Resumo em Inglês:

Abstract Furfural is a base chemical with a wide range of applications and with a great opportunity for market growth in the near term. Derived from biomass, its production may be incorporated to the Brazilian chemical industry using sugarcane bagasse as feedstock. In this context, the integration of a furfural plant to a first generation bioethanol facility, within the biorefinery concept, was simulated considering different scenarios compared to an autonomous bioethanol distillery. The economic analysis of the different scenarios showed that the revenues from furfural commercialization increase the internal rate of return of the project for maximum furfural production (22.0%) in comparison to a conventional ethanol distillery (13.5%), despite the decrease in electricity output. Moreover, the economic analysis of the results pointed out the possibility of lowering furfural prices to levels that could lead to its use as a precursor for biofuels.

Resumo em Inglês:

ABSTRACT The activity coefficient at infinite dilution (&IN1) and distribution ratios at infinite dilution (&IN2) were determined for alkanols (methanol, ethanol, 1-propanol, 1-butanol, 2-butanol, and 2-methyl-2-propanol) in the ionic liquid (IL) 1-butyl-3-methylimidazolium methyl sulfate ([BMIM][CH3SO4]) by HS-SPME (Headspace - Solid Phase Micro Extraction) at four temperatures (298.15, 313.15, 333.15, and 353.15K) using headspace - solid phase microextraction (SPME-HS). The results showed significant agreement with literature data. In addition, partial molar excess enthalpies at infinite dilution (&IN3), excess Gibbs energies (&IN4), and excess entropies (&IN5) were calculated from the (&IN6) values.

Resumo em Inglês:

Abstract Biosensors based on nanomaterial composites have been investigated for their potential to function as high sensitivity signal response devices. In the present study, we report the fabrication of silver nanoparticles (AgNPs) on a graphite epoxy composite electrode (GEC) and mixed with the polyaniline (a conductive emeraldine salt form polymer) composite electrode (AgNPs/PANI/GEC), in order to compare the performance of the generated electrochemical response signals. Cyclic voltammetry tests were conducted to compare the quality and intensity of signals from the different prepared electrodes. Tests for the AgNPs/PANI/GEC electrodes were made with and without the enzymes alcohol oxidase and horseradish peroxidase immobilized on the composite surface. The prepared AgNPs/PANI/GEC nanocomposite was evaluated by thermal analysis. Scanning electron microscopy images and EDX were obtained for characterization of the electrode surface morphology. Square wave voltammetry techniques were then employed for ethanol analysis with the AOX/HRP/AgNPs/PANI/GEC biosensor achieving good results in a range of 0.37M to 0.65 M.

Resumo em Inglês:

ABSTRACT Encapsulation of poly-unsaturated fatty acid (PUFA)is an alternative to increase its stability during processing and storage. Chia (Salvia hispanica L.) oil is a reliable source of both omega-3 and omega-6 and its encapsulation must be better evaluated as an effort to increase the number of foodstuffs containing PUFAs to consumers. In this work chia oil was extracted and encapsulated in stearic acid microparticles by the hot homogenization technique. UV-Vis spectroscopy coupled with Multivariate Curve Resolution with Alternating Least-Squares methodology demonstrated that no oil degradation or tocopherol loss occurred during heating. After lyophilization, the fatty acids profile of the oil-loaded microparticles was determined by gas chromatography and compared to in natura oil. Both omega-3 and omega-6 were effectively encapsulated, keeping the same omega-3:omega-6 ratio presented in the in natura oil. Calorimetric analysis confirmed that encapsulation improved the thermal stability of the chia oil.

Resumo em Inglês:

ABSTRACT In this study, we have optimized production of bacterial cellulose (BC) by Komagataeibacter hansenii ATCC 23769 in a static cultivation using sisal juice, an agroindustrial residue, as substrate. Optimization of fermentation parameters has been carried out using the one-variable-at-a-time method. Effect of initial sugar concentration, pH, nitrogen supplement, and cultivation time was evaluated. The influence of nitrogen source and quantity for bacterial cellulose production was studied using a central composite rotational design (CCRD).The highest production of BC (3.38 g/L) was obtained after 10 days of cultivation, using sisal juice (pH 5) at 15 g/L of sugars and supplemented with 7.5 g/L of extract yeast. The cellulose production yield in selected sisal culture conditions was three times higher than the yield in synthetic medium, indicating that sisal juice is a suitable substrate for BC production.

Resumo em Inglês:

Abstract Candida antarctica Lipase B (CALB) immobilized onto iron magnetic nanoparticles was evaluated as biocatalyst for the synthesis of flavor esters. Methyl and ethyl butyrate were synthesized by esterification of butyric acid with methanol and ethanol, respectively, in a medium containing solvent. The nanoparticles were produced by the co-precipitation method. The process parameters (type of solvent, temperature, substrate concentration, molar ratio, amount of biocatalyst, stirring speed and reaction time) were studied. The optimum conditions for both esters were achieved at 25 °C, 0.5 mol/L (methyl butyrate) and 0.4 mol/L (ethyl butyrate), molar ratio of 1:1, amount of biocatalyst: 10 mg, 150 rpm and 8 h of reaction, using heptane as solvent. Under those conditions, the maximum conversions of methyl butyrate and ethyl butyrate were higher than 90 %. The synthesis of flavor esters was also conducted by using Novozym® 435, a commercial catalyst, for comparison purposes.

Resumo em Inglês:

Abstract The high cost of the enzymes used for the hydrolysis of lignocellulosic biomass is one of the bottlenecks in the production of second-generation ethanol and the use of local biomass, such elephant grass, can help to reduce this cost. In this investigation elephant grass biomass was evaluated as a carbon and inducer source of production of cellulases and xylanases by the fungus Penicillium echinulatum strain 9A02S1 in solid-state cultivation. The highest filter paper activity (13.26 U.g-1 dry matter) and β-glucosidase activity (138.34 U.g-1 dry matter) were obtained on the fifth day of cultivation, in medium containing biomass pre-treated with sulfuric acid and untreated, respectively. The highest endoglucanase activity was 158.44 U.g-1 dry matter in the presence of elephant grass pre-treated with sulfuric acid. The xylanase activity was highest with medium that was formulated with 75% untreated elephant grass and 25% wheat bran (372.62 U.g-1 dry matter). In conclusion, the results showed that it is possible to obtain large amounts of cellulases and xylanases using a cosmopolitan and very low cost substrate such as elephant grass.

Resumo em Inglês:

Abstract - Textile effluent is rich in hydrolyzed dyes that need to be removed. This study presents an evaluation of the potential of the enzyme horseradish peroxidase to remove the hydrolyzed dyes Reactive Blue 21 (RB 21) and Reactive Red 195 (RR 195) from cotton fiber and the effluent of the dyeing process. The parameters pH, dye concentration and temperature were evaluated to determine the optimal conditions to remove the dyes. The studies of removal of the dyeing effluent led to an increase of degradation for all tested colors. The use of the enzyme horseradish peroxidase as a biocatalyst can be a viable technological alternative to remove some hydrolyzed dyes.

Resumo em Inglês:

Abstract Fodder radish (FR) is an oilseed crop with a high potential for biodiesel production due to its high productivity and the quality of its seed oil. FR oil extraction results in a residue that is rich in protein and fiber. In this study, FR cake (FRC) was evaluated as carbon and nitrogen source for the production of cellulases and xylanases using Penicillium echinulatum S1M29 during solid-state cultivation. It was determined that it is possible to partially replace wheat bran (WB) by FRC, resulting in 24.22 ± 0.25U/g Filter Paper Activity (144 hours), 210.5 ± 5.8U/g endoglucanase activity (144 hours), 22.62 ± 0.01U/g (-glucosidase activity (96 hours) and 784.7 ± 70.19U/g xylanase activity (120 hours). These values are equal or higher than the enzymatic activity obtained using WB. These results may contribute to the reduction of the cost of enzymes used in the production of cellulosic ethanol or other biotechnological applications.

Resumo em Inglês:

Abstract Contaminants like nitrate (NO3), phosphorus (P) and heavy metals in water are often associated with agricultural activities. Various soil and water remediation techniques have been employed to reduce the risk associated with these contaminants. A study was conducted to examine the extent of leaching of heavy metals (Cd, Ni, Pb and Cr), NO3 and P. For this purpose sandy and silt loam soils were amended with different waste materials, namely wood ash, solid waste ash, vegetable waste, charcoal, and sawdust. The soils were saturated with wastewater. Irrespective of the waste applied, the pH and EC of the amended soils were found to be greater than the control. Charcoal, sawdust and wood ash significantly decreased heavy metals, nitrate and phosphorus concentrations in the leachate. Treatments were more efficient for reducing Ni than other heavy metals concentrations. Waste amendments differed for heavy metals during the process of leaching. Heavy metals in the soil were progressively depleted due to the successive leaching stages. This research suggests that waste material may act as an adsorbent for the above contaminants and can reduce their leachability in soils.

Resumo em Inglês:

Abstract This study evaluates the impact of biofuels on the air quality of the city of Rio de Janeiro using an air quality model based on the trajectory model OZIPR associated with the SAPRC chemical model. The results show that the increase in biodiesel use reduces ozone levels in the atmosphere by 10.2 %, using Biodiesel with Ethanol and Diesel mixture (BE-Diesel), in 5.28 %, using B20 mixture and only 0.33 % using B10. An increase was observed in NOx emissions of 5.66 and 2.83 % for BE-Diesel mixture and B20, respectively. The low ozone levels are attributed to its consumption by NO. The CO concentration reductions for BE-Diesel, B20 and B10 were 13.11, 6.56 and 4.12 %, respectively. The presence of oxygen atoms within the biodiesel chain leads to a better combustion process, reducing CO emissions.

Resumo em Inglês:

ABSTRACT In this study, a high salt-tolerant and glyphosate-degrading strain named BZ8 was isolated from activated sludge. According to 16S rDNA sequencing methods, morphological, physiological and biochemical analysis, strain BZ8 was identified as Agrobacterium tumefaciens. The growth and glyphosate-degrading capability of A. tumefaciens BZ8 were investigated and the results showed that the optimum conditions for glyphosate degradation under 6% of NaCl concentration were found as follows: inoculation size of 10% (v/v), incubation temperature 37℃ and initial pH of 5.0. Salt tolerance test showed that A. tumefaciens BZ8 grew well and could thoroughly degrade 2000 mg/L glyphosate in 36 h if the concentration of NaCl was lower than 6%, while the degradation rate decreased gradually with increasing NaCl concentration. But the glyphosate degradation rate could still reach 62% when the salt concentration was 8%. In addition, the kinetic parameters for A. tumefaciens BZ8 grown on 100-2800 mg/L glyphosate according to Haldane’s model could predict the cell growth tendency successfully. These results showed that A. tumefaciens BZ8 could be used to control glyphosate wastewater with high salt content. Therefore, it has potential application.

Resumo em Inglês:

ABSTRACT Cement and clay beads coated with TiO2were used for the photo-degradation and mineralization of 2-chloro-4-nitrophenol (2Cl4NP) along with a heterogeneous solar photo-Fenton process using foundry sand (FS) as the iron source. The degradation process was optimized using slurry photocatalysis where 96% degradation of 2Cl4NP was achieved in 120 min at optimized conditions of C0=50 mgL-1, pH=4, 0.75 gL-1 TiO2 and H2O2= 0.1 mL/200 mL. Degradation of 2Cl4NP was analyzed through HPLC along with UV-Visible spectrophotometer at 266 nm. The degradation of 68% and 52% of 2Cl4NP was attained in fixed-bed photocatalysis using cement and clay beads, respectively. The durability studies of cement and clay beads were carried out in terms of number of recycles. 97.19% degradation was obtained in a solar photo-Fenton process after 105 min at pH=3. Complete mineralization of 2Cl4NP was confirmed through reduction in COD along with the disappearance of the parent compound peak in HPLC chromatograms.

Resumo em Inglês:

Abstract This study assessed the feasibility of an anaerobic sequencing batch and fed-batch biofilm reactor (AnSBBR) with mechanical stirring for vinasse treatment and biomethane production. The amount of liquid medium used was 3 L, and the treated volume was 1 L per cycle. The cycle time was 8 h, with feeding times of 10 min (batch mode) and 240 min (fed-batch mode). Methane productivity increased with the increase in organic load from 1.0 to 10.0 gCOD.L-1.d-1. The maximum molar productivity and yield of methane were 123.4 molCH4.m-3.d-1 and 13.8 mmolCH4.gCOD-1 (88% of the theoretical), respectively. These parameters were lower in fed-batch mode than in batch mode and were lower at 45°C than at 30°C due to biomass adaptation. In general, the values of the kinetic parameters increased with organic load and were similar for the batch and fed-batch modes. Therefore, the increase in organic load positively influenced the process by increased COD removal and lower volatile acids accumulation as the load increased. The batch mode performed better than did the fed-batch mode and 30°C was more suitable than 45°C to produce methane under the studied conditions.

Resumo em Inglês:

Abstract Drilling an oil well involves using drilling fluids that perform cleaning and cooling functions, but that most importantly maintain the fluids of the geological formation contained by hydraulic pressure. A fundamental role in predicting the hydraulic pressure of the well consists of monitoring the fluid’s rheological behavior. This paper summarizes an ongoing effort to measure, by evaluating the performance of two online viscometers, drilling fluids’ rheological behavior in real time. One online method proposes a modified Couette system. The other consists of a standard pipe viscometer with default modeling. The performances of the online devices were compared with an offline method - a Couette device commonly used in oilfields as a benchmark. For Newtonian fluids, agreement between the rheological behaviors was found for all instruments, validating the methodology proposed. For non-Newtonian fluids, there were divergences, which were investigated and their probable causes determined to be the following: homogeneity, slippage effects, and interaction in the fluid/gap interfaces. A case study demonstrated that these divergences were not significant during the prediction of hydraulic pressure, meaning that the methodology proposed has the potential to improve overall drilling performance.

Resumo em Inglês:

Abstract The mass transfer coefficient (K L ) determined using an electrochemical technique was used in this work as a parameter to evaluate the hydrodynamics of hollow fiber membrane modules. A new microfiltration module configuration was investigated, taking advantage of the hydrocyclone concept aimed at reducing the concentration of the polarization layer near the membrane surface promoted by the centrifugal field. The mass transfer coefficient for the new configuration was compared with that of a conventional longitudinal module. The experimental determination of K L was obtained by monitoring the electrochemical reactions that occur at the electrode surface under mass transfer-limiting conditions. The performance of the microfiltration modules, both hybrid and longitudinal, was evaluated based on parameters such as packing density and fluid flow regimes. The results achieved for the mass transfer coefficient with the electrochemical technique allowed for performance evaluations of the proposed new module configuration and a comparison with the longitudinal module.

Resumo em Inglês:

Abstract Supercritical carbon dioxide extraction was employed to extract solids from fresh tea leaves (Camellia sinensis L.) at various pressures(15 to 35 MPa) and temperatures (313 to 333K) with addition of ethanol as a polarity modifier. The diffusion model and Langmuir model fit well to experimental data and the correlation coefficients were greater than 0.94. Caffeine solubility was determined in supercritical CO2 and the Gordillo model was employed to correlate the experimental solubility values. The Gordillo model fit well to the experimental values with a correlation coefficient 0.91 and 8.91% average absolute relative deviation. Total phenol content of spent materials varied from 57 to 85.2 mg of gallic acid equivalent per g spent material, total flavonoid content varied from 50.4 to 58.2 mg of rutin equivalent per g spent material and the IC50 value (antioxidant content) varied from 27.20 to 38.11 µg of extract per mL. There was significant reduction in polyphenol, flavonoid and antioxidant content in the extract when supercritical CO2 extraction was carried out at a higher pressure of 35 MPa.

Resumo em Inglês:

Abstract The interest in biodiesel as an alternative source of energy has been extremely intensified by its use as a renewable and economically viable fuel. As a result, continuous production processes have been a requirement to supply growing demand. This work presents experimental and simulated results of two biodiesel production pilot plants and makes a comparison between the processes they use. The first one was designed with three plug flow reactors (PFRs) connected with recycle streams. The second one was composed of a reactive distillation process for biodiesel production. Repeated tests in Aspen Plus and Matlab showed that multiple PFRs with high volume are required for 98% ester conversion. However, a single unit of reactive distillation resulted in 99% conversion. In short, to produce large quantities of biodiesel this work indicates continuous reactive distillation as the most adequate process.

Resumo em Inglês:

ABSTRACT The phosphate recovery from a 20 mg L-1 Na2HPO4 solution through precipitation with Ca(OH)2 followed by electroflotation was evaluated. X-ray diffraction and particle size measurements indicated that the precipitates were a mixture of hydroxyapatite and calcium-deficient hydroxyapatite, with size ranging from 3 to 10 μm. Electroflotation with Na-oleate as surfactant was used to recover the precipitates. The surfactant adsorption was evaluated through zeta potential measurements. The influence of Na-oleate concentration, pH and bubble size on phosphate recovery was investigated. In the absence of Na-oleate, a phosphate recovery of 50% was achieved, while in the presence of 20 mg L-1 of Na-oleate it was increased to 90%, at pH 11. The phosphate recovery also increased with Ca(OH)2 concentration increase and bubble size decrease, reaching 100% at 300 mg L-1 Ca(OH)2 and bubble size around 39 µm.

Resumo em Inglês:

ABSTRACT This study evaluated the potential of macauba pulp oil (MPO) as a feedstock for continuous ester production using ethanol under pressurized conditions. Experiments were performed in order to obtain data for the effect of process variables on ethyl ester (FAEE) and free fatty acid (FFA) conversion in a catalyst-free process. From the results, it appears that the MPO to ethanol mass ratio and the pressure were the variables with more favorable effect on the evaluated response variables. The addition of n-hexane caused an increase in the production of esters; however, this had a negative effect on FFA conversion. The addition of water was unfavorable for oil processing with high acidity. In this process, esterification and transesterification occur simultaneously, and the high FFA content in MPO provides high yields (85 wt% of esters; 93% FFA conversion) at low temperature, since the esterification reaction rate is higher than the transesterification. The decomposition of fatty acids was evaluated and levels <5% were observed under the evaluated experimental conditions.

Resumo em Inglês:

Abstract The present study aims at studying the supercritical water gasification (SCWG) of leftover Brazilian ginseng roots after phytochemicals extraction for synthetic natural gas (SNG) production, envisioning the development of a promising Brazilian ginseng roots valorization using sub/supercritical fluids in different steps. A multi-objective energetic-economic-environmental optimization of the proposed SCWG process was assessed through the use of computational simulation tools. The results showed that, for a given leftover biomass input of 20MW, a specific cost of 62-66 USD/MWh of SNG is obtained, which is higher than the average price on the Brazilian market. On the other hand, the production process of SNG from this residue showed to be a promising option, being energetically self-sufficient and environmentally friendly. In order for this alternative process to become more economically attractive we proposed the construction of the SCWG and the sub/supercritical extraction units in the same location, sharing part of the same high-pressure equipment.

Resumo em Inglês:

Abstract Rules for control structure design for industrial processes have been extensively proposed in the literature. Some model-based methodologies have a sound mathematical basis, such as the self-optimizing control technology. The procedure can be applied with the aid of available commercial simulators, e.g., PRO/IITM and AspenPlus®, from which the converging results are obtained more suitably for industrial applications, lessening the effort needed to build an appropriate mathematical model of the plant. Motivated by this context, this work explores the development and application of a tool designed to automatically generate near-optimal controlled structures for process plants based on the self-optimizing control technology. The goal is to provide a means to facilitate the way possible arrangements of controlled variables are generated. Using the local minimum singular value rule supported by a modified version of a branch-and-bound algorithm, the best sets of candidate controlled variables can be identified that minimize the loss between real optimal operation and operation under constant set-point policy. A case study consisting of a deethanizer is considered to show the main features of the proposed tool. The conclusion indicates the feasibility of merging complex theoretical contents within the framework of a user-friendly interface simple enough to generate control structures suitable for real world implementation.

Resumo em Inglês:

Abstract An efficient numerical method for solution of boundary value problems with additional condition is presented. The approach is based on the shooting method but the procedure of seeking “the proper shot” allows one to satisfy “additional” boundary conditions. General considerations are illustrated by a real example. The computational example concerns the “dead zone” regime for the non-linear diffusion-reaction equation in heterogeneous catalysis. Accuracy and efficiency of the presented method confirm results obtained for a wide range of changes of process parameters, including the vicinity of a critical point. Calculations were performed with the use of the Maple® program.

Resumo em Inglês:

Abstract-The effects of solvent-to-feed (S) and temperature (T) on the kinetics and thermodynamics of the microwave assisted extraction (MAE) of flavonoids from dried fruits of Phyllanthus emblica using water as solvent have been studied. The flavonoid concentration - time data was analyzed using second order and diffusion models. Both the temperature and solvent-to-feed ratio influenced the initial extraction rate and equilibrium concentration. Biot numbers were found to be greater than 50, implying that the internal mass transfer was the rate controlling step in MAE. The composition of extracts obtained using MAE and conventional extraction was similar. However, the effective diffusion coefficients were doubled in MAE when compared to conventional extraction. An empirical correlation was developed to predict the kinetics of MAE as a function of solvent-to-feed ratio and temperature. The study will be of interest to food and pharmaceutical industries.

Resumo em Inglês:

Abstract The present study investigated the dynamics of manganese adsorption onto bone char in a continuous fixed bed column using a mathematical model that incorporates: (i) the backmixing model to describe the fluid flow through the bed and (ii) the shrinking core model to describe the kinetic and mass transfer phenomena within spherical adsorbent particles. The proposed model consists of an ordinary differential equation system. Hydrodynamic, kinetic and diffusive parameters were determined by fitting the mathematical model to the experimental data obtained by Sicupira et al. (2015). For the operating conditions evaluated in this study, the intraparticle diffusion represented the controlling step of the adsorption process (Bim> 3.8). The increase in the feed rate of the column (3.0-7.5 mL min-1) and the decrease in the height of the bed (8-16 cm) resulted in a decrease in the time required for the saturation of the column bed. The model is flexible for a variety of flow conditions and adequately reproduced the behavior of the manganese adsorption process in the fixed bed column operation (R²> 0.99) with an average percentage error less than15%.

Resumo em Inglês:

Abstract The present study investigated liquid-liquid equilibria of polyvinylpyrrolidone (PVP) K30 + tri-sodium citrate + urea (5% and 10% mass) aqueous two-phase systems at 25°C and pH values of 6.2, 7.4, and 10.0. Results showed that the binodal was displaced toward higher concentrations as the urea concentration increased. The effect of pH, polymer/salt (w/w) ratio, urea concentration, tie line length, and slope of tie line on the partition behavior of urea was examined. The viscosity, density, electrical conductivity, and refractive index of PVP (K30) + tri-sodium citrate + urea + water two-phase systems were measured versus pH value. The relation between tie line length and the density and viscosity of the aqueous two-phase systems was also examined.

Resumo em Inglês:

ABSTRACT Physical extraction studies of pyruvic acid from dilute aqueous solutions (0.025 kmol·m-3 to 0.200 kmol·m-3) using several pure solvents (tri-n-butylphosphate (TBP), 1-decanol, 1-octanol, toluene, Methyl-isobutylketone (MIBK), and n-heptane) and their binary mixtures are reported in this work. All the batch extraction experiments were carried out at isothermal conditions (T=303±1K) and the results are reported in terms of distribution coefficient (K D). The results obtained by the equilibrium studies of the different extraction system were correlated with solvatochromic parameters of the solvents. A linear solvation energy relationship (LSER) model was applied to interpret the extraction equilibrium which specifically considers physical interactions. The values of the LSER model parameters for the extraction system were optimized by regression technique and the model equations have been proposed. Experimental and model values were in good agreement (RMSD < 0.1).Reported outcomes are useful in the selection of a suitable extraction system and understanding the extraction mechanism for the separation of pyruvic acid from dilute aqueous solutions.