Green Chemistry for Sustainable Water Purification E-Book
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- Herausgeber: John Wiley & Sons
- Kategorie: Wissenschaft und neue Technologien
- Sprache: Englisch
GREEN CHEMISTRY for Sustainable Water Purification
Green Chemistry for Sustainable Water Purification provides systematic coverage of the most recent research and development in clean water treatment technologies based on green materials and nanocomposites.
Providing safe drinking water is one of the top priorities for scientists and industrialists working on projects, and one particular problem is the contamination of groundwater with toxic organic and inorganic compounds released by various industries. The presence of contaminants or industrial effluents in drinking water systems has increasingly become a major environmental challenge. To address the problem, several methods, including ion exchange, membrane filtration, advanced oxidation, biological degradation, photocatalytic degradation, electro-coagulation, and adsorption, are in operation for removing or minimizing these wastes. The purification process of wastewater using conventional methods, however, has proved to be markedly ineffective, very difficult, and highly expensive.
On the other hand, for the remediation of water resources, a concept like green chemistry, based on the application of biological agents including polymers, bacteria, and fungi, has received great scientific attention as it helps to avoid the toxic by-products of conventional techniques and enhances eco-friendly wastewater treatment approaches.
This book discusses the different treatment technologies with a special focus on the green adsorption approach, using biological and hybrid biochemical treatment technologies to prevent water contamination and maintain the ecosystem. It discusses the analysis of organic and inorganic pollutants from industrial wastewater. It also focuses on the removal and recovery of organic and inorganic contaminants from the environment and several case studies describing the removal and recovery of environmental pollutants using green technology are given. The recycling of low-cost along with green adsorbent technology is explained in detail. Finally, the book highlights treatment technologies with effective pollutant removal capacities that are used in modern water treatment units.
Audience
The book will serve as an important resource for materials scientists, chemists, chemical engineers, biotechnologists, textile engineers and environmental scientists. It will also be valuable to industrial organizations, consulting engineering companies, etc. for the selection and implementation of the most sustainable wastewater treatment technologies.
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Veröffentlichungsjahr: 2023
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Table of Contents
Cover
Series Page
Title Page
Copyright Page
Preface
1 Green Chemistry for Water Remediation
1.1 Introduction
1.2 Challenges in Water Remediation
1.3 Green Chemistry as a Novel Alternative to Conventional Wastewater Treatment
1.4 Conclusion
Acknowledgment
References
2 Advances in Wastewater Treatment Using Natural and Modified Zeolites
2.1 Global Impact of Wastewater Treatment
2.2 Different Wastewater Treatments
2.3 Technologies to Treat Chemical Industry Effluents
2.4 Oil–Water Separator—Treatment of Oily Effluent
2.5 Coagulation–Flocculation
2.6 Techniques for Treating Wastewater Using Adsorption
2.7 Adsorption of Dyes
2.8 Zeolite in Wastewater Treatment
2.9 Negative Impact of Heavy Metals on Health
2.10 Wastewater Treatment Using Different Zeolites
2.11 Treatment of Surface Waters, Ground, and Underground Waters
2.12 Drinking and Greywater Treatment
2.13 Heavy Metal Removal Comparison by Zeolites
2.14 Adsorption Kinetics and Thermodynamics
2.15 Conclusion
References
3 Sustainable Green Synergistic Emulsion Liquid Membrane Formulation for Metal Removal from Aqueous Waste Solution
3.1 Introduction
3.2 Theoretical
3.3 Experimental
3.4 Results and Discussion
3.5 Conclusion
Acknowledgment
References
4 Chemical Activation of Carbonized Neem Seed as an Effective Adsorbent for Rhodamine B Dye Adsorption
4.1 Introduction
4.2 Materials and Methods
4.3 Results and Discussion
4.4 Conclusions
References
5 Green Water Treatment for Organic Pollutions: Photocatalytic Degradation Approach
5.1 Introduction
5.2 Solar Energy
5.3 Green Photocatalysis
5.4 Organic Pollutants
5.5 Reactive Species Responsible for Green Photocatalysis Treatment
5.6 Advancements in Photocatalysts
5.7 Green Treatment of Pollutants
5.8 Conclusion
References
6 Treatment of Textile-Wastewater Using Green Technologies
6.1 Introduction
6.2 Green Water Treatment Technique for Textile Effluents
6.3 Conclusions
References
7 Photocatalytic Activity of Green Mixed Matrix Membranes for Degradation of Anionic Dye
7.1 Introduction
7.2 Materials and Methods
7.3 Results and Discussion
7.4 Conclusion
References
8 Advanced Technologies for Wastewater Treatment
8.1 Introduction
8.2 Advanced Approaches for Wastewater Treatment
8.3 Conclusion and Future Recommendations
Acknowledgments
References
9 PDMS-Supported Composite Materials as Oil Absorbent
9.1 Introduction
9.2 Fabrications Techniques of PDMS Sponges as Oil Absorbent
9.3 PDMS Sponges as an Oil/Water Separation
9.4 Conclusion
References
10 Polymer Nanocomposite-Based Anode for Bioelectrochemical Systems: A Review
10.1 Introduction
10.2 Conventional Anode Materials Based on Carbon
10.3 Modification of Anode with Nanomaterials Based on Carbon
10.4 Metal or Metal Oxide-Based Modified Anode
10.5 Polymer-Based Modified Anode
10.6 Polymer Nanocomposites for Anode Modification
10.7 Concluding Remarks and Future Perspectives
References
11 Electrospinning Setup Design and Modification for Fabrication of Photocatalytic Electrospun Nanofibrous Membranes for Water Treatment
11.1 Introduction
11.2 Application of Electrospun Nanofibers Polymeric Membranes (ENPM) on Wastewater Treatments
11.3 Improvements in Morphology and Physical Structure of ENPM
11.4 Setup and Configurations of Electrospinning for Core-Sheath Structures of EPNM for Photocatalytic Membranes
11.5 Future Directions and Challenges
11.6 Conclusion
11.7 Acknowledgment
References
Index
Also of Interest
End User License Agreement
List of Tables
Chapter 2
Table 2.1 List of few adsorbents and corresponding dyes removed [35].
Table 2.2 Drinking water standards.
Table 2.3 Different zeolites compared for their ability to remove Cr
3+
[84–87]...
Table 2.4 Comparison for Cd
2+
removal by different zeolites [89–93].
Table 2.5 Different zeolites used for the removal of Pb
2+
[89, 96].
Table 2.6 Different zeolites used for the removal of Zn
2+
[86, 87].
Chapter 3
Table 3.1 LM formulation for metal extraction.
Table 3.2 LM formulation using a single carrier (Experimental conditions: stir...
Table 3.3 LM formulation using a mixed carrier (Experimental conditions: extra...
Chapter 4
Table 4.1 The physicochemical characteristics of the prepared adsorbents.
Table 4.2 RNS kinetics parameters of Rhodamine B dye adsorption.
Table 4.3 CNS kinetics parameters of Rhodamine B dye absorption.
Table 4.4 MCNS kinetics parameters of Rhodamine B dye absorption.
Table 4.5 Isotherms parameters of Rhodamine B dye absorption.
Table 4.6 Comparison of neem seed-derived adsorbents with literature reports.
Table 4.7 Thermodynamic parameters of Rhodamine B dye absorption.
Chapter 5
Table 5.1 Different kinds of semiconductors photocatalyst and their efficienci...
Table 5.2 The most important factors influencing the photocatalytic process.
Chapter 6
Table 6.1 Standards for effluent released by textile processing industries in ...
Table 6.2 Standards for domestic effluent discharge [11].
Table 6.3 Dyes and pigment waste released by textile industries.
Table 6.4 The parameters affecting the bacterial degradation of dyes.
Table 6.5 Advantages and disadvantages of solar evaporation method.
Table 6.6 Multiple effect evaporation plant (MEEP) operating parameters [28].
Table 6.7 The electrocoagulation process of various dyes present in textile wa...
Table 6.8 Eco-friendly nanofiltration membranes for textile dye removal.
Table 6.9 Adsorbents used for textile effluent removal.
Chapter 7
Table 7.1 Contact angle measurement.
Chapter 8
Table 8.1 List of nanosorbents and their application in pollutants removal (re...
Table 8.2 The remediation efficiency of toxic metals through MFCs in previous ...
Chapter 10
Table 10.1 Performance of BES (MFC) using modified polymer nanocomposite mater...
List of Illustrations
Chapter 1
Figure 1.1 Generation of biofuel by-products [5].
Figure 1.2 Atom economy for Grignard reagent [5].
Figure 1.3 Few examples of reactions involving green reactions [5].
Figure 1.4 The ecofriendly technologies in use [4].
Figure 1.5 Illustration of wastewater treatment by Fenton’s oxidation process ...
Figure 1.6 Mechanism of TiO
2
photocatalysis [47].
Figure 1.7 Two different photocatalytic membranes [56].
Chapter 2
Figure 2.1 The framework projections and the ring size for the most-studied fr...
Figure 2.2 The tetrahedral framework of clinoptilolite zeolite. Modified from ...
Chapter 3
Figure 3.1 An illustration of process flow during the ELM process.
Figure 3.2 The coupled transport mechanism in the type II ELM system.
Figure 3.3 Overall metal extraction procedure using single and mixed carriers.
Figure 3.4 Stoichiometric study of mixture system on silver ions extraction at...
Figure 3.5 Stoichiometric study of mixture system toward the extraction of sli...
Figure 3.6 Stoichiometric study of mixture system at fixed (a) Cyanex 272 and ...
Figure 3.7 Stoichiometric of D2EHPA towards nickel extraction at a rigid LIX63...
Figure 3.8 Stoichiometric of LIX63 towards nickel extraction at a rigid D2EHPA...
Figure 3.9 Stoichiometry of zinc extraction equilibrium using D2EHPA.
Figure 3.10 Stoichiometry of zinc extraction equilibrium using Cyanex 302.
Chapter 4
Figure 4.1 (a) chemical structure of Rhodamine B dye and (b) neem seed.
Figure 4.2 XRD spectra of (a) raw neem seed and (b) carbonized neem seed and (...
Figure 4.3 The FTIR spectra for RNS, CNS, and MCNS before and after adsorption...
Figure 4.4 SEM images of (a) raw neem seed and (b) carbonized neem seed and (c...
Figure 4.5 (a) TGA of raw neem seed (b) effect of biomass dosage n the amount ...
Figure 4.6 Effects of contact time and pollutant concentration on the amount o...
Figure 4.7 (a) point zero charges of RNS, CNS, and MCNS and (b) effect of solu...
Figure 4.8 Kinetic data for the sorption of Rhodamine B onto the surface of MC...
Figure 4.9 Isotherm plots for the sorption of Rhodamine B by (a) RNS, (b) CNS ...
Figure 4.10 Vant Hoffe plot of
ln Kd
versus 1/T for the adsorption of Rhodamin...
Chapter 5
Figure 5.1 Illustration of photodegradation process of organic contaminates.
Figure 5.2 Schematic diagram explaining the role of reactive species during th...
Figure 5.3 (a, b) Schematic diagram showing the route synthesis of (a) Sm@POA-...
Figure 5.4 (a) Photodecomposition of RhB dye over CoFe
2
O
4
/BiOCl composite unde...
Figure 5.5 Schematically shows photodegradation of antibiotic ciprofloxacin.
Figure 5.6 (a) Bisphenol-A removal by TiO
2
photocatalyst in three different sy...
Chapter 6
Figure 6.1 Wastewater characteristic for various levels of the textile process...
Figure 6.2 The techniques for treating wastewater of textile industries 2.
Figure 6.3 Solar-evaporation-based plant grafted in textile industries.
Figure 6.4 The process of interaction between the dye molecule and biomass [10...
Figure 6.5 The categories of textile-based adsorbents.
Chapter 7
Figure 7.1 (a) FT-IR Spectra of natural rubber composite filled with 6% nanopa...
Figure 7.2 SEM image of TiO
2
nanoparticle.
Figure 7.3 SEM image of Ag-TiO
2
nanoparticle.
Figure 7.4 SEM image of Ag-Zn-TiO
2
nanoparticle.
Figure 7.5 EDS Mass spectrum of TiO
2
nanoparticle.
Figure 7.6 EDS mass spectrum of Ag-TiO
2
nanoparticle.
Figure 7.7 EDX mass spectrum of Ag-Zn-TiO
2
nanoparticle.
Figure 7.8 (a) SEM image of natural rubber (NR), (b
)
SEM image of NR-4% TiO
2
, ...
Figure 7.9 Thermograms of NR and composite membranes.
Figure 7.10 Photodegradation of methyl orange dye by NR with 4 and 6% photocat...
Figure 7.11 UV-Vis spectra of methyl orange by NR.
Figure 7.12 UV-Vis spectra of methyl orange by NR 4% TiO
2
.
Figure 7.13 UV-Vis spectra of methyl orange by NR 6% TiO
2
.
Figure 7.14 UV-Vis spectra of methyl orange by NR 4% Ag-TiO
2
.
Figure 7.15 UV-Vis spectra of methyl orange by NR 6% Ag-TiO
2
.
Figure 7.16 UV-Vis spectra of methyl orange by NR 4% Ag-Zn-TiO
2
.
Figure 7.17 UV-Vis spectra of methyl orange by NR 6% Ag-Zn-TiO
2
.
Figure 7.18 Photocatalytic degradation of methyl orange dye by NR and composit...
Figure 7.19 The degradation rates of methyl orange dye by NR composite membran...
Chapter 8
Figure 8.1 Environmental exposure to heavy metals has an effect on the body’s ...
Figure 8.2 Nanophotocatalyst potential applications.
Figure 8.3 A basic photocatalytic mechanism for degradation of pollutants (ada...
Figure 8.4 MFCs setup with the mechanism of electron transfer from a bacterial...
Chapter 9
Figure 9.1 Schematic representation of the sugar template technique for produc...
Figure 9.2 A schematic example of the PDMS porous scaffold production method e...
Figure 9.3 Three stages are involved in the fabrication of PDMS/SiO
2
composite...
Figure 9.4 The schematic design for the manufacture of porous PDMS-CNT nanostr...
Figure 9.5 The schematic diagram of the preparation of S-OPCG [34] (adapted wi...
Figure 9.6 Manufacturing of PDMS/PVDF composite membrane [39].
Chapter 10
Figure 10.1 Single- and two-chamber BES.
Chapter 11
Figure 11.1 (a) TEM image of Ag
3
PO
4
/PAN nanofiber, (b) schematic diagram of pr...
Figure 11.2 SEM images of (a) neat CA nanofiber membrane (b) SiW
12
/CA composit...
Figure 11.3 Degradation of isoproterenol mechanism by CQDs-Bi
20
TiO
32
/PAN elect...
Figure 11.4 Schematic diagrams for surface modification of electrospun PAN nan...
Figure 11.5 Schematic flow path of fabrication of Pdopa-ZNRs/PU through surfac...
Figure 11.6 (a) The four steps of the PAN/AgBr/Ag fibrous membrane fabrication...
Figure 11.7 Images of TNF, PBZ/TNF, and TiNFNP membrane are shown in a schemat...
Figure 11.8 Electrospinning and fabrication methods.
Figure 11.9 SEM image of nanofibers embedded in TiO
2
micro/nanospheres: (a) a ...
Figure 11.10 Diagram of a setup for electrospinning and electrospraying simult...
Figure 11.11 FSEM images of the pristine nylon-6 mat (a) and TiO
2
/nylon-6 mat ...
Figure 11.12 (a) The fabrication of a PVA-co-PE/TiO
2
hybrid membrane and the f...
Figure 11.13 Using a combination of electrospinning and precipitation methods,...
Figure 11.14 Under UV light irradiation, (a) MB photocatalytic degradation pro...
Figure 11.15 Schematic diagram and a digital image of laser-heated melt electr...
Guide
Cover Page
Series Page
Title Page
Copyright Page
Preface
Table of Contents
Begin Reading
Index
Also of Interest
WILEY END USER LICENSE AGREEMENT
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Scrivener Publishing100 Cummings Center, Suite 541JBeverly, MA 01915-6106
Publishers at ScrivenerMartin Scrivener ([email protected])Phillip Carmical ([email protected])
Green Chemistry for Sustainable Water Purification
Edited by
Shahid-ul-IslamAbid Hussain Shalla
and
Mohammad Shahadat
This edition first published 2023 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© 2023 Scrivener Publishing LLCFor more information about Scrivener publications please visit www.scrivenerpublishing.com.
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Library of Congress Cataloging-in-Publication Data
ISBN 978-1-119-85229-2
Cover image: Pixabay.ComCover design by Russell Richardson
Preface
Living beings regard water as the most important component in sustaining their lives. It is a vital source of human life because of its organic minerals, essential metal ions, and other caloric sources. The presence of minerals in water is essential for the biological activity of living beings. Water has the potential to transform into various forms, and the discharge of industrial waste into bodies of water without pre-treatment contaminates water, which becomes the main cause of water pollution. On the other hand, drinking pollutant-containing water results in the disturbance of biological activities and a number of disorders and diseases in living beings. People around the globe are facing a crisis of safe portable water and more than three billion people still need appropriate drinking water. It is expected that a huge water crisis will be faced by 2065 owing to the expansion of the population and industrialization worldwide. There, it is necessary to treat industrial waste before releasing it into any body of water. Today, pre-treatment of wastewater has been performed using physical, biological, and chemical treatment methods, which include filtration, anaerobic treatment, solar disinfection, reverse osmosis, oxidation-reduction, plasma treatment, and clay-based low-cost adsorbent nanocomposite materials. Among various treatment techniques, green chemistry, being an environmentally-friendly technology with ease of operation and significant pollutant removal capacity, shows the most significant academic research interest.
This book discusses the different treatment technologies with a special focus on the green adsorption approach, using biological and hybrid biochemical treatment technologies to prevent water contamination and maintain the eco-system. The book discusses the analysis of organic and inorganic pollutants from industrial wastewater. It also focuses on the removal and recovery of organic and inorganic contaminants from the environment. Several case studies describing the removal and recovery of environmental pollutants using green technology are an attractive feature of the present book. The recycling of low-cost along with green adsorbent technology is explained in detail. Finally, the book highlights treatment technologies with effective pollutant removal capacities that are used in modern water treatment units.
We are highly thankful to all the contributing authors for accepting our invitation and contributing their valuable projects in the form of book chapters. All the book chapters are well written, updated with the recently published literature, and we hope the content will be very useful for the researchers, environmental scientists, engineers, and students directly involved with wastewater treatment technology.
Editors
October 2022
1Green Chemistry for Water Remediation
Syed Wazed Ali*, Satyaranjan Bairagi and Swagata Banerjee
Department of Textile and Fiber Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, India
Abstract
With the curve of industrialization growing exponentially, the quality index of natural resources is facing a deteriorating trend. Water is one of the most abundantly available natural resources that is being exploited tremendously by humans. Gallons of water are consumed in our day-to-day activities, starting from industrial to household. This exploitation has proved to be a boomerang for them and, hence, ways are being sought to recover, reuse, and preserve this natural resource. Treatment of wastewater has been a subject of interest for a long time, and techniques have been established for the same. However, the chemical treatments of wastewater often adversely affect the environment. The by-products of these processes are often toxic and pose serious health hazards. Hence, a concept like green chemistry has come into the picture for the remediation of water resources. It has proved to be one of the key tools to achieve sustainability by providing appropriate solutions to existing problems. It helps to avoid the toxic by-products of conventional techniques and enhances ecofriendly wastewater treatment approaches. This chapter deals with the various principles of green chemistry in brief and the methods of water remediation in detail. Various chemical treatments of water using green technology have been discussed in detail. Various challenges faced in the path of treatment have also been highlighted.
Keywords: Green chemistry, water remediation, eco-friendly
1.1 Introduction
It has been stated by the World Health Organization (WHO) that a person consumes about 50 to 100 liters of water daily to fulfil their essential needs and maintain their health. The right to acquire a sufficient and nontoxic quantity of drinking water applies to every living being in our society ignoring what financial status and society they belong to. It has been surveyed that 13.6% of the world’s population is not able to access safe drinking water [1] and on the other hand 2.6 billion people face a shortage of the required hygiene. Earlier in the 21st century, around 600 km3 per year of water was consumed by people staying throughout the world, whereas during the start of this century, the total consumption of drinking water has been elevated to 5300 km3 per year. It has been surveyed that after the year 2060, there will be some stabilization with four billion human beings staying in city areas proving a very high demand for water consumption [2]. Furthermore, the future prediction states that around 1.8 billion living beings will be facing a shortage of water and approximately 66% of the whole population worldwide will live with the problem of water shortage from the year 2025 [3]. It has also been observed that the main cause for such a disaster is the pollution generated by various industries on our natural water resources. The various wastes from industries, households, agriculture, and farming adversely affect our worldwide drinking water resources.
In the upcoming era, the management of water quality can be done by refining the raw water available in our nature, improving the technology related to such raw water treatment, and properly maintaining the network related to the drinking water supply. Also, it has been stated by many researchers that managing, improving, and inventing new technologies related to water supply can give rise to ways that can achieve efficient and pure quality water supply. In this context, scientists have come up with methodologies that can improve the quality of water by using less toxic or environmentally friendly approaches, some of which are elaborated on in the upcoming section of this chapter. Researchers have also added in their studies that such green approaches give rise to improved and less toxic chemicals, minimization of wastes, and less consumption of energy resources [4]. Therefore, from these approaches, the idea of introducing green chemistry for water purification has approached the minds of various scholars. The idea of such introduction to green chemistry is termed by 12 different principles, which can be stated as follows: preventing the generation of wastes, incrementing the rate of reaction conversions, developing less toxic chemicals, developing safe products made with much less toxic chemicals, increasing efficient energy technologies, utilizing renewable feedstocks, eliminating toxic derivatives of chemicals, utilizing catalysts to increase the rate reactions, designing biodegradable chemical-based products, analyzing ways to diminish pollution, and reducing the causes that lead to accidents [5].
1.2 Challenges in Water Remediation
Several green movements have objected to the use of chemicals in water treatment that harms the environment. Some ask for abolishing the use of such chemicals while others aim at replacing them. Chlorine is one such chemical that is used for disinfecting water while having harmful impacts on the surroundings at the same time [6, 7]. Chlorine kills the microorganisms responsible for diseases like cholera, typhoid, hepatitis, etc. At the same time, however, it is responsible for the formation of compounds like chloroform that are carcinogenic. Disinfecting with chloramines helps to prevent the formation of chloroform, but the cyanogen chloride formed as a by-product is toxic. Several reagents have been tried to eliminate the chloroform formation [8].
Water has an organic matter of natural origin and synthetic origin. The naturally present organic matter in water is called natural organic matter while the organic matter added to water due to human activities is called synthetic organic matter. The percentage of synthetic organic matter is less compared to that of natural organic matter; however, synthetic organic matter is more harmful compared to natural organic matter. The Blackfoot disease is a well-known disease in Taiwan that causes numbness and coldness of limbs [9, 10]. It is thought to be due to the presence of fluorinated compounds in water. Humic acid is one such fluorinated compound that causes organ-related diseases. It is a high molecular weight complex molecule that negatively impacts the erythrocytes via the generation of reactive oxygen species [11]. Metals like copper and aluminum are also related to toxicity issues [12, 13].
1.3 Green Chemistry as a Novel Alternative to Conventional Wastewater Treatment
1.3.1 Green Chemistry
The conceptualization of green chemistry was a result of the Pollution Prevention Act, in the year 1990 [4]. It stated the US national policy to eradicate pollution by improvising its design and processes rather than the treatment and disposal of products. In other words, the term green chemistry refers to the design and development of products that would help to reduce or get rid of the production of any hazardous substances [14]. There exists a small line of difference between environmental chemistry and green chemistry. Environmental chemistry deals with environmental pollutants. Green chemistry, on the other hand, aims at designing new techniques and improving existing technologies that would minimize the generation of waste. Green chemistry also includes certain crucial ideas. One is the impact of all raw materials used in product synthesis and not just the principal raw material. The other is the optimization of an efficient process with the least negative impacts. Green chemistry is based on twelve principles that may be stated as under. The “Twelve Principles” related to “Green Chemistry” were introduced in the year 1998 [5]. These principles provide a strong guideline to manufacture ways of different less harmful chemical products and technologies, which apply to almost all life cycle processes, including the raw materials utilized for enhancing the productivity and safeness of the principles used, along with the toxic nature and degradability of different products and chemicals used in this green chemistry approach. Some of them are listed as prevention, atom economy, less hazardous chemical synthesis, designing safer chemicals, safer solvents, and auxiliaries, design for energy efficiency, use of renewable feedstocks, reducing derivatives, catalysis, design for degradation, real-time analysis for pollution prevention and inherently safer chemistry for accident prevention.
Proper waste handling: It aims to prevent waste generation rather than treat and clean them up when produced. It is one of the most important of the twelve different principles of this green chemistry approach. It is always safer to avoid the accumulation of waste other than to clean up after it has been formed. Waste can be defined as anything that has no appreciated importance or the product produced from any damage caused to any energy technology. Also, it has been stated in many studies that wastes can take different forms and can cause an impact on nature in a different way depending on the waste’s nature, toxicity, quantity, or the way it has been drained out [15]. When huge quantities of the precursors are utilized in a method of synthesis, then much of them are lost due to the original design of the procedure itself and this generation will give rise to undesirable wastes. One of such examples to minimize waste quantity is to use molecular oxygen, thereby eliminating the requirement for chlorine. This has dropped the generation of wastes close to 0.3 kg of than when done by the conventional method. Scientists have reported that this new method can produce more than 16 times less amount of waste than the conventional method, thereby removing the generation of wastewater [16]. It has also been reported in the literature that when we are not able to avoid by-products, then another new approach must be taken into consideration and an approach that is productive to search for an environment-friendly industrial process that can cause waste to transform into a newer type of material with an important value for other processes as it can reenter our life cycle. This method is used for the generation of biofuel (Figure 1.1).
Atom economy: It aims to include all raw materials in the synthesized product. In the year 1990 Barry Trost established the idea of using the efficiency of synthetics i.e. Atom Economy abbreviated as A.E., also known as Atom Efficiency [17]. The concept refers to maximizing the utilization of precursors which can cause the final end-products to have more atoms prevailing from the reactant side. The perfect reaction will have all the atoms present on the reactant side. The atomic efficiency is estimated as the ratio of molecular weights of the product to that of all the reactants used in this reaction, as shown in Figure 1.2. AE is a theoretical value used to evaluate the process by which a reaction will take place efficiently. A few examples of such reactions are Grignard, A3 coupling, and the Diels–Alder reaction. Figure 1.2 shows a typical Grignard reaction and application of the Grignard reagent to create a propargylic amine type of structure. The AE value for such a reaction is 56%, which indicates losing half amount of the precursor used in this reaction.
Figure 1.1 Generation of biofuel by-products [5].
Safe reaction: The reactions should be so designed that they have little or no toxic effect on the environment. As shown in Figure 1.3, many new works in this field of green chemistry have improved the present scenario of causing water remediation. The reactions involved in such a green chemistry approach are modifications of reactions that have been invented a long time back. Less hazardous reactions involving cycloadditions [17] rearranging or multiple components using coupling type of reactions [18] were known long back and comprise one efficient category to provide green chemical reactions. Cascade type or tandem type of reactions [19], carbon and hydrogen activation [20] metathesis [21] and reactions involving enzymes [22, 23] are innovative ways to depict efficient examples of more clean and less toxic synthetic tools present to different organic chemists.
Safe chemicals: The chemicals should be designed so that they carry out their functionalities without any toxic side effects. This principle for providing efficient green chemistry is to design chemical products that do not exhibit toxicity to our environment. Such designed structures offer different functions in the field of medicines to materials, which are less toxic than the conventional made materials. Understanding the properties of a molecule that have an impact on the environment and the transformations that take place in the biosphere is essential to sustainability. Through a mastery of this understanding, chemistry will be able to genuinely design molecules that are safer for humans and the environment [5].
Figure 1.2 Atom economy for Grignard reagent [5].
Figure 1.3 Few examples of reactions involving green reactions [5].
Safe solvent and auxiliaries: The use of auxiliaries should be avoided to the extent possible and if it is necessary, should be harmless.
Energy-efficient process: The synthetic methods should be energy efficient at the same time cost-effective.
Utilizing renewable feedstocks: The use of nondepleting resources is preferred to nonrenewable feedstocks.
Reduction of derivatives: Unnecessary derivatization of products to be avoided.
Catalysis: Use of catalytic reagents over stoichiometric reagents.
Biodegradability: The use of materials that disintegrate after their purpose is served and do not accumulate in the environment is preferred.
Real-time process monitoring: Analysis of the process at every step to control the generation of hazardous substances.
Use of safer chemicals to minimize the risk of an accident: The substances used, and the form of the substance preferred in a chemical pathway should not be accident-prone.
Keeping in mind the aims of green chemistry, several new ecofriendly technologies have evolved. Some of them have become proven technologies while others still need to show their potential. Figure 1.4 shown below gives an idea about the various ecofriendly technologies preferred in use today. Advancements concerning the synthesis of materials have also been carried out. Special reactors like continuous flow reactors, microchannel reactors have been designed to make processes more efficient and ecofriendly. These reactors may be combined with the green chemistry methods to design improved technologies that aim at providing better results.
Figure 1.4 The ecofriendly technologies in use [4].
1.3.2 Applications of Green Chemistry in Water Remediation
Conventional water treatment technologies are associated with the generation of highly toxic chemicals that affect the land, water, and air ecosystems. Sustainability being the need of the hour, novel green solutions are being preferred and searched for the treatment of this nonrenewable valuable natural resource. These green technologies seek to curb the overexploitation and misuse of water resources in the first place. The green remediation methods eliminate the chances for the liberation of highly toxic by-products that would otherwise harm the environment [24]. In this manner, they meet the needs of the present without compromising the needs of future generations. Some of the green technical approaches for water remediation are discussed below:
Advanced oxidation processes: This is a chemical treatment of water that proceeds with oxidation reactions. This process seeks to remove organic compounds from wastewater with the help of some highly reactive species. They have also been used for the removal of dyes from effluents [25, 26]. The advanced oxidation processes may be grouped into two based on the use of UV light for the procedure, namely nonphotochemical and photochemical advanced oxidation processes.
The nonphotochemical methods produce reactive hydroxyl radicals in the absence of light through processes like ozonation, Fenton’s reagent oxidation, wet air oxidation, and electrochemical oxidation. The ozonation process is a widely preferred ecofriendly process that helps to break down the chromophoric groups in organic compounds into smaller molecules. This process is carried out in three steps consisting of ozone generation, dissolution of ozone in the wastewater, and finally oxidation of organic compounds in wastewater [27]. Ozone is a strong oxidizing agent. It indulges in slow chemical reactions which are driven kinetically than by thermodynamics. As far as water treatment is concerned, direct ozonation is a selective and slow process wherein the compounds in water containing certain functional groups are only attached by ozone. For instance, ozone is not preferred for the removal of compounds like hydrocarbons (alkanes) or chlorinated organic compounds. They are used for the oxidation of phenolic compounds and polyaromatic hydrocarbons [28]. In such situations, ozone is used along with some homogenous and heterogeneous catalysts that help to promote the degradation of the organic compounds [29]. The removal of dyes from aqueous media through ozonation has also been established as a viable technique [30, 31]. Another oxidation-based process is Fenton’s reagent oxidation (Figure 1.5). The Fenton’s reagent comprises a mixture of chemical oxidizers, hydrogen peroxide, ferrous ions as the catalyst, and an acid source for maintaining pH. The easy availability and nontoxicity of the constituents make this reagent a cost-effective oxidizing agent. The ferrous ion catalyst act on hydrogen peroxide to produce hydroxyl radicals through several cyclic reactions [32]. The reaction mechanism is explained as below [33]:
Figure 1.5 Illustration of wastewater treatment by Fenton’s oxidation process [32].
The presence of UV light further helps to increase the process efficiency. This is then called the photo-Fenton process. The equations have been shown below [33]:
The Fe3+ ions complexes generate additional hydroxyl radicals and regenerate Fe2+ ions for further reaction with hydrogen peroxide. This reagent has also been used for the removal of dye from effluents [34, 35].
The wet air oxidation process also removes the organic contaminants from wastewater with the help of oxygen or air at high temperatures and pressure. In this process, the contaminants are broken down into biodegradable substances with the release of harmless gases like carbon dioxide and nontoxic by-products like water and inorganic salts. This treatment comprises a physical phase and a chemical phase. The diffusion of oxygen from gas to the liquid and the release of carbon dioxide from the liquid into the gaseous phase is part of the physical phase. The reactions concerning the degradation of organic matter refer to the chemical phase [36, 37]. The electrochemical model of oxidation is another advanced oxidation process used for the treatment of organic pollutants in water. It is electrogenerated in situ hydroxyl radicals that help to disintegrate the organic matter present in the wastewater. The electrodes of the reaction serve as the sites for the generation and consumption of electrons. The shape and material of the construction of the electrodes exert a great influence on the electrochemical process of reduction [38]. Electrocoagulation is another green method that is employed for the treatment of wastewater. It mainly deals with the generation of coagulants in situ. These coagulants may be generated from the dissolution of aluminum or iron ions from their respective electrodes. The metal ions are released at the anode while hydrogen gas is liberated at the cathode. This hydrogen gas helps to keep the flocculants afloat in water. A network is formed by the liberated metal ions that help in the chemical adsorption of the contaminants. This whole process is referred to as electrocoagulation [39]. A certain amount of metal ions are required for the treatment of a given level of polluted wastewater. Iron being cheaper than aluminum is preferred for the treatment of wastewater and aluminum for treating water. Textile wastewater [40] and municipal sewage [41] have also been treated through electrocoagulation. Electrofloatation is another process that involves the water treatment process by helping to keep the pollutants afloat. The release of oxygen and hydrogen gases at the electrodes through water electrolysis forms tiny bubbles that float the pollutants at the water surface. Hydrogen is released at the cathode and oxygen is liberated at the anode. The size of the bubbles formed also affects the removal efficiency of the pollutants. The bubble size in turn depends on the pH of the solution [42]. While hydrogen bubbles are small at neutral pH, the size of the oxygen bubbles increases as the pH increases. The smaller the size of the bubbles, the higher is the surface area provided. This helps to increase the separation efficiency of the electro flotation method. Hence the efficacy of the electrolocation process increases with the tiny bubbles with greater uniformity. Other factors like electrode composition, cell design, and water conductivity also affect the electrolocation process [43].
Another category of advanced oxidation processes is the photochemical advanced oxidation process. This category of processes deals with the principles of photochemistry. The reactions thus are carried out at much lower temperatures and with processes being substratesspecific [44]. Photocatalytic oxidation is one such method of wastewater treatment. Photocatalysts like TiO2 (Figure 1.2), ZnO, Fe2O3, and CdS, mainly semiconductors are used to disintegrate organic contaminants in the presence of light energy. TiO2, however, is usually preferred for photocatalytic degradation due to its availability, low cost, nontoxicity, and appreciable physical and chemical properties [45]. To enhance the photocatalytic activity of these photocatalysts, they are sometimes immobilized onto substrates like activated carbon, zeolites, which provide a large surface area for adsorption. It provides further advantages of leaching prevention and photocatalyst recovery [46].
Another advanced oxidation process becoming popular nowadays is the oxidation by hydrogen peroxide in the presence of UV light. Hydrogen peroxide generates hydroxyl radicals in the presence of UV light. Hydrogen peroxide alone can remove pollutants in water. However, it is unable to remove complex contaminants by the process of oxidation (Figure 1.6). The activity and efficiency of hydrogen peroxide are enhanced in the presence of a light energy source that enables it to generate more hydroxyl radicals. This method has also been used for the treatment of textile dye effluents [48, 49]. With a similar approach, ozonation has been combined with UV light sources to enhance the effectiveness in the removal of organic pollutants in wastewater. UV assists in improving ozone decomposition that increases the yield of hydroxyl radicals, in turn enhancing the ozonation rate. The initiation of the reaction in the case of photocatalytic ozonation is by the electron transfer from photocatalyst to oxygen forming starting radical. This mechanism differs for ozonation alone where the starting radical is formed by the reaction of hydroxyl ions and ozone [50].
Figure 1.6 Mechanism of TiO2 photocatalysis [47].
A novel technique to decontaminate wastewater is through the absorption of pollutants on the surface of a catalyst [51]. Catalysts like activated carbon, silica gel, etc. are used as the substrate for the adsorption of contaminants. Gradually, the implementation of nanoparticles emerged in this field. The advantage of high surface area was also realized for the adsorption of the contaminants. Magnetic nanoparticles bearing the structural formula AB2O4 were used for this purpose [52, 53]. They provided an additional advantage of the catalyst recovery through magnetic separation, which is otherwise difficult with the other adsorbents. Magnetic nanoparticles are used for preferential adsorption of arsenic ions followed by magnetic decantation [54].
There are also membrane processes that are used for wastewater treatment [55]. The membrane processes offer advantages of low chemical and energy consumption, good stable water quality, which does not depend on the quality of the water to be treated, easy to maintain technology with a good scalability potential. The membranes may differ in their characteristics, ranging from organic to inorganic, porous or dense, electrically charged or neutral, etc. Based on this, the driving force of the mechanism of treatment may be pressure-driven or concentration gradient of electric potential difference. The photocatalytic membrane reactors are a membrane technology process where photocatalysis is combined with membrane technology, the driving force being the pressure difference. These membranes can be engineered in different ways. In one case a photoactive layer deposited on a nonphotoactive layer acts as the separating layer. The nonphotoactive layer acts as the supportive layer. The second way is to deposit a nonphotoactive layer on a photoactive layer where the nonphotoactive layer serves as the separating layer (Figure 1.7).
Figure 1.7 Two different photocatalytic membranes [56].
Membrane bioreactor technology couples a biological process with a membrane separation step [57]. This is another green method for wastewater treatment. It offers advantages like a decrease in sludge production, reduced footprint, etc.compared to the conventional treatment procedures. The cost of membrane fabrication and the energy demand of this process leads to its reconsideration as a green technology [24]. Modifications of the method have been carried out to render them energy efficient [58, 59].
1.4 Conclusion
Water remediation has become the need of the hour if we are to save our future generations from facing a water crisis. The existing water treatment techniques aim to purify water out of its contaminants, releasing some harmful by-products at the same time. These by-products in turn affect the environment and its surviving species. Thus, water technologists and chemists have evolved with green techniques for treating water. These are based on the fundamental principles of green chemistry. A total of 12 principles are included under green chemistry that has been discussed in detail in this chapter. Novel green water remediation techniques have been dealt with in detail in this chapter. Starting from advanced oxidation processes to adsorption techniques, extending to membrane technologies have been explored for their water remediation potentials. These are some of the novel green methods of water decontamination that serve the purpose to the fullest without any adverse effect on the surroundings. These methods are therefore gaining attention nowadays for the treatment of water. Modifications of these methods are also underway, which will serve as green technologies for water remediation shortly.
Acknowledgment
The authors are thankful to the Indian Institute of Technology Delhi (IITD), India, forgiving platform to write this chapter.
References
1. WHO, The Human Right to Water and Sanitation Media brief, UN-Water Decad. Program.
Advocacy Commun. Water Supply Sanit. Collab. Counc.
, 1–8, 2011.
http://www.un.org/waterforlifedecade/pdf/human_right_to_water_and_sanitation_media_brief.pdf
.
2. Jain, S. and Singh, V.,
Water resources systems planning and management
, Elsevier, 51, 3–858, 2003,
https://books.google.co.in/books?hl=en&lr=&id=dR1sFWlUpPUC&oi=fnd&pg=PP1&dq=Jain+and+Singh,+2003,+Water+Re-sources+Systems+Planning+and+Management,+Volume+51,+3-858&ots=n-l81Tpvel3&sig=l9khk3m1ZH2K2AayDmnhGZOTNxg
.
3. Pritchard, A., Statistical bibliography or bibliometrics.
J. Doc.
, 25, 348, 1969.
4. Ghernaout, D., Ghernaout, B., Naceur, M.W., Embodying the chemical water treatment in the green chemistry-A review.
Desalination
, 271, 1–10, 2011,
https://doi.org/10.1016/j.desal.2011.01.032
.
5. Anastas, P. and Eghbali, N., Green chemistry: Principles and practice.
Chem. Soc Rev.
, 39, 301–312, 2010,
https://doi.org/10.1039/b918763b
.
6. Gribble, G.W.,
Natural production of organohalogen compounds
, Springer, 2003,
http://www.springerlink.com/index/10.1007/b10466
.
7. Gordon, G.W., of Natural production chlorinated compounds.
Environ. Sci. Technol.
, 28, 310–319, 1994.
8. Stefan, M.I.,
Advanced oxidation processes for water treatment
, I. Mihaela (Ed.), IWA Publishing, 2019.
9. Cheng, M.L., Ho, H.Y., Chiu, D.T.Y., Lu, F.J., Humic acid-mediated oxidative damages to human erythrocytes: A possible mechanism leading to anemia in Blackfoot disease.
Free Radic. Biol. Med.
, 27, 470–477, 1999,
https://doi.org/10.1016/S0891-5849(99)00072-6
.
10. Tseng, C.H., Blackfoot disease and arsenic: A never-ending story.
J. Environ. Sci. Heal. - Part C Environ. Carcinog. Ecotoxicol. Rev.
, 23, 55–74, 2005,
https://doi.org/10.1081/GNC-200051860
.
11. Gau, R.J., Yang, H.L., Suen, J.L., Lu, F.J., Induction of oxidative stress by humic acid through increasing intracellular iron: A possible mechanism leading to atherothrombotic vascular disorder in Blackfoot disease.
Biochem
.
Biophys. Res. Commun.
, 283, 743–749, 2001,
https://doi.org/10.1006/bbrc.2001.4832
.
12. Beccaria, A., Lahiri, D.K., Bondy, S.C., Chen, D.M., Hamadeh, A., Li, H., Taylor, R., Campbell, A., Aluminum and copper in drinking water enhance inflammatory or oxidative events specifically in the brain.
J. Neuroimmunol.
, 176, 16–23, 2006,
https://doi.org/10.1016/j.jneuroim.2006.03.025
.
13. Levesque, L., Ligand specific effects on aluminum incorporation and toxicity. pdf.
Brain Res.
, 877, 191–202, 2000.
14. Sinha, P., Sustainable textiles.
Radar
, 2, 19–21, 2011,
https://doi.org/10.5920/radar.2011.2119
.
15. Sheldon, R.A., E factors, green chemistry and catalysis: An odyssey.
Chem. Commun.
, 29, 3352–3365, 2008,
https://doi.org/10.1039/b803584a
.
16. Kilty, P.A. and Sachtler, W.M.H., Catalysis reviews: Science and engineering, in:
The mechanism of the selective oxidation ethylene to ethylene
, vol. n.d., pp. 37–41.
17. Trost, B.M., On inventing reactions for atom economy.
Acc. Chem. Res.
, 35, 695–705, 2002,
https://doi.org/10.1021/ar010068z
.
18. Yavari, I., Nematpour, M., Hossaini, Z., A synthesis of phosphorylated dioxohexahydropyrimidines from N,N′-dimethylurea, activated acetylenes, and trialkyl phosphites.
Mol. Divers.
, 14, 617–620, 2010,
https://doi.org/10.1007/s11030-009-9193-1
.
19. Nicolaou, K.C., Montagnon, T., Snyder, S.A., Tandem reactions, cascade sequences, and biomimetic strategies in total synthesis.
Chem. Commun.
, 3, 551–564, 2003,
https://doi.org/10.1039/b209440c
.
20. Labinger, J.A. and Bercaw, J.E., Understanding and exploiting C-H bond activation.
Nature
, 417, 507–514, 2002,
https://doi.org/10.1038/417507a
.
21. Grubbs, R.H., Olefin metathesis.
Tetrahedron.
, 60, 7117–7140, 2004,
https://doi.org/10.1016/j.tet.2004.05.124
.
22. Dannenberg, J.J., Book reviews,
J. Am. Chem. Soc.,
123, 1009–1011, 1998.
23. Cavell, K., Golunski, S., Miller, D., Handbook of green chemistry - green catalysis.
Platin. Met. Rev.
, 54, 233–238, 2010,
https://doi.org/10.1595/147106710x527928
.
24. Azimi, S.C. and Pendashteh, A., Green technologies for wastewater treatment.
Green Technologies for Wastewater Treatment Second International Conference in New Research on Chemistry & Chemical Engineering
, 2018.
25. Atalay, S. and Ersöz, G., Advanced oxidation processes for removal of dyes from aqueous media.
Green Chem. Dye. Remove. Wastewater Res. Trends Appl.
, 83–117, 2015,
https://doi.org/10.1002/9781118721001.ch3
.
26. Nidheesh, P.V., Zhou, M., Oturan, M.A., An overview on the removal of synthetic dyes from water by electrochemical advanced oxidation processes.
Chemosphere
, 197, 210–227, 2018,
https://doi.org/10.1016/j.chemosphere.2017.12.195
.
27. Palit, S. and Studies, E., An overview of ozonation associated with nano-filtration as an effective procedure in treating dye effluents from textile industries with the help of a bubble column reactor.
Int. J. Chem. Sci.,
10, 27–35, 2016.
28. Peleg, M., The chemistry of ozone in the treatment of water.
Water Res.
, 10, 361–365, 1976,
https://doi.org/10.1016/0043-1354(76)90052-X
.
29. Kasprzyk-hordern, B., Ziółek, M., Nawrocki, J., Catalytic ozonation and methods of enhancing molecular ozone reactions in water treatment.
Appl. Catal. B,
46, 639–669, 2003,
https://doi.org/10.1016/S0926-3373(03)00326-6
.
30. Recycling, E., Hu, E., Shang, S., Removal of Reactive Dyes in Textile effluents by Catalytic Ozonation Pursuing on-Site.
Molecules
, 19, 1–21, 2019.
31. Sevimli, M.F. and Sarikaya, H.Z., Ozone treatment of textile effluents and dyes: Effect of applied ozone dose, pH and dye concentration.
J. Chem. Technol. Biotechnol.,
842–850, 2002,
https://doi.org/10.1002/jctb.644
.
32. Xu, M., Wu, C., Zhou, Y., Advancements in the Fenton process for wastewater treatment.
Adv. Oxid. Process. - Appl. Trends, Prospect.
, 1–17, 2020,
https://doi.org/10.5772/intechopen.90256
.
33. Ameta, R., Chohadia, A.K., Jain, A., Punjabi, P.B., Fenton and photo-Fenton processes, pp. 49–87, Elsevier, 2018,
https://doi.org/10.1016/B978-0-12-810499-6.00003-6
.
34. Patil, A.D. and Raut, P.D.P.D., Treatment of textile wastewater by Fenton’s process as a advanced oxidation process.
IOSR J. Environ. Sci. Toxicol. Food Technol.
, 8, 29–32, 2014,
https://doi.org/10.9790/2402-081032932
.
35. Nidheesh, P.V., Gandhimathi, R., Ramesh, S.T., Degradation of dyes from aqueous solution by Fenton processes: A review.
Environ. Sci. Pollut. Res.
, 20, 2099–2132, 2013,
https://doi.org/10.1007/s11356-012-1385-z
.
36. Levec, J. and Pintar, A., Catalytic wet-air oxidation processes: A review.
Catal. Today
, 124, 172–184, 2007,
https://doi.org/10.1016/j.cattod.2007.03.035
.
37. Zhou, M., Särkkä, H., Sillanpää, M., A comparative experimental study on methyl orange degradation by electrochemical oxidation on BDD and MMO electrodes.
Sep. Purif. Technol.
, 78, 290–297, 2011,
https://doi.org/10.1016/j.seppur.2011.02.013
.
38. Al Khatib, M., Bellini, M., Pogni, R., Giaccherini, A., Innocenti, M., Vizza, F., Lavacchi, A., Effect of electrode shape and flow conditions on the electrochemical detection with band microelectrodes.
Sensors
, 18, 31–39, 2018,
https://doi.org/10.3390/s18103196
.
39. Chen, G. and Hung, Y., Electrochemical wastewater treatment processes.
Adv. Physicochem. Treat. Technol.,
5, 57–106, 1946.
40. Ln, S. and Peng, C., Treatment of textile wastewater by electrochemical method.
Water Resour.
, 28, 277–282, 1994.
41. Pouet, M. and Grasmick, A., Electrocoagolation and flotation.
Water Sci. Technol.
, 31, 275–283, 1989,
https://doi.org/10.1016/0273-1223(95)00230-K
.
42. Alam, R. and Shang, J.Q., Bubble size distribution in a laboratory-scale electroflotation study,
Environ. Monit. Assess.
, 189, 193, 1–14, 2017,
https://doi.org/10.1007/s10661-017-5888-4
.
43. Reds, T.F., Columns, B., Beds, L.F., Angelino, H., Burckhart, B., Zoll, G., Transfer, M., Stepanek, J.B., Beds, T.F., Worthington, H., Beds, F., Beds, G.F., Nicolais, L., Landel, F., Liquids, N., Transfer, M., Suchozebrski, W., Reds, L.F., Schumpe, A., Yu, Y.H., Lee, S., Kitakyushu, T., Removal of colloidal particles in electroflotation.
AlCHE J.
, 31, 201–208, 1985.
44. Bendicho, C., Pena, F., Costas, M., Gil, S., Lavilla, I., Photochemistry-based sample treatments as greener approaches for trace-element analysis and speciation.
Trends Anal. Chem.
, 29, 681–691, 2010,
https://doi.org/10.1016/j.trac.2010.05
.003.
45. Wang, Y., Sun, C., Zhao, X., Cui, B., Zeng, Z., Wang, A., Liu, G., Cui, H., The application of nano-TiO2 photo semiconductors in agriculture.
Nanoscale Res. Lett.
, 11, 1–7, 2016,
https://doi.org/10.1186/s11671-016-1721-1
.
46. Velasco, L.F., Haro, M., Parmentier, J., Gadiou, R., Vix-guterl, C., Ania, C.O., Tuning the photocatalytic activity and optical properties of mesoporous TiO ??, in:
Spheres by a carbon scaffold
, 2013.
47. Ibhadon, A.O. and Fitzpatrick, P., Heterogeneous photocatalysis: Recent advances and applications.
Catalysts
, 3, 189–218, 2013,
https://doi.org/10.3390/catal3010189
.
48. Reagents, U.V.H.O.F., Treatment of textile dyeing wastewater by photo oxidation using treatment of textile dyeing wastewater by photo oxidation using UV / H2O2 / Fe2 + Reagents.
Sci. Asia,
, 32, 181–186, 2016,
https://doi.org/10.2306/scienceasia1513-1874.2006.32.181
.
49. Al-kdasi, A. and Idris, A., Treatment of textile wastewater by advanced axidation processes – A review.
Global NEST: The Int. J.
, 6, 222–230, 2005.
50. Agustina, T.E., Ang, H.M., Vareek, V.K., A review of the synergistic effect of photocatalysis and ozonation on wastewater treatment.
J. Photoch. Photobio. C,
6, 264–273, 2006,
https://doi.org/10.1016/j.jphotochemrev.2005.12.003
.
51. Segneanu, A.E., Orbeci, C., Lazau, C., Sfirloaga, P., Vlazan, P., Bandas, C., Grozescu, I., Wastewater tretment methods.
Water Treat
, 53–80, 2013,
http://dx.doi.org/10.5772/53755
.
52. Shen, Y.F., Tang, J., Nie, Z.H., Wang, Y.D., Ren, Y., Zuo, L., Preparation and application of magnetic Fe3O4 nanoparticles for wastewater purification.
Sep. Purif. Technol.
, 68, 312–319, 2009,
https://doi.org/10.1016/j.seppur.2009.05.020
.
53. Gao, F., An overview of surface-functionalized magnetic nanoparticles: Preparation and application for wastewater treatment.
Chem. Select
, 4, 6805– 6811, 2019,
https://doi.org/10.1002/slct.201900701
.
54. Zeng, H., Zhai, L., Qiao, T., Yu, Y., Zhang, J., Li, D., Efficient removal of As(V) from aqueous media by magnetic nanoparticles prepared with Iron-containing water treatment residuals.
Sci. Rep.
, 10, 1–12, 2020,
https://doi.org/10.1038/s41598-020-65840-1
.
