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1

Effect of grain size on the physicomechanical properties

Ossia C. V., Big-Alabo A., Ekpruke E. O.

Advances in Manufacturing Science and Technology

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2020

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Vol. 44, nr 4

135--144

EN

In this study, locally available waste coconut (Cocos nucifera) shells (CSs) were investigated as possible replacement for asbestos-based brake pads. The CS-based brake pad was tested for its physicomechanical properties and compared with a commercial brake pad used as control sample. The results showed that (a) an improved interfacial bonding between the CS particles and the binder as the grain size decreases; (b) the 90 μm grain size sample had better physicomechanical properties than the control sample in all tests except the thermal conductivity and stability tests; and (c) the hardness, compressive strength, and density of the CS-based brake pad decreased with increasing grain size, whereas the absorption properties increased with increasing grain size. The study showed that further reduction of the grain size below 90 μm and matrix impregnation with metals of good thermal conductivity could provide significant improvements to properties of the CS-based brake pad.

2

Utilization of coconut shell residual in green roof: hydraulic and thermal properties of expansive soil amended with biochar and fbre including theoretical model

Wang Hao, Garg Ankit, Zhang Xiaoyong, Xiao Yangyang, Mei Guoxiong

Acta Geophysica

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2020

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Vol. 68, no. 6

1803--1819

EN

The study intends to explore hydraulic and thermal properties of expansive soils treated with fbre, biochar and biochar–fbre mix. Both fbre and biochar are derived from coconut shell, which is highly common in coastal regions around the world. Besides, benefts, limitations and engineering feasibility of these geomaterials in green roofs are explored. Theoretical framework for thermal–hydraulic analysis is proposed based on mass conservation and the frst law of thermodynamics. Heat capacity, thermal conductivity, water retention curve, crack intensity factor (CIF) and saturated and unsaturated hydraulic conductivities of four kinds of soils are evaluated and compared. Characterizations of geomaterials are also investigated via thermal mass loss, micro-structure, surface area and functional groups identifcation. Both biochar and fbre admixtures contribute to improvement in soil heat capacity and saturated and unsaturated hydraulic conductivities. Biochar enhances saturated and residual water contents of expansive soil by 10% and 8%, respectively. Also, biochar decreases soil thermal conductivity and CIF by 31% and 5%, respectively, while fbre decreases soil-saturated and residual water contents by 15% and 29%, respectively, and reduces soil thermal conductivity and CIF by 21% and 50%, respectively. Soil–biochar–fbre composite is also recommended due to low air-entry value, acceptable water-holding capacity and limited crack propagation. The study flls the knowledge gap of how soil thermal–hydraulic properties are afected due to biochar and/or fbre admixture. It is recommended to pay more attention on production and utilization of biochar derived from coconut shell currently utilized for fbre extraction.

3

The Use of Coconut Shells for the Removal of Dyes from Aqueous Solutions

Jóźwiak T., Filipkowska U., Bugajska P., Kalkowski T.

Journal of Ecological Engineering

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2018

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Vol. 19, nr 4

129--135

EN

The main purpose of the work was to check the possibility of using coconut shells for the removal of the dyes popular in the textile industry from aqueous solutions. The sorption abilities of an unconventional sorbent were tested against four anionic dyes: Reactive Black 5, Reactive Yellow 84, Acid Yellow 23, Acid Red 18 as well as two cationic dyes: Basic Violet 10 and Basic Red 46. The scope of research included investigation pertaining to the effect of pH on the effectiveness of sorption of dyes, conducted in order to determine the time of equilibrium of sorption and determine the maximum sorption capacity of coconut shells with respect to pigments. The most favorable pH of sorption for the anionic dyes and Basic Violet 10 was pH 3 and for Basic Red 46 – pH 6. The equilibrium time of sorption was the shortest in the case of acidic dyes (Acid Yellow 23/ Acid Red 18 – 45 min), while the longest in the case of alkaline dyes (Basic Red 46 – 90 min, Basic Violet 10 – 180 min). The sorption capacity of coconut shells in relation to anionic dyes was for Reactive Black 5 – 0.82 mg/g, Reactive Yellow 84 – 0.96 mg/g, Acid Yellow 23 – 0.53 mg/g and for Acid Red 18 – 0.66 mg/g. The tested sorbent showed much higher sorption capacity with respect to the cationic dyes, i.e. Basic Violet 10 (28.54 mg/g) and Basic Red 46 (68.52 mg/g).

4

Activated Carbons from the Compressed Plant Materials (Coconut Shell) and Copolymers of Furfural

Kishibayev K. K., Kabulov A. T., Tokpayev R. R., Atchabarova A. A., Yefremov S. A., Voropaeva N. L., Nechipurenko S. V., Nauryzbayev M. K., Tasibekov K. S.

Inżynieria Mineralna

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2016

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R. 17, nr 1

181--188

EN

This paper dwells upon the physical and chemical properties of activated carbons based on compressed plant materials (coconut shell) and on furfural copolymers, the paper also gives the results of their elemental analysis by ICP-MS method, the structure and morphology of the obtained sorbents have been determined by scanning electron microscopy. The specific surface of the obtained activated carbons has shown that a sorbent based on coconut shell has the highest specific surface (Sspecific surface = 1100 m2/g) if compared to the sorbent based on copolymers of furfural (Sspecific surface = 653 m2/g). However, the sorbent based on furfural copolymers has a higher mechanical resistance to abrasion (98%) and a low ash content (0.3%) compared to the indices of the sorbent based on coconut shell (mechanical strength = 92%, ash content = 2.5%). The study of the structure and morphology of the obtained activated carbons has shown that within the structure of the sorbent based on the copolymers of furfural mesopores predominate together with micropores, when in the structure of the sorbents based on coconut shells micropores are mostly predominant. The elemental analysis of the adsorbents has shown that they are mainly composed of carbon, but there were also some trace amounts of some other elements.

PL

Artykuł dotyczy fizycznych i chemicznych właściwości aktywnego węgla z materiałów roślinnych (łupiny kokosowe) oraz kopolimerów z furoaldehydu. Ponadto przedstawiono w artykule wyniki ich składów pierwiastkowych uzyskanych za pomocą metody ICP-MS a także struktury i morfologii otrzymanych sorbentów za pomocą elektronowego mikroskopu skaningowego. Powierzchnia właściwa otrzymanego aktywnego węgla wykazała, że sorbent bazujący na skorupach kokosowych ma największą powierzchnię właściwą (Sspecific surface = 1100 m2/g) porównując ją z sorbentem opartym na kopolimerach z furoaldehydu (Sspecific surface = 653 m2/g). Jednakże, sorbent oparty o kopolimery z furoaldehydu mają większą odporność na abrazję (98%) i niską zawartość popiołu (0.3%) w porównaniu do wskaźników sorbentu opartego o łupiny kokosowe (wytrzymałość mechaniczna = 92%, zawartość popiołu = 2.5%). Badanie struktury i morfologii otrzymanego węgla aktywnego wykazało, że wewnątrz struktury sorbentu opartego na kopolimerach z furo aldehydu jest równie wiele mezoporów, jak i mikroporów, podczas gdy struktura sorbentów bazujących na łupinach kokosowych jest zdominowana głownie przez mikropory. Analiza pierwiastkowa adsorbentów wykazała, że są one głównie złożone z węgla, ale zawierają również nieco śladowych ilości innych pierwiastków.

5

Characterization and feasibility of biomass fuel pellets made of Colombian timber, coconut and oil palm residues regarding European standards

Forero Núnez C. A., Jochum J., Sierra Vargas F. E.

Environmental Biotechnology

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2012

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Vol. 8, No. 2

67--76

EN

Strong correlation between economic development, energy demand and fossil fuels utilization during last decades has caused some negative impacts worldwide, based on it, the renewable resources for energy production should be employed to mitigate these effects. Nowadays, biomass is one of the most prominent renewable sources, but factors such as low density and high moisture content are some drawbacks. In order to overcome these problems, some companies use different types of biomass to provide solid biofuels with higher energy density, mechanical resistance and standardized dimensions. Wood pellet industry has increased exponentially during last years, faster than timber industries; therefore, new raw materials should be evaluated to guarantee pellets demand in the near future. Some of them are agricultural residues. Colombia is a country with an interesting potential for biomass production because there is a rising generation of agricultural products. This work aims to assess main properties of Colombian timber industry residues, coconut shells and oil palm shells and compare the characteristics of pellets made from these raw materials with European standards. Pellets made from these feedstocks have an average density between 850 and 1025kg·m-3, low ash contents and heating values around 18000kJ·kg-1. Coconut shell pellets have low compression ratios and problems during pretreatment; whereas, sawdust, wood shavings and oil palm shell pellets proved to be an attractive opportunity for pellet industry development in Colombia.