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Chemical and physical changes are necessary to improve the transport properties of polymeric membranes. Cellulose fiber pulp from Pinus taeda was processed in knives and balls mills in order to reduce the dimensions of the fibers for later application in polysulfone (PSf) membranes. By adding cellulosic fibers in PSf membranes, a composite membrane with improved morphological properties, permeate flux and good resistance to pressure was obtained. The fibers as well as the PSf and PSf/cellulose fibers membranes were morphologically characterized by scanning electron microscopy. Tests of pure water permeate flux were performed with pressure up to 20 bar. The addition of 0.2% (wt) of cellulose fibers in the formation of composite membranes resulted in the elimination of macrovoids, causing an increase in pure water flux (50% ± 10) when pressure was risen. [ABSTRACT FROM AUTHOR]

Abstract: Asymmetric membranes may be used in a broad range of applications such as reverse osmosis, hemodialysis and separation of organic mixtures. In this paper, asymmetric membranes were produced using cellulose acetate (CA) from biomass: newspaper and mango seed. The degree of substitution of CA was 2.65±0.07. Different formulations were used to prepare the CA membranes: CA/dichloromethane/water with and without magnesium perchlorate. The asymmetry of the membranes was characterized by scanning electron microscopy (SEM). Membranes produced with magnesium perchlorate presented higher water vapor flux than those produced without this salt. This difference is due to pore formation in the membrane skin when using magnesium perchlorate. Membrane substructure showed to be a determining factor in ion diffusion experiments. The coefficient of ion diffusion for the membrane of cellulose acetate from mango seed was 1.82×10−8 cm2 s−1 while for the membrane of cellulose acetate from newspaper was 7.43×10−8 cm2 s−1 which similar to the value reported in the literature for commercial CA (8.46×10−8 cm2 s−1). [Copyright &y& Elsevier]

The objective of this work was to evaluate the influence of the oxygen percentage, heating rate, and total gas flow variables in the pyrolysis process of sugarcane straw through thermogravimetric (TG) and differential scanning calorimetry (DSC) analyses. The experimental conditions of oxygen percentage, heating rate, and total gas flow were optimized using the design of experiments and canonical analysis. The investigated conditions show that to optimize the whole pyrolysis process, the best values for carrying out the process are oxygen concentrations and heating rates around the central level of 10%, and 298 K/min, respectively, where the total gas flow, within the studied constrains, was not statistically significant for the pyrolysis process, according to the regression equations. This condition resulted in approximate values of required heat and percent residual residue of 181.74 kJ/kg and 9.89%, respectively. In addition, the percentage of remaining residue decreases as the heating rate decreases and the percentage of oxygen in the gas mixture increases. The optimum oxygen percentage obtained was also validated by carrying out an autothermal fast pyrolysis in a pilot plant scale. Image 1 • TG and DSC analysis for sugar cane straw oxidative fast pyrolysis optimization. • Autothermal oxidative fast pyrolysis. • Optimization of oxidative pyrolysis process with lower energy consumption and appropriate oxygen content. [ABSTRACT FROM AUTHOR]

Abstract: In this work, the viability of recycling newspaper for producing cellulose acetate was tested. Newspaper recycling is extremely important not only for the environment preservation, but also from the economical point of view of aggregating value to this residue. Cellulose acetate was produced from a homogeneous acetylation, and then characterized by FTIR, DSC and TGA. Acetylation times were 48h for as received newspaper (CA48) and 24h for delignified newspaper (CA24), resulting in cellulose diacetate (DS=1.98±0.22) for CA48 and cellulose triacetate (DS=2.79±0.02) for CA24, respectively. Membranes of these materials were produced and characterized according to the previously mentioned techniques and by measurements of water vapor flux, which were compared to membranes of nanofiltration SG from Osmonix®. Results showed that independently of a purification step, it is possible to produce cellulose acetate membranes through the chemical recycling of newspaper and that membrane CA24 presents thermal stability comparable to membranes produced of commercial cellulose acetate. [Copyright &y& Elsevier]

In this work we performed an optimization process of the acetylation reaction of sugarcane bagasse cellulose. The optimization was carried out varying acetic acid, acetic anhydride and catalyst volume, as well as reaction and activation times. Intrinsic viscosity was used as parameter for determining the quality of the produced material. Cellulose acetate viscosity-average molecular weight increased from 5.5×103 to 55.5×103 gmol−1. [Copyright &y& Elsevier]

This study was carried out to determine the prevalence of neosporosis in an area of intensive dairy production, in Portugal. Sera samples were obtained in a random basis from 114 cows in 49 herds (group A), and from 1237 cows in 36 herds with a history of abortion outbreaks (group B). All sera samples were tested for neosporosis by direct agglutination test (DAT). Additionally, attempts to isolate Neospora caninum in 42 aborted bovine fetuses from 38 dairy herds (group C) were carried out, utilizing a bioassay with immuno-depressed Swiss Webster mice. Parasitological confirmation was done by indirect fluorescent antibody test (IFAT). The prevalence of neosporosis in the group A was 28%. Group B had a significantly (P<0.001) higher prevalence (46%) and Neospora caninum was isolated in 36% of the aborted fetuses (group C). These results indicate that neosporosis, a disease only recently (2001) diagnosed in Portugal, has a high prevalence in the country, particularly in populations with a story of abortion. Thus, neosporosis should systematically be considered in the differential diagnosis of abortion. In the context of embryo transfers, the importance of selecting Neospora-free embryo recipients is discussed, as well as the pertinence of assessing the Neospora status of traded and imported cattle. [Copyright &y& Elsevier]

Abstract: In previous works, methylcellulose (MC) was prepared from sugarcane bagasse cellulose in heterogeneous medium using dimethyl sulfate (DMS) as etherification agent. MC was produced in a range of degrees of substitution (DS) from 0.70 to 1.40 and the materials showed low water solubility. In this work methylcellulose was prepared with 5h (MC5h) of reaction with reagent substitution at each hour. MC5h showed a DS of 1.89±0.04. An aqueous viscous suspension was produced with MC5h for application as viscosity enhancing admixture of cimentitious adhesive mortars. It was observed a 40.37% increase on the consistency index (CI) and a 27.70% increase on the Potential Tensile Adhesion Strength. Such characteristics show the potential of this material for the utilization in situations that require good workability, improve viscosity and adhesive properties such as for tile setting in civil engineering. [Copyright &y& Elsevier]

Abstract: 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 2900cm−1 and O–H stretching at around 3400cm−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. [Copyright &y& Elsevier]

Abstract: In the present paper, methylcellulose was produced from cellulose extracted of sugar cane bagasse, using dimethyl sulfate in heterogeneous conditions. The infrared spectra of the cellulose and of the methylcellulose present significant differences at the regions from 3600 to 2700cm−1 and from 1500 to 800cm−1. The ratio between the absorption intensities of the Oing band (∼3400cm−1) and the Cing band (∼2900cm−1) in the spectra of the methylated samples is lower than that in the cellulose spectrum, evidencing the methylation of the samples. The effect of using toluene and acetone during the synthesis was studied. Without using the solvent, the degree of substitution (DS) of the methylated sample was 0.70, reaching a DS of 1.2 when using acetone. The produced methylcellulose presents chemical and physical properties that increase its range of application and aggregate value to this agro-industrial residue. [Copyright &y& Elsevier]