Cellulose Fiber Isolation and Characterization from Sweet Blue Lupin Hull and Canola Straw

In this study, cellulose fibers were removed from crop by-products using a combination of sodium hydroxide treatment followed by acidified sodium chlorite treatment. The objective was to obtain high recovery of cellulose by optimizing treatment conditions with sodium hydroxide (5–20%, 25–75 °C and 2–10 h) followed by acidified sodium chlorite (1.7%, 75 °C for 2–6 h) to remove maximum lignin and hemicellulose, as well as to investigate the effect of lignin content of the starting materials on the treatment efficiency. Samples were characterized for their chemical composition, crystallinity, thermal behavior and morphology to evaluate the effects of treatments on the fibers’ structure. The optimum sodium hydroxide treatment conditions for maximum cellulose recovery was at 15% NaOH concentration, 99 °C and 6 h. Subsequent acidified sodium chlorite treatment at 75 °C was found to be effective in removing both hemicellulose and lignin, resulting in higher recovery of cellulose in lupin hull (~?95%) and canola straw (~?93%). The resultant cellulose fibers of both crop by-products had increased crystallinity without changing cellulose I structure (~?68–73%). Improved thermal stabilities were observed with increased onset of degradation temperatures up to 307–318 °C. Morphological investigations validated the effectiveness of treatments, revealing disrupted cell wall matrix and increased surface area due to the removal of non-cellulosics. The results suggest that the optimized combination of sodium hydroxide and acidified sodium chlorite treatments could be effectively used for the isolation of cellulose fibers from sweet blue lupin hull and canola straw, which find a great number of uses in a wide range of industrial applications.     

Lignin Functionalized by Thermally Curable Propargyl Groups as Heat-Resistant Polymeric Material

Lignin was chemically functionalized via Williamson etherification reaction with propargyl bromide to prepare a thermosetting bio-resin, propargyllignin. The optimum reaction conditions were found at 70?°C for 4?h under the catalysis of sodium hydroxide in the ethanol solution. The propargllignin resin had highly improved processing capability, evidenced by good solubility, low melting point (<100?°C) and thermal curability. Upon heating, propargyllignin resin solidified with an exotherm around 180?C280?°C peaking at 240?°C, implying its thermal cure reaction via ethynyl polymerization. Compared with lignin feedstock, the propargyllignin resin showed much higher thermal properties: an onset decomposition temperature of 410?°C and a residue yield of 58?% at 800?°C (for lignin, onset decomposition temperature of 250?°C and residue yield of 34?%). Different from the lignin feedstock, propargyllignin was readily applied as curable thermosetting resin for composite matrix, and exhibited high mechanical and thermal properties.     

Solidification/stabilization of ash from medical waste incineration into geopolymers

In the present work, bottom and fly ash, generated from incinerated medical waste, was used as a raw material for the production of geopolymers. The stabilization (S/S) process studied in this paper has been evaluated by means of the leaching and mechanical properties of the S/S solids obtained. Hospital waste ash, sodium hydroxide, sodium silicate solution and metakaolin were mixed. Geopolymers were cured at 50 °C for 24 h. After a certain aging time of 7 and 28 days, the strength of the geopolymer specimens, the leachability of heavy metals and the mineralogical phase of the produced geopolymers were studied. The effects of the additions of fly ash and calcium compounds were also investigated. The results showed that hospital waste ash can be utilized as source material for the production of geopolymers. The addition of fly ash and calcium compounds considerably improves the strength of the geopolymer specimens (2–8 MPa). Finally, the solidified matrices indicated that geopolymerization process is able to reduce the amount of the heavy metals found in the leachate of the hospital waste ash.     

Anaerobic Biodegradation of Poly (Lactic Acid) Film in Anaerobic Sludge

The anaerobic biodegradation rates of four different sizes of poly (lactic acid) (PLA) films (thickness 25???m) in anaerobic sludge at 55?°C were examined. The anaerobic biodegradation rates of small pieces of PLA film were slower than for large pieces of PLA film. We also examined whether PLA film could also be used as a reference material in the anaerobic biodegradation test in addition to PLA powder. The anaerobic biodegradation rate of PLA film became slower with lower activity sludge, but the rate of decrease was gradual, and the anaerobic biodegradation rate of PLA film was faster than the PLA powder (125?C250???m). The anaerobic biodegradation rate of the PLA powder (125?C250???m) reflected the plastic anaerobic biodegradation activity of the sludge more accurately than the thin PLA film (thickness 25???m). Consequently, PLA powder (125?C250???m) is more suitable than thin PLA film (thickness?<?25???m) for use as a reference material to assess the plastic anaerobic biodegradation activity of the sludge in an anaerobic biodegradation test at 55?°C.     

Pyrolysis of municipal plastic wastes II: Influence of raw material composition under catalytic conditions

In this work, the results obtained in catalytic pyrolysis of three plastic waste streams which are the rejects of an industrial packing wastes sorting plant are presented. The samples have been pyrolysed in a 3.5 dm(3) reactor under semi-batch conditions at 440 °C for 30 min in nitrogen atmosphere. Commercial ZSM-5 zeolite has been used as catalyst in liquid phase contact. In every case, high HHV gases and liquids which can be useful as fuels or source of chemicals are obtained. A solid fraction composed of the inorganic material contained in the raw materials and some char formed in the pyrolysis process is also obtained. The zeolite has shown to be very effective to produce liquids with great aromatics content and C3-C4 fraction rich gases, even though the raw material was mainly composed of polyolefins. The characteristics of the pyrolysis products as well as the effect of the catalyst vary depending on the composition of the raw material. When paper rich samples are pyrolysed, ZSM-5 zeolite increases water production and reduces CO and CO(2) generation. If stepwise pyrolysis is applied to such sample, the aqueous liquid phase can be separated from the organic liquid fraction in a first low temperature step.     

Effects of Sodium Bisulfite on the Physicochemical and Adhesion Properties of Canola Protein Fractions

This study focused on investigating the potential of using canola protein fractions as bio-degradable wood adhesives. Native and sodium bisulfite (NaHSO₃)-modified canola protein fractions isolated successively at different pH values (7.0, 5.5, and 3.5) was used as adhesives. Wood specimens were assembled with adhesives at a pressure of 2?MPa at 150, 170, or 190?°C for 10?min. The adhesion performance of adhesives were evaluated by wet, soak, and dry shear strength. Their physicochemical properties: extractability, electrophoresis profiles, thermal, rheological and morphological properties were also characterized. Results showed that canola protein had the highest protein yield and purity at pH 5.5. Electrophoresis profile proved that NaHSO₃ cleaved the disulfide bonds in canola protein. This could induce extra charges (RS-SO₃ ^?) on the protein surface, leading to the reduced apparent viscosity. Thermal analysis implied that the thermal transition temperature of canola protein decreased with modification of NaHSO₃. Canola protein adhesives showed excellent dry and soak shear strength with 100?% wood cohesive failure in all curing temperatures. The wet adhesion strength of native and modified canola protein fraction adhesives at pH 5.5 and pH 3.5 (3.9?C4.1?MPa) was higher than the fractions at pH 7.0. NaHSO₃ had insignificant effects on the adhesion performance of canola protein adhesives but notably improved the handling and flow-ability properties of canola protein adhesives.     

Synthesis of zeolite from Italian coal fly ash: Differences in crystallization temperature using seawater instead of distilled water

In this study Italian coal fly ash was converted into several types of zeolite in laboratory experiments with temperatures of crystallization ranging from 35 up to 90 °C. Distilled and seawater were used during the hydrothermal synthesis process in separate experiments, after a pre-treatment fusion with NaOH.The results indicate that zeolites could be formed from different kind of Italian coal fly ash at low temperature of crystallization using both distilled and seawater. SEM data and the powder patterns of X-ray diffraction analysis show that faujasite, zeolite ZK-5 and sodalite were synthesized when using both distilled and seawater; zeolite A crystallized only using distilled water. In particular the experiments indicate that the synthesis of zeolite X and zeolite ZK-5 takes place at lower temperatures when using seawater (35 and 45 °C, respectively). The formation of sodalite is always competitive with zeolite X which shows a metastable behaviour at higher temperatures (70–90 °C).The chemical composition of the fly ash source could be responsible of the differences on the starting time of synthesized zeolite with distilled water, in any case our data show that the formation of specific zeolites takes place always at lower temperatures when using seawater.     

Pore structure and adsorption properties of carbonized material prepared from waste paper

We have already reported the adsorptivity and pore structure of activated carbon made from waste newspaper in order to use the waste paper for purposes other than paper-making stock. However, manufacturing the activated carbon may not necessarily be an advantageous method based on environmental concerns and the effective use of the resource because the reaction during the activating process is endothermic and the amount of carbon consumed is significant. Here, we examine the pore structure and adsorption properties of waste newspaper used as an adsorbent in the form of a carbonized material. Waste newspaper was carbonized for 2 h in the temperature range 400°–1000°C. The specific surface area of the carbonized material obtained, 418 m²/g, was highest for the sample carbonized at 800°C, which was equal to or greater than that of commercially available charcoal. Moreover, the iodine adsorption number of 581 mg/g was the highest and the rate of adsorption was the fastest for the sample carbonized at 800°C. However, the humidity control capability was highest for the material carbonized at 600°–700°C. It has been determined that it is advantageous to carbonize waste paper at 800°C in order to use the carbonized material as an adsorbent, while carbonization at 600°–700°C is more advantageous for use as a humidity control material. Received: June 23, 2000 / Accepted: January 17, 2001     

Production of hydrogen by steam gasification of dehydrochlorinated poly(vinyl chloride) or activated carbon in the presence of various alkali compounds

Steam gasification of dehydrochlorinated poly(vinyl chloride) (PVC) or activated carbon was carried out in the presence of various alkali compounds at 3.0 MPa and 560°C–660°C in a batch reactor or in a semi-batch reactor with a flow of nitrogen and steam. Hydrogen and sodium carbonate were the main products, and methane and carbon dioxide were the minor products. Yields of hydrogen were high in the presence of sodium hydroxide and potassium hydroxide. The acceleration effect of the alkali compounds on the gasification reaction was as follows: KOH > NaOH > Ca(OH)₂ > Na₂CO₃. The rate of gasification increased with increasing partial steam pressure and NaOH/C molar ratio. However, the rate became saturated at a molar ratio of NaOH/C greater than 2.0.     

Thermo-chemical extraction of fuel oil from waste lubricating grease

This study investigated the recovery of oil from waste grease through the process of thermal degradation in an aqueous solution of potassium hydroxide (KOH) followed by solvent extraction. Waste high temperature metal bearing grease was dissolved in a 15 w/w% KOH solution at 80 °C while being agitated at 2000 rpm using a shear action agitator for a period of 15 min. Two distinct layers were observed after 8 min of settling time. The top layer being of dark brown oil and the bottom layer was a heterogeneous mixture. The two layers were separated by decantation. The bottom layer was cooled down to 45 °C followed by slow addition of toluene (C₇H₈) while agitating at 1200 rpm for 15 min to prevent solids settling and minimise rapid volatilisation of the organic compounds in the mixture. Two distinct layers were also formed, the top homogeneous mixture of light brown oil–toluene mixture and the bottom sludge layer. The solvent was recovered from the oil for re-use by fractional distillation of the homogenous mixture. It was observed that 15 w/w% potassium hydroxide solution can chemically degrade the soap matrix in the grease and extract up to 49 w/w% of the fuel oil when subjected to high shear stress at a temperature of 80 °C. The 26 w/w% extraction of oil in the remaining sludge was obtained by solvent extraction process with mass ratios of sludge to solvent of 2:1. Solvent recovery of 88% by mass was obtained via fractional distillation method. The combined extraction processes brought an overall oil yield of 75 w/w% from the waste grease. The fuel oil obtained from this process has similar properties to paraffin oil and can be blended with other oils as an alternative energy source.     

Synthesis of zeolite from waste fly ash for adsorption of CO2

Zeolitic sorbents for CO₂ adsorption were prepared from waste coal fly ash (FA) through hydrothermal treatment at various ratios of NaOH/FA and NaAlO₂/FA, including an initial alkali fusion step. The fusion step decomposed the fly ash into very small amorphous particulate zeolite forms. The fly ash was converted to Na-P1 type with a NaOH/FA ratio of 0.5 and Na-A type with a NaAlO₂/FA ratio of 0.53. The product properties were affected by the reaction temperature: Na-P1 and Na-A types were formed at 100°C. Temperatures above 140°C led to the formation of more sodalite because of the redissolving and recrystallization of zeolite crystals. Alkali metal and alkaline earth metal cations were impregnated in the synthesized Na-P1 and Na-A zeolite through an ion-exchange method. The completed zeolitic sorbents were applied to the adsorption of low-level CO₂. As a result of the experiments, calcium ions were found to be the best for CO₂ adsorption owing to their electrostatic behavior and acid-base interaction.     

Recovery of glass fibers from glass fiber reinforced plastics by pyrolysis

Fiber-reinforced plastic sheets containing unsaturated polyester cross-linked with styrene, CaCO₃ and glass fibers as fillers were pyrolyzed in a helium and steam atmosphere in order to recover glass fibers and valuable organic pyrolysis products. Glass fibers were separated from CaCO₃ and CaO by dissolving calcium salts in hydrochloric acid. Residual organic material was burnt afterwards. Best results were obtained at a pyrolysis temperature of 600 and 700 °C, resulting in a large liquid fraction high in styrene, leaving little residual organic material on the surface of the glass fibers. At a pyrolysis temperature of 500 °C, the degradation of the polymer matrix was incomplete, and at 900 °C, glass fibers were destroyed in the presence of CaO, leaving CaSiO₃ as a product.     

Steam gasification of epoxy circuit board in the presence of carbonates

To recover useful metals from end-of-life electronic devices and to convert plastic components from these devices into clean fuel gas, steam gasification of epoxy board samples was carried out at 600–700?°C and 0.1?MPa pressure in the presence of a ternary eutectic carbonate (lithium carbonate, sodium carbonate, and potassium carbonate). Hydrogen and carbon dioxide were the main products, and methane and carbon monoxide were detected as minor products. The gasification proceeded in two steps: an initial rapid pyrolysis followed by secondary steam gasification of char produced from the pyrolysis. The ternary eutectic carbonate accelerated not only the latter steam gasification but also the initial rapid pyrolysis. The activation energy for the steam gasification of epoxy board samples in the presence of the carbonate was 122?kJ/mol.     

Tar and soot generation behaviors from ABS,PC and PE pyrolysis

In this study we performed a non-isothermal thermogravimetric analysis on three thermoplastics—ABS, PC and PE. The Coats and Redfern method (Nature 201:68–69, 1964) was then used to approximate the kinetic parameters of each material. In addition, we performed a series of pyrolysis experiments in a batch reactor, for each plastic. The experiments were performed over the temperature range of 600–1000 °C at a constant residence time. The liquid and solid products of the pyrolysis, were collected, separated and weighted. Those products were categorized as soot, tar and char (PC only), and their relative weight to initial sample weight (DAF) was plotted against the temperature. The tar measured was exclusively medium to high molecular weight (>80 g/mol). Results revealed that relative tar and soot production, for all three materials, first increases and then decreases with temperature increase. The maximum achieved tar yields for ABS, PC and PE were at 700, 650 and 800 °C, respectively; and the maximum soot yields were at 1000, 1000, 950 °C, respectively.     

Preparation of zeolitic material with simultaneous removal of NH4 + and PO4 3− from paper sludge ash via acid leaching

This study investigates the preparation of zeolitic material with removal of both NH₄ ⁺ and PO₄ ^3? from paper sludge ash (PSA) via acid leaching. PSA typically has a low Si and high Ca content, owing to the presence of calcite fillers. Acid leaching with 3 M HCl was used firstly to reduce the Ca content of the PSA, whereafter a zeolite-P (Na-P) product with high cation exchange capacity (CEC) was synthesized through reaction with 2.5 M NaOH solution at 80 °C. Ca-P zeolitic products were prepared by Ca-treatment with the leachant that had been in contact with the PSA. The product with high CEC capacity including Na-P could be synthesized from the acid-leached ash, and the high Ca content in the ash could be reduced by extraction of the Ca into the leachant via the acid leaching. The Ca-P zeolitic product could be prepared by Ca-treatment with the solution obtained from neutralization of the leachant with NaOH. This product was capable of removing NH₄ ⁺ and PO₄ ^3? from aqueous solution, simultaneously.     

Tensile Strength, Elongation, Hardness, and Tensile and Flexural Moduli of PLA Filled with Glycerol-Plasticized DDGS

Rapid growth of the biofuel industry is generating large amounts of coproducts such as distillers dried grains with solubles (DDGS) from ethanol production and glycerol from biodiesel. Currently these coproducts are undervalued, but they have application in the plastics industry as property modifiers. The objective of this research effort is to quantify the effects on mechanical properties of adding DDGS and glycerol to polylactic acid (PLA). The methodology was to physically mix DDGS, as filler, with PLA pellets and injection mold the blends into test bars using glycerol as a plasticizer. The bars were subject to mechanical testing procedures to obtain tensile strength, tensile and flexural moduli, elongation to break, and surface hardness of blends from 0 to 90?%, by weight, of plasticized filler. Blends were typically relatively brittle with little or no yielding prior to fracture, and the addition of glycerol enabled molding of blends with high levels of DDGS but did not increase strength. Any presence of filler decreased the tensile strength of the PLA, and 20?C30?% filler reduced strength by 60?%. The 35?C50?% filled PLA had about one-fifth the value for pure PLA; at 60?C65?% filler level, about 10?% tensile strength remained; and over 80?% filler, 95?% of the strength was lost. Over 20?% filler, the tensile modulus decreased. The 35?% plasticized, filled blend yielded about one-half the stiffness as the pure PLA case; flexural modulus trended in the same manner but demonstrated a greater loss of stiffness. Most blends had less than 3?% elongation to break while surface hardness measurements indicated that up to 60?% filler reduced Shore D hardness by less than 20?%. The tensile strength and modulus data are consistent with the findings of other researchers and indicate that the type of filler and amount and sequence of plasticization are secondary effects, and the total PLA displaced is the dominant factor in determining the mechanical strength of the PLA and DDGS blends. Up to 65?% plasticized DDGS filler can be injection molded, and sufficient mechanical strength exists to create a variety of products. Such a novel material provides higher-value utilization of the biofuel coproducts of glycerol and DDGS and maintains the biodegradable and biocompatible nature of PLA.     

Physical characteristics of sintered fly ash aggregate containing clay binders

A comprehensive research has been conducted to explore the influence of sintering on the properties of fly ash aggregate containing clay binders (bentonite and kaolinite). Fly ash aggregate containing clay binders, have been subjected to various sintering temperatures at different durations of 700?C1400?°C and 15?C120?min, respectively. The variation in aggregate properties, viz strength, water absorption, density and shrinkage during sintering, have been determined and discussed. In addition to these, the uniformity of sintering and rate of water absorption of sintered aggregate were also determined. No significant changes in aggregate properties were observed for aggregate sintered up to 900?°C, due to the insufficient sintering temperature range. However, the aggregate properties substantially enhanced for temperature above 1000?°C, which is attributed to the activation of liquid phase sintering. For temperatures between 1000 and 1300?°C, the aggregate with bentonite shows significant increase in shrinkage (30?%), density (density ratio 0.70), higher ten percent fines value (TPFV) (6.13?tonne), reduction in porosity (35?%), and water absorption of 4?%. However, at 1400?°C, the aggregate properties degraded due to the decomposition of mineral phases in bentonite. For aggregates with kaolinite, highest TPFV of 8.5?tonne with lowest water absorption of 2?% have been observed at 1400?°C. The presence of a higher amount of interconnected pores for aggregates sintered between 700 and 1000?°C leads to a higher rate of water absorption and then reduces to 30?% for temperatures between 1200 and 1300 and 1200 to 1400?°C for bentonite and kaolinite aggregates, respectively. This reduction is due to the reduced interconnected pores. Duration of sintering has no impact on the aggregate properties for temperatures up to 800 and 1000?°C for aggregates with bentonite and kaolinite, respectively. However, between 1000 and 1400?°C, there has been considerable improvement in the aggregate properties for increasing duration up to 60?min. In comparison, during sintering, aggregates with bentonite possessed better properties for temperature less than 1000?°C, whereas aggregates with kaolinite exhibited superior properties between 1100 and 1400?°C.     

Debromination of flame-retarded TV housing plastic waste

The thermal stability and degradation kinetics of TV housing plastic and brominated flame retardants were studied by means of thermogravimetry. The effects of the treatment temperature on the removal rate of Br were investigated using a tube furnace reactor under isothermal and vacuum conditions. The results showed that the weight loss of TV housing plastic was divided into two stages: the thermal degradation of brominated flame retardants mainly occurred at 290°–350°C, and the degradation of the high-impact polystyrene resin mainly occurred at 350°–455°C. Nearly 90% of Br can be removed from TV housing plastic when the treatment temperature exceeds 280°C.     

PET from Used Beverage Bottles: A Material for Preparation of Biologically Degradable Copolyesters

Poly(ethylene terephthalate) from used colorless beverage bottles was solvolyzed by ethane-1,2-diol. Hydroxyl end-groups present in the mixture of polyols formed were used to initiate the polymerization of ??-caprolactone (CLO) at 190?°C. Polycondensation (190?°C) of the reaction mixture containing an equilibrium amount of lactone corresponding to the reaction temperature yield an aliphatic?Caromatic copolyester. A variety of copolyesters containing 20?C60?mol. % CLO structural units was prepared. The microstructure of their macromolecules was analyzed using ¹H?NMR spectroscopy. Copolyesters were characterized by thermal analysis and tensile tests and their biodegradation potential was checked by the composting test.     

Investigative studies for inert transformation of toxic chrysotile tailing

In an attempt to find ways to reduce consumption of natural raw material and recycle chrysotile tailing waste (CTW), cordierite ceramics were produced using CTW, kaolin tailing waste (KTW) and waste alumina. Before synthesizing the cordierite ceramics, the inert transformation of CTW was investigated via a thermal treatment. Experimental results indicated that CTW was converted into nonhazardous forsterite and enstatite at temperatures above 1000 °C. The characterizations of the synthesized cordierite ceramics were examined using thermal analyses, X-ray diffraction (XRD), morphological structure analyses, compressive strength measurement, coefficient of thermal expansion (CTE) and toxicity characteristic leaching procedure (TCLP). Thermal analyses indicated that significant weight loss below 900 °C was the release of structural water and gases. XRD indicated that the cordierite became the main crystalline phase at 1350 °C. Compressive strength test indicated that compressive strength of the cordierite ceramics was 260 MPa, and CTE of cordierite ceramics was 2.4 × 10^?6 °C^?1. This technology for the of utilization of CTW and KTW could be used to produce industrial cordierite ceramics, in accordance with the concepts of sustainable development.