Brazilian Journal of Chemical Engineering This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.

CARBON DIOXIDE BIOFIXATION BY Chlorella sp. IN A BUBBLE COLUMN REACTOR AT DIFFERENT FLOW RATES AND CO2 CONCENTRATIONS
Abstract CO2 biofixation of the microalgae Chlorella sp. for different CO2 concentrations and gas flow rates in a bubble column reactor has been investigated in this study. Microalgae were cultivated under different CO2 concentrations (at 1.75% and 9.45% v/v) and gas flow rates (at 30, 50 and 70 ml/min). The maximum specific growth rate of Chlorella sp. was obtained for the CO2 concentration of 1.75 % and the gas flow rate of 50 mL/min. The highest biomass productivity rate (at 0.17 g L-1 day-1) was for a sample with 1.75 % CO2 at a flow rate of 70 ml/min. Moreover, the results have shown that the specific growth rate and ...
Source: Brazilian Journal of Chemical Engineering - October 1, 2019 Category: Chemistry Source Type: research

OPTIMIZATION OF BIOFLOCCULANT PRODUCTION BY Bacillus spp. FROM SUGARCANE CROP SOIL OR FROM SLUDGE OF THE AGROINDUSTRIAL EFFLUENT
Abstract Biological flocculants are advantageous due to their biodegradability and safety to living beings. In this work, four bacterial strains, isolated from sugarcane cropped soil (Bacillus megaterium LBPMA-APFSG3Isox and B. toyonensis LBPMA-ACOPR1.Isox) and sludge of an agroindustrial effluent (B. pumilus LBPMA-BLD07 and B. thuringiensis LBPMA-EFIII), were studied. It was found that all of them secreted bioflocculants, at 37 ± 1 °C, with no pH changes over time and the flocculant activity increased during the time course of incubation. These results stimulated the optimization of the culture conditions to improve flo...
Source: Brazilian Journal of Chemical Engineering - October 1, 2019 Category: Chemistry Source Type: research

ALKALINE PROTEASE PRODUCTION BY Bacillus licheniformis LBA 46 IN A BENCH REACTOR: EFFECT OF TEMPERATURE AND AGITATION
Abstract The production of protease from Bacillus licheniformis LBA 46 was studied in a 6 L reactor using the experimental design tool. The higher protease production was obtained in the exponential phase of growth reaching maximum activity (~3,000 U/mL) after 48 h of fermentation at 30 ºC and 300 rpm in a culture medium made of agroindustrial by-products. In the thermostability study, the semi-purified enzyme retained about 78% of the initial activity after 120 min at 50 ºC. The protease was purified 3.33 times by ammonium sulfate precipitation and DEAE-Sepharose column chromato graphy and had a molecular mass estimated...
Source: Brazilian Journal of Chemical Engineering - October 1, 2019 Category: Chemistry Source Type: research

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 pH1/2 = ...
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 amine conce...
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