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.

KINETIC MODELING AND EXPERIMENTAL VALIDATION OF A PHOTOCATALYTIC FLUIDIZED BED REACTOR FOR n-HEXANE DEGRADATION
Abstract This work presents a modeling procedure for a tall photocatalytic fluidized bed photoreactor used for the photocatalytic oxidation of n-hexane on the anatase TiO2 surface. The modeling strategy split the reactor into two parts: a lower dense phase, with high solids concentration behaving as a bubbling bed treated as a continuous stirred tank reactor (CSTR); and an upper lean phase of low solids concentration behaving as a plug-flow reactor (PFR). The Langmuir-type kinetic parameters were obtained for the flow rate of 1.67 × 10-4 m3 s-1 and catalyst mass of 0.1 kg. The model revealed a good adjustment with experim...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

In situ DEPOSITION OF COPPER NANOPARTICLES ON POLYETHYLENE TEREPHTHALATE FILTERS AND ANTIBACTERIAL TESTING AGAINST Escherichia coli AND Salmonella enterica
This study reports a synthesis of copper nanoparticles (CuNP) deposited on polyethylene terephthalate (PET) filters and antibacterial evaluation of the obtained filters against Escherichia coli and Salmonella enterica. CuNP were synthesized by a two-step method involving adsorption of [Cu(OH)4]2- ions onto a PET filter and subsequent chemical reduction by ascorbic acid without using other capping agents. The synthesized CuNP were 105 ±26 nm (mean±SD) in size and agglomerated into clusters on the PET fibres. Increasing the immersion time of the filters in [Cu(OH)4]2- solutions yielded higher amounts of deposited CuNP. SEM...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Preliminary assessment of the processing of high-acidity fatty materials using solid catalysts for the obtainment of fatty acid methyl esters
Abstract This work presents the processing of a high-acidity oil through sequential reactions of esterification using montmorillonite K10 and transesterification using zinc monoglycerolate. Since these solids had not been employed along with this approach beforehand, the objective of this work is to provide a general insight of the proposed process and demonstrate its technical feasibility. In this sense, the processing of a synthetic mixture containing soybean oil and lauric acid provided a reduction of the free fatty acid content from (40.8 ±0.1) % to (3.1±0.4) % after the esterification reaction and a fatty acid methy...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Evaluation of silica nanoparticle colloidal stability with a fiber optic quasi-elastic light scattering sensor
Abstract Colloidal silica is an important biocompatible, inert and non-toxic material for imaging, therapy, and drug delivery biomedical applications. In this context, the evaluation of colloidal suspensions and their stabilities by a Fiber Optic Quasi-Elastic Light Scattering sensor is proposed. Two different silica nanoparticles were prepared and characterized by scanning electron microscopy and X-ray diffraction, being completely amorphous, with mean diameters of 125 and 159 nm and average specific weight of 1.94 g.cm-3. The nanoparticles were dispersed in deionized water in different concentrations ranging from 0 to 2%...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

EVALUATION OF THE PHOTOCATALYTIC ACTIVITY OF SiO2@TiO2 HYBRID SPHERES IN THE DEGRADATION OF METHYLENE BLUE AND HYDROXYLATION OF BENZENE: KINETIC AND MECHANISTIC STUDY
Abstract Silica spheres coated with titania (SiO2@TiO2) were synthesized using chitosan as template. The N2 adsorption/desorption isotherms of the spheres point to meso and macroporous characteristics and the elemental mapping by EDS shows uniform distribution of Ti on the surface of the silica spheres, leading to formation of an amorphous structure (XRD). The results from the model reaction of photocatalytic degradation of methylene blue (MB) show a good stability of the spheres regarding their reuse. The tests with various additives pointed to hydroxyl radical production as the main via of MB degradation. The photocataly...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Biodiesel synthesis from waste cooking oil using a variety of waste marble as heterogeneous catalysts
Abstract The research article is based on biodiesel synthesis by the transesterification of waste cooking oil with methanol in the presence of heterogeneous catalysts prepared from different marble. Eight samples of marble were successfully converted into potential catalysts by calcination. The thermal treatment of waste marbles at 300oC-1000oC converted the metal carbonates (CaCO3) to metal oxides (CaO). The calcined marble was analyzed by chemical tests, flame atomic absorption spectroscopy (FAAS), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction studies (XRD). The presence of CaO in these catalysts...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Numerical and experimental investigation of air-water system to simulate bubble dynamics in liquid sodium pool
We report an in-house experimental technique to depict the bubble dynamics along with numerical support to establish similarity behavior between water and liquid sodium, to reduce the number of experiments in sodium systems for in-depth knowledge of bubble dynamics in the case of the fast breeder reactor. In the present work, 3-D bubble dynamics is studied in the OpenFOAM platform and the validated numerical model is used to study bubble dynamics in sodium to establish similitude between the water and sodium systems. The bubble aspect ratio of 0.9 cm diameter bubbles in the sodium system is found to be in close agreement w...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Experimental and numerical analysis of chaotic advection as an efficient approach to maximize homogeneous laminar mixing in a batch mixer
Abstract In the present work, the impacts of effective parameters on the mixing of Stokes flows in a chaotic batch mixer are numerically and experimentally studied. The batch mixer consists of a container and two circular rotors where the rotors can rotate independently. To investigate the possibility of improving the mixing, the effect of non-constant speeds, contra-rotating rotors, and varying rotor speeds are studied. The results showed that varying the rotor speed while rotating in the same direction does not significantly increase mixing. However, if the rotors rotate in opposite directions, 10-times more mixing is ac...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Study of parameters affecting the coalescence of dimethyl disulfide drops in a merox unit
This study focuses on the coalescence of dimethyl disulfide drops with the mother phase at a flat aqueous-organic interface between dimethyl disulfide and different sodium hydroxide solutions. Drop coalescence is an important part of the Merox process for regenerating the solvent. A digital high-frame rate camera was used for recording drops coalescence and duration time. Drops of dimethyl disulfide were directed in different sodium hydroxide solutions as the continuous phase. Applying the experimental design method, the influences of independent variables of drop size and physical properties on coalescence time were inves...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Simulation and experimental investigation of power consumption, gas dispersion and mass transfer coefficient in a multi-phase stirred bioreactor
Abstract Bio-oxidation leaching of refractory gold concentrate was carried out in a typical gas-liquid-solid three-phase stirred bioreactor. The bacteria, which adhered to solid particle surfaces and spread over the liquid phase, require sufficient oxygen and nutrient of carbon and nitrogen, and then the mass transfer rate should be considered. However, the mass transfer coefficient, which could be used to evaluate the mass transfer rate, was determined by gas holdup, bubble diameter and power consumption. Therefore, a three-phase Eulerian equation with k- ε turbulence model and additional models of two bubble diameter, ...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Cantilever nanobiosensor based on the enzyme urease for detection of heavy metals
Abstract Cantilever nanobiosensors have emerged as an alternative to conventional methods of analysis to monitor heavy metals, which are being highlighted by detecting substances at the micro and nanoscale through the use of sensor layers. In the present study, a new cantilever nanobiosensor was developed functionalized with urease enzyme by self-assembled monolayers for the detection of heavy metals (lead, nickel, cadmium, zinc, cobalt, and aluminum) in water. From the calibration curves, using the statistical method of Principal Component Analysis, it was possible to observe that the nanobiosensor was highly efficient in...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

DISRUPTION OF Nannochloropsis gaditana (EUSTIGMATOPHYCEAE) RIGID CELL WALL BY NON-THERMAL PLASMA PRIOR TO LIPID EXTRACTION AND ITS EFFECT ON FATTY ACID COMPOSITION
This study assessed the effect of non-thermal plasma (NTP) on Nannochloropsis gaditana cell rupture and subsequent lipid extraction. Micrograph images showed that the surface of original N. gaditana cells appeared smooth and had no apparent holes, whereas after NTP the cells showed a non-uniform apparently fractured surface with many pores and large splits. Maximum lipid recovery from N. gaditana cells (~19%) for NTP-assisted rupture was observed at 10 min, similar to extraction after 10 min sonication (19.0%). The lipid recovery after both pretreatments (average 19.0%) was 2-fold higher than the control treatment (no pret...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

STABILIZATION STUDY OF TETRAMERIC Kluyveromyces lactis β-GALACTOSIDASE BY IMMOBILIZATION ON IMMOBEAD: THERMAL, PHYSICO-CHEMICAL, TEXTURAL AND CATALYTIC PROPERTIES
Abstract We investigated the immobilization of a tetrameric Kluyveromyces lactis β -galactosidase (EC: 3.2.1.23) (KL-Gal) on Immobead 150 using different support modification strategies. Immobead support was modified using an acid solution of H2SO4:HNO3 (3:1) (Immobead-Ac) or 5 % (v/v) glutaraldehyde (Immobead-Glu). Its unmodified form (Immobead) was also tested. Immobilization yields and efficiencies were evaluated by testing protein loads from 10 to 200 mg.g-1 support. The thermal, physico-chemical, textural and catalytic properties of the supports (modified and unmodified) and their derivatives (Immobead-KL-Gal, Immobe...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

ENZYMATIC PRODUCTION OF β-CYCLODEXTRIN FROM JACKFRUIT SEEDS (Artocarpus intergrifolia L.)
The objective of this study was to produce β -CD using an alternative source of starch, such as jackfruit seed (Artocarpus intergrifolia L.) bran (JSB) by a commercial CGTase. The highest productivity of β -CD (52.10 µM/h.g) was obtained from 10 g of JSB in 100 mL of citrate buffer (10 mM / pH 6.0), with 17 % (v/v) of ethanol and 1.34 U/g of CGTase, at 59 °C for 4 hours. These same conditions were applied to starches extracted from the JSB (SJSB) and ginger (SG) and also, potato starch (SP). The SJSB and SG pe rformances were similar to SP, and resulted in productivities around 2.7 times higher in relation to JSB. Thus...
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research

Study of solubility in supercritical fluids: thermodynamic concepts and measurement methods - a review
This study reviews the fundamental knowledge of solubility in supercritical fluids and investigates the significant topics in this field, including high-pressure phase behavior, experimental measurement methods, modeling, and molecular simulation of solubility. (Source: Brazilian Journal of Chemical Engineering)
Source: Brazilian Journal of Chemical Engineering - January 14, 2020 Category: Chemistry Source Type: research