Showing papers in "Journal of Biobased Materials and Bioenergy in 2013"

Activated Carbon from Various Agricultural Wastes by Chemical Activation with KOH: Preparation and Characterization

Abstract: Activated carbons (AC) were prepared by pyrolysis from oil palm empty fruit bunch (EFB), bamboo stem (BS), and coconut shells (CNS) at 800 � C by using potassium hydroxide under nitrogen atmosphere. The influence of temperature and type of agricultural biomass on surface area and morphological properties investigated. Activated carbon produced from BS have a higher specific surface area (1212 m 2 g −1 ) and microporosity percentage than those produced from oil palm EFB, and CNS lies in the range of commercial activated carbons. The morphological analysis of the samples was determined by scanning electron microscopy. The external surfaces are full of cavities and quite irregular as a result of activation. X-ray diffraction analysis showed degree of crystallinity 13.25% in case of AC-BS sample while AC-EFB and AC-CNS showed a crystallinity of 1.68% and 8.19%, respectively.

Spent Coffee Grounds as a Renewable Source of Bioactive Compounds

Abstract: Spent coffee grounds (SCG) are the main residues from the soluble coffee industry. The objective of this work was to evaluate different extraction methods of oil and diterpenes (kahweol and cafestol) from SCG, such as solid–liquid extraction, supercritical extraction or direct saponification, as well as to determine the phenolic composition and antioxidant capacities (by radical scavenging activity, inhibition of linoleic acid oxidation and -carotene bleaching method) of SCG and defatted SCG. Among assayed oil extraction methods, the Soxhlet extraction process recovered the highest oil amounts (26.4%). The free fatty acid profile showed a high content of polyunsaturated fatty acids (50%) for the lipid fraction extracted from SCG by each method used, mainly linoleic and palmitic acids (about 45 and 30%, respectively). SCG was found to be an important source of polyphenolic compounds, showing 255 and 273 mg GAE/g dm in ethanolic extracts from SCG and defatted SCG, respectively, and was active as an antioxidant. The method that reached the highest level of diterpenes (214 mg/100 g SCG for kahweol and 466 mg/100 g SCG for cafestol) was direct saponification compared with the saponification of oil extracted by solid–liquid extraction or supercritical extraction. Finally, the presence of bioactive compounds of SCG identified in this study could be of great interest for the food, cosmetic and pharmaceutical industries, giving added value to a residue generated from instant coffee industrial processing, readily available in large quantities.

Drying, grinding and pelletization studies on raw and formulated biomass feedstock's for bioenergy applications.

Abstract: The United States has an abundant potential of biomass resources that can be used as bioenergy feedstocks; however, biomass in its raw, “as-harvested” form is not necessarily in a format (low bulk density and high moisture content) that meets the needs for the biofuel or bioenergy industry. Both high production and niche crops must be used together to meet the U. S. Department of Energy (DOE)’s goal to supply 36 billion gallons of renewable transportation fuels by 2022. To reach this goal, the United States must use more than just the common biomass sources such as corn stover, switchgrass, and other high production energy crops; it must also find ways to combine additional feedstocks as well. This study shows that the formulation of mixed feedstocks using niche and high production crops can produce feedstocks that meet the uniform format required by industry. Corn stover, switchgrass, lodgpole pine, and eucalyptus were combined during preprocessing followed by densification into pellets, resulting in a denser, higher energy value, more durable feedstock than the average of these fuels individually. This study also compares the energy consumption involved in preprocessing biomass. In the case of grinding energies for both Stage-I and Stage-II processes, corn stover and switchgrass consumed the least at about 19 and 34 kW hr/ton and 11 and 18 kW hr/ton, respectively, whereas the highest was both woody biomass types at about 94 and 43–49 kW hr/ton. The bulk density of pelletized blended feedstock is about 729 kg/m3 and is higher than what corn stover and switchgrass pelletized individually can achieve. The heating values are highest for woody biomass at about 18.37–19.30 MJ/kg and lowest for corn stover and switchgrass, which were both in the range of 16.74–16.97 MJ/kg. From these results, we can conclude that the physical and energy properties of blended feedstocks are better than just individually pelletized herbaceous biomass.

Biochar Derived from Agricultural and Forestry Residual Biomass: Characterization and Potential Application for Enzymes Immobilization

Abstract: Very much attention has been focused on lipases as these enzymes can be used as biocatalysts, allowing a cost effective and environmentally friendly method to efficiently catalyze specific reactions. However, its application at industrial scale is still limited due to several shortcomings including low stability in their native state, inhibition by organic solvents and exhaustion of enzyme activity. To overcome these problems, lipases have been immobilized by several methods onto various supports. In this context, biochar, a low-cost material derived from the pyrolysis of residual biomass, constitutes a promising immobilization support material for enzymes due its suitable physicochemical and structural properties. In this study a complete physico-chemical and mineralogical characterization of biochar derived from pyrolyzed oat hull and pine bark at 300 and 500 � C is presented. In addition, a preliminary study on the immobilization of Candida rugosa lipase using biochar derived from oat hull pyrolyzed at 300 � C is reported. The results obtained showed that the structural and chemical properties of biochar depend on the raw materials used and pyrolysis temperature. The specific surface area (BET) presented a similar trend, increasing with an increase in pyrolysis temperature. High enrichment of trace elements such as Ba, Cr, Cu, V and Zn was detected in biochar from pine bark and was discarded for lipase immobilization purposes. The binding efficiency of lipase was in the range of 40–60%, depending on biochar particle size. The higher enzymatic activity yields were associated to small particle size of oat hull biochar. However, a reduction in Candida rugosa lipase activity yield compared with the free enzyme was obtained.

Effect of Nanosilica and Titania on Thermal Stability of Polypropylene/Oil Palm Empty Fruit Fibre Composite

Abstract: Degradation of polypropylene (PP) composites at elevated temperature for prolonged period has shortened the lifetime of PP composites. Thus, variety of fillers has been incorporated into PP matrix to improve thermal degradation stability. The effects of titania and nanosilica in PP reinforced with oil palm empty fruit bunch fibres (EFB) were investigated in this study. Mechanical properties of the samples were determined before and after thermal ageing. Morphology of the composite with varies fillers composition were analyzed using scanning electron microscope. The introduction of nanosilica into PP/EFB composite filled with titania has increased both the melting and glass transition temperature of PP. Chain splitting in molecular chains reduced with the incorporation of nanosilica and titania into PP and PP/FEB composites. The TGA study has showed that the addition of nanosilica has further enhanced the thermal stability effect of titania in PP/EFB composite. However, both the Izod impact strength and tensile strength of the composite reduced greatly after 20 days of thermal ageing.

Physico-chemical characterization of cellulose extracted from ficus leaves

Abstract: Physico-Chemical Characterization of Cellulose Extracted from Ficus Leaves Kanchireddy Obi Reddy1 ∗, Chidige Uma Maheswari2, and Mukul Shukla1 3 1Department of Mechanical Engineering Technology, University of Johannesburg, Johannesburg 2028, South Africa 2Department of Chemical Engineering Technology, University of Johannesburg, Johannesburg 2028, South Africa 3Department of Mechanical Engineering, MNNIT, Allahabad, UP 211004, India

Biochar as a Partial Replacement of Peat in Pesticide-Degrading Biomixtures Formulated with Different Soil Types

Abstract: Biochar is a source of carbon with physico-chemical and biological properties that allow it to promote microbial growth, to absorb moisture and to improve the adsorption and/or degradation of pesticides. We evaluated the effects of biochar as a partial replacement of commercial peat in the pesticide-degrading biomixtures of a biopurification system known as a biobed. Each biomixture was prepared with one type of soil (clay, trumao and sandy), straw, peat and biochar in different volumetric proportions. In each biomixture, the residual pesticide (atrazine, carbendazim, chlorpyriphos, isoproturon, iprodione and diazinon) concentration, the pH, and the levels of organic carbon (OC) and total Kjeldahl nitrogen (TKN) were measured at the beginning (day 0) and the end (day 40) of the pesticide degradation assay. The obtained results demonstrated that at day 0, the pH of the biomixtures, regardless of soil type, increased incrementally with increasing amounts of biochar, whereas the OC and TKN values remain constant. At the end of the pesticide degradation assay, changes were observed in the biomixtures that demonstrated differences among their pesticide degradation abilities. In general, pesticide degradation was higher in the control biomixtures (without biochar) than in biomixtures prepared with biochar. An exception was the pesticide iprodione, which presented a higher degradation efficicency when biochar was included in the biomixture. Although the use of biochar as a replacement of peat in the biomixtures did not significantly improve pesticide degradation, a decrease in the initial residual concentration of the pesticides was observed. Therefore, biochar may represent an interesting material to replace peat in biomixtures designed to degrade and/or adsorb pesticides.

Lignin Removal from Lignocellulosic Hydrolyzates by Flocculation with Polyethylene Oxide

Abstract: Hydrolyzates produced by pretreatment of lignocellulosic materials contain phenolic and other organics that can be potent inhibitors for fermentation. We found that the application of polyethylene oxide (PEO) causes flocculation and rapid separation of lignin from the hydrolyzates, while preserving the carbohydrates in solution. Flocculation is measured by the turbidity and settling velocity changes. The maximum flocculation was found to depend on the dosage of the polymer, but was independent of the pH of the hydrolyzates (from 2 through 9). At temperatures below 21.5 � C flocculation was absent. The hemicellulose fraction in the supernatants was close to the raw extract showing that flocculation does not remove significant amount of fermentable sugars. Flocculation and clarification with PEO were also demonstrated on large pilot scale batches of 1000 kg of extracts with a 99.5% reduction in turbidity, from 12000 NTUs in the raw extract to 50 NTUs in the filtrate.

Effect of Water Absorption on Mechanical Properties of Sugar Palm Fibre Reinforced Sugar Palm Starch (spf/sps) Biocomposites

Abstract: A novel biocomposite where both natural fibre and matrix are derived from underutilized parts of sugar palm tree was successfully developed. This 100% green materials can lead to solve depletion and non degradable polymer waste disposal problems. Unfortunately, since moisture absorption is a matter of concern in biocomposites, the effect of water absorption on mechanical properties of sugar palm fibre reinforced sugar palm starch (SPF/SPS) composites has been studied. From this investigation, it can be seen that tensile and impact strengths of biocomposites increase with the increase of fibre content. This enhancement indicates the effectiveness of the SPF to act as reinforcement for composites. But the mechanical properties of the biocomposites dropped after being stored for 72 hours at RH = 75%. In general, the weight gain due to water absorption of all biocomposites linearly increased with the increase of square root of immersion time and it tends to be more constant after a 48 h, following a Fickian diffusion process. Furthermore, moisture absorption decreased with the increase of sugar palm fibre (SPF) content. SEM micrographs showed good dispersion and adhesion between sugar palm starch (SPS) and SPF but large cracks appear on the surface of the matrix (SPS) due to water absorption.

Dilute-Acid Hydrolysis of Apple, Orange, Apricot and Peach Pomaces as Potential Candidates for Bioethanol Production

Abstract: Chemical composition of four selected fruit pomaces (agro industrial wastes) was evaluated. The effect of temperature, time, acid concentration and solid:liquid (S:L) ratio on dilute-acid hydrolysis of selected pomaces were investigated using 2(4) factorial and central composite design and optimum hydrolysis conditions were determined. A preliminary study was initiated using apple hydrolysate and the fungus Tricoderma harzianum in order to explore and demonstrate their potential uses in bioethanol production. Chemical composition of pomaces was promising as fermentation media. The highest reducing sugar yield from the optimization step was 31%, 49 /0, 56% and 52% for apple, apricot, orange and peach pomaces, respectively under optimum hydrolysis conditions. Neither furfural nor hydroxmethylfurfural (HMF) were detected in hydrolysates. The highest bioethanol production (1.67 g/L) was obtained in 6 days in a non-static incubator using Tricoderma harzianum pre-grown in minimal medium. It was demonstrated that selected pomaces holds potential for bioethanol production and can be eliminated without being potential waste problem to the environment, with economical return. Although, this work is an initial study in showing the potential of these pomaces and T harzianum in bioethanol production, an extensive study on the optimization of fermentation parameters is recommended for further increase of bioethanol production.

Effect of fibre surface modification on properties of Kenaf/Poly(vinyl alcohol) composite film

Abstract: Kenaf/poly(vinyl alcohol) (PVA) composite films having 5, 10, 15% wt% of fibre loadings were pre-pared via aqueous mixing. The mixture was casted as composite film and it was characterized. Tensile properties, Fourier transform infra-red (FTIR) and morphology analyses were reported. The effect of fibre surface modification on the properties of composite film was investigated in the study. The result of citric acid modification was much better than the traditional mercerization of fibres via sodium hydroxide solution. The biodegradability of the composite films was evaluated by soil burial test. The soil burial test revealed that the modified Kenaf/PVA composite film was biodegradable in nature environment. It achieved the highest ∼ 8.91% reduction after 15 days buried under soil and exposed to environmental condition.

Potential of methane production by thermophilic anaerobic co-digestion of pulp and paper sludge with pig manure.

Abstract: This study investigated the potential of methane production of thermophilic anaerobic co-digestion of diluted pulp and paper sludge (DPPS) with diluted pig manure (DPM). The mixture ratios, that is, pulp and paper sludge (PPS) and pig manure (PM) were mixed with tap water to create slurry with a volatile solid (VS) content of 4% as substrate, respectively. The co-digestion was carried out in a 2 liter reactor tank which was stirred semi-continuously with a five phase organic loading rate (OLR) consequently the contents were being drawn-and-fed daily. This experimental design was operated by a triplicate with steady state operations during a thermophilic condition of 50 � C and a constant solid retention time (SRT) of 10 days. The results demonstrated that the co-digestion of DPPS and DPM mixture ratio (50:50) resulted in higher methane production, specific methane yields (SMY), and soluble chemical oxygen demand (SCOD) removal efficiency. The highest methane content of biogas, SMY, volatile solid (VS) degradation rate and SCOD removal efficiency of 5654 ± 421%, 7158 ± 875 ml-CH4/g-VSadded ,5 574 ± 027% and 8354 ± 632%, respectively, were achieved with process stability. However, it added too high mixture ratio of PM to reduce methane yield and SCOD removal efficiency. This study showed that there was a good potential of PPS and PM on thermophilic anaerobic co-digestion for methane production.

Thermal and mechanical properties of glycerol-based polymer films infused with plant cell wall polysaccharides.

Abstract: Poly(glutaric acid-co-glycerol) films were produced by first synthesizing polymer gels from the uncatalyzed polyesterification of glutaric acid and glycerol in toluene. Residual amounts of starting materials in the gel matrices were determined by gas chromatography (GC) to contain 16.4% glutaric acid and 0.2% glycerol or 0.6% glutaric acid and 15% glycerol, respectively for the 2:1 and 1:2 (glutaric acid:glycerol) molar ratio formulations. The 2:1 (glutaric acid:glycerol) polymer gel formulation was cured with and without the incorporation of lignocellulosic biomass (sugarcane bagasse) or purified plant cell wall polysaccharides (corn fiber gum, pectin, or microcrystalline cellulose) at 135 C for 12 h to form polymer composite films. The 1:2 (glutaric acid:glycerol) gel formulation was cured at 135 C for 24 h. ATR-IR results suggest that the films were completely cured. Heat capacity ( Cp) and glass transition temperature (Tg for all specimens averaged 0.41 (±0.1) J/g∗ C and −14.8 (±2.0) C, respectively. The thermal curves of the polymers showed total degradation for all polymer films at approximately 400 C. The addition of microcrystalline cellulose into the polymer matrix showed a 3-fold increase in tensile strength and Young’s modulus and a two-fold increase in fracture energy when compared to the cellulose-free polymer film made only from a 2:1 molar ratio of glutaric acid to glycerol.

Extraction of rubber (hevea brasiliensis) seeds oil using supercritical carbon dioxide

Abstract: In this study, supercritical carbon dioxide is chosen for the extraction and purification of omega-3 fatty acids from Hevea brasiliensis (rubber) oil because this method is environmental friendly and the extracted oil has improved nutritional and functional values. In addition, extraction using this method also can prevent organic solvent residual inside the extracted oil. During the extraction using supercritical carbon dioxide, the oil yield is increased with the increase of temperature and pressure. The best operating condition is pressure of 30 MPa, and temperature of 80 C giving 21.4714% oil yield. The analysis of fatty acids composition is using gas-chromatography. The extracted rubber seeds oil is converted to fatty acids methyl esters (FAME) make it more accessible for chromatogram analysis. From the analysis, the omega-3 fatty acids inside rubber seeds oil especially alpha-linolenic acid (ALA) is the highest compare to soybean oil and olive oil. Beside this, rubber seeds oil also contains oleic acid which is omega-9 and linoleic acid is omega-6. This is the reason rubber seeds oil can be regard as oleic-linolenic seed oil. Alpha-linolenic acid is the precursor to convert polyunsaturated fatty acids (PUFAs) to docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Oleic acid (Omega-9) has the potential for heart protection and cancer prevention but still in the state of prove. On the other hands, the linoleic acid, the element of omega-6 has the benefits to treat to treat arthritis and autoimmune disease. Therefore, rubber seeds oil has very high potential to be developed into difference products in difference industries such as pharmaceutical, cosmetics, oleochemical and foods.