Green Chemistry for Dyes Removal from Waste Water

Research Trends and Applications

Sanjay K. Sharma

• Publisher: Wiley-Scrivener
• Year: 2015
• Print ISBN: 9781118720998
• eBook ISBN: 9781118721186
• Edition: 1
• Topic: Physical Sciences
• Subtopic: Industrial & Technical Chemistry

The use of synthetic chemical dyes in various industrial processes, including paper and pulp manufacturing, plastics, dyeing of cloth, leather treatment and printing, has increased considerably over the last few years, resulting in the release of dye-containing industrial effluents into the soil and aquatic ecosystems. The textile industry generates high-polluting wastewaters and their treatment is a very serious problem due to high total dissolved solids (TDS), presence of toxic heavy metals, and the non-biodegradable nature of the dyestuffs in the effluent.

The chapters in this book provide an overview of the problem and its solution from different angles. These problems and solutions are presented in a genuinely holistic way by world-renowned researchers. Discussed are various promising techniques to remove dyes, including the use of nanotechnology, ultrasound, microwave, catalysts, biosorption, enzymatic treatments, advanced oxidation processes, etc., all of which are "green."

Green Chemistry for Dyes Removal from Wastewater comprehensively discusses:

• Different types of dyes, their working and methodologies and various physical, chemical and biological treatment methods employed
• Application of advanced oxidation processes (AOPs) in dye removal whereby highly reactive hydroxyl radicals are generated chemically, photochemically and/or by radiolytic/ sonolytic means. The potential of ultrasound as an AOP is discussed as well.
• Nanotechnology in the treatment of dye removal types of adsorbents for removal of toxic pollutants from aquatic systems
• Photocatalytic oxidation process for dye degradation under both UV and visible light, application of solar light and solar photoreactor in dye degradation

Chapter 1

Removal of Organic Dyes from Industrial Effluents: An Overview of Physical and Biotechnological Applications

Mehtap Ejder-Korucu¹, Ahmet Gürses^*,2, Çetin Doğar³, Sanjay K. Sharma⁴ and Metin Açιkyιldιz⁵

¹Kafkas University, Faculty of Science and Arts, Department of Chemistry, Kars, Turkey

²Ataturk University, K.K. Education Faculty, Department of Chemistry, Erzurum, Turkey

³Erzincan University, Education Faculty, Department of Science Education, Erzincan, Turkey

⁴Green Chemistry & Sustainability Research Group, Department of Chemistry, JECRC University, Jaipur, India

⁵Kilis 7 Aralιk University, Faculty of Science and Arts, Department of Chemistry, Kilis, Turkey

*Corresponding author: [email protected]

Abstract

The textile industry produces a large amount of dye effluents, which are highly toxic as they contain a large number of metal complex dyes. The use of synthetic chemical dyes in various industrial processes, including paper and pulp manufacturing, plastics, dyeing of cloth, leather treatment and printing has increased considerably over the last few years, resulting in the release of dye-containing industrial effluents into the soil and aquatic ecosystems. The textile industry generates highly polluted wastewater and its treatment is a very serious problem due to high total dissolved solids (TDS), the presence of toxic heavy metals and the non-biodegradable nature of the dyestuffs present in the effluents. There are many processes available for the removal of dyes by conventional treatment technologies including biological and chemical oxidation, coagulation and adsorption, but they cannot be effectively used individually.

Many approaches, including physical, chemical and/or biological processes have been used in the treatment of industrial wastewater containing dye, but such methods are often very costly and not environmentally safe. Furthermore, the large amount of sludge generated and the low efficiency of treatment with respect to some dyes have limited their use.

Keywords: Natural dyes, acid dyes, disperse dyes, cationic dyes, adsorption, membrane filtration, ion exchange, irradiation, electrokinetic coagulation, aerobic and anaerobic degradation

1.1 Introduction

Water, which is one of the abundant compounds found in nature, covers approximately three-fourths of the surface of the earth. Over 97% of the total quantity of water is in the oceans and other saline bodies of water and is not readily available for our use. Over 2% is tied up in polar ice caps and glaciers and in atmosphere and as soil moisture. As an essential element for domestic, industrial and agricultural activities, only 0.62% of water found in fresh water lakes, rivers and groundwater supplies, which is irregularly and non-uniformly distributed over the vast area of the globe, is accessible [1].

A reevaluation of the issue of environmental pollution made at the end of the last century has shown that wastes such as medicines, disinfectants, contrast media, laundry detergents, surfactants, pesticides, dyes, paints, preservatives, food additives, and personal care products which have been released by chemical and pharmaceutical industries, are a severe threat to the environment and human health on a global scale [2]. The progressive accumulation of more and more organic compounds in natural waters is mostly a result of the development of chemical technologies towards organic synthesis and processing. The population explosion and expansion of urban areas have had an increased adverse impact on water resources, particularly in regions in which natural resources are still limited. Currently, water use or reuse is a major concern which needs a solution. Population growth leads to a significant increase in default volumes of wastewater, which makes it an urgent imperative to develop effective and low-cost technologies for wastewater treatment [3].

Especially in the textile industry, effluents contain large amounts of dye chemicals which may cause severe water pollution. Also, organic dyes are commonly used in a wide range of industrial applications. Therefore, it is very important to reduce the dye concentration of wastewater before discharging it into the environment. Discharging large amounts of dyes into water resources, organics, bleaches, and salts, can affect the physical and chemical properties of fresh water. Dyes in wastewater that can obstruct light penetration and are highly visible, are stable to light irradiation and heat and also toxic to microorganisms. The removal of dyes is a very complex process due to their structure and synthetic origins [4].

Dyes that interfere directly or indirectly in the growth of aquatic organisms are considered hazardous in terms of the environment. Nowadays a growing awareness has emerged on the impact of these contaminants on ground water, rivers, and lakes [5–8].

The utilization of wastewater for irrigation is an effective way to dispose of wastewater [9]. Although various wastewater treatment methods including physical, chemical, and physicochemical have been studied, in recent years a wide range of studies have focused on biological methods with some microorganisms such as fungi, bacteria and algae [10]. The application of microorganisms for dye wastewater removal offers considerable advantages which are the relatively low cost of the process, its environmental friendliness, the production of less secondary sludge and completely mineralized end products which are not toxic [11]. Numerous researches on dye wastewater removal have been conducted which have proven the potential of microorganisms such as Cunninghamella elegans [12], Aspergillus nigerus [13], Bacillus cereus [14], Chlorella sp. [15] and also Citrobacter sp. [16,17].

1.1.1 Dyes

A dye or a dyestuff is usually a colored organic compound or mixture that may be used for imparting color to a substrate such as cloth, paper, plastic or leather in a reasonably permanent fashion. The dye that is generally described as a colored substance should have an affinity for the substrate or should fix itself on the substrate to give it a permanent colored appearance, but all the colored substances are not the dye [18,19]. Unlike many organic compounds, the dyes which contain at least one chromophore group and also a conjugated system and absorb light in the visible spectrum (400–700 nm) and exhibit the resonance of electrons, possess special colors [20].

The relationships between wavelength of visible and color absorbed/observed [21] are given on Table 1.1.

Table 1.1 Wavelengths of light absorption versus the color of organic dyes.

Wavelength range absorbed (nm)	Color absorbed	Color observed
400–435	Violet	Yellow-Green
435–480	Blue	Yellow
480–490	Green-Blue	Orange
490–500	Blue-Green	Red
500–560	Green	Purple
560–580	Yellow-Green	Violet
580–595	Yellow	Blue
595–605	Orange	Green-Blue
605–700	Red	Blue-Green

In general, a small amount of dyes in aqueous solution can produce a vivid color because they have high molar extinction coefficients. Color can be quantified by spectrophotometry (visible spectra), chromatography (usually high performance liquid, HPLC) and high performance capillary electrophoresis [19].

With regard to their solubility, organic colorants fall into two classes, dyes and pigments. The key distinction is that dyes are soluble in water and/or an organic solvent, while pigments are insoluble in both types of liquid media. Dyes are used to color substrates to which they have a specific affinity, whereas pigments can be used to color any polymeric substrate by a mechanism quite different than that of dyes [22,21].

1.1.2 Historical Development of Dyes

Humans discovered that certain roots, leaves, or bark could be manipulated, usually into a liquid form, and then used to dye textiles. They used these techniques to decorate clothing, utensils, and even the body, as a religious and functional practice. Records and cloth fragments dating back over 5000 years ago indicate intricate dyeing practices. Certain hues have historical importance and denote social standing [23]. The dye made from the secretions of shellfish, which is a clear fluid that oxidizes when exposed to the air, was used to produce a red to bluish purple. This dye was difficult to create and used only on the finest garments; hence it became associated with aristocrats and royalty [23]. Until the middle of the last century most of the dyes were derived from plants or animal sources by long and elaborate processes. Ancient Egyptian hieroglyphs contain a thorough description of the extraction of natural dyes and their application in dyeing [18]. In the past, only organic matter was available for use in making dyes. Today, there are numerous options and methods for the colorization of textiles. While today’s methods capitalize on efficiency, there is question as to whether the use of chemicals is harmful to the environment.

In 1856, Sir William Perkin discovered a dye for the color mauve, which was the first synthetic dye. The method related to the dyeing of this color using coal and tar led to many scientific advances and the development of synthetic dyes [24,25].

Initially the dye industry was based on the discovery of the principal that dye chromogens associated with a basic arrangement of atoms were responsible for the color of a dye. Essentially, apart from one or two notable exceptions, all the dye types used today were discovered in the 1800s. The discovery of reactive dyes in 1954 and their commercial launch in 1...

Table of contents

• Cover
• Half Title page
• Title page
• Copyright page
• Dedication
• Preface
• Acknowledgements
• About the Editor
• Chapter 1: Removal of Organic Dyes from Industrial Effluents: An Overview of Physical and Biotechnological Applications
• Chapter 2: Novel Carbon-Based Nanoadsorbents for Removal of Synthetic Textile Dyes from Wastewaters
• Chapter 3: Advanced Oxidation Processes for Removal of Dyes from Aqueous Media
• Chapter 4: Photocatalytic Processes for the Removal of Dye
• Chapter 5: Removal of Dyes from Effluents Using Biowaste-Derived Adsorbents
• Chapter 6: Use of Fungal Laccases and Peroxidases for Enzymatic Treatment of Wastewater Containing Synthetic Dyes
• Chapter 7: Single and Hybrid Applications of Ultrasound for Decolorization and Degradation of Textile Dye Residuals in Water
• Chapter 8: Biosorption of Organic Dyes: Research Opportunities and Challenges
• Chapter 9: Dye Adsorption on Expanding Three-Layer Clays
• Chapter 10: Non-conventional Adsorbents for Dye Removal
• Chapter 11: Hen Feather: A Remarkable Adsorbent for Dye Removal
• Index