ancient art of all times. Most of the natural dyes have very low affinity towards fabric, therefore a fixing agent is required to attach dye on fabric. Mordants are substances that are able to form complexes with molecules of dyes. Mordants can be applied before dyeing, after dyeing or within dyeing mixed in a dye pot. Process of Mordanting improves the color fastness properties of dyed fabric. Mordants are classified in three categories such as Metallic mordants, Tannins and Oil mordants [39]. The fourth category is bio-mordant, which is generally obtained from natural resources.
1.7.1 Metallic Mordants
i. Aluminum:
Potash alum is the most widely used aluminum mordant for natural dyeing. Alum does not affect the color. The shade of dye depends on the amount of mordant. If deeper shades are required on fabric a greater amount of mordant is needed. Alum forms weak sulfuric acid when dissolved in water during the mordant process. This can result in acidic fumes which are corrosive, and irritating when inhaled.
ii. Iron:
Iron salts in the form of ferrous sulfate (also known as green vitriol) are extensively used in dyeing and printing. Mordanting with iron salts produces a black or gray color to the fabric and reduces the darkness of other colors. Repeated high exposures may lead to nausea, vomiting, stomach pain, constipation and may affect liver.
iii. Copper:
In copper mordanting, fabric treatment is done with the help of copper sulfate (blue vitriol). It is known for improving the light fastness of various dyed materials. High temperature operations such as boiling in dyeing generate fumes that have different health effects. Long-term exposure of copper can cause irritation, burn the skin, eyes and throat. It can cause headache, nausea, vomiting, diarrhea and abdominal pain.
iv. Tin:
Tin mordant brightens the color. Stannous and stannic chloride are used as mordants. Stannic chloride is preferred for cotton. It causes severe skin burns and eye damage. It also causes skin allergies.
v. Chromium:
Potassium dichromate is used in mordanting procedure and referred as Chrome. It is highly toxic and quite hazardous to health. Small amounts can cause contact dermatitis. It is a known carcinogen meaning it causes cancer.
1.7.2 Tannins and Tannic Acid
Tannic acid or tannins are used as a primary mordant for cotton and cellulosic fibers which do not have much affinity for metallic mordants. A cotton fabric treated with tannic acid can absorb all types of dyes.
1.7.3 Oil Mordants
In the past, castor and til (sesame) oils were used as mordants but they were later replaced by Turkey Red Oil (TRO). Sulfated castor oil is largely used in textile industries.
Many metal salts such as chrome, copper, tin and lead are seldom used now due to research evidence of their extreme toxicity either to human health, ecological health or both. Only a small amount of these metal salts get fixed on the fabric and the rest is discharged as effluent which leads to the contamination of land and water resources. In order to make natural dye sustainable many scientific workers are developing natural mordants that can be replaced with metallic-salt-based mordants.
1.7.4 Bio-Mordants
Bio-mordants are those substances that can be obtained from natural sources. According to many researchers bio-mordants are eco-friendly and effective to use than synthetic mordants [40]. There are some examples of bio-mordants:
i. Myrobalan:
It is one of the most important and widely used mordants in dyeing processes. It can be considered as dye and mordant both. Myrobalan mordant is obtained from fruits of
Terminalia chebula
commonly known as ‘Harda’. It gives pale yellow color on fabric.
ii. Oak gall:
Gallnuts are obtained from the oak tree. It is the earliest and richest source for natural tannin. These are collected and ground for use as a tannin mordant.
iii. Sumac:
The leaves of sumac contain tannin which can be used in the process of mordanting cotton.
Rhus glabra
species of sumac also known as “rhubarb”. Leaves of sumac are rich in tannin suitable for dyeing and their use as mordant.
iv. Pomegranate rind:
Dried pomegranate rind (
P. granatum
) powder also used as mordant in natural dyeing. Sangeetha
et al
. applied lemon leaves extract using
P. granatum
rinds as mordant on Silk fabric [41].
v. Catechu:
Catechu was used as a natural mordant since the ancient times as myrobalan [42, 43]. Catechu is extracted from the heartwood of
Acacia catechu
. It produces various shades of brown. Catechu mordants were applied with
Sticta coronate
a lichen that produces dye for coloring silk fabric [42].
vi. Aloe vera:
Aloe vera leaves contain sticky substance. Researchers are working on exhibited fixing properties of aloe. Fresh leaves of aloe vera can be taken as biomordant for dyeing silk fabric [44].
Other than above mentioned names many sources have been explored for bio-mordants. Adeel et al. explored the fixing properties of acacia (Acacia nilotica), henna (Lawsonia inermis), turmeric (C. longa), pomegranate (P. granatum) and rose (Rosa indica) with natural dye extracted from cinnamon bark. New shades observed on silk fabric with improved fastness properties [45]. Bark of Xylocarpus moluccensis tested to be used as a biomordant, and significant improvement in the percentages of dye absorbed in the silk fabric was observed [46]. Wool yarn dyed with madder roots with gallnut (Quercus infectoria) extract as biomordant [47]. Rani et al. investigated that harda powder, pomegranate peel, orange peel and amla powder can be used as alternative copartner of metal mordants. Dyeing was done on protein fabrics with Carica papaya leaf natural extract [48]. Wool yarn dyeing performed with Adhatoda vasica extract. The effect of various metal salts and extracts of gallnut, pomegranate peel and babool bark as mordants were comparatively evaluated [49]. Aminoddin extracted Berberine from Berberis vulgaris wood and applied on wool fiber using the extract of roots of Rumex hymenosepalus as biomordant [50]. Banana pseudostem sap was applied as a biomordant with Senegalia catechu stem extract on wool [51]. To provide best options of synthetic mordants various scientists are exploring and developing the new and effective bio-mordants.
1.7.5 Method of Application
i
.
Pre Mordanting (Chrome mordant process):
This is two bath process in which fabric is first mordanted in a dye bath then squeezed and immersed for dyeing at required temperature.
ii
.
Post Mordanting (After chrome method):
The method involves first dyeing the fabric and then treating it with mordants, later on material is taken out for washing, squeezed and dried.
iii
.
Simultaneous Mordanting (Meta-Chrome process):
The meta-chrome process involves only one single step because dye and mordant is mixed together to work simultaneously on fabric.
1.8 Fibers/Fabrics Used for Natural Dyeing
Dyeing is a process where dye molecules transport to a substrate surface from the dye solution. The substrates are fabric or fiber. Mainly fibers have two groups i.e. Natural and Man-made (Synthetic) fibers. These fibers/fabrics are mainly used to perform natural dyeing [52].
1.8.1 Cellulosic Fiber
a)
Cotton:
Cotton is a natural fiber obtained from different species of
Gossypium
plant. The fiber is almost pure cellulose, soft, fluffy, staple that grows in a ball around the seeds of cotton plants.
b)
Jute:
Jute is a long, soft and shiny bast fiber. It is one of the strongest natural fibers.
c)
Linen:
Linen has a very good quality of absorption. Flax (
Linum
sp.) plants commonly known as linseed are the source of linen fiber.
d)
Hemp:
It is obtained from a variety of
Cannabis sativa
plant species as bast fiber.
1.8.2 Protein Fiber
a)
Wool:
It is an animal fiber. Wool is obtained from the sheep or other hairy mammals.
b)
Silk:
It is a natural protein fiber and made up of Fibroin. Silk fibre is obtained from the cocoons of silkworms.
1.8.3 Synthetic Fiber
a)
Nylon:
It is produced by reaction of amino acid with itself or between diamines and diacids.
b)
Acrylic:
Polymer acrylonitrile found in acrylic fiber. It is soft, light weight and warm fiber.
c)
Polyester:
They are polymer and contain ester functional groups in their main chain.
1.9 Extraction of Natural Dyes
Extraction of color from natural dye is one of the most important steps of dyeing. Raw materials of natural dyes are leaves, barks, fruits, flowers and roots of many plants as well as some animals and minerals as described earlier. Sources of natural dyes are carbohydrates, proteins, lipids, fats and many other cell inclusions, so only the desired coloring material requires an extraction process. In the extraction process of natural dyes, the cost of extraction and the yield of color affects the cost of dyeing. Following methods generally used for extraction of coloring materials:
i
.
Aqueous extraction:
Aqueous extraction method is a traditional and most popular procedure in natural dyeing. Small pieces of fresh or dried dye material are ground in powdered form. That is soaked in water, boiled, filtered to obtain aqueous dye solution. Aqueous extraction depends on many factors such as time and temperature of the boiling, fresh or dried dye material and material to liquor ratio. Maryam
et al
. gave one such example i.e. extraction of color from Onion (
Allium cepa
) skin in aqueous condition as 5 g of dye dissolved in 100 ml water at the temperature of 100 °C for 60 min [53].
ii
.
Alkali or acid extraction:
Glycosides can be hydrolyzed in acidic or alkaline condition. Mostly, natural dyes constitute glycosides, so extraction in acidic or alkaline medium can improve color yield. Some of the natural dyes are pH sensitive therefore; they destroy their dyeing properties in unwanted pH condition.
iii
.
Microwave and ultrasonic assisted extraction:
The extraction of natural dye can be done by microwave and ultrasonic assistance. Microwave energy used in extraction of natural dye with a very minimum amount of solvent. Microwave increases the rate of the processes so the extraction can be completed in a shorter time with better yield. Thangabai and Kalaiarasi’s studies revealed that microwave assisted extraction of Padauk (
Pterocarpus
sp.) wood are more efficient as compared to conventional extraction methods [54]. Natural dye from Sorghum husk extracted with the help of ultrasound-microwave-assistance [55].
iv
.
Fermentation:
Indigo extraction is the best example of fermentation method of extraction. In presence of indimuslin enzyme, glucoside indican breaks into glucose and indoxyl [56]. The enzymes produced by the microorganisms present in the atmosphere or those present in the natural resources used in fermentation for assisting the extraction process.
v
.
Solvent extraction:
Natural dyes can also be extracted depending upon their solubility by using organic solvents such as acetone, petroleum ether, chloroform, ethanol, methanol, or a mixture of solvents such as ethanol and methanol, mixture of water with alcohol, and so on.
vi
.
Supercritical fluid extraction:
Supercritical fluid extractions have become popular in recent years to isolate the organic compound from herbs and dyes as well as dye from natural sources. In supercritical fluid extraction a dense gas as a solvent that usually has carbon dioxide above its critical temperature (31 °C) and critical pressure (74 bar) for extraction is used [14].
1.10 Dyeing Process
1.10.1 Preparation of Fabric Before Dyeing
Raw textile materials are required to prepare base before processing such as dyeing and printing etc. Natural and man-made fibers contain undesirable matter like dirt or stains which are regarded as impurities. Textile materials in this “raw” state are to be “cleaned” and “finished” to make gray yarn or gray fabric.
a)
Weighing:
The weight of textile material helps us to know about the amount of soap for washing, the quality and quantity of chemicals and dye stuff to use in the mordanting and dyeing processes. Therefore, the first step is to weigh the yarn of fabric while it is still dry [57].
b)
Soaking:
Fiber or fabric is soaked for 12 h in tap water to remove the water soluble impurities.
c)
Scouring:
Fibers contain oil and fats on their surface; they are hydrophobic in nature which affects the absorbency of the fibers. The outer hydrophobic layer has to be removed before dyeing. The process by which this water resistance layer is removed from the fabric is called “Scouring”.
d)
Bleaching:
Bleaching is the process of discoloration or removal of natural and other coloring matter from fibers. This is a process of whitening fibers using oxidizing agents.
1.10.2 Mechanism of Dyeing
a)
Adsorption:
Firstly the dye molecules in the dye bath move towards the fiber and those that are nearest to the fiber get “adsorbed” on to the fiber surface. They form a very thin layer of molecules on the surface of fiber.
b)
Penetration:
Secondly the adsorbed dye molecules adhered to the outer surface of fiber gradually penetrate or infiltrate into the pores or canals of the structure.
c)
Fixation:
The final step is one where the dye molecules find suitable locations according to dye size where they get “fixed” or “anchored”.
1.10.3 Process of Dyeing
a)
Pre-Soaking the Material:
Textile stuff, whether it is fabric, yarn or loose fiber is thoroughly wet in water before dyeing begins. Such wetting is achieved by soaking for hours. A thoroughly wet textile dyes well.
b)
Enzyme Assisted Dyeing:
Enzyme assisted dyeing is also performed for textile coloration [58]. Ultrasonic dyeing on cotton and silk fabric is performed with
Terminalia arjuna
,
Punica granatum
and
Rheum embodi
dye. In pretreatment enzyme protease, amylase, diastase and lipase are complexed with tannic acid. Both fabrics showed rapid dye adsorption kinetics and total higher adsorption [59]. Raja and Thilagavathi demonstrated that alkaline protease enzyme process improve the quantity of natural dye exhausted [60].
c)
Sonicator Assisted Dyeing and Plasma Treatment:
Ultrasonic dyeing technique is also called Sonicator dyeing that improves the penetration of dye in fiber or fabric and increases color strength. It is a rapid dyeing process and can be run under mild conditions and low temperatures. Dyeing of wool fabrics carried out with natural dye “lac” through conventional and ultrasonic techniques [61]. In another study
Eclipta
leaves were taken as natural dye for cotton fabric using both conventional and sonicator methods. Results revealed that Ultra-sonication method showed higher color strength values [62]. Vankar
et al
. demonstrated the sonicator dyeing method to improve dye uptake on cotton, silk and wool [63]. Plasma treatment in dyeing is conducted for improving the dye uptake of fabric. It is a surface modification technique that performs before dyeing on textile materials [64]. Low-temperature plasma is widely used in non-destructive surface modification of textiles where a wide range of properties can be obtained. Plasma treatment performed on silk fabric and dyeing done with natural dye extracted from
Phytolacca decandra
[65]. Plasma treatment was conducted to improve the adhesion of chitosan on cotton fibers. After that the cotton is dyed with natural dye extracted from pomegranate rinds. The results exhibited that plasma treatment can enhance the color strength of the dyed sample [66].
d)
Printing:
Printing on textile in India has been a part of India’s cultural identity for thousands of years [67]. Printing produces more colorful effect on the fabric. Printing is a process where colorful designs are created which can be done by hand or machine. Hand printing is done by two methods viz., block printing and screen printing. Boruah and Kalita revealed that turmeric dye produced various soft and stable natural print on eri silk. Three different mordants alum, stannous chloride and ferrous sulfate were selected for printing [68]. Kavyashree investigated the efficiency of natural dye in screen printing on cotton and silk fabrics. Three natural dyes indigo, madder, and sappanwood were selected for screen printing. The results revealed that these dyes can be considered as the recommendable alternative to harmful synthetic dyes [69]. Jimmy
et al
., investigated the color resistant material from flour of
Colocasia esculenta
using
Acacia catechu
as natural dye for batik technique [70].
e)
Dyeing Condition
i. Dyeing Condition for Cellulosic Material
Cotton is the most popular textile material. Many researchers have attempted to dye on cotton with the natural dyes. Each fabric performs differently in dye bath on the basis of their chemical structure. Dyeing parameters such as dyeing time, temperature, pH, material liquor ratio, dye and mordant concentration play an important role in dyeing. Several studies standardized the dyeing condition for cotton and reported the results as dyeing temperature, 70–100 °C, dyeing time, 60–120 min, material to liquor ratio, 1:20–1:100, and pH, 10–12 may be required for natural cellulosic material.
Vankar et al. used Eclipta as natural dye for dyeing cotton fabric by conventional and sonicator methods [62]. Teli and Paul attempted to dye cotton fabric with extraction of coffee seed coat. Dyeing was done by pre, meta and post-mordanting methods using various mordants. The results showed that coffee seed extract can develop a range of shades with good fastness properties [71]. In another study only coffee seeds were used for dyeing purposes. Some mordants such as FeSO4, CuSO4 and SnSO4 were applied for improvement of color strength of cotton fabric [72]. Shanker and Vankar applied dye extracted from Hibiscus mutabilis using 1:40 for M:L ratio on cotton fabric. Dyed cotton fabric exhibited good fastness properties [73]. Dayal et al. isolated dye from Parthenium hysterophorus and employed on cotton fabric. The dyeing done with M:L ratio 1:100 at 95–98 °C for 60 min on dyebath [74]. Indi and Chinta the fruits of Phyllanthus reticulatus utilized for dye extraction and application. Premordanting was done with alum (8%) and tannic acid (4%) at the temperature 80 °C for 60 min. Same treatments were performed for Post mordanting. Dyeing was carried out for 10% shade at 80 °C for 45 min at pH from 3–7 [75]. Vankar and Shanker dyed cotton with aqueous extraction of N. oleander flowers. Mordanting was done with metal salt i.e. FeSO4, SnCl2, CuSO4, SnCl4, K2Cr2O7 and alum at 60 °C for 30 min. Then, dye is applied on cotton while keeping the M:L ratio as 1:30 and pH was set at 4 [76]. A study has been conducted for improvement of washing and light fastness by Mukherjee et al., where pre mordanting was carried out with aluminum sulfate, zinc sulfate, copper sulfate, magnesium sulfate and sodium dichromate. Dyeing was done with M:L ratio 1:20 at the temperature of 90 °C for 45 min. Natural dyes obtained from Curcuma longa, Butea monosperma, Tagetes erecta and Nyctanethes arbor-tristis were taken for experiment by different researchers [77].
Kulkarni et al. attempted dyeing cotton with natural dyes isolated from Pomegranate peel. Copper sulfate and ferrous sulfate were applied in ratios for mordanting. About 4% dye extraction was applied at 80 °C for 60 min with M:L ratio 1:40 [78]. Srivastava et al. studied the dyeing capability of Lichi peels on cellulosic fabrics. Many experiments were performed to determine the dyeing parameters, such as extraction medium, optimum concentration of dye material, extraction time and concentration of mordants and mordanting methods. One such example revealed that 5 g of dye material with mordant like FeSO4, alum and tannic acid at 60 °C for 1 h produced good results in dyeing after experimentation [79]. A report by Jain presented that three natural mordants Anar, Arjun and Babul bark were applied on cotton fabric for better results. However, on the other hand colorant extracted from Jamun leaves, bark, bark peel and fruit in pre mordanting method dyed for 60 min at 60 °C temperature gave good results too [80]. Single jersey cotton knitted fabric that has been mordanted with some natural extract like pomegranate peel seeds, pomegranate peel bark and some of Gymnosperm leaves Thuja orientalis and Araucaria excelsa gives significant results at 95 °C temperature for 60 min in exhaust method. Then, dyeing of samples was done with natural dyes extracted from mango seed kernel (Mangifera indica L.) after above mordanting. The dyeing was carried out at 100 °C temperature for 60 min [81]. In a series of studies eco-friendly garments, inner wears, child clothing and home furnishing materials were prepared by dyeing cotton material with Myrobalan (T. chebula) and Turmeric (C. longa). Compared to the synthetic dyed cotton fabric, the above dyed fabrics showed excellent results in terms of fastness properties. Herbal Textile is finished entirely with herbal extractions, without using any chemicals [82]. Chandel et al. attempted to extract organic dye from Brassica oleracea Var. botrytis (Cauliflower) and applied it on 100% pure cotton. It revealed that different shades from cauliflower can be prepared using different mordants [83].
Singam et al. studied natural dyes based on Lawsonia inermis, Azadirachta indica and Curcuma longa were used to produce eco-friendly and non-toxic fabric for the people. The extraction process of natural dyes is an aqueous technique and then proceeded to hot bath dyeing later. The aim was to find the optimum concentration of natural dyes and super hydrophobic coating removal from cotton fabric for the green technology dyeing process [84]. Pan and his colleague explored that extract of Deodara, Jackfruit and Eucalyptus leaves yield light brown and light mustard shades on jute fabric. Fastness properties toward washing showed good in all manners [85].
ii. Dyeing Condition for Protein Material
Wool and silk fibers both have complex chemical structure and are susceptible to alkali treatment. They respond very well in acidic conditions. Mehtab et al. have utilized neem bark (A. indica
