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1.
Corn distillers’ dry grain, corncob powder, hardwood powder, and sugar beet pulp were separately anionized by oxidation with sodium hypochlorite in aqueous solution. Solid reaction products instantly precipitated upon admixing each of the above-oxidized materials with soy protein isolate. Infrared spectra and differential scanning calorimetry supported the hypothesis that soy protein isolate complexed with all of the above-oxidized polysaccharides. Reaction products with either oxidized corn distillers’ dry grain or oxidized sugar beet pulp provided hard, brittle pellets with tensile strengths as high as 9.5 MPa, suggesting that these materials could be viable as biodegradable plastics.  相似文献   

2.
The possibility of utilizing kraft black liquors generated in a paper mill, using Eucaliptus globulus as raw material, for the production of a nitro-humic soil conditioner was studied. Two processes were considered: (1) oxidation of the kraft black liquors with nitric acid; and (2) precipitation of the lignin contained in kraft black liquors with CO2 and further oxidation of this lignin by nitric acid. The second process was more efficient regarding product yield and safety of operation. Screening tests at different operating conditions of the latter process indicate that high quality nitro-humic materials can be obtained.  相似文献   

3.
Soy protein plastics are a renewable, biodegradable alternative to fossil fuel-based plastic resins. Processing of soy protein plastics using conventional methods (injection molding, extrusion) has met with some success. Viscosities of processable formulations that contain soy protein along with the necessary additives, such as glycerol and cornstarch, have not been reported, but are necessary for extrusion modeling and the design of extrusion dies. Resins consisting of soy protein isolate-cornstarch ratios of 4:1, 3:2, and 2:3 were plasticized with glycerol and soy oil, compounded in a twin screw extruder and adjusted to 10% moisture. The effects on viscosity of added sodium sulfite, a titanate coupling agent and recycling were evaluated using a screw-driven capillary rheometer at shear rates of 100–800/s. The viscosities fit a power-law model and were found to be shear thinning with power-law indices, n, of 0.18–0.46 and consistency indices, m, of 1.1 × 104–1.0 × 105. Power-law indices decreased and consistency indices increased with increasing soy protein-to-cornstarch ratio and in the absence of sodium sulfite. Addition of the titanate coupling agent resulted in increased power-law index and decreased consistency index. Viscosities at a shear rate of 400/s decreased with recycling, except for the 4:1 soy protein isolate to cornstarch formulation, which displayed evidence of wall slip. Power-law indices were unaffected by recycling. Viscosities in the tested shear rate range were comparable to polystyrene and low-density polyethylene indicating soy protein plastics are potential drop-in replacements for commodity resins on conventional plastics processing equipment.  相似文献   

4.
Chemical recycling of waste poly(ethylene terephthalate) (PET) using phosphoric acid–modified silica gel as a solid catalyst is reported. Advantageously, microwave irradiation was used to progress the depolymerization of PET. In this study, depolymerization of PET with a small amount of water is suggested as a suitable method. The depolymerized product, terephthalic acid was obtained and assigned by 1H NMR and FT-IR spectroscopy. Finally, over 90 % conversion to terephthalic acid was achieved when waste plastic bottles were treated with the method. This results confirm the importance of the microwave power technique as a promising recycling method for plastic bottles made from PET, resulting in monomer recovery in addition to substantial energy saving.  相似文献   

5.
Photocatalytically-oxidized cross-linked chitosan-glutaraldehyde (CS-GLA) was obtained via irradiation of a simple assemblage of an immobilized layer-by-layer TiO2/CS-GLA system on a glass plate with a 45-W fluorescent lamp. The oxidation process was observed to occur only in the presence of oxygen and TiO2 within 5 cycles (10 h) of irradiation. Characterizations studies of the oxidized cross-linked polymer involving swelling index, pH-potentiometric titration and ionic conductivity measurements, as well as CHN, FTIR, 13C solid-state NMR,UV–Vis DRS and photoluminescence spectroscopy analyses generally indicated that the oxidation led to the formation of carbonyl groups, partial elimination of some un-reacted amino groups and change of visual color to be more brown without altering much of the whole molecular structure of the CS-GLA. This study also indicated that the photocatalytic performance of TiO2/oxidized CS-GLA system was higher than both TiO2/CS-GLA system and TiO2 single layer for the removal of phenol. Moreover, the adsorption effect was extremely negligible and the photodegradation of phenol was mainly due to the photocatalytic process.  相似文献   

6.
Polyethylene terephthalate (PET) waste fibers were initially depolymerized using a glycolysis route in the presence of sodium sulfate as a catalyst, which is a commonly used chemical and ecofriendly as compared to heavy metal catalysts. Good yield of the pure monomer bis(2-hydroxyethylene terephthalate) (BHET) was obtained. Further, to attempt its reuse, the purified BHET was converted to different fatty amide derivatives to obtain quaternary ammonium compounds that have a potential for use as softener in the textile finishing process. The products were characterized by infrared spectroscopy. Application of these synthesized compounds was carried out on cotton fabric; they were evaluated for performance and were found to give good results. The chemicals used during depolymerization and reuse of PET are inexpensive and comparatively less harmful to the environment, and thus offer advantages in the chemical recycling of polyester waste fibers.  相似文献   

7.
Availability and properties of materials for the Fakse Landfill biocover   总被引:1,自引:0,他引:1  
Methane produced in landfills can be oxidized in landfill covers made of compost; often called biocovers. Compost materials originating from seven different sources were characterized to determine their methane-oxidizing capacity and suitability for use in a full-scale biocover at Fakse Landfill in Denmark. Methane oxidation rates were determined in batch incubations. Based on material availability, characteristics, and the results of batch incubations, five of the seven materials were selected for further testing in column incubations. Three of the best performing materials showed comparable average methane oxidation rates: screened garden waste compost, sewage sludge compost, and an unscreened 4-year old garden waste compost (120, 112, and 108 g m−2 d−1, respectively). On the basis of these results, material availability and cost, the unscreened garden waste compost was determined to be the optimal material for the biocover. Comparing the results to criteria given in the literature it was found that the C/N ratio was the best indicator of the methane oxidation capacity of compost materials. The results of this work indicate that batch incubations measuring methane oxidation rates offer a low-cost and effective method for comparing compost sources for suitability of use in landfill biocovers.  相似文献   

8.
Blending soy protein with polyesters using a polyvinyllactam as a compatibilizer successfully made soy protein-based plastics. The polyesters used to produce blends included polycaprolactone (PCL) and Biomax (a commercial biodegradable polyester). The blends were processed by compounding extrusion and injection molding. Blends containing soy protein/Biomax-poly(vinyl alcohol) had tensile strengths ranging from 16–22 MPa, with samples containing larger percentages of the synthetic polymer exhibiting greater strengths. Blends made from soy protein, Biomax, and PCL had tensile strengths ranging from 27–33 MPa. All the blends had high Young's moduli but demonstrated brittle characteristics as evident from their low elongations at break, ranging from 1.8–3.1%. Plastics made from soy protein/polyester blends exhibited low water absorption and had good stability under ambient conditions relative to the plastics made from soy protein alone. Blends made from soy protein flour produced plastics with the lowest water absorption.  相似文献   

9.
A modified sequential mass-suspension polymerization was employed to ensure adequate dispersion of lignin into the monomeric phase. Due to its complex macromolecular structure and low compatibility with styrene, eucalyptus wood-extracted lignin, via a modified Kraft method, was esterified with methacrylic anhydride to ensure organic phase homogeneity into the reaction medium. Infrared spectroscopy showed a decrease in the hydroxyl band, a characteristic of natural lignin (3200–3400 cm?1) and an increase in the characteristic ester band (1720–1740 cm?1) whereas nuclear magnetic resonance measurements exhibited intense peaks in the range from 1.7 to 2.05 ppm (–CH3) and 5.4 to 6.2 ppm (=CH2), related to methacrylic anhydride. Comparatively, the esterified lignin also displayed an increase of its glass transition temperature for 98?°C, related to natural lignin, whose T g was determined to be equal to 91?°C. Styrene/lignin-based polymers exhibited higher average molar masses in comparison to the values observed for polystyrene synthesized with similar amounts of benzoyl peroxide, due to the ability of lignin to act as a free-radical scavenger. Composites obtained with styrene and natural or esterified lignin were successfully synthesized, presenting regular morphology and proper lignin dispersion. Based on a very simple polymerization system, it is possible to enhance the final properties of polystyrene through the incorporation of lignin, which represents an important platform for developing attractive polymeric materials from renewable resources.  相似文献   

10.
Dialdehyde starch (DAS) and zein, a hydrophobic corn protein, were investigated to produce biodegradable plastics with improved water resistance and mechanical properties. In the study, dialdehyde starch and zein ratio, plasticizers, and degree of starch oxidation were examined. Increased molding temperature and level of starch oxidation decreased water absorption of the plastic. Tensile strength and Young's modulus increased with starch oxidation. The biodegradation of starting materials and ground plastic specimens was studied in aerobic soil reactors maintained at 25°C for 180 days. Biodegradation of corn starch, zein, and dialdehyde starch for 180 days produced CO2 equivalent to 64, 63, and 10% of theoretical carbon, respectively. Specimens of molded DAS and zein (3 : 1) plastic showed accelerated CO2 evolution compared to DAS and other raw materials alone. By 180 days, specimens made with starch of low oxidation (1 and 5% oxidized) demonstrated a 60% biodegradation, and specimens with highly oxidized starch (90% oxidized) achieved 37% biodegradation.Paper presented at the Bio/Environmentally Degradable Polymer Society—Third National Meeting, June 6–8, 1994, Boston, Massachusetts.Journal Paper J-15927 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Project No. 3258.  相似文献   

11.
Journal of Material Cycles and Waste Management - Polyamide 66 was efficiently depolymerized and chemically converted by treatment with supercritical MeOH in the presence of glycolic acid. The...  相似文献   

12.
A novel solventless delignification of a defatted Picea glehnii wood flour sample was performed using a TiO2/polyethylene oxide (PEO) photocatalyst system. A cell wall structure of the wood flour was directly observed, showing that its lignin fraction was removed by the photodegradation. The total lignin amount was slightly decreased as compared with that of the pristine sample, and the vanillin formation was confirmed by the 1H-NMR measurement. The TiO2 worked as a radical initiator, and simultaneously acid and aldehyde compounds produced by the PEO photolysis did as an accelerator for the solventless delignification. Although the photocatalyst system showed high delignification activity even for a low molecular lignin model, the delignification of the wood flour sample was confined to the surface. It was found that the suppressed delignification behavior was due to crosslinked structure of lignin.  相似文献   

13.
Chemical modification of soy protein with monomers such as maleic anhydride, glycidyl methacrylate and styrene was accomplished using reactive extrusion technology. Thermal and mechanical properties of the modified soy protein plastics were characterized with differential scanning calorimetry (DSC), a dynamic mechanical analyzer (DMA) and a United Testing System load frame. It was found that the denaturation temperature and the glass transition temperature of soy protein plastic changed. In addition, the tensile properties of modified soy protein plastic improved. Attenuated total reflection Fourier transform infrared (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) were used to characterize the structure of modified soy proteins. A suggestion of the interaction between soy protein and functional group in functional polymers is given. Through the in-situ interaction between the polymer and soy protein plastic, the mechanical properties of the soy protein plastic can be adjusted and controlled.  相似文献   

14.
The green rigid polyurethane (PU) foam has been developed with 100 % soy polyol after optimization of formulation ingredients and lignin has been introduced and isocyanate content reduced in the green rigid PU foam. The cellulosic nanofibers have also been successfully incorporated and dispersed in green rigid PU foam to improve the rigidity. The influence of nano cellulose fiber modification (enzymatic treatment, hydrophobic modification with latex) on the foam density, open cell content, foam raise height, water vapor, and mechanical properties of rigid PU foam were studied. The foamed structures were examined using scanning electron microscopy to determine the cell size and shape due to the addition of cellulosic nanofibers. The odor test were performed to evaluate the odor concentration 100 % soyol based PU foam including lignin and nanofiber and compared to 100 % synthetic based polyol PU foam. The experimental results indicated that the compression and impact properties improved due to the modification of nano cellulosic fibers. The odor concentration level of nanofiber reinforced rigid PU foam reduced significantly compared to 100 % PU foam due to the replacing of isocyanate content. It can be said that with an appropriate combination of replacing isocyanate by lignin and addition of nanofiber, rigid PU foam properties could be improved.  相似文献   

15.
Delignification from the cell walls with a combination of ozone oxidation and dioxane–water extraction using thin sections of a softwood, Japanese cypress (Chamaecyparis obtusa Endl.), was studied to determine its suitability for the production of recyclable cellulose-based materials from wood waste. The visible-light absorption spectra of treated wood sections revealed that delignification from the cell walls with ozone increased with increasing ozonization time. Ozone delignification proceeded from the lumen side toward the middle lamella within the secondary wall of a cell, and it proceeded faster in early wood than in late wood within an annual ring. Mild ozonization for 10–30 min was sufficient for the removal of lignin from the cell walls when sections were extracted with dioxane after ozonization. The results obtained here demonstrate that microspectrometry coupled with the Wiesner reaction is useful for the quantitative analysis of lignin in cell walls.  相似文献   

16.
The dynamics and changes in the potential activity and community structure of methanotrophs in landfill covers, as a function of time and depth were investigated. A passive methane oxidation biocover (PMOB-1) was constructed in St-Nicéphore MSW Landfill (Quebec, Canada). The most probable number (MPN) method was used for methanotroph counts, methanotrophic diversity was assessed using denaturing gradient gel electrophoresis (DGGE) fingerprinting of the pmoA gene and the potential CH4 oxidation rate was determined using soil microcosms. Results of the PMOB-1 were compared with those obtained for the existing landfill cover (silty clay) or a reference soil (RS). During the monitoring period, changes in the number of methanotrophic bacteria in the PMOB-1 exhibited different developmental phases and significant variations with depth. In comparison, no observable changes over time occurred in the number of methanotrophs in the RS. The maximum counts measured in the uppermost layer was 1.5 × 109 cells g dw?1 for the PMOB-1 and 1.6 × 108 cells g dw?1 for the RS. No distinct difference was observed in the methanotroph diversity in the PMOB-1 or RS. As expected, the potential methane oxidation rate was higher in the PMOB-1 than in the RS. The maximum potential rates were 441.1 and 76.0 μg CH4 h?1g dw?1 in the PMOB and RS, respectively. From these results, the PMOB was found to be a good technology to enhance methane oxidation, as its performance was clearly better than the starting soil that was present in the landfill site.  相似文献   

17.
Silicones are well-known useful materials varying in structure, reactivity, and chemical and physical properties, but they all contain a covalent bond between the silicon atom and an organic group. Most common of these polymers are those based on polydimethylsiloxane (PDMS) having a siloxane (Si–O–Si) repeat unit and two methyl groups on each silicon atom. All these polymers are manmade, and the organosilicon linkage is not found in nature. It was therefore erroneously assumed that these polymers do not degrade naturally in the environment. It is the purpose of this review to refute this myth and to describe the degradation processes of PDMS in the environment and any potential ecological impact on the terrestrial, aquatic, and atmospheric compartments. Although it was found that minor degradation takes place by hydrolysis of PDMS to dimethylsilandiol followed by oxidation of the methyl group to aldehyde and ultimately to CO2 by Arthobacter and Fusarium oxysporium schlechtendahl, the major degradation processes are abiotic. High molecular weight PDMS are initially depolymerized by soil hydrolysis of the siloxane bonds to yield organosilanol terminated oligomers. These organosilanols and low molecular weight linear PDMS and cyclics are evaporated into the atmosphere and are oxidized there by hydroxyl radicals to benign silica, water, and CO2.  相似文献   

18.
Size resolved particle composition and nitric acid (HNO3)measurements from the ASEPS'98 experiment conducted in the BalticSea are used to provide observational evidence of substantialgas-particle transfer of oxidized nitrogen (N) compounds in themarine boundary layer. We then focus on the importance ofHNO3 reactions on sea salt particles in determining spatio-temporal patterns of N dry deposition to marine ecosystems.Modelling results obtained assuming no kinetic or chemical limiton HNO3 uptake and horizontally homogeneous conditions withnear-neutral stability, indicate that for wind speeds 3.5 – 10 ms-1 transfer of HNO3 to the particle phase to formparticle nitrate (NO3 -) may decrease the N depositionvelocity by 50%. We extend this research using the CHEM-COASTmodel to demonstrate that, in a sulphur poor environment undermoderate wind speeds with HNO3 concentrations representativeof those found in the marine boundary layer, inclusion ofheterogeneous reactions on sea spray significantly reducesmodelled NO3 - deposition in the near coastal zone.  相似文献   

19.
Lignins in general have been extensively studied, while beech wood lignin in particular is rarely researched. In the present work, Organosolv isolated lignin from beech wood (OBL) has been characterized. The isolation was done by two methods: (a) by using sulfuric acid at 170 °C and a reaction time of 120 min and (b) at a temperature of 180 °C for 240 min. A range of analytical methods were applied including elemental analysis, FT-IR, UV–Vis, 31P NMR, SEC, Pyrolysis-GC/MS and HPLC to gain information about establish the purity, structure, molecular weight, thermal behavior and to determine carbohydrate residues according to the NREL protocol. FT-IR and UV–Vis spectra of OBL revealed expected typical absorptions for lignins. NREL analysis presented a carbohydrate-free lignin fraction which has not been achieved to date. TGA and DSC are used to study the thermal behavior of the isolated lignins and showed a relatively low glass transition temperatures (Tg: 123 °C) and decomposition temperatures of 348 and 381 °C. The pyrograms generated from the pyrolysis–GC/MS at 550 °C consisted mainly of fragments of syringyl, guaiacyl and hydroxyphenyl units, thereby confirming the results of the NMR analysis. Our findings support Organolsolv as an efficient method to isolate pure lignin fractions from beech wood with practical value in industry.  相似文献   

20.
Hydrolytic depolymerization of polyamide waste in water was studied using 0.5 L high pressure autoclave at temperatures of 235, 240, 245, 250 °C and at autogenious pressure 480, 500, 520, and 600 psi (pound per square inch).The reaction rate constant, energy of activation, enthalpy of activation, entropy of activation and equilibrium constant were calculated from the experimental data obtained. The maximum depolymerization (59.2%) of polyamide waste into monomer caprolactum was obtained at 250 °C and 600 psi pressure. The reaction rate constant was obtained on basis of measurement of amine value and residual weight. The depolymerization reaction was found to be pseudo first order with reaction rate constant of the order of 10−3 min−1. The enthalpy, entropy and free energy of activation were recorded as 85.75, −0.1354 and 156.59 kJ mol−1 respectively at the experimental conditions for maximum depolymerization of polyamide waste. The thermodynamic equilibrium constant for this hydrolysis reaction was found to be 2.3 × 10−16.  相似文献   

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