Papers by Keyword: Lignocellulosic Fiber

Abstract: This work developed activated carbon loaded lignocellulosic fibers (kraft pulp) by pulp refining process and used them to form activated carbon paper (AC-paper). AC-paper was used for the removal of dye and heavy metal ions from aqueous solutions. In pulp refining process, kraft pulp was mixed with activated carbon using high consistency refiner with the addition of cationic starch as a binder. The effects of cationic starch and activated carbon concentration on AC-paper properties were investigated. Activated carbon amount of 0, 10, 20, 30, 40 and 50%, and cationic starch amount of 0, 0.25 and 0.50% (% by oven dried weight pulp) were examined. The AC-paper was prepared at basis weight of 60±5 g/m². Paper mechanical properties, including density, tensile index, burst index, ring crush index, and tear index, were tested according to ISO 5270. The results show that all paper strength properties declined when the amount of activated carbon was increased. Especially, when the activated carbon content above 30%, paper strength was greatly reduced. The improvement of paper strength was observed when with the cationic starch was added. However, the increased of cationic starch amount from 0.25 to 0.50% showed no significantly difference in paper strength. Paper adsorption of dye (methyl orange, (MO)) and heavy metal ions (zinc and iron) were also studied. The AC-paper prepared from fiber with 50% activated carbon and 0.50% cationic starch provided highest adsorption values of both dye and metal ions from aqueous solutions. In this work, the use of 30% activated carbon and 0.50% cationic starch in pulp refining process was chosen as a suitable condition for the preparation of activated carbon loaded fiber because the activated carbon content above 30% could disrupt paper strength. The fiber obtained from this suitable condition gave the paper with adsorption values of 0.62, 16.38 and 16.72 mg/g for MO, Zn²⁺, and Fe²⁺, respectively. The developed activated carbon loaded lignocellulosic fibers could be potentially used for various specialty paper products, such as absorbent paper, filter paper and active packaging, in the future.

Abstract: Lignocellulosic residues obtained after the sustainable harvesting of heart of palm from pejibaye (Bactris gasipaes) palms were managed to produce chopped fibers. These fibers can be used to manufacture agglomerated panels and also as reinforcement in polymer-matrix composites. Polypropylene (PP) is a convenient polymer to be loaded with these residues due to its large applications, including under-the-bonnet applications by the automotive industry. PP-pejibaye composites with 10wt% of fiber mass fraction were manufactured and their creep behavior was studied. The experimental results were suitably described analyzing the variation of the creep modulus fitting the experimental data points to the three-element model where the Kelvin-Voigt element is attached to an independent spring. The results obtained show that the incorporation of the chopped pejibaye fibers to not affect the creep performance of the composite. This behavior is very promising, since untreated fibers were used, meaning that the use of expensive and many times environmentally detrimental fiber surface chemical treatments can be avoided.

Abstract: Lignocellulosic fibers present several advantages over synthetic fibers, such as low cost and biodegradability. In this work the tensile mechanical behavior of as-received and surface treated curaua fibers was analyzed. Mercerization and three different enzyme surface treatments were used. The tensile stress data were analyzed using the Weibull statistical distribution, and SEM was used to characterize the surface modifications caused by the treatments. The results show that mercerization causes an increase of the deformation capacity of the fibers. This result was attributed to the removal of hemicellulose, and to an increase of mobility of the internal fibrils. The increase of NaOH concentration at the alkali solution affects both the surface characteristics and the tensile properties. Solutions with more than 5%wt NaOH degraded the fibers. The enzyme treatments increase the tensile mechanical properties, but also increase their brittleness.

Abstract: In this work, the effect of heat treatment on chemical and crystalline structure of vetiver powder was studied. The vetiver powder was heat treated at 170°C, the temperature below thermal decomposition of hemicellulose, for 2-6 hours. The chemical structure, crystalline structure, and thermal decomposition of untreated and heat-treated vetiver were examined via FTIR spectrometer X-ray diffractometer, and thermogravimetric analyzer, respectively. In addition, the particle size and size distribution, fiber surface, and specific surface area were investigated by particle size analyzer, scanning electron microscope, and BET surface analyzer, repectively. It was founded that some waxes, lignin, and hemicellulose were removed by the thermal treatment. This resulted in smaller particle size of heat-treated vetivers. In addition, moisture content was minimized from 7 to 4 wt% by the treatment. However, removal of those compositions did not influence crystal structure of cellulose and surface functional groups of heat-treated vetiver.

Abstract: Combination of lignocellulosic fiber with thermoplastic is leading to the new areas of research in plastic composite field. Due to the problem of petroleum shortages and encouragement for reducing the dependence on fossil fuel products, thus increased the people interest in maximizing the utilize of renewable materials like kenaf fiber. By adding optimum natural fiber to thermoplastics could provide some cost reduction to the world of plastic industry as well as to dominance the agro-based industry. With a view to identifying the effect of fiber content and effect of coupling agent in kenaf fiber reinforced unplasticized poly (vinyl chloride) (UPVC) composite on the mechanical properties, the fiber and matrix mixture were mixed with poly [methylene poly (phenyl isocyanate)] (PMPPIC) using thermal mixing process followed by compression molding technique for the composite preparation that required for tensile characteristic (ASTM D638). The fiber loading were 10%, 20%, 30%, and 40% in weight. Since the kenaf fiber and UPVC are chemically different, the compatibility and dispersability of kenaf fiber in UPVC can be improved by lowering the surface energy of the fiber to make it less polar, consequently more similar to the plastic matrix. Generally, PMPPIC act as a bonding agent that facilitates the optimum stress transfer at the interface between fiber and matrix which gives an optimal mechanical performance of kenaf fiber reinforced UPVC composites. Meanwhile, the addition of 30% fiber contents with PMPPIC was successful to enhance the tensile properties and the efficiency of PMPPIC was verified using Fourier Transform Infra-Red (FTIR) spectroscopy.

Abstract: In this study lignocellulosic fibers, such as kenaf bast, kenaf core, sugar cane bagasse, cotton, coconut coir, and spruce, which are environment friendly natural materials, were tested for their ability to remove copper, nickel and zinc ions from aqueous solutions. The fibers were analyzed for Klason lignin content, water sorption capacity and dry volume. The fiber with the highest level of heavy metal removal in the separate and mixed solution was kenaf bast.. In the mixed solution kenaf bast, sugar cane bagasse and cotton removed more copper and nickel ion than in the separate solution, and the amounts of removed heavy metal ions were changed in some lignocellulosic fibers, compared to those of the separate solution. In the mixed solution heavy metal ions may compete with one another for sorption sites on the surface of lignocellusic fiber. In kenaf bast to remove heavy metal ions most, Klason lignin content was the second lowest, and water sorption and dry volume were the lowest in all tested lignocellulosic fibers. It showed that removal of heavy metal ions does not correlate with any chemical and physical factors, but may be affected by the cell wall structure of lignocellulosic fibers and how many free phenolic groups in lignin, which are considered as the heavy metal ion binding site, are exposed on the surface of fibers. Cotton, with about 1% Klason lignin, was very low in heavy metal ion removal, while all other fibers containing greater than about 10% lignin did remove heavy metal ions. It showed that even the lignin content of lignocellulosic fibers does not correlate with heavy metal ion removal but lignin does play a role in heavy metal ion removal.

Abstract: Kenaf core was tested for its ability to sorb diesel oil from the pure diesel oil bath and the diesel oil containing water bath after extracting with diethyl ether to remove wax from fiber surface, grinding to disrupt lumen structure and presoaking in water. Oil sorption capacity was the highest as 8.0 g/g in diethyl ether extracted fiber in oil bath, and the lowest as 1.3 g/g in water soaked kenaf core in water bath. Diesel oil sorption capacity was much higher in oil bath than in water bath. In diethyl ether extraction the diesel oil sorption capacity was not changed much in kenaf core, compared to that of control. Also, even after grinding and passing through 20 mesh screen (0.86mm) the diesel oil sorption capacity was almost same. When kenaf core was presoaked in water the oil sorption capacity was decreased to about half of control as 1.3g/g in water bath. Grinding, extracting and water presoaking all contributed to the changes in oil sorption capacity. The results show that if in lignocelluloscic fiber like kenaf core the fiber structure is not disrupted during processing and the intact lumen structure can be kept, the oil sorption capacity may not be affected much by physical and chemical changes.

Abstract: Cotton, a lignocellulosic fiber and environment friendly natural material, was tested for its ability to sorb diesel oil from the pure diesel oil bath and the diesel oil containing water bath. The fiber was ground to disrupt the lumen structure or extracted with diethyl ether to remove wax from cotton. Diethyl ether is an organic solvent and extracts only extractives in the cell wall. Oil sorption capacity was the highest in control as 30.6 g/g in the pure diesel oil bath, and the lowest in ground cotton as 0.8 g/g in the diesel oil containing water bath. Cotton is mainly composed of hydrophilic components and sorb water more easily than oil. As a result diesel oil sorption capacity was much higher in the oil bath than in the water bath. However, after grinding and passing through 20 mesh screen (0.86 cm), wax is preserved but the lumen structure of cotton, of which the fiber length is about 18 mm, is disrupted by grinding and can not hold oil. Therefore, the diesel oil sorption capacity of cotton was decreased significantly to 5.2 g/g in the pure diesel oil bath, and to 0.8 g/g in the water bath, compared to those of control. And because wax is removed but lumen structure is not destroyed after diethyl ether extraction, the diesel oil sorption capacity decreased slightly to 27.7 g/g in the oil bath and to 7.5 g/g in the water. When cotton was presoaked in water, cotton sank during the presoaking process, and so the oil sorption capacity could not be determined. Grinding, extractingand presoaking all contributed to the changes in oil sorption capacity. The most significant change is attributed to the reduction in the particle size of cotton.

Abstract: Kenaf bast, coconut coir, and cotton, which are lignocellulosic fibers and environment friendly natural materials, were tested for their ability to remove copper, nickel, and zinc ions from aqueous solutions according to their physical and chemical changes by solvent extraction. The order of the lignin and xylose content in unextracted fibers is coconut coir>kenaf bast>cotton. The fiber with the highest level of heavy metal removal, however, was kenaft bast. It showed that removal of heavy metals does not correlate with lignin and xylose content. Cotton, with about 1.1% lignin and 0.3% xylose, was very low in heavy metal ion sorption while other two fibers containing lignin and xylose did remove heavy metal ions. It indicates that lignin and xylose play a role in heavy metal ion sorption. Extraction with the various solvents removed different cell wall components and changed the cell wall structure, and thus did change the heavy metal ions removal capacity of lignocellulosic fibers.

Abstract: Kenaf bast, which is lignocellulosic fiber and environment friendly natural material, was tested for its ability to remove copper, nickel and zinc ions from aqueous solutions. The fiber was analyzed for xylose, lignin content, weight loss and dry volume, and extracted with diethyl ether, ethyl alcohol, hot water, or 1% sodium hydroxide to change physical and chemical characteristics of keanf bast. Diethyl ether and ethyl alcohol are organic solvents, which extract only extractives in the cell wall. The weight losses are less than 4.1%, the dry volumes increase up to 0.68 cm3/g, and the changes of lignin content are less than 0.6%. The differences of the heavy metal ions removal capacities are less than 0.05 mg/g, compared to those of control. Hot water and 1% sodium hydroxide remove cell wall components as well as extractives in the cell wall. In addition, during the extraction process the cell wall is swollen by the delamination of cell wall layers, xylose and lignin are exposed. The weight losses increases up to 24.0%, the dry volumes increase up to 1.20 cm3/g, and the changes of lignin content are less than 0.6%. The difference of the heavy metal ions removal capacities of kenaf bast increase up to 0.14 mg/g, and are much higher than those of diethyl ether and ethyl alcohol. The above results show that to increase the heavy metal ions removal capacities, the extraction chemicals may swell the cell wall more than water does and remove the cell wall components as well as extractives to change cell wall chemistry and architecture.