Mentha arvensis IN OIL SOLID-LIQUID EQUILIBRIUM
ABSTRACT L-menthol is an essential oil produced from Mentha arvensis. An experimental L-menthol solid-liquid equilibrium in menthol oil constituents was determined in the temperature range between 271 K and 300 K, by the method of creating a saturated solution at a given temperature by using an excess of crystals in the suspension. The mole fraction of the experimental data, on a logarithmic basis, were fitted against T by the Apelblat equation and by a linear equation with good results. The equations were: ln(x) =#091;- 52.45 + 1,170.70/T + 8.48.ln(T) #093; and ln(x) = 3.98 -1,249.65/T with T in K. Both equations give a g...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Thermophysical properties of 1-ethyl-3-methylimidazolium chloride solution from 293.15 to 323.15 k
The objective of this experiment was to obtain the thermo-physical properties of density, refractive index, electrical conductivity, molar volume, thermal expansion coefficient and apparent specific volume of the ionic liquid 1-ethyl-3-methylimidazolium chloride. The thermo-physical properties of aqueous solutions of this ionic liquid were measured as a function of the mass fraction w = (0.05, 0.125, 0.2, 0.275 and 0.35), temperature T = (293.15, 303.15, 313.15 and 323.15) K and pH = (7.5, 8.0 and 8.5). Models representing the combined effects between variables were fit since they are required for industrial applications w...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Numerical and computational aspects of cosmo-based activity coefficient models
ABSTRACT In the present work, some numerical and computational aspects of COSMO-based activity coefficient models were explored. The residual contribution in such models rely on the so called self-consistency equation. This equation does not have a closed-form solution and is usually solved by the successive substitution method. The performance of a classical Newton-Raphson method was tested in solving the self-consistency equation. The results obtained by the Newton implementation and by successive substitution agreed within the convergence tolerance. The CPU times for solving the model using both methods also were compar...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Evaluation of distillation curves for bio-oil obtained from thermal cracking of waste cooking oil
In this study, the distillation curves were constructed for samples of bio-oils obtained from the thermal cracking of WCO in order to predict the properties (such as molecular weight, viscosity and refractive index). Although it is not often employed for bio-oil analyses, the distillation curve method is commonly used in the petroleum industry. Atmospheric and vacuum distillations were performed according to ASTM D86 and ASTM D1160 standards, respectively, for six samples of bio-oil and one sample of crude oil. The results were converted to true boiling point (ASTM D2892) according to the API method (1997) and common petro...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Thermodynamic analysis and modeling of brazilian crude oil and asphaltene systems: an experimental measurement and a pc-saft application
The objective of this paper is to model Brazilian crude oil and asphaltene systems using the PC-SAFT equation of state. Asphaltenes were extracted from crude oil through the addition of different n-alkanes. The PC-SAFT was capable of accurately predicting liquid density for toluene and asphaltenes and boiling point elevation for crude oil at different concentrations of toluene. Asphaltene precipitation from model oil allowed us to evaluate the influence of binary interaction parameters on modeling results. The influence of precipitant agent (n-hexane and n-heptane) on the asphaltene phase behavior was analyzed, showing tha...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

EXTRACTION OF BIOACTIVE COMPOUNDS OF LEAVES OF Duguetia furfuracea (ANNONACEAE) USING GREEN AND ORGANIC SOLVENTS
ABSTRACT Duguetia furfuracea (Annonaceae) is a shrub found in the Brazilian Cerrado that is used in popular medicine as an antirheumatic, for wound healing, treatment of kidney pain and against pediculosis. The aim of this study was to analyze the extraction of leaves of Duguetia furfuracea, using supercritical CO2, ethanol and hexane as solvents. For the supercritical extraction, an experimental planning 23 with triplicates of the central point was used to evaluate the effects of temperature (313-333 K), pressure (15-23 MPa) and volumetric flow rate (3-6 mL min-1) on the extraction yield, total phenolic content and antiox...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Competing solvent extraction of calcium and/or nickel with cyanex 272 and/or d2ehpa
ABSTRACT The present study assessed the competing behavior between metals and extractants applied to the solvent extraction of calcium and/or nickel present in sulfuric solutions using the extractants Cyanex 272 (bis-2,4,4-trimethylpentyl phosphinic acid) and/or D2EHPA (di-2-ethylhexyl phosphoric acid). Tests were designed to allow equivalent competing conditions between metals and extractants. Considering metal competition in the aqueous phase, calcium extraction remained unaffected in the presence of nickel, while nickel extraction curves with pH displaced to the right in the presence of calcium when D2EHPA ( Δ pH1...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Light n-paraffins separation by inverse gas chromatography with cuban volcanic glass
ABSTRACT In this work the applicability of a natural volcanic glass (technological type I material) from Cuba is investigated as adsorbent for separation of mixtures of C1-(C5; C6; C7; C8; C9) hydrocarbons by inverse gas chromatography under fl ow conditions in a temperature range of 328-343 K. The experimental results indicated that the material was mainly composed of silica and, in a lower proportion, of alumina, that provided surface Si-OH and Al-OH groups to favor the interaction and separation of the different components of paraffin mixtures. In fact, the calculated heats of adsorption were high enough to facilitate ...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Production and characterization of precipitated silica from palm oil mill fly ash using co2 impregnation and mechanical fragmentation
ABSTRACT In this research, sol-gel precipitation using CO2 impregnation and mechanical fragmentation method was applied to produce precipitated silica from Palm Oil Mill Fly Ash (POMFA). Carbon dioxide (CO2) was used in order to reduce the cost of the process and to enable sodium hydroxide recovery. The precipitation process was done in a stirred temperature-controlled baffled glass precipitator. The response surface method with the central composite design was applied to optimize the stirring speed and the CO2 flow rate. The pH and the temperature of the precipitation process were varied for tailoring the specific surface...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Development of inexpensive cellulose-based sorbents for carbon dioxide
This study reports chemical modification of cellulose fibers extracted from rice husk with different amines and their potential for CO2 capture. The obtained compounds were characterized by different techniques. The CO2 sorption capacity was gravimetrically assessed in a Magnetic Suspension Balance. Quantum mechanical simulations and experimental results revealed that -NH- and -NH2 represent major working sites of the employed compounds. The best result for CO2 sorption was attained for the amine-modified cellulose CL-D-400 with a sorption capacity of 409 µmol CO2/g at 1 bar and 1091 µmol CO2/g at 10 bar with a...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Pvc membranes prepared via non-solvent induced phase separation process
ABSTRACT Polyvinylchloride (PVC) based membranes are prepared via a phase inversion method using N,N-dimethylacetamide (DMAc) as solvent and water as precipitation bath. Polyvinylpyrrolidone (PVP) and lithium nitrate (LiNO3) are used as additives. Experimental cloud point data and solution viscosity measurements are evaluated. Precipitation rates, transport properties and membrane morphology are quantified. Membranes with different morphologies and transport properties are prepared by changing the additive and its concentration, changing the PVC concentration and by varying the exposure time to the environment before immer...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

SEQUENTIAL PROCESSING OF Psidium guajava L. LEAVES: STEAM DISTILLATION AND SUPERCRITICAL FLUID EXTRACTION
ABSTRACT Extracts from the leaves of Psidium guajava L have been studied due to their importance as a source of natural antioxidant components with possible applications in the pharmaceutical and food industries. In this work, the sequential use of steam distillation and supercritical fluid extraction was studied to obtain the essential oil from the leaves and non-volatile compounds from the residue. The non-volatile compounds were obtained by CO2 supercritical extraction. Experiments were performed in a automated pilot-scale extractor at constant pressure of 15 MPa, at 313 K and 333 K in three different flow rate conditio...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Development of a start-up operation and dynamic behavior of a thermally coupled extractive distillation scheme
ABSTRACT The startup operation of distillation columns is one of the most complex steps performed in the industry. This complexity becomes even greater for thermally coupled extractive distillation systems. Thermally coupled configurations are commonly used in order to minimize the excessive amount of energy required to perform distillation. In view of this, this study aimed to develop a startup procedure for the thermally coupled extractive distillation system to obtain anhydrous ethanol by simulation using the computational package Aspen Plus Dynamics. From the startup procedure developed, the complex dynamic behavior of...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Optimization of pressure-swing distillation for anhydrous ethanol purification by the simulated annealing algorithm
ABSTRACT The present study addresses the novel application of the simulated annealing algorithm (SAA) to optimize the pressure-swing distillation (PSD) process for anhydrous ethanol purification. Three different softwares (Aspen Plus ®, Excel® and Matlab®) were integrated to simultaneously optimize seven design and operational variables. The configuration with the best TAC represented a 40.2% saving per year in comparison to the non-optimized PSD. Such reduction was achieved by using the higher acceptance probability and the slower temperature decrement. This saving is mainly related to operational cost reducti...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Model predictive control for production of ultra-low sulfur diesel in a hydrotreating process
ABSTRACT There is a continual desire around the world to reduce the sulphur content of diesel fuel to ultra-low levels (below 10 ppm) due to environmental concerns and the intention of improving air quality and lowering harmful exhaust emissions of diesel engines. In this work, a hydrodesulfurization unit fed with multiple diesel streams was addressed using a phenomenological mathematical model aiming to produce Ultra-Low Sulfur Diesel (ULSD). A three-phase model of a trickle-bed reactor was considered. A model-based predictive control strategy (MPC) was implemented with the objective of controlling the sulfur concentratio...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

State estimation and trajectory tracking control for a nonlinear and multivariable bioethanol production system
ABSTRACT In this paper a controller is proposed based on linear algebra for a fed-batch bioethanol production process. It involves finding feed rate profiles (control actions obtained as a solution of a linear equations system) in order to make the system follow predefined concentration profiles. A neural network states estimation is designed in order to know those variables that cannot be measured. The controller is tuned using a Monte Carlo experiment for which a cost function that penalizes tracking errors is defined. Moreover, several tests (adding parametric uncertainty and perturbations in the control action) are car...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

K-rank: an evolution of y-rank for multiple solutions problem
ABSTRACT Y-rank can present faults when dealing with non-linear problems. A methodology is proposed to improve the selection of data in situations where y-rank is fragile. The proposed alternative, called k-rank, consists of splitting the data set into clusters using the k-means algorithm, and then apply y-rank to the generated clusters. Models were calibrated and tested with subsets split by y-rank and k-rank. For the Heating Tank case study, in 59% of the simulations, models calibrated with k-rank subsets achieved better results. For the Propylene / Propane Separation Unit case, when dealing with a small number of sample...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Statsscandleplot: a new way of monitoring operational performance indicators
ABSTRACT Operational KPIs play an extremely important role in the process industry, aiding in decision making. However, they need to be reliably calculated to be representative. The present work presents a schematic methodology for the calculation of these KPIs, including techniques of steady-state detection, denoising, error propagation and sensitivity analysis, presented, as far as it is known, in the form of a new graphical tool proposed by the authors named StatSSCandlePlot. The methodology was applied in a real case study of a gas fired boiler in which the indicator studied was its efficiency evaluated by the Stack Lo...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Sensitivity analysis for model comparison and selection in tissue engineering
In this study, the contribution of oxygen to Contois growth kinetics and porosity variation with time due to polymer degradation was evaluated through a sensitivity analysis. The effect of initial glucose concentration, porosity and thickness of the scaffold on the cell volume fraction and substrate concentration was analyzed for three models. Even with the inclusion of oxygen concentration in the model, the output variables are more affected by the initial cell number, while the model with variable porosity is quite robust to variations in the input variables. (Source: Brazilian Journal of Chemical Engineering)
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

On the performance of different rans based models to describe the turbulent flow in an agitated vessel using non-structured grids and piv validation
ABSTRACT The performances of the Standard κ - ε , RNG, Realizable, κ - ω and RSM turbulence models to describe the behavior of the flow in agitated tank reactors were evaluated. Because most of these tanks have complex geometries, structured meshing schemes are not a practical alternative in engineering. Two particular unstructured meshing schemes composed of either Cartesian Cut-Cell (CC) or Tetrahedral elements were tested in domains larger than 3 million cells. In this work, the blade thickness, which is usually disregarded, was accounted for. The performance of the turbulence models was valida...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Comparison between experimental and simulated results of biodiesel production by reactive distillation and energetic assessment
ABSTRACT Biodiesel appears to be a likely substitute to conventional diesel. However, the main challenge has been the creation of a competitive advantage for the biodiesel production process in terms of innovation and efficiency. The reactive distillation technique for biodiesel production is possibly a key force to overcome this technological issue because it combines chemical reaction and the separation process inside the same unit. This work presents kinetic data for biodiesel production via the ethylic route and compare them with the methylic one. It also compares experimental results in a 1.5m reactive distillation pi...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Simulation of thermal decomposition in an open cavity: entropy analysis
ABSTRACT This paper presents a numerical analysis of entropy generation in a two-dimensional rectangular channel where the inlet flow undergoes thermal decomposition resulting from a chemical reaction. The model considered viscosity and thermal conductivity to be dependent of temperature. Irreversibility due to mass transport was included in the entropy generation analysis. Relevant applications of this study are possible for the design of power generation systems and reactors. The effects of the Reynolds number, Schmidt number, and length of the heat source on thermal fluid dynamics, mass transfer, and irreversibility wer...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Reliability-based multi-objective optimization applied to chemical engineering design
ABSTRACT Chemical engineering optimization represents a significant challenge due to the complexity of the mathematical models that are frequently required in this area. These models are normally associated with nonlinear equations that represent mass, energy, and momentum balances, which are submitted to physical, constitutive, environmental, and design limitations. The design of chemical systems is generally carried out by considering the model, the vector of design variables, and system parameters as deterministic values, i.e., small variations in these quantities do not affect the objective function. In this contributi...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

The role of sulfonated activated carbons as catalysts for the hydrolysis of cellobiose
ABSTRACT In this work the production of glucose via hydrolysis of cellobiose using sulfonated active carbons as catalysts was studied. Commercial carbons presenting different types of porous system (micropores and mesopores) have been treated with sulfuric acid at different temperatures, being characterized afterwards. Such carbons have been tested as catalysts in the reaction of cellobiose hydrolysis. The results indicated that the type and density of sulfonic sites are not the only parameters responsible for the activity of the catalysts. Indeed, the porosity of the catalysts also plays an important role in the determina...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Esterification of oleic acid in a semi-batch bubble reactor for biodiesel production
ABSTRACT A semi-batch bubble reactor has been developed to produce fatty acid ethyl ester (biodiesel) by acid-catalyzed esterification of oleic acid with superheated ethanol vapor. In this paper, the effects of reaction temperature (110, 130 and 150 °C), ethanol volumetric flow rate (1.35, 2.50 and 3.65 mL/min) and vapor bubble size on the reactor performance were evaluated. The results demonstrated that temperature and volumetric flow rate have significant effects on the chemical reaction, gas phase solubility and mass transfer limitations. I n addition, the free fatty acid conversion velocity was increased by approxi...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Production of fatty acid methyl esters from an olive oil industry waste
This study shows that pomace oil can be used as a raw material for biodiesel production. At short reaction times and under moderate operating conditions, it was possible to convert triglycerides and fatty acids selectively toward FAME. (Source: Brazilian Journal of Chemical Engineering)
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Characterization and behaviour of pt catalysts supported on basic materials in dry reforming of methane
ABSTRACT Different basic materials, such as K-L zeolite, K-Al2O3, K-Mg/Al mixed oxide and MgO, were used as supports of Pt-catalysts for the dry reforming of methane (DR) reaction. The effects of the distribution of basic strength in the support on the metal-support properties and catalyst performance were evaluated. The density of strong and the total basic sites decreased as follows: MgO>K(Mg-Al)>K-Al2O3>K-L. The total basic sites decrease from 214 to 23 µmol CO2. g-1, for MgO and KL, respectively. Pt catalysts supported on materials with high density of strong basic sites such as MgO were the most adequat...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Ni-mo supported nanoporous graphene as a novel catalyst for hds and hdn of heavy naphtha
ABSTRACT Reducing sulfur and nitrogen compounds is essential in producing clean fuels for providing a green environment. In this regard, a novel nanocatalyst has been proposed for Hydrodesulfurization (HDS) and Hydrodenitrogenation (HDN) of heavy naphtha. To this end, Ni-Mo was loaded on nanoporous graphene (Ni-Mo/NG) through the incipient wetness impregnation method. The synthesized nanocatalyst was characterized by FE-SEM, ICP, BET, FTIR, XRD and TPR methods. The catalytic activity of the Ni-Mo/NG catalyst was evaluated at 290 ºC and 30 bar. For the synthesized Ni-Mo/NG catalyst, conversions of total sulfur, total n...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Preparation and characterization of thin-film composite reverse osmosis membrane on a novel aminosilane-modified polyvinyl chloride support
ABSTRACT Herein, the influence of pure and modified polyvinyl chloride (PVC) support layers on the performance of thin-film composite (TFC) membranes was investigated in water desalination. Accordingly, the PVC support was modified using (3-Aminopropyl) triethoxysilane (APTES) through bulk modification. The supports were synthesized at different doses of APTES (0-6 wt%) and characterized with various analytical techniques. The results showed that APTES affected considerably both the morphology and surface properties of the support layer. Afterwards, the polyamide (PA) layer was formed via an identical interfacial polymeriz...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

SYNTHESIS, CHARACTERIZATION AND in vitro CYTOTOXICITY OF Acacia mearnsii PROANTHOCYANIDIN LOADED PLGA MICROPARTICLES
ABSTRACT One of the highlighted areas in the development of new materials is the generation of micro- and nanoparticles as drug carriers which allow the progress in formulations with the ability to release active agents in a controlled way. The proanthocyanidins (PAC) extracted from the bark of the Black Wattle have stood out for their biological activities. However, most polyflavonoids have some features which limit their application in the pharmaceutical field, such as light fastness, low bioavailability of active agents, and unpleasant taste. In this context, this study aims to present the synthesis and characterization...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Rheological behavior of a silver aqueous nanofluid stabilized with aminosilane-based surfactant under confined flow
ABSTRACT The rheological behavior of an aqueous suspension of silver nanoparticles stabilized with aminosilane-based surfactant flowing under confinement was investigated. Three stability levels were defined based on the zeta potential: high (41.73 mV, pH 4.3), medium (10.44 mV, pH 7.4), and low (0.74 mV, pH 8.6). Furthermore, the preliminary investigation showed that the surface charge remained positive, and the formation of agglomerates was not observed. Due to the particle coating and the ionization of the amino groups of the surfactant an electrosteric stabilization was evidenced. Shear rates ranging from 50 to 1000 s-...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Effect of steel plate thicknesses and fluid flow characteristics of an impinging air jet on heat transfer at the stagnation point
ABSTRACT The design and process of heat transfer elements, from its source to heat sink through various media vary according to the product and system concerned. The effect of thickness of a steel plate on heat transfer characteristics with an impinging air jet at the stagnation point was studied. Experiments were carried out with different nozzles, heights, and velocities. It was concluded that the heat transfer increases with the increase in velocity and the increase in Reynolds Number, but decreases with the increase in nozzle height from the impinging point. A maximum stagnation Nusselt number of 309.06 was obtained at...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Researching new ways to reduce n2o emission from a granular sludge sequencing batch reactor treating domestic wastewater under subtropical climate conditions
ABSTRACT N2O emissions from wastewater treatment plants have become an important issue, since this compound is a significant greenhouse gas that affects the sustainability of sewage treatment. This work aimed to investigate and to reduce N2O emission from a pilot-scale aerobic granular sludge sequencing batch reactor (AGS-SBR) operated for carbon and nitrogen removal from domestic wastewater under subtropical climate condition. Three operational strategies (S-I, S-II and S-III) with different anoxic phase durations were compared regarding treatment efficiency and N2O emission. For all the studied strategies, volatile suspe...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

A fair comparison between bismuth catalysts for application in photodegradation under visible and solar light
ABSTRACT Three different bismuth catalysts (Bi2WO6, BiOI and BiVO4) were synthesized using solvo- and hydrothermal methods. Different reaction times, calcination and the addition of poly (vinyl pyrrolidone) during synthesis were tested to investigate the effect of these variables on the catalysts ’ morphology and photocatalytic activity. The photocatalytic activity was evaluated using the degradation of rhodamine B dye under both visible light and natural solar radiation. The Bi2WO6 samples presented good crystallinity and morphological similarities, despite having undergone different treatments. The BiOI and Bi2WO6 ...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

The influence of different electrolytes on sulfentrazone dechlorination by iron-nickel bimetallic nanoparticles
ABSTRACT Kinetic studies of sulfentrazone herbicide dechlorination by Fe/Ni nanoparticles were performed in the presence of different electrolytes such as: Cl-, SO42-, NO3-, Cu2+, Na+ and Zn2+. In the presence of Cl- and SO42- the reaction occurred efficiently, reaching approximately 100% of dechlorination after 30 minutes of reaction. In the presence of NO3- and Cu2+ ions the sulfentrazone dechlorination was significantly inhibited, because these ions tend to compete with the substrate for the electrons donated by Fe0. In the presence of Na+ ions, the dechlorination efficiency remained approximately 100%, however, this el...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

APPLICATION OF POLYCARBOXYLIC ACIDS AS BINDERS FOR TiO2 IMMOBILIZATION ON COTTON TEXTILES
ABSTRACT Immobilizing the photocatalyst on a support is an alternative solution to a critical issue in photocatalysis, which is the need for unit operations to remove the photocatalyst from the effluent. In this work, TiO2 was immobilized onto a cotton textile substrate by polycarboxylic acid binders (succinic and citric acids) using a solution deposition method, and the most appropriate conditions for pre-treatment and the relationship between variables were determined by an experimental design. Then, samples prepared at optimum conditions were exposed to UV for an extended period of time to evaluate the deactivation. The...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Optimization of lipase immobilization on maghemite and its physico-chemical properties
ABSTRACT Nanomaterial-based biocatalysts have emerged as current carriers suitable for enzyme immobilization. The nano-sized materials provide large surface area for enzyme attachment, thus increasing the probability for its efficient catalyst activity. By using magnetized nanomaterials, enhancement of the downstream processing is evident as it eases the immobilized enzyme separation from the reaction mixture further. Lipase / maghemite composites were prepared by initial maghemite surface modification to cater to the needs for biocatalyst attachment. Surface modification using chitosan and subsequent cross-linking with gl...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Isolation and identification of yeast strains from sugarcane molasses, dates and figs for ethanol production under conditions simulating algal hydrolysate
ABSTRACT Yeast strains were isolated from sugar cane molasses (S1), dates (S2) and figs (S3) and the ethanol production was evaluated in batch condition. A comparison was made with the yeast Saccharomyces cerevisiae. The strains showed tolerant characteristics to stressful conditions like salinity and ethanol. The isolated strains produced ethanol; at 20 h of fermentation ethanol yields were 0.38-0.39 g.g-1, and the productivities were almost 0.58 g.L-1. S. cerevisiae and S1 tolerated up to 14% (v/v) of ethanol; while interestingly the isolates S2 and S3 were highly tolerant, up to 20% (v/v) ethanol. Thus, S2 and S3 could ...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Dilute acid hydrolysis of sweet sorghum bagasse and fermentability of the hemicellulosic hydrolysate
This study aimed to determine the best dilute acid hydrolysis condition for the hemicellulosic fraction of sweet sorghum bagasse for ethanol production by Scheffersomyces stipitis. The experiment followed a 23 factorial design with four central points, and had as variables: sulfuric acid concentration, temperature and hydrolysis time. Sorghum bagasse presented the following chemical composition: 24.77% of lignin, 31.28% of hemicellulose and 34.80% of cellulose. The hydrolysis that resulted in the highest sugars concentration (14.22 g/L of xylose and 2.42 g/L glucose) was 1.75% H2SO4, 121 ºC and 40 minutes. This same c...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Influence of pretreatments on crystallinity and enzymatic hydrolysis in sugar cane residues
ABSTRACT This research evaluated the effect of different delignification pretreatments (enzymatic and organosolv), on the crystallinity and enzymatic hydrolysis of harvested sugar cane residues. The Crystallinity Index (CrI), the Relative Number of Intensity (Ir), the degree of cellulose mercerization (IIC-%), and the Global Index of Saccharification (GIS) were used as measurement parameters for six different substrates obtained from sugar cane residues (tops and leaves) by different processes. In this characterization, the spectroscopic ty Techniques of Fourier Transform infrared spectroscopy (FTIR), X-ray diffraction and...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Carotenoid-producing yeasts in the brazilian biodiversity: isolation, identification and cultivation in agroindustrial waste
ABSTRACT Different yeast strains from forests located in southern Brazil, with potential to produce carotenoids, were isolated. Three microorganisms were selected as potential carotenoid producers. Sporiodiobolus pararoseus, Rhodotorula mucilaginosa and Pichia fermentans were grown in Yeast Malt (YM) medium and the carotenoids produced identified as cryptoxanthin and β -carotene. In order to reduce production costs, agroindustrial residues were used in the formulation of medium A (parboiled rice water and crude glycerol) and medium B (parboiled rice water and sugar cane molasses). The highest carotenoid production was...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Biotechnological application of surface modified cerium oxide nanoparticles
ABSTRACT Re-engineering of chemical materials at the nanoscale level that employ modification and improvement in their physical and chemical properties has been constantly pursued for application in biomedical and biotechnology industries. Moreover, immobilization of catalysts on these bio/chemically modified nanomaterials improved the performance of enzymes in a plethora of industrial uses. Hence, in this study, cerium oxide nanoparticles (CNPs) were synthesized and their morphology was investigated by TEM and UV-spectra. They were modified by carboxylation and glutaraldehyde to achieve highly efficient surface functional...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Valorization of solid wastes from the brewery and biodiesel industries for the bioproduction of natural dyes
This study aims to assess a new approach for concomitant valorization of two industrial wastes - raw glycerin and spent brewer ’ s yeast - for the bioproduction of valuable carotenoids. Microbial pigments have numerous applications in the food and cosmetic industries. First, four cultures of yeasts were screened using pure glycerol and either (NH4)2SO4 or urea as carbon and nitrogen sources, respectively. The ability of the best performing culture to accumulate carotenoids was investigated in a medium in which only wastes were supplemented as carbon and nitrogen sources. All the fermentations were carried out in 500 ...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

A NOVEL Scytalidium SPECIES: UNDERSTAND THE CELLULOLYTIC SYSTEM FOR BIOMASS SACCHARIFICATION
ABSTRACT In order to overcome the bottlenecks related to lignocellulosic-derived sugars, the search for more efficient enzymatic cocktails, containing a broad-spectrum of specific activities, relies on an important feature. This paper describes new enzyme activities derived from the novel strain of the Scytalidium genus isolated from the Amazonas rainforest. The production of the enzymatic cocktail was induced by delignified-hydrothermal bagasse (DHB), and yeast extract was used to improve secretion activities, resulting in a positive influence on total cellulase activity. The enzymatic cocktail produced by this novel stra...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

ASSESSMENT OF POLYHYDROXYALKANOATE SYNTHESIS IN SUBMERGED CULTIVATION OF Cupriavidus necator AND Burkholderia cepacia STRAINS USING SOYBEAN AS SUBSTRATE
In this study, evaluation and characterization of PHA produced by Cupriavidus necator (IPT 026 and IPT 027) and Burkholderia cepacia (IPT 119 and IPT 400), using soybean as substrate, were carried out (soybean 15 g L-1, pH 7.0, 150 rpm, 72 hours). The highest polymer production was achieved using IPT 027 (0.84 ± 0.07 g L-1). All PHA produced showed the characteristic bands of polyester functional groups in the FTIR spectra. Polymers synthesized by Cupriavidus necator exhibited initial temperatures of degradation superior to 300oC and higher molecular weights than the ones produced by Burkholderia cepacia , which in ...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

KINETICS OF THE BIODEGRADATION OF MONOAROMATICS BY Pseudomonas aeruginosa
ABSTRACT Water contamination by monoaromatic compounds has risen throughout time, which leads to the necessity of developing new water treatment technology, capable of minimizing their negative effect on the environment. In this context, biological processes present themselves as a solution to the processes of extraction. Bioremediation makes use of microbial groups capable of using hydrocarbons as a source of carbon to perform their metabolic functions. This work evaluated the biodegradation efficiency of Pseudomonas aeruginosa strain isolated from contaminated matrices, for the substrates benzene, ethylbenzene and toluen...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

INDUSTRIAL PLANT FOR PRODUCTION OF Spirulina sp. LEB 18
The objective of this work was to study the behavior of physico-chemical variables and kinetic and biological responses in industrial cultivation of Spirulina sp. LEB 18, aiming at the operation of a microalgal photobiorefinery. The maximum specific growth rate (0.133 1/d), the minimum generation time (5.2 d) and maximum productivity (14.9 g/m ².d) were obtained in the first 9 d of microalgae growth. The maximum biomass concentration (1.64 g/L) was obtained in 37 d of cultivation. The highest levels of carbohydrates, proteins and lipids in the biomass were 10.6, 57.0 and 11.7%, respectively. The plant monitoring demon...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

ELEPHANT GRASS (Pennisetum purpureum Schumach) IS A PROMISING FEEDSTOCK FOR ETHANOL PRODUCTION BY THE THERMOTOLERANT YEAST Kluyveromyces marxianus CCT 7735
ABSTRACT Elephant grass (Pennisetum purpureum Schumach) is regarded as a promising feedstock for second generation ethanol production, due to its high cellulose content, biomass production and rapid growth. The yeast Kluyveromyces marxianus CCT 7735 is capable of producing ethanol from agroindustrial residues, such as lignocellulosic biomass. Therefore, this study aimed to establish the optimal conditions for ethanol production by K. marxianus CCT 7735 from elephant grass. Five factors were evaluated: temperature (35-45 ºC), pH (4.5-5.8), agitation (50-150 rpm), cellulase concentration (7.5-22.5 FPU/mL) and elephant g...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

A simple equation for total reducing sugars (trs) estimation on sweet potato and ethanol yield potential
ABSTRACT Sweet potato is an attractive feedstock for ethanol production due to its high starch content and favorable agronomic characteristics. This paper proposes a simple equation to estimate the total reducing sugars (including glucose from starch) in sweet potatoes based on their moisture content (low cost and simple measurement). It allows the calculation of the ethanol production potential of a given sweet potato mash. According to the equation, the ethanol potential increases non-linearly with increasing concentrations of sweet potato mash in the fermenting medium (w/v), reaching a constant value for high concentrat...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research

Functionalized graphene-based materials as innovative adsorbents of organic pollutants: a concise overview
ABSTRACT The functionalization of graphene nanosheets is the cutting edge of materials sciences nowadays. Such research promotes the development of innovative, low cost and highly capable sorbents. This review article aims to assemble the available information on functionalized graphene used for the adsorption of organic pollutants and establishes a critical comparison between the data reported in the literature. Various optimal experimental conditions (pH, temperature, contact time, adsorbent dosage) and adsorbent characterization methods (FTIR, Raman, XPS spectra, XRD, TEM and AFM) have been listed to enlighten adsorptio...
Source: Brazilian Journal of Chemical Engineering - July 16, 2019 Category: Chemistry Source Type: research