Sustainable Applications of Coir and Other Coconut By-products

227 Pages·2019·11.114 MB·English

by  Narendra Reddy

Narendra Reddy
Sustainable
Applications of
Coir and Other
Coconut
By-products
Sustainable Applications of Coir and Other
Coconut By-products
Narendra Reddy
Sustainable Applications
of Coir and Other Coconut
By-products
Narendra Reddy
Centre for Incubation, Innovation, Research
and Consultancy
Jyothy Institute of Technology
Bangalore, Karnataka, India
ISBN 978-3-030-21054-0 ISBN 978-3-030-21055-7 (eBook)
https://doi.org/10.1007/978-3-030-21055-7
© Springer Nature Switzerland AG 2019
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Preface
Coconut trees and their produce and residues are one of the most distinct crops that
have supported humans and animals for their food and nonfood needs since primi-
tive times. In addition to being one of the primary sources for food in many coun-
tries and cultures, the produce, the tree, and the by-products are utilized for a variety
of non-food applications. Unlike most other resources, almost all parts of a coconut
plant and the coproducts are considered to be of high utility and value. Coir fibers
obtained from the husks of the fruit are the primary residues and commercially
traded as a commodity product. The outer shells of the nuts, leaf, sheath, and trunk
have also been used for various applications. There is probably no other crop that
has such versatile end uses comparable to the coconut tree.
The increase in demand for biodegradable and environmentally friendly products
has put new impetus on the use of agricultural resources. Coir and other coconut
by-products are readily available and have unique properties and hence considered
as potential resources for a multitude of new applications. Cocopeat obtained during
the processing of coir is being extensively used as a soilless growth media. Similarly,
coconut shells are being converted into carbon as a high-level sorbent for the
removal of solid, liquid, and gaseous pollutants. Production of enzymes and biofu-
els and their conversion into supercapacitors and conducting fibers are some of the
newer applications of coir and their by-products. Coir fibers are also being made
into composites either alone or in combination with other fibers. Unusually high
lignin content, high durability, and good resistance to environmental degradation
make coconut by-products a preferred resource for various applications. This book
provides a comprehensive review of the structure and properties of coir fibers and
also the conventional and new uses of coir and other coconut by-products.
Narendra Reddy expresses his sincere thanks to the Director, Center for
Incubation, Innovation, Research and Consultancy and Jyothy Institute of
Technology for his support to complete this work. The assistance to Narendra Reddy
v
vi Preface
by the Department of Biotechnology, Ministry of Science and Technology,
Government of India, through the Ramalingaswami Re-entry Fellowship is also
thankfully acknowledged.
Bangalore, Karnataka, India Narendra Reddy
Contents
1 Processing and Properties of Coconuts . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Extraction of Fibers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2.1 Production of Coir Fibers Through Retting . . . . . . . . . . . . . 4
1.2.2 Chemical Extraction of Coir . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2.3 Microbial Extraction of Coir . . . . . . . . . . . . . . . . . . . . . . . . 9
1.2.4 Extraction of Fibers with Plasma . . . . . . . . . . . . . . . . . . . . . 10
1.3 Structure and Properties of Coir Fibers . . . . . . . . . . . . . . . . . . . . . . 11
1.3.1 Morphological Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.3.2 Thermal Properties of Coir . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.3.3 Acoustic Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.3.4 Changes in Properties Due to Geography . . . . . . . . . . . . . . 16
1.3.5 Changes in Coir Properties Due
to Chemical Treatments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
1.3.6 Changes Due to Loading and Unloading . . . . . . . . . . . . . . . 20
1.4 Chemical Modifications of Coir Fibers . . . . . . . . . . . . . . . . . . . . . . 20
1.5 Properties of Coir Pith . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
2 Agricultural Applications of Coir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
2.1 I ntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
2.2 Coir Mulching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
2.3 Coir Geotextiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
2.4 Miscellaneous Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
3 B iotechnological Applications for Coir and Other Coconut Tree
By-products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
3.2 Production of Enzymes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
3.3 Production of Ethanol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
3.4 Substrate for Preparation of Catalysts . . . . . . . . . . . . . . . . . . . . . . . 65
vii
viii Contents
3.5 Chemicals and Pharmaceuticals . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
3.6 Coir Pith as Substrate for Production of Mushrooms . . . . . . . . . . . 69
3.7 Purification of Apple Juice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
3.8 Removal of Urea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
4 A pplications of Coir Fibers in Construction . . . . . . . . . . . . . . . . . . . . 75
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
5 Energy Applications of Coir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
5.1 Coir as Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
5.2 Carbonization of Coconut Fiber and Shells
for Supercapacitor Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
5.3 Gasification of Coir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
5.4 Catalysts for Biodiesel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
6 Coir for Environmental Remediation . . . . . . . . . . . . . . . . . . . . . . . . . . 115
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
6.2 Removal of Dyes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
6.3 Removal of Heavy Metals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
6.4 Chemicals and Compounds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
6.5 Desalination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
6.6 Sorption of Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
6.7 Desulfurization of Diesel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
7 Composites from Coir Fibers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
7.1 Coir Fibers as Reinforcement for Synthetic Polymers . . . . . . . . . . 141
7.1.1 Polyester Composites Reinforced with Coir Fibers . . . . . . . 141
7.1.2 Polypropylene Composites Reinforced
with Coir Fibers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
7.1.3 Polyethylene Reinforced Coir Composites . . . . . . . . . . . . . 147
7.1.4 Epoxy Reinforced with Coir Fibers . . . . . . . . . . . . . . . . . . . 149
7.1.5 Phenol Formaldehyde Based Coir Fiber Composites . . . . . 152
7.1.6 Rubber Composites Containing Coir Fibers . . . . . . . . . . . . 152
7.1.7 UV Treatment of Coir Fibers . . . . . . . . . . . . . . . . . . . . . . . . 154
7.2 Biocomposites from Coir Fibers . . . . . . . . . . . . . . . . . . . . . . . . . . . 155
7.2.1 Poly(Lactic) Acid Based Coir Biocomposites . . . . . . . . . . . 155
7.2.2 Poly(Caprolactone) Based Biodegradable
Coir Composites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
7.2.3 Coir Fiber Composites Developed using Proteins
and Starch as Matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
7.3 Hybrid Composites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
7.4 Coir Shell and Coir Pith Composites . . . . . . . . . . . . . . . . . . . . . . . . 178
7.5 Coconut Sheath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
Contents ix
8 Miscellaneous Applications for Coir and Other Coconut
By-products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
8.1 Synthesis of Cellulose Nanoparticles . . . . . . . . . . . . . . . . . . . . . . . . 187
8.2 Carbon Nanospheres and Nanotubes . . . . . . . . . . . . . . . . . . . . . . . . 191
8.3 Synthesis of Silver Nanoparticles . . . . . . . . . . . . . . . . . . . . . . . . . . 193
8.4 Sorption of Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
8.5 Cooling Pads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
8.6 Pest Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
8.7 Gas Diffusion Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
8.8 Fire Resistant Coatings and Biosorption . . . . . . . . . . . . . . . . . . . . . 199
8.9 Wood Vinegar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
8.10 Paper/Boards from Coir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
8.11 Precursor for Ceramic Production . . . . . . . . . . . . . . . . . . . . . . . . . . 203
8.12 Brake Lining . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204
8.13 Superabsorbent Hydrogels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
8.14 Development of SiC Whiskers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
8.15 Corrosion Inhibition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208
8.16 Production of Bio-oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210
8.17 Manufacture of Conducting Fibers . . . . . . . . . . . . . . . . . . . . . . . . . 212
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
Chapter 1
Processing and Properties of Coconuts
1.1 Introduction
The structure and properties of coir and other coconut by-products vary consider-
ably with the variety, climatic conditions at the place of growth, and processing
conditions. In addition, the application of coconut and its by-products also varies
depending on the culture, living environments, value addition desired, and societal
needs. For example, raw coconuts are primarily consumed for the water and also
dried and processed to extract oil. A picture of the various products that can be
manufactured from coconuts is shown in Fig. 1.1. Apart from the coconuts being the
primary product, the leaves, trunk, and flowers of coconuts/trees are also used for
various applications. Typically, raw or undried coconuts contain about 50% solids
and 50% liquid. However, there are considerable variations observed between coco-
nuts, even from the same location and in fact from the same tree (Table 1.1). In
addition to the size of the coconuts, the extent of husk covering the nuts and thick-
ness of the shell vary among the nuts and cause differences in processing of the nuts.
For instance, dehusking a dry coconut took an average of 857 N compared to 745 N
for green coconuts (Varghese and Jacob 2017), whereas it takes an average breaking
force of 4427 N to break a coconut shell having a thickness of 3 mm and diameter
of 95 mm.
1.2 Extraction of Fibers
A majority of coconuts are processed commercially for obtaining oil and other
products. These coconuts are processed after the water inside gets naturally evapo-
rated and nuts are considered dry during which the size of the coconuts reduces
considerably and the coconuts turn brown. After drying, the coconuts are broken
and the inside part is collected and processed for oil. During such commodity
© Springer Nature Switzerland AG 2019 1
N. Reddy, Sustainable Applications of Coir and Other Coconut By-products,
https://doi.org/10.1007/978-3-030-21055-7_1