Study the Structure, Morphology, and Thermal

Journal of Natural Fibers

ISSN: 1544-0478 (Print) 1544-046X (Online) Journal homepage: http://www.tandfonline.com/loi/wjnf20

Study the Structure, Morphology, and Thermal Behavior of Banana Fiber and Its Charcoal Derivative from Selected Banana Varieties M. D. Y. Milani, D. S. Samarawickrama, G. P. C. A. Dharmasiri & I. R. M. Kottegoda To cite this article: M. D. Y. Milani, D. S. Samarawickrama, G. P. C. A. Dharmasiri & I. R. M. Kottegoda (2016) Study the Structure, Morphology, and Thermal Behavior of Banana Fiber and Its Charcoal Derivative from Selected Banana Varieties, Journal of Natural Fibers, 13:3, 332-342, DOI: 10.1080/15440478.2015.1029195 To link to this article: http://dx.doi.org/10.1080/15440478.2015.1029195

Published online: 01 Jun 2016.

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Date: 01 June 2016, At: 22:34

JOURNAL OF NATURAL FIBERS 2016, VOL. 13, NO. 3, 332–342 http://dx.doi.org/10.1080/15440478.2015.1029195

Study the Structure, Morphology, and Thermal Behavior of Banana Fiber and Its Charcoal Derivative from Selected Banana Varieties M. D. Y. Milani

, D. S. Samarawickrama, G. P. C. A. Dharmasiri, and I. R. M. Kottegoda

Downloaded by [Yoga Milani] at 22:34 01 June 2016

Materials Technology Section, Industrial Technology Institute, Colombo, Sri Lanka ABSTRACT

KEYWORDS

The structure, the morphology and the thermal behavior of fibers extracted from common banana varieties (‘Ambun’ (Cavendish AAA), ‘Ambul’ (Mysore AAB), ‘Kolikuttu’ (Silk AAB), ‘Seenikesel’ (Pisang Awak ABB),’ Alukesel’ (ABB) found in Sri Lanka have been investigated using XRD, FTIR, SEM, and DSC. All the samples exhibited similar X-ray diffraction patterns, FTIR spectrums and DSC thermograms. SEM analysis revealed the presence of rough surface with filaments in all five banana varieties and detailed analysis revealed that there is a hollow structure in the aforesaid fiber varieties. Considering the similarity of the different fibers, the possibility of using a mixture of banana fiber varieties to prepare economical banana fiber charcoal was also investigated. Prepared charcoal was also characterized using XRD, FTIR & SEM. It was observed that the charcoal prepared from two or five different banana varieties showed similar X-ray diffraction patterns, FTIR spectra as well as similar morphology. Since the properties of banana fiber as well as the banana charcoal are irrespective to the banana variety used to prepare them, the collection and the manipulation of the banana waste becomes facile in commercial application.

Charcoal; DSC; fiber; FTIR; SEM; XRD 关键词

炭；DSC；纤维；红外光谱；扫瞄式电子显微镜； X射线衍射

香蕉纤维的结构、形态和热性能及所选品种的炭衍生物的研究

在斯里兰卡已经利用XRD，FTIR、SEM、DSC对普通的香蕉品种 (‘Ambun’ (Cavendish AAA), ‘Ambul’ (Mysore AAB),‘Kolikuttu’ (Silk AAB), ‘Seenikesel’ (Pisang Awak ABB),’ Alukesel’ (ABB) 中提取的纤维的结构，形态，热性能进行了研究。所有的样品表现出类似的X射线衍射、红外光谱、DSC热分析图。扫描电镜分析表明，在所有五个香蕉品种中，存在粗糙的表面，并进行了详细的分析，结果表明上述纤维品种有一个中空结构。考虑到不同的纤维的相似性，混合香蕉品种纤维的制备经济香蕉纤维木炭的可能性。利用X射线衍射仪、红外光谱和扫描电镜对所制备的炭进行了表征观察。观察到，从两个或五个不同的香蕉品种制备的炭表现出类似的X-射线衍射图案，红外光谱以及类似的形态。由于香蕉纤维以及香蕉的炭衍生物跟香蕉品种无关的特性，在商业应用中，香蕉废物的收集和操作变得简便。

1. Introduction In recent years the growing interest in using natural materials as a substitute for synthetic compounds has led to the investigation of the properties and uses of biodegradable natural fibers. A number of plant-based natural fibers, such as jute, Agave, cotton, coir and sisal have already been established to replace their synthetic counterparts in several applications (Bilba et al. 2007; Saraswat and Gope 2014; Sinha and Rout 2009; Silva et al. 2010; Xiong et al. 2014). Most of these natural fibers, with the exception of coir, are harvested from plants which are grown for the sole

CONTACT M. D. Y. Milani [email protected] Research Scientist, Materials Technology Section, Industrial Technology Institute, 363, Bauddhaloka Mawatha, Colombo 07, Sri Lanka. Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/wjnf. © 2016 Taylor & Francis


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purpose of extracting fiber. The possibility of using agricultural waste from food crops as alternative sources of natural fiber is being extensively researched worldwide (Kengkhetkit and Amornsakchai 2014). Banana is one such plant that has emerged to be a promising source for biodegradable fiber and is being utilized for various value addition processes in some countries such as India. However, banana cultivation in Sri Lanka continues to produce underutilized agricultural waste. Products developed from banana fiber have cost competitiveness compared with fiber from other agricultural waste materials such as coir, bamboo which is already used for value added applications. Banana plant belongs to the family Musaceae and is cultivated primarily for its fruit. Banana is the second most widely consumed fruit after citrus, contributing to about 16% of the world’s fruit production (Mohapatra et al. 2010). It is also one of the most widely grown tropical fruits, cultivated over 130 tropical and subtropical countries. The most common banana variety being grown in many countries is “Cavendish AAA,” corresponding to about one-third of worldwide production (Oliveira et al. 2007). Banana (Musa spp.) is also the most widely cultivated and consumed fruit in Sri Lanka. There are more than twenty varieties cultivated locally (Mohapatra et al. 2010) and currently, nearly 60,000 ha (20000 ha and 40000 ha in wet zone and dry + intermediate zones, respectively) of land is under banana cultivation in Sri Lanka. This is about 54% of the total fruit lands. The annual banana production of Sri Lanka is around 780,000 metric tonnes and the average yield is about 13 Mt/ha2. Among the said twenty varieties, five common banana varieties such as ‘Ambun’ (Cavendish AAA), ‘Ambul’ (Mysore AAB), ‘Kolikuttu’ (Silk AAB), ‘Seenikesel’ (Pisang Awak ABB),’ Alukesel’ (ABB) are found across the country. Among them, ‘Alukesel’ (ABB) is cultivated as a cooking plantain whilst the other varieties are cultivated as dessert plantains. (Hirimburegama et al. 2004). Each fruit has a unique taste; there is a sugary taste in Pisang Awak ABB and sour taste in Mysore AAB. Silk AAB and Cavendish AAA are favorite varieties in Sri Lanka which are more expensive than the others. Data on physicochemical properties of the aforesaid banana varieties is however limited. Therefore present work also aims at collecting such data. Since the edible fruit, constitutes only 12% by weight of the banana plant (Liyanage et al. 1998), statistics show that banana plantations in Sri Lanka generate a considerable amount of residual mass once fruits are harvested. The leftover waste biomass consisting of pseudostems, leaves, leaf sheaths, rachis and other wastes are generally disposed at a landfill or left to decompose slowly in the field. This practice encourages the buildup of banana pathogens and pests and causes environmental problems in banana farming areas. Banana fiber can be extracted from the residue of pseudo-stems and leaves left over after harvesting of fruits. The pseudo stem is rich in fiber, while the leaf sheaths and the rachis also contain a fair amount of extractable fiber. The extraction of fiber from the pseudo stem is not a common practice and much of the stem is not used for production of fibers. However, studies have shown that pseudo stem fiber bundles have a higher specific strength modulus and lower strain at break than the fiber bundles obtained from sheaths and the rachis (Mohapatra et al. 2010) which indicates that banana pseudo-stem fibers have the best potentiality as an alternative for synthetic fibers. Utilization of raw banana fibers through composite technology would lead to novel bio composite materials for applications, such as automotive parts, household equipments, structural and semi structural components, packing and insulating materials (Chaudhary et al. 2011; Saraswat and Gope 2014). Bio-composites and bio charcoal have received increasing attention in recent decades (Hashemian et al. 2014; Saraswat and Gope 2014) as a consequence of the global awareness and focus on environmental conservation and the need for necessary legislation. Traditional composite materials have been reinforced with glass fibers or inorganic minerals (Saraswat and Gope 2014). In contrast, bio composites prepared with waste banana fiber have several advantages, such as low cost, lighter weight, environmental friendliness, and recyclability. Further, developing countries become part of the global composite industry when such materials are used in composites. Value addition to banana waste would result in increased revenue and job opportunities in these countries and lead to extra income for farmers. As a result attempts have been made widely to characterize the lignocellulosic fibers.


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Thus banana growing countries have the potential to use the biomass left after banana harvest to environmental and economic benefit. (http://wikieducator.org/Sri_Lanka/L3_Farmers/University_ of_Colombo). However, few scientific and systematic studies have been reported on the utilization of these fibers for high impact value added products. Charcoal is such a value added product which can be prepared from plant and animal waste. Banana waste is an eminently suitable source for producing bio-charcoal. Bio charcoal prepared from waste banana fiber has a wide spectrum of applications. It may be used as fuel, as a supplier of negative ions, in medicine, smoking, warming effect of far infrared rays, water purification, humidity regulation, oxidization prevention, a rich source of minerals and scrubbers to remove oil spills (Lin et al., 2014; Xiang et al. 2014). Biochar production offers a simple, sustainable tool for managing agricultural wastes and it is a powerful simple tool to address some of the most urgent environmental problems (Srinivasan and Sarmah 2015). A combination of waste management, bio energy production and sustainable soil management can be achieved with this approach without any deforestation. Converting agricultural waste into a powerful soil enhancer with sustainable bio-char preserves plant diversity. It retains nitrogen and may be reduced emissions of nitrous oxide leading to greenhouse effect. Turning agricultural waste into bio-char also reduces methane (another potent greenhouse gas) generated by the natural decomposition of the waste. It is a soil enhancer, makes soil more fertile, boosts food security and reduces the need for some chemical and fertilizer inputs. In addition to that, bio-char improves water quality by helping to retain nutrients and agrochemicals in soil for use by plants and crops, resulting in less pollution. Production of wood charcoal is the main problem for deforestation. Therefore utilization of waste for preparing charcoal is eco-friendly value addition. The present work aims at examining the physicochemical properties of the fibers extracted from the waste pseudo stems of five most commonly available banana varieties and studying the possibility of preparing banana fiber charcoal using the mixture of said varieties. The mixture of stems was used for the present investigation since differentiation of banana waste collection is not feasible for commercial application and mass scale production. Results from these studies will be of use in countries where banana cultivation is wide spread and where pseudo stems remain an agricultural waste.

2. Materials and methods 2.1. Materials Four cultivars of dessert bananas grown in Sri Lanka, namely ‘Ambun’ (Cavendish AAA), ‘Ambul’ (Mysore AAB), ‘Kolikuttu’ (Silk AAB), ‘Seenikesel’ (Pisang Awak ABB), and one cultivar of cooking plantains ‘Alukesel’ (ABB) (Hirimburegama et al. 2004) were selected for this study. Variety Cavendish AAA is commonly grown in many countries (Oliveira et al. 2007). 2.2. Methodology 2.2.1. Extraction of banana fibers Banana pseudo stems from the above five varieties were collected from a local plantation and fiber was extracted by the following method. First, the dried and damaged outer sheath parts were removed from the banana pseudo stems. The resulting stem was cut into chunks approximately 90 cm in length and the inner leaf sheath stripped off. The stripped sheaths were passed through a fiber extracting machine to separate the fibers. The extracted fibers were sun dried for 48 hours until it is completely dried. The fiber extraction process is schematically presented in Figure 1. 2.2.2. Preparation of banana fiber charcoal Two varieties of banana fibers (Cavendish AAA, Mysore AAB) were boiled in 2% borax solution (1:10 ratio) at 100°C for 2 hours. Fibers were drained from the solution and carbonized at 350°C in an open air. This procedure was repeated for the mixture of five aforesaid banana varieties.

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Remove dried and damaged outer sheaths from banana pseudo stems

Cut into chunks of approximately 90 cm in length

Strip out the inner leaf sheaths

Separate fiber from the sheaths using fiber extracting machine


Sun-dry the extracted fiber until it is completely dried for 48 hours Figure 1. Schematic diagram of banana fiber extraction process.

2.3. Characterization Fibers extracted from the pseudo stems of the five banana varieties and banana charcoal prepared as described in Section 2.3 were characterized using FTIR, SEM, XRD and DSC. 2.3.1. FT-IR spectroscopic analysis FT-IR spectroscopy was used to investigate the changes in functional groups in the banana fiber as well as banana charcoal. A Bruker TENSOR 27 spectrophotometer was used to provide the spectrum of each sample. Spectra were taken at a resolution of 4 cm−1, with a total of 16 scans for each sample. The FT-IR spectrum of each sample was taken in the range of 4000–600 cm−1 in the transmission mode. 2.3.2. Scanning electron microscopy (SEM) The surface morphologies and the cross-section of the banana fibers and the surface morphology of charcoal were examined at 21 kV by using LEO 1420 VP model scanning electron microscope. The specimens were coated with a thin gold layer using Sputter Coater to avoid electrical charge accumulation during examination. 2.3.3. X-Ray powder diffraction (XRD) analysis XRD measurements were performed using a Rigaku Ultima IV system. The diffracted intensity of Cu Kα radiation (0.154 nm, 40 kV, 30 mA) was measured in a 2θ range between 5° and 120°. The crystallinity index (Icr) was calculated using the Buschle-Diller and Zeronian equation (Guimarães et al. 2009) [Eq. (1)]: Icr ¼ I Imin =Imax

(1)

where Imin is the intensity at the minimum of the crystalline peak (18◦