Benzylated pulps from sugar cane bagasse

An optimized ethanol/water process has been employed for the pulping of fibres from sugar cane bagasse. After pretreatment with aqueous NaOH, unbleached pulps were subjected to benzylation at 110 °C for different periods of time. The resulting purified products were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), gel permeation chromatography (GPC) and infrared spectroscopy (IR). The results showed that benzylation proceeded to various extents depending on the reaction time, as assessed by weight gain. During the first 3 h, a loss of mass was observed due to the occurrence of benzylation of low molecular weight polyoses, which were eliminated in the purification step. After that period of time a drastic weight increase was observed probably because crystalline regions had developed. The samples with low degrees of benzylation were insoluble, whereas the more benzylated counterparts showed limited solubility in THF. Partially soluble samples and a completely soluble one showed very different GPC elution profiles. This may be attributed to the efficiency of the pre treatment which, in the latter case, employed more concentrated alkali. Thermogravimetric analyses showed that all samples were degraded above 310 °C. Glass transition temperatures ranged between 42 °C and 65 °C, increasing as the extent of benzylation increased This revised version was published online in August 2006 with corrections to the Cover Date.     

Production of ethanol from sugar cane bagasse hemicellulose hydrolyzate byPichia stipitis

The ability ofPichia stipitis to fermentd-xylose andd-glucose in the acid-hydrolyzed hemicellulose component of sugar cane bagasse depends on the alkali used to neutralize the hydrolyzate to pH 6.5. With NH₄OH and NaOH no fermentation occurred, whereas neutralization with Ca(OH)₂ gave the best results (Q_pmax=0.25 g/L-h; Y_p/s =0.38 g/g sugar). However, the volumetric productivity was still considerably less than observed in a semisynthetic medium with a sugar composition similar to the hydrolyzate. L-arabinose was not fermented but assimilated. Sequential neutralization methods failed to improve the fermentation. Acetic acid and lignin derivatives present in the hydrolyzate were major components that inhibited the fermentation.     

Characterization of methylcellulose produced from sugar cane bagasse cellulose: Crystallinity and thermal properties

In the present work, methylcellulose produced from sugar cane bagasse was characterized by FTIR, WAXD, DTA and TGA techniques. Two samples were synthesized: methylcellulose A and methylcellulose B. The only difference in the process was the addition of fresh reactants during the preparation of methylcellulose B. The ratio between the absorption intensities of the C-H stretching band at around 2900 cm⁻¹ and O-H stretching at around 3400 cm⁻¹ for methylcellulose B is higher than for methylcellulose A, indicating that methylcellulose B showed an increase in the degree of substitution (DS). Methylcellulose A presents a more heterogeneous structure, which is similar to the original cellulose as seen through FTIR and DTA. Methylcellulose B showed thermal properties similar to commercial methylcellulose. The modification of methylcellulose preparation method allows the production of a material with higher DS, crystallinity and thermal stability in relation to the original cellulose and to methylcellulose A.     

Efficient carbon adsorbent for hydrogen sulfide produced from sugar cane bagasse

It was found that a carbon-containing adsorbent produced from sugar cane bagasse and activated by oxidative alkaline treatment has rather high adsorption activity towards H₂S     

Pretreatment of sugar cane bagasse for enhanced ruminal digestion

Applied Biochemistry and Biotechnology - Crop residues, such as sugar cane bagasse (SCB), have been largely used for cattle feeding However, the close association that exists among the three major...     

Adsorption of phenol and 2,4-dichlorophenol on carbon-containing sorbent produced from sugar cane bagasse

1. Download : Download high-res image (149KB)
2. Download : Download full-size image

     

Physicochemical characterisation of sugar cane bagasse lignin oxidized by hydrogen peroxide

The oxidation of soda lignin extracted from sugar cane bagasse was studied in acid medium. Soda lignin was precipitated from black liquor by adding (36N) sulphuric acid until the pH of the resultant solution was close to 2. The resultant, dried, material was oxidized using hydrogen peroxide. Soda lignin oxidized at different times was investigated by CHNS and EDX chemical analysis, GPC, FTIR and solid state CP-MAS ¹³C NMR spectroscopy. Oxidation increased the amount of carboxylic groups, while that of associated carbohydrates decreased. In addition, self-condensation with increase of molecular weight was observed.     

Modeling of the hydrolysis of sugar cane bagasse with hydrochloric acid

Sugar cane bagasse was hydrolyzed under different concentrations of hydrochloric acid (2–6%), reaction times (0–300 min), and temperatures (100–128°C). Sugars obtained (xylose, glucose, arabinose, and glucose) and deg-radation products (furfural and acetic acid) were determined. Based on the Saeman model and the two-fraction model, kinetic parameters for predicting these compounds in the hydrolysates were developed. The influence of temperature was studied using the Arrhenius equation. The optimal conditions selected were 128°C, 2% HCl, and 51.1 min. Using these conditions, 22.6g xylose/L, 3.31 garabinose/L, 3.77 g glucose/L, 3.59 g acetic acid/L, and 1.54 g furfural/L were obtained.     

Maximizing the xylitol production from sugar cane bagasse hydrolysate by controlling the aeration rate

Batch fermentations of sugar cane bagasse hemicellulosic hydrolysate treated for removing the inhibitors of the fermentation were performed byCandida guilliermondii FTI20037 for xylitol production. The fermentative parameters agitation and aeration rate were studied aiming the maximization of xylitol production from this agroindustrial residue. The maximal xylitol volumetric productivity (0.87 g/L h) and yield (0.67 g/g) were attained at 400/min and 0.45 v.v.m. (K_La 27/h). According to the results, a suitable control of the oxygen input permitting the xylitol formation from sugar cane bagasse hydrolysate is required for the development of an efficient fermentation process for large-scale applications.     

Effects of pre-irradiation with X-rays on the liquefaction of sugar cane bagasse

In a search for new energy and chemical feedstocks the pre-irradiation of sugar cane bagasse with X-rays before the conversion process has been studied. Different X-ray doses for the pre-irradiation process were used after which the samples were submitted to a liquefaction process. The product obtained was then submitted to a PLC-8 fractionation. It was verified that pre-irradiation to low doses increases the yield of the liquid product obtained. It was also observed that the product quality can be altered by controlling the irradiation process. An increase in the relative concentrations of hydrocarbons and resins as a function of pre-irradiation suggests the potential use of these fibers as feedstocks.     

Pretreatment of sugar cane bagasse hemicellulose hydrolyzate for ethanol production by yeast

The cellulase system ofBacillus circulans F-2 effectively hydrolyzed carboxymethyl cellulose (CMC), xylan, avicel, cellobiose, filter paper, cotton, andp-nitrophenyl-Β-D-cellobioside, and the crude enzyme produced mainly glucose from digestion of avicel. Two major and one minor peaks of enzyme activities were eluted on DEAE ion-exchange chromatography, and designated cellulase complex I(C-I) and complex II(C-II) for the two major peaks, and cellulase-III for a minor peak. C-I and C-II were further purified on gel filtration column of a TSK-Gel SW G3000 ×L. The molecular masses of C-I and C-II were estimated to be about 669 and 443 kDa, respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of the C-I and C-II complexes showed that the C-I complex was present as a multiple protein complex, consisting of at least five CMCases and two xylanases, and that the C-II complex was consisted of at least three CMCase and four xylan ases. C-I showed high activities of cellohydrolase, CMCase, xylanase, and Β-glucosidase, whereas C-II showed high activities of CMCase, xylanase, avicelase, and Β-glucosidase. The outstanding property of the C-II was its high hydrolytic activity toward filter paper, a highly resistant substrate against enzymatic degradation. However, cellulaseIII showed only strong avicelase activity. These results indicated that the cellulase system of the strain exists as multiple complex forms.     

Use of steam explosion liquor from sugar cane bagasse for lignin peroxidase production by Phanerochaete chrysosporium

The possibility of using two by-products of the sugar cane industry, molasses and bagasse steam explosion liquor (SEL), for lignin peroxidase (LiP) production by Phanerochaete chrysosporium was investigated. For comparison, the fungus was initially cultivated in synthetic media containing either glucose, sucrose, xylose, or xylan as sole carbon sources. The effect of veratryl alcohol (VA) was also investigated in relation to the enzyme activity levels. Results showed that sucrose was not metabolized by this fungus, which precluded the use of molasses as a carbon source. Glucose, xylose, and xylan promoted equivalent cell growth. Enzyme levels in the absence of VA were lower than 28 UI/L and in the presence of VA reached 109 IU/L with glucose and 85 IU/L with xylose or xylan. SEL was adequate for P. chrysosporium LiP production as LiP activity reached 90 IU/L. When VA was added to this medium, enzyme concentration increased to 155 IU/L.     

Determination of sugar cane herbicides in soil and soil treated with sugar cane vinasse by solid-phase extraction and HPLC-UV

This work reports on the development and validation of a small-scale and efficient SPE-HPLC-UV method for the simultaneous determination of the most used herbicides (diuron, hexazinone, and tebuthiuron) applied to soil and soil treated with sugar cane vinasse (soil-vinasse) in areas where sugar cane crops are grown in the state of São Paulo, Brazil. The analytical procedure was optimized for solvent extraction and HPLC-UV conditions. Extraction and clean-up were combined in a single step employing solid-phase extraction, avoiding sophisticated techniques, organic-solvent-water mixtures and consequently a longer concentration step. Recovery studies with soil and soil-vinasse samples spiked at two herbicides levels (around 0.25 and 2.0 mg kg⁻¹) and sample stability (sample frozen for 20 days before analysis) were applied as parameters to control the efficiency of the method. Good accuracy and precision were achieved with average recoveries ranging from 78% to 120% and relative standard deviations less than 10% throughout the whole recovery test. The method's limit of detection ranged between 0.025 and 0.050 mg kg⁻¹ for diuron, hexazinone, and tebuthiuron in soil and soil-vinasse. The feasibility of this method was applied to determine the herbicide half-lives (t_1/2) in soil and soil-vinasse in a laboratory study. Sugar cane vinasse added to soil increased the degradation of diuron and tebuthiuron (p < 0.05), reducing the t_1/2 from 80 to 7 days and 128 to 73 days, respectively. This method is presented as an alternative which could be applied to assess herbicide behavior in soil in order to prevent water contamination and to contribute to establish pesticide limits in soil.     

Production of char from vacuum pyrolysis of South-African sugar cane bagasse and its characterization as activated carbon and biochar

The potential of vacuum pyrolysis to convert sugar cane bagasse into char materials for wastewater treatment and soil amendment is the focus of this research paper. Vacuum pyrolysis produces both bio-oil and char in similar quantities. Vacuum pyrolysis has the potential to produce high quality chars for wastewater treatment and soil amendment directly during the conversion process, with no further upgrading required. In the present study, chars with the required porous structure was obtained directly from the vacuum pyrolysis process, making it very efficient as adsorbent both in terms of methylene blue (MB) adsorption with a N₂-BET surface area of 418 m² g⁻¹. Further steam activation of the chars benefited the development of meso- and macroporosity, although this upgrading step was not essential to achieve the required performance of char as an MB adsorbent. The development of large pores during the vacuum pyrolysis favored physisorption of MB, rather than chemisorption. The chemical nature of the vacuum pyrolysis char resulted in a slightly acidic surface (pH 6.56). The biochar from vacuum pyrolysis can be considered as a highly beneficial soil amendment, as it would enhance soil nutrient and water holding capacity, due to its high cation exchange capacity (122 cmol_c kg⁻¹) and high surface area. It is also a good source of beneficial plant macro- and micronutrients and contains negligible levels of toxic elements.     

Characterization of poly(vinyl acetate)/sugar cane bagasse lignin blends and their photochemical degradation

The acetone-soluble lignin fraction (ASLF) of sugar cane bagasse, from a sugar and alcohol factory residue, was obtained after extraction with formic acid and used to prepare blends with poly(vinyl acetate) (PVAc) by casting. PVAc and ASLF/PVAc blends were irradiated with ultraviolet light (Hg lamp). Blend formation and the irradiation effects were examined through thermal analysis (TG and DSC), scanning electron microscopy, and atomic force microscopy. The DSC results show PVAc glass transition temperature (T _g) shifts because of both, irradiation and ASLF incorporation. Non-irradiated pure PVAc presented a smooth surface, while after UV irradiation, light surface spots are observed. ASLF/PVAc 10/90 and 5/95 blends did not exhibit differences before and after UV irradiation, suggesting that lignin protects PVAc from photochemical degradation.     

Radiation and NRSP effect on protein,filtration efficiency and crude fiber degradation after sugar cane bagasse fermentation by mushroom fungi

The upgrading of sugar cane bagasse with natural rubber waste by irradiation and three mushroom fungi was studied in order to produce economical animal feed and mushrooms. The protein concentrations changed a little at 0, 1% of NRSP but greatly increased at 5% NRSP concentration with irradiation and nonirradiation in liquid fermentation. The filtration rate decreased at 5% NRSP concentration after liquid fermentation but it increased by 2.7, 10.2, 11.1 times with irradiation for P. sajor-caju, C. phlytidosprorus and P. flavellatus. The amounts of crude fiber were decreased due to the irradiation and the different concentration of NRSP after 42 days of solid fermentation by P. sajor-caju.     

Inkjet application, chromatography, and mass spectrometry of sugars on nanostructured thin films

Ultrathin-layer chromatography (UTLC) potentially offers faster analysis, reduced solvent and sample volumes, and lower costs. One novel technique for producing UTLC plates has been glancing angle deposition (GLAD), a physical vapor deposition technique capable of aligning macropores to produce interesting separation properties. To date, however, GLAD-UTLC plates have been restricted to model dye systems, rather than realistic analytes. This study demonstrates the transfer of high-performance thin-layer chromatography (HPTLC) sugar analysis methods to GLAD-UTLC plates using the office chromatography framework. A consumer inkjet printer was used to apply very sharp low volume (3–30 nL) bands of water-soluble analytes (lactose, sucrose, and fructose). Analytic performance measurements extrapolated the limits of detection to be 3–5 ng/zone, which was experimentally proven down to 60–70 ng/band, depending on the sugar. This qualitative analysis of sugars in a commercially available chocolate sample is the first reported application of GLAD-UTLC to food samples. The potential utility of GLAD-UTLC is further exemplified by successful coupling with electrospray ionization mass spectrometry for the first time to characterize underivatized sugars.

Studies on polymers and composites from lignin and fiber derived from sugar cane

Sugarcane fiber (i.e. bagasse) lignin has a larger fraction of aromatics unsubstitution in the ortho position than hardwood or softwood lignin and hence has the greater ability to be derivatized. Furthermore, organosolv lignin has a higher purity than sulfonated and kraft lignins. This work examines the purification of organosolv lignin derived from bagasse and the physico‐chemical properties of the lignin and lignin‐phenol formaldehyde (PF) resin coatings, and composites. The wetability tests have shown that lignin and lignin‐PF resin films are effective water barrier coatings, though the contact angles of lignin‐PF resin films were considerably less than the wax films. The overall mechanical properties (i.e. peak stress, peak strain and modulus) of the bagasse fiber composites were lower than the values obtained with the composites without the inclusion of bagasse fiber. Copyright © 2007 John Wiley & Sons, Ltd.     

Solvent dependent fabrication of bifunctional nanoparticles and nanostructured thin films by self assembly of organosilanes

Designing the self-configured framework of nanoporous lattices, to assemble bifunctional nanomaterials on solid substrates, retaining the well-defined nanogeometry is the chief objectives of the present study. Organofunctionalised alkoxysilanes (3-aminopropyltrimethoxysilane (APTMS), 2-(3, 4-epoxycyclohexyl) ethyltrimethoxysilane (EETMS)) containing the functional groups, amino, epoxy, hydroxyl etc., are the potential candidates for the fabrication of nanostructured and monolayered assembly of mono (PdNPs) and bimetallic (Au@PdNPs, Ag@PdNPs) nanomaterials, via sol–gel processing, in aqueous and non-aqueous media with thickness in the range 6–8?nm. The interactions between the silane coupling agents are studied using dynamic light scattering (DLS) technique. The range of hydrodynamic radii (R_H) in different solvents is attributed to the multistage directional alignment of colloidal solutions of alkoxysilane functionalized nanomaterials on solid substrates. The difference in the tendency of the formation of aggregate structures is a function of solvent, critical micelle concentration (CMC) of the surfactant. 2-propanol based colloidal dispersions of nanoparticles are exceptionally more homogenously dispersed and have relatively lower z-average values, as the possibility of cluster formation is reduced. The micellar behavior of APTMS and reactivity of EETMS directs the formulation of the stable and catalytically dynamic nanomaterials. The sensitivity of monolayer deposition lies with the water content of the micellar solution, therefore uniform coating is promised by employing nonaqueous solvents (0.66?nm) which tend to slowdown the rate of condensation. Pore diameter and overall architecture are achieved due to less branched structures of the EETMS and APTMS, which are acting as scaffolds for thin film fabrication, and relative rates of evaporation of solvents.

Open image in new window

     

Reactivity of sugar cane bagasse as a natural solid phase extractor for selective removal of Fe(III) and heavy-metal ions from natural water samples

This work introduces the feasibility of using sugar cane bagasse (SCB) – a sugar cane industry waste – as a selective solid phase extractor for Fe(III). The order of metal uptake capacities in μmol g^?1 for the extraction of six tested metal ions from aqueous solution using static technique is Fe(III) > Cu(II) > Pb(II) > Zn(II) > Cd(II) > Co(II). Since SCB exhibits remarkable binding characteristics for Fe(III), special interest was devoted for optimizing its uptake and studying its selectivity properties under static and dynamic conditions. In this respect, batch experiments were carried out at the pH range 1.0–4.0, initial concentration of metal ion (10–100 μmol), weight of phase (25, 50, 75, 100, 125 and 150 mg) and shaking time (10, 30, 45, 60, 90, 120 and 150 min). FT-IR spectra of SCB before and after uptake of Fe(III) were recorded to explore the nature of the functional groups responsible for binding of Fe(III) onto the studied natural biosorbent. The equilibrium data were better fitted with Langmuir model (r² = 0.985) than Freundlich model (r² = 0.934). Moreover, Fe(III) sorption was fast and completed within 60 min. The adsorption kinetics data were best fitted with the pseudo-second-order type. As a view to find a suitable application of SCB based on its unique property as a benign sorbent, it was found that, Fe(III) spiked natural water samples such as doubly distilled water (DDW), drinking tap water (DTW), natural drinking water (NDW), ground water (GW) and Nile River water (NRW) was quantitatively recovered (>95.0%) using batch and column experiments, with no matrix interferences.