In view of the biomass-based procurement organizations, the extensive changes in the amounts of biomass available with respect to the county are observed and there­fore, it may be more advantageous if one can estimate the biomass availability and costs associated with its supply to each selected power plant. Goerndt et al. (2013) estimated the biomass amounts and its delivered costs for a simulated concentric procurement radii (R) from 10 to 100 km by 10 km intervals around the selected powerplant locations in Northern America using the ArcGIS software (Environmental Systems Research 2013; http://www. esri. com). In the study while dealing with large procurement radii, they observed that the total procurement area around the major power plants is consisting of several counties of varying sizes. Hence based on this, Goerndt et al. (2013) anticipated that it is of extreme importance to estimate the total woody biomass (B) which can be available annually from each procurement area at a county level of any size. The following Eq. 12.7 can be used to estimate the total amount of annually available woody biomass per county and is based on an assumption that the biomass resources are distributed uniformly across the county.

m

B = Yjaibi (12.7)

i=1

where ai is the percentage of the area of a county i and bi is the total annually available woody biomass for the same county i that falls within the procurement area under study.

N. Saba, M. Jawaid, and M. T. Paridah

Contents

15.1 Introduction………………………………………………………………………………………………….. 248

15.2 Potential Non-edible Feedstock…………………………………………………………………………… 249

15.3 Homogeneous and Heterogeneous Catalyst……………………………………………………………… 251

15.3.1 Types of Heterogeneous Catalyst…………………………………………………………… 251

15.4 Activated Carbon-Carbon-Based Acid Catalyst…………………………………………………….. 252

15.5 Chemical Activation………………………………………………………………………………………… 252

15.5.1 Biomass for Activated Carbon………………………………………………………………… 256

15.5.2 Methods of Preparation of Activated Catalyst……………………………………………. 256

15.6 Structure of Activated Carbon…………………………………………………………………………….. 258

15.6.1 Catalyst Leaching………………………………………………………………………………. 259

15.6.2 Optimization of Parameters for Chemical Activation Reaction………………………… 260

15.7 Characterization of Activated Catalyst……………………………………………………………………. 261

15.8 Biomass Derived Activated Sulfonated Catalyst……………………………………………………. 261

15.8.1 Sulfonation of Activated Catalyst…………………………………………………………… 262

15.8.2 Structure and Figure of Sulfonated Catalyst…………………………………………….. 263

15.9 Conclusions………………………………………………………………………………………………….. 264

References …………………………………………………………………………………………………………….. 265

N. Saba • M. T. Paridah

Department of Biocomposite Technology, Institute of Tropical Forestry and Forest Products (INTROP), Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia

M. Jawaid, Ph. D. (*)

Department of Biocomposite Technology, Institute of Tropical Forestry and Forest Products (INTROP), Universiti Putra Malaysia, Serdang, Selangor 43400, Malaysia

Department of Chemical Engineering, College of Engineering, King Saud University, Riyadh 11451, Saudi Arabia

e-mail: jawaid@upm. edu. my; jawaid_md@yahoo. co. in

K. R. Hakeem et al. (eds.), Biomass and Bioenergy: Processing and Properties,

DOI 10.1007/978-3-319-07641-6_15, © Springer International Publishing Switzerland 2014

Abstract The lignocellulosic material is most prevalently used in the production of agro based activated carbons. These catalysts have been established as benign alterna­tives to the heterogeneous alkaline catalysts and the unrecyclable-homogeneous acid and base catalysts heterogeneous catalyst have been considered a viable alternative since they eliminate the usual difficulties related to homogenous catalyst and can be reused several times and hence solved many problems. Biomass derived solid acid catalyst is the renewable source of energy whereas homogeneous catalyst are non-renewable and also contribute to the environmental degradation as their synthesis and production pro­cess are hazardous. The thermal inertness, good mechanical and thermal stability prop­erties make the carbon-based solid acids as the ideal catalysts for many reactions. Heterogeneous catalyst associated with high water tolerance, high selectivity, and high activity properties. Sulfonated carbons are the most promising solid acids. In the coming future need and the demand of more biodiesel is expected to increase, this encourages to consider the use of non-edible oil seeds as reliable as a sustainable feedstock for biofuel production. This work is aimed to give an overview on the production of solid acid cata­lyst and the potential of non-edible oil and cake waste as an alternative feedstock for the heterogeneous acid catalyst. This study also reviewed current literature on the activities and advantages of solid acid catalysts used in biodiesel production.

Keywords Non-edible oil • Feedstocks • Activated carbon • Sulfonated activated carbon • Biodiesel

15.1 Introduction

Major issues and the priorities in the present situation are the climate change and energy security in light of the environmental problems causing increased production of bio-catalyst as important source of solid acid catalyst, in both developed and developing countries. At present the prime focus of the scientists and the research­ers is the introduction of eco-friendly Green Technology. A solid acid catalyst must have the possibility to possess high activity and stability in the requirement for its utilization in low cost, renewable, and biodegradable biodiesel production. About more than 300 types of trees species are classified as oil bearing seeds and are potential source for biocatalysts generation (Subramanian et al. 2005).

Most usually all carbon-containing lignocellulosic materials are the promising mate­rials for activated carbon preparation (Ugar et al. 2009) although the coal is the impor­tant precursor of the activated carbon but the cost of production is high, the main concept is to consider cheap and efficient materials for the production of activated carbon.

Non-edible feedstocks are easily available and are economically feasible with respect to edible feedstock. In comparison to edible feedstock, non-edible like rubber seed, jatropha, sea mango are not suitable for human consumption because of its toxic and anti-nutritional components or constituent (Kumar and Sharma 2011). In contemporary research the main commodity sources for catalyst production from the non-edible discarded parts, different agricultural biomass based wastes and raw materials derived from plant species have been presented in Table 15.1. Moreover the cost of plantation for edible oil crops is higher than the non-edible oil crops, with an

exemption to palm oil plant (Kumar and Sharma 2011). Apprehension regarding environmental safety has improved over the years from a universal viewpoint. Nowadays rapidly fluctuating technologies, industrial goods and practices create waste that could impend towards public health and the environment (Shen 1995). Agricultural waste biomass presently one of the most challenging issue, which gained widespread serious attention from the past decades (Andrew et al. 2003). During the manufacture process of the olive in mills, olive mill waste water is pro­duced in large quantities, this waste water can be used as raw materials to yield valu­able product by both physical and chemical activation (Moreno-Castilla et al. 2001). Several variety of agricultural by-products (lignocellulosics) including peach stones (Molina-Sabio et al. 1995), date stones (Girgis and El-Hendawy 2002) and (Haimour and Emeish 2006), waste apple pulp in cider production (Suarez-Garcia et al. 2002), rice husks (Chuah et al. 2005), pistachio-nut shells (Yang and Lua 2006), and grain sorghum (Diao et al. 2002) have been investigated as activated carbon precursors. However, waste cakes received much less attention as a precursor lignocellulosic material for activated carbon production (Cimino et al. 2005; Bagaoui et al. 2001). Agricultural cake wastes are generated in each growing season like olive cake, some of them are used in boilers, some are dumped in the environment, and there they release harmful and toxic compounds by the action of fungi.

Irrigation largely depends on local climatic conditions. Jatropha is well adapted to dry soils and can stand without water for long periods (as long as 2 years) and can resume growth once rains return (Nahar 2011). Jatropha with high-quality seeds has an average 1 L/plant/day water consumption rate throughout the growing season (PSO 2010). Although J. curcas by shedding its leaves, can survive on precipitation as low as 300 mm, but under such conditions it does not produce well. To produce healthy fruits, an indicative of economically sustainable oil production, minimum and optimal rainfalls are 600 mm ha-1 y-1 and 1,000-1,500 mm ha-1 y-1 (Henning 2007). The crop should be artificially irrigated during dry period whenever required.

17.3.3 Fertilization

Jatropha is adapted to low soil fertility, however organic or artificial fertilization might be required for plantations aiming at oil production. Application of N-P-K and cow manure annually is highly recommended (PSO 2010). Jatropha plantations on poor-quality soils when fertilized with phosphorus (P), nitrogen, calcium (Ca), potassium (K), magnesium (Mg), and sulfur (S) rich fertilizers produce higher yield than Jatropha planted on soils without fertilizers (Achten et al. 2008; Mohapatra and Panda 2011; Moore et al. 2011).

Physical pretreatment processes employ the combination of mechanical and irradiation processes to change only the physical characteristics of biomass. Physical pretreat­ment is usually carried out before a following processing step which is often needed

Effect of Pretreatment

Cellulose

Ilcmicellulose

Fig. 20.2 Schematic representation on biomass pre-treatment (Mosier et al. 2004) to reduce the particle size, make material handling easier, reduce volume, and increase surface area. This can be done by a combination of chipping, grinding, or milling depending on the final particle size of the lignocellulose biomass (10-30 mm after chipping and 0.2-2 mm after milling or grinding) (Sun and Cheng 2002). Different milling processes (ball milling, two-roll milling, hammer milling, colloid milling, and vibro energy milling) can be employed to improve the enzymatic hydrolysis of ligno- celullosic biomass (Taherzadeh and Karimi 2008). Mechanical pretreatment factors such as operating costs and depreciation of equipment are very important.

Sameen Ruqia Imadi, Isra Mahmood, and Alvina Gul Kazi

Contents

2.1 Introduction 28

2.2 Bamboo Fiber Preparation…………………………………………………………………………………….. 29

2.3 Bamboo Fiber Processing…………………………………………………………………………………….. 30

2.3.1 Processing by Rolling…………………………………………………………………………….. 31

2.3.2 Mechanical Comb Fiber Technology……………………………………………………………. 31

2.3.3 Degumming Defibrase System Technology by Explosion…………………………………… 31

2.3.4 Chemical Mechanical Processing Technology…………………………………………………. 32

2.3.5 Processing Technology by Cracking…………………………………………………………….. 32

2.4 Properties of Bamboo Fiber 32

2.4.1 Durability…………………………………………………………………………………………… 32

2.4.2 Elasticity…………………………………………………………………………………………… 33

2.4.3 Elongation…………………………………………………………………………………………. 33

2.4.4 Flexural Strength…………………………………………………………………………………… 33

2.4.5 Hardness…………………………………………………………………………………………….. 34

2.4.6 Impact Strength…………………………………………………………………………………….. 34

2.4.7 Linear Density……………………………………………………………………………………… 35

2.4.8 Moisture Absorption………………………………………………………………………………. 35

2.4.9 Specific Gravity……………………………………………………………………………………. 35

2.4.10 Specific Strength…………………………………………………………………………………… 36

2.4.11 Tensile Load………………………………………………………………………………………… 36

2.4.12 Tensile Modulus…………………………………………………………………………………… 36

2.4.13 Tensile Strength…………………………………………………………………………………… 37

2.4.14 Thermal Resistance………………………………………………………………………………… 38

2.4.15 Weight……………………………………………………………………………………………… 38

2.4.16 Biodegradability……………………………………………………………………………………. 38

S. R. Imadi • I. Mahmood • A. G. Kazi (*)

Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), Islamabad, Pakistan e-mail: alvina_gul@asab. nust. edu. pk

K. R. Hakeem et al. (eds.), Biomass and Bioenergy: Processing and Properties, 27

DOI 10.1007/978-3-319-07641-6_2, © Springer International Publishing Switzerland 2014

2.5 Applications of Bamboo Fibers………………………………………………………………………………. 39

2.5.1 Biofuel Production…………………………………………………………………………………… 39

2.5.2 Construction Material………………………………………………………………………………. 39

2.5.3 Food and Feedstock…………………………………………………………………………………. 40

2.5.4 Musical Instruments…………………………………………………………………………………. 40

2.5.5 Paper Industry……………………………………………………………………………………….. 40

2.5.6 Pharmaceutical Industry…………………………………………………………………………….. 41

2.5.7 Textile Industry………………………………………………………………………………………. 41

2.5.8 Cosmetic Industry…………………………………………………………………………………… 42

2.5.9 Sports Industry………………………………………………………………………………………. 42

2.6 Conclusion and Future Prospects…………………………………………………………………………….. 42

References ………………………………………………………………………………………………………………. 42

Abstract Bamboo fiber is a cellulosic fiber that is regenerated from bamboo plant. It is a great prospective green fiber with outstanding biodegradable textile material, having strength comparable to conventional glass fibers. Bamboo used for fiber preparation is usually 3-4 years old. Fiber is produced through alkaline hydrolysis and multi-phase bleaching of bamboo stems and leaves followed by chemical treat­ment of starchy pulp generated during the process. Bamboo fiber has various micro­gaps, which make it softer than cotton and increase its moisture absorption. They are elastic, environment-friendly, and biodegradable. The fiber is bacteriostatic, anti­fungal, antibacterial, hypoallergenic, hydroscopic, natural deodorizer, and resistant against ultraviolet light. Furthermore, it is highly durable, stable and tough and has substantial tensile strength. Due to its versatile properties, bamboo fibers are used mainly in textile industry for making attires, towels, and bathrobes. Due to its anti­bacterial nature, it is used for making bandages, masks, nurse wears, and sanitary napkins. UV-proof, antibiotic and bacteriostatic curtains, television covers, and wallpapers and many other things are also prepared from bamboo fibers to lessen the effects of bacteria and harm of ultra violet radiations on human skin. Bamboo fibers are also used for decoration purpose.

Keywords Bamboo • Bamboo fibers • Tensile properties • Mechanical properties • Processing

2.1 Introduction

Bamboo is a common term applied to approximately 1,250 species of large woody grasses, ranging from 10 cm to 40 m in height (Scurlock et al. 2000). Bamboo is considered to be the second largest resource of forestry in the whole world because of its rapid growth potential. Bamboo forests are distributed extensively in tropical and sub-tropical climates in frigid zones. The area covered by bamboo forestry is estimated to be around 20 million hectares. China is considered to be rich in bam­boo resources and there are about 40 families and 400 species of bamboo found only in China. This rich resource of bamboo in China covers an area of about 7 million hectare; 35 % of the area covered by bamboo forests in the whole world (Yao and Zhang 2011). Bamboo is called a cash crop because the time required for its cultivation is less, can be grown in deprived regions and has a variety of uses. Furthermore, the plant is harvested after 3-4 years (Erdumlu and Ozipek 2008). Bamboo is observed to produce an adult tree in only 1 year.

Bamboo is supposed to be one of the best functionally gradient composite mate­rials available. It is observed that in a piece of bamboo, 1 mm2 area near outer periphery contains approximately eight fibers and inner periphery contains two fibers (Ray et al. 2005). Bamboo fiber is a new kind of natural material, which has high potential in textile field due to some of its specific properties (Liu and Hu

2008) . Bamboo fibers are also known as breathable fabric as they resemble puffball of light and cotton in untwisted form (Yao and Zhang 2011). These fibers are cel — lulosic in nature and are obtained from natural, reproducible resource of bamboo plants. Bamboo fibers are made from pulp of the plant, which is extracted from the plant’s stems and leaves.

Total culm of bamboo comprises of 60 % parenchyma, 40 % fibers, and 10 % conducting tissues (vessels and sieve tubes). Bamboo culm constitutes 60-70 % of fiber content by weight (Liese 1992). Bamboo fibers consist of cellulose, hemi- cellulose, and lignin in the ratio 2:1:1 (Tung et al. 2004; Fukushima et al. 2003). Bamboo monofilament has four layers where crystallized cellulose micro-fibrils (MF) are aligned longitudinally with reverence to the axis of the fiber. MFCs are bonded together with lignin and hemi-cellulose (Fukushima et al. 2003). Lignin is hydrophobic and plays an important role in formation of fibers in the form of matrix whilst MFCs play a role in reinforcement. The overall structure appears to have a hydrophilic surface with hydrophobic lignin core (Jain et al. 1992).

Bamboo fibers have good properties of moisture adsorption, moisture desorp­tion, and air permeability (Yao and Zhang 2011). Being natural they are available in abundance, have high strength, are biodegradable and renewable (Deshpande et al. 2000). The current scenario of research and investigation on bamboo fibers is lim­ited because of limited extraction of fibers from bamboo plant (Jain et al. 1992; Jindal 1988).

The Philippines, being the world’s leading producer of abaca fiber, has been reported to supply about 84 % of the global abaca requirement followed by Ecuador which supplies about 16 % fiber requirement (FIDA 2009). The abaca industry has been found to maintain a stronghold in both national/domestic and international markets since 1989 as the demand for raw abaca fibers or processed products has grown to a great extent and is expected to grow further with the advancement in technology and scientific formulations which will ultimately boost the Philippine economy. Moreover, with the availability of new international markets, the demand of abaca fibers (raw) or the processed products has increased to a great extent which is reflective of the marginal increase in its export. As per the reports, the export volume of abaca products has registered a growth rate of 121.4 % per year (Lalusin

2010) . The growing concern for environment protection or forest conservation is an important reason of ever-increasing demand for natural fibers, so is the case with abaca and there is an expectation that the demand will continue to increase keeping in view the potential of the fiber and its processed products. Despite the increasing demand and higher market prize, the production of abaca has not been found to keep pace with the demand. The main reasons for this gap between demand and supply are the low yield and low fiber quality (Moreno 2001) . Moreover, low — income generation from abaca farming, the laborious process of fiber extraction and availability of less human resources (who prefer jobs than traditional farming) is also responsible for its reduced productivity. Furthermore, the old typhoon dam­aged or disease-infected plantations (Sharman et al. 2000a, b; Villajuan-Abgona et al. 2001) add to the problem. Banana bunchy top virus (BBTV), Banana bract mosaic virus (BBrMV), Abaca mosaic virus (AMV), and Cucumber mosaic virus (CMV) are the four main viruses which have been found to infect abaca plants (Bajet and Magnaye 2002; Furuya et al. 2006; Pietersen and Thomas 2001; Pinili et al. 2011; Sharman et al. 2000a, b) of which BBTV (transmitted by banana aphid; Pentalonia nigronervosa Coq) has been reported to contribute to huge economic loss and resulted in destruction of many abaca plantations in Philippines (Calinisan 1939; Raymundo and Bajet 2000). Recently, the mutation breeding program has been initiated to produce virus-resistant (BBTV and BBrMV) abaca cultivars by using gamma irradiation (Cobalt 60) in two abaca cultivars Tangongon (TG) and Tinawagan Pula (TP) (Dizon et al. 2012).

The water is a non-wetting liquid for kapok fiber due to the formation of large contact angle (>90°) between water and kapok fiber. Therefore, the water is not accessible to the large lumen of kapok fiber. Then, the kapok fiber should experi­ence a chemical or physical pretreatment to be hydrophilic for further application as the adsorbent for removing different kinds of pollutants from aqueous solution. Wang et al. (2012b) found that after NaClO2 treatment, the water drop can form a large spreading radius on the corresponding fiber surface, suggesting that by NaClO2 treatment, the surface of kapok fiber has been transformed from intrinsic hydrophobic-oleophilic to hydrophilic. In addition, NaClO2 treatment can lead to the de-esterification of kapok fiber, thus reducing the aggregate structure and expanding the proportion of amorphous region in kapok fiber (Wang et al. 2012a). In this case, Liu et al. (2012a) investigated the adsorption behaviors of a cationic dye methylene blue from aqueous solution using NaClO2-treated kapok fiber as the adsorbent. In order to alter the hydrophobicity to hydrophilicity, a series of chemical modifications on the kapok fibers via the combination processes of chlorite — periodate oxidation have also been carried out (Chung et al. 2008). When treated with NaClO2 for lignin degradation and NaIO4 for sugar degradation, the chemi­cally oxidized kapok fibers retained their hollow tube shape and evidenced elevated ability to adsorb heavy metal ions, with the adsorption rates of 93.55 %, 91.83 %, 89.75 %, and 92.85 % for Pb, Cu, Cd, and Zn ions, respectively. This enhanced adsorption of heavy metal ions onto the chemically oxidized kapok fibers can be attributed to the generation of — COOH groups during the oxidation process. When the kapok fiber is washed with dichloromethane to remove the botanic wax and further treated with NaOH solution, the resultant fiber can be modified with diethy — lenetriamine pentaacetic acid (DTPA). The resultant kapok-DTPA shows a fast adsorption for the metal ions with the adsorption equilibrium being reached within 2 min for Pb2+ and Cd2+, and 5 min for Cu2+ . Maximum adsorption capacities of kapok-DTPA are 310.6 mg/g for Pb2+. 163.7 mg/g for Cd.+. and 101.0 mg/g for Cu2+, respectively (Duan et al. 2013).

G. M. Arifuzzaman Khan, Md. Ahsanul Haque, and Md. Shamsul Alam

Contents

10.1 Introduction…………………………………………………………………………………………………… 158

10.2 Functionalization of Okra Bast Fibre……………………………………………………………………… 160

10.3 Okra Bast Fibre-Reinforced Phenol Formaldehyde Resin Composites………………………………. 162

10.3.1 Thermosetting Phenol Formaldehyde Resin…………………………………………………. 162

10.3.2 Fabrication Techniques…………………………………………………………………………. 164

10.3.3 Mechanical Properties…………………………………………………………………………… 166

10.3.4 Thermal Degradation……………………………………………………………………………. 169

10.3.5 Biodegradation…………………………………………………………………………………… 171

10.4 Conclusion……………………………………………………………………………………………………. 172

References……………………………………………………………………………………………………………. 172

Abstract Bast fibres are mainly composed of lignocellulosic materials. It is extracted from the outer cell layers of the stems of different plants species. In ancient times, bast fibres were used for making various products like rope, bags, mats and coarse textile materials to mitigate daily demands. However, such trendy usages of bast fibres were decreased behind the invention of cheap synthetic fibre. Although synthetic fibres have good strength and longibility, they are causing serious environ­mental pollution for their nonbiodegradable nature. To achieve the ‘sustainable development’, the usages of bast fibres are explored again. Diversified use of bast fibres as reinforcements of polymer matrix composites becomes popular due to its satisfactory engineering properties. The plant kingdom has a vast source of bast fibres. Few of them are utilized for reinforcing polymer composites and many spe­cies remain unexplored. Okra (Abelmoschus esculentus) bast fibre has no commer­cial value currently. It is considered as agricultural waste product after collecting

G. M.A. Khan (*) • Md. A. Haque • Md. S. Alam

Department of Applied Chemistry and Chemical Technology, Islamic University, Kushtia 7003, Bangladesh e-mail: arif@acct. iu. ac. bd

K. R. Hakeem et al. (eds.), Biomass and Bioenergy: Processing and Properties,

DOI 10.1007/978-3-319-07641-6_10, © Springer International Publishing Switzerland 2014 vegetable. In fact, its chemical composition is almost similar to other commercial bast fibres, such as a-cellulose (60-70 %), hemicelluloses (15-20 %), lignin (5-10 %) and pectins (3-5 %) along with trace amount of water-soluble materials. The fibre exhibited high breaking tenacity (40-60 MPa) and high breaking elongation (3-5 %). In this chapter, okra bast fibre is introduced as a reinforcement material for fabrication of phenol formaldehyde resin composites. Manufacturing techniques and effect of fibre modification on their mechanical, thermal and biodegradation properties are discussed.

Keywords Okra bast fibre • Thermosetting phenol formaldehyde resin • Interface modification • Composite fabrication • Properties of composite

10.1 Introduction

Environmental awareness is encouraging scientific research to produce cheaper, environment-friendly and more sustainable packaging as well as construction mate­rials. Natural fibre-reinforced thermoplastic composites are strong, stiff, light weight and recyclable and have the potential to meet this requirement. Because of their low cost, low density and excellent mechanical properties, natural fibres such as sisal, jute, hemp, flax, banana, PALF, coir and palm are promising reinforcement with thermoplastic composites (Sreekumar et al. 2011; Kabir et al. 2012; Virk et al.

2012) . Among the 2,000 fibre-containing plants species, fewer have economical value. Jute and hemp were extensively used from past days (Mwaikambo and Ansell 1999; Mondal and Khan 2008). But high production cost with large cultivation area limits its use. Okra bast fibre (OBF) is a lignocellulosic fibre which is obtained from okra plant that grows everywhere abundantly in the world. Nowadays, it is rejected as agricultural waste products. However, due to the favourable mechanical properties of OBF, it has been transferred successfully to thermoplastic composite materials so far (Fig. 10.1).

OBF comes from the species ‘esculentus’, in the family ‘malvaceae’. It is culti­vated throughout the tropical and warm temperate regions of the world for its fibrous fruits or pods containing round, white seeds. The fruits are harvested when imma­ture and eaten as a vegetable. The vegetable can be collected from plant up to the period of 3-6 months. The plant was then subject for direct combustion. This opera­tion causes not only environmental pollution but also waste valuable fibre compo­nents. The chemical composition of OBF is a-cellulose (60-70 %), hemicelluloses (15-20 %), lignin (5-10 %) and pectins (3-5 %) along with trace amount of water — soluble materials (Khan et al. 2009). Though it contains higher percent of cellulose, it may have potentiality to make good-quality composite with thermoplastic/ thermoset resins. Fortunati et al. (2013) prepared OBF-PVA composites and stud­ied its degradation properties. The fibres possess good mechanical properties and biodegradable characteristics. But such properties are not sufficient as engineering or commodity plastics. Besides, like other vegetable fibres, OBF possesses few

weak points such as hydrophilic nature and degradation after prolong exposure to sunlight and is much prone to creasing, possibly due to high degree of orientation of cellulose in the fibre.

Thermoset resins are promising materials for natural fibre composite industries because they are insoluble and infusible and have high-density networks. A number of studies have been reported on thermoset-plastics-natural fibre composites. Injection and extrusion moulding processes for fabrication of short fibre/thermoplastic com­posites are proficient and economic (Sun et al. 2010; Paulo et al. 2007). In extrusion moulding process, fibres are well distributed into a matrix which is most desirable for enhanced composite properties. Besides, fibre content, fibre diameter, fibre length, void content, fibre orientation and fibre-matrix bonding are very important parameters for natural fibre-reinforced thermoplastic/thermoset-plastic composites (Joseph et al. 1993; Alam et al. 2010). Kalaprasad et al. (1996) found high mechani­cal strength, modulus and thermal resistance of sisal/glass hybrid fibre-reinforced low density polyethylene (LDPE) composites by varying fibre length and fibre distribution. Void possesses in composites reduced mechanical properties. Again, weak interface between fibre and matrix increases the probability of void content in composite as a result decreases the flexural strength, the off axis strength and the compression strength. Improvement of interfacial strength gives substantial improvement in tensile strength and modulus of short fibre composites. Since the chemical nature of fibre and matrices is different, strong interfacial adhesion is compulsorily required for an effective transfer of stress. Ray et al. (2001) reported that alkali-treated jute improves interfacial bonding of jute/vinylester composites.

Mild alkaline treatment creates rough surface topography of fibre by removing both intercellular and adhering impurities. On the other hand, fibrillation took place (breakdown the fibre bundle into smaller fibres) when fibre was treated in strong alkaline condition. As a result, the effective surface area of fibre increases which help it for easy wetting in matrix resin. Therefore, by increasing the fibre aspect ratio through alkali treatment, it can be possible to get better fibre-matrix interface adhesion and increase of mechanical properties (Weyenberg et al. 2006). This chapter deals with the fabrication process of OBF-PFR composites and their mechanical, thermal and biodegradation studies.

Some of the techniques used for biomass cultivation are:

13.2.2.1 Photoautotrophic Production

This form of cultivation takes place when algae utilize an energy source (light) and a carbon source (inorganic carbon) to form carbohydrates through a process termed as photosynthesis. This is the most general method used for cultivating algae and results in the formation of algal cells with lipid content ranging from 5 to 68 % depending on the algal specie being cultivated. If algae are cultivated for oil produc­tion, then the prime advantage of using this cultivation technique is to utilize carbon dioxide to meet the carbon requirement.

13.2.2.2 Heterotrophic Production

In this method, the algal specie is grown on a carbon substrate like glucose thus eliminating the need of light energy. This process can be performed in a reactor with a small surface to volume ratio. A much higher degree of growth control is achieved and harvesting budget is lowered due to production of high-density cells. The set-up cost is negligible but more energy is used as compared to the process utilizing light energy because photosynthetic processes are utilized to form the carbon source on which the algae are grown. Studies have shown that heterotrophic method of bio­mass production has a higher yield and cells have higher lipid content (55 % as compared to 15 % in autotrophic cells).

Raw material and activated carbons tests were performed on dry basis according to International Organization for Standardization (ISO) and American Society for Testing and Materials (ASTM) procedures to determine their main property. Fixed carbon content was determined by difference (Angin et al. 2013a, b). Acid densities of the carbons were determined by titration method using phenolphthalein indicator (Konwar et al. 2013). Textural property of the prepared activated carbon including pore size distribution, surface area (SBet), and total pore volume (Vtot) were deter­mined from N2 adsorption at 77 K using an Autosorb1-Quantachrome instrument (Baccar et al. 2012). Pore size distribution, surface area, and pore volume of the activated carbons were determined by the BET equation and t-plot analysis software (Angin et al. 2013a, b). The carbonaceous materials porosity and irregular shapes are clearly visible by means of Scanning Electron Microscopy. Characterization also involved Elemental Analysis of the porous carbon materials before and after sulfonation, Transmission Electron Microscopy (TEM), Infrared Spectroscopy for the determination of the functional groups like sulfonic, carbonyl group in the acti­vated carbon (KBr pellet), Raman spectroscopy, X-ray Powder Diffraction used for illustrating the amorphous nature of the carbonaceous materials and Thermo Gravimetric Analysis for the determination of the thermal stability (Konwar et al.

2013) . The carbon, hydrogen, and nitrogen contents of the precursor material and activated carbon were analyzed by Elemental Analyzer. However oxygen contents were calculated by difference. The DR (Dubinin-Radushkevich) method used to determine the micropore volume accordingly. Fourier transform infrared spectra (FTIR) used extensively to determine surface functional groups (Angin et al. 2013a, b). The -SO3H densities of sulfonated carbons were estimated from elemental analysis by considering that all sulfur present in the carbon samples was due to — SO3H groups (Konwar et al. 2013).