Effect of stirring speed on conversion and time to particle stabilization of poly (vinyl chloride) produced by suspension polymerization process at the beginning of reaction
Abstract The effect of changes in the stirring speed during suspension polymerization of vinyl chloride monomer (VCM) was investigated near the particle stabilization. Preliminary tests were conducted to check the highest conversion and information regarding the porosity and particle stabilization of two formulations, which are based on different concentrations of initiators and dispersing agents. The influence of stirring speed during the first 2 h of reaction was investigated for the best formulation, indicating that there was a proportional relationship between the increase in speed and the increase in conversion. The r...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Synthesis of zeolite 4a for obtaining zeolite 5a by ionic exchange for full utilization of waste from paper industry
Abstract In order to minimize environmental impact zeolite A was synthesized using waste from the paper industry. This waste is composed of cellulose, kaolin and calcium carbonate. Waste purification was carried through thermal and chemical treatment, which consisted of initial calcination, acid washing with HCl, then calcination of the solid fraction to obtain metakaolin and evaporation of the liquid fraction to obtain CaCl2. Zeolite 4A was produced by static autoclaving under hydrothermal synthesis at different temperatures, crystallization times and NaOH concentrations. As a source of aluminum and silicon metakaolin was...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Convective-diffusive heat transfer in tubes: role of the hydrodynamics of flow on the feasibility domain of the asymptotic temperature profiles
Abstract In this contribution, an assessment of the role of the hydrodynamics of flow on the asymptotic solutions used to describe convective-diffusive heat transfer in packed-bed and capillary tubes of cylindrical geometry is reported. Such asymptotic solutions are intrinsically dependent from the type of hydrodynamics present in the tubes. They describe the temperature profiles for heat transfer problems found in packed-bed and capillary systems with axial convective and radial diffusive transport and having a constant heat flux at the outer tube wall. The role of the hydrodynamics of the flow on the asymptotic temperatu...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Liquid-liquid extraction of aromatics from hydrocarbon mixtures in capillaries
Abstract An aromatics extraction study was conducted in capillaries of internal diameters in the range of 0.8 mm to 2 mm. The systems chosen for study were ‘ n-heptane + toluene + propylene carbonate ’ , ‘ n-heptane + toluene + furfural ’ and ‘ synthetic naphtha reformate + (propylene carbonate + tetraethylene glycol) ’ . The aim of the work was to evaluate the feasibility of conducting aromatic separation in micro-capillaries and evaluate maximum efficiency. The results showed efficiencies ranging from 46.3 % to 97.3 %, depending upon the combination of the flow velocity, residence time and channel diameter. ...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Effect of fluidized-bed process variables on controlled-release of nitrogen and coating
This study can help produce green fertilizer at bigger scale. (Source: Brazilian Journal of Chemical Engineering)
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Dependency of nanofluid rheology on particle size and concentration of various metal oxide nanoparticles
Abstract Impact of the nanoparticle size and concentration on the rheology of ethylene glycol based nanofluids containing nanoparticles of five different metal oxides is investigated. Particle mass concentrations ranged from 5 to 20 wt %. Types of the nanoparticles and their particle size are TiO2 (30 nm, 50 nm), MgO (20 nm, 40 nm), ZnO (10-30 nm, 35-45 nm, 80-200 nm), SiO2 (20-30 nm, 60-70 nm) and CuO (40 nm, 80 nm). A stress controlled rheometer fitted with a cone-and-plate system is employed for the rheological characterization of the nanodispersions at temperatures between -5 ˚ C and 35 ˚ C. The non-linear measuremen...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

TREATMENT OF WASTEWATER FROM BIODIESEL GENERATION AND ITS TOXICITY EVALUATION BY Raphidocelis subcapitata
ABSTRACT Biodiesel was developed to solve vast economic and environmental problems related to the use of petroleum as fuel. However, large quantities of water are necessary for biodiesel production, generating a high volume of effluent waste. Therefore, it is important to treat this wastewater in order to meet the environmental legislations according to the Brazilian Resolution Number 430/2011 (CONAMA). This work aimed to treat this effluent by coagulation/flocculation (CF) and an electrochemical advanced oxidation process. The combination of CF techniques (pH = 6.5) and electrochemical oxidation (boron doped diamond - BDD...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Simulated dairy wastewater treatment in a pilot plant scale magneto-active hybrid anaerobic biofilm reactor (ma-habr)
Abstract The aim of this study was to determine the effects of magneto-active microporous packing media manufactured by extrusion technology and modified by the addition of relevant amounts of metal catalysts and magnetic activation on the effectiveness of simulated dairy wastewater (SDW) treatment and biogas productivity in a pilot plant scale hybrid anaerobic biofilm reactor with full mixing. The best performance was found at an organic loading rate (OLR) in the range 6.0 - 8.0 kg COD/m3 ·d, where the chemical oxygen demand (COD) removal was about 80%, the biogas yield ranged from 256.7 - 310.9 L/kg CODremoved, the meth...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Acid mine drainage treatment and metal removal based on a biological sulfate-reducing process
ABSTRACT The key purpose of this research was to explore the capacity of an anaerobic stirred batch reactor (ASBR) to deal with acid mine drainage (AMD) based on the activity of sulfate reducing bacteria (SRB). The tests showed that SRB produced hydrogen sulfide that precipitated the metals Fe2+, Zn2+, and Cu2+. Ethanol was used as both the only source of carbon and electron donor. Throughout the experiment, the ratio of chemical oxygen demand (COD) to sulfate was constant at 1.0. The reactor was operated for 218 days using synthetic AMD at pH 4.0 containing 1000 and 1500 mg ·L-1of sulfate,100 mg·L-1of Fe2+, 20 mg·L-1Zn...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Treatment of wastewater with high fat content employing an enzyme pool and biosurfactant: technical and economic feasibility
ABSTRACT The combination of 0.5% weight per volume (w/v) crude enzyme consortia produced by solid state fermentation with Penicillium brevicompactum and 27 milligrams per liter (mg/L) of rhamnolipid biosurfactant produced by submerged fermentation with Pseudomonas aeruginosa was employed to pretreat wastewater from a poultry slaughterhouse in bench upflow anaerobic sludge blanket (UASB) bioreactors. One bioreactor was fed with untreated wastewater (Control) and another with pretreated wastewater (Test). Under an organic loading rate of 11 kg COD/m3.d, the Test bioreactor showed higher specific methane production (67.8 mL C...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Organophosphate esters removal by uv/h2 o2 process monitored by 31p nuclear magnetic resonance spectroscopy
Abstract The present work aims to study the photocatalytic degradation of three organophosphate esters considered environmental emerging contaminants by the UV/H2O2 system with the use of 31P NMR spectroscopy to investigative their removal after the treatment. Results demonstrated the efficiency of the oxidation system in removing the esters tris(2-butoxyethyl) phosphate (TBEP), tris(2-chloroethyl) phosphate (TCEP) and tri-butyl phosphate (TBP) from aqueous solutions when they were individually present and mixed. High levels of degradation of these chemicals were achieved, in addition to the good performance of the analyti...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

CAROTENOID PRODUCTION BY Sporidiobolus pararoseus IN AGROINDUSTRIAL MEDIUM: OPTIMIZATION OF CULTURE CONDITIONS IN SHAKE FLASKS AND SCALE-UP IN A STIRRED TANK FERMENTER
Abstract Biotechnological production of carotenoids can be affected by cultivation conditions, such as temperature, pH and agitation. The aim of this study was to maximize carotenoid production by Sporidiobolus pararoseus in shake flasks with agroindustrial by-products as substrates. The best conditions were used in a stirred tank fermenter. The medium consisted of corn steep liquor and sugar cane molasses pretreated with sulfuric acid. In order to evaluate the effects of the variables, a central composite rotatable design was used. The highest values of total carotenoids (565 µg L-1), biomass (13.6 g L-1) and Yp/s (10.9 ...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Assessment of kinetic and metabolic features of two hybridomas in suspension culture for production of two monoclonal antibodies for blood typing
Abstract The aim of this study was to analyze kinetic and metabolic features of two hybridomas for monoclonal antibodies (MAbs) production for blood typing. Two lines of hybridomas, ED7 and ED9, were evaluated to produce anti-A and anti-AB, respectively. Experiments with ED7 and ED9 lines were conducted in a 500mL spinner flask and 2L bioreactor, using two different basal culture media, both with 10 % v/v addition of fetal bovine serum. The results revealed the necessity of additional supplementation of the culture media to meet the nutritional demands of the cells. Through nutritional balance and cultivation in better con...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

BIOCHEMICAL RESPONSES FROM BIOMASS OF ISOLATED Chlorella sp., UNDER DIFFERENT CULTIVATION MODES: NON-LINEAR MODELLING OF GROWTH KINETICS
In this study, the effect of different modes of cultivation viz., photoautotrophic (AT), heterotrophic (HT) and photomixotrophic (MT), on the growth and biochemical responses of Chlorella sp. isolated from local ponds. The performance of microalgal growth was quantified using nonlinear growth models such as Gompertz, logistic, Baranyi-Roberts, Morgan under different cultivation conditions. The results revealed that microalgae could grow better in MT than in other cultivation modes with a major increase in biochemical responses for carbohydrates, which showed higher accumulation under HT. The maximum biomass concentration w...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research

Ethanol precipitation as a downstream processing step for concentration of xylanases produced by submerged and solid-state fermentation
Abstract Xylanases have applications in different industries, being produced by microbial cultivations using submerged (SmF) or solid-state fermentation (SSF). Precipitation stands out as a potential method for the concentration of xylanases, especially with the use as ethanol as the precipitant due to its compatibility with the biorefinery concept. This paper presents a comparative laboratory scale study of ethanol precipitation of xylanases produced by Aspergillus niger cultivated under SSF and SmF. Precipitation conditions were selected according to a central composite design. Statistical analysis showed a significant e...
Source: Brazilian Journal of Chemical Engineering - October 5, 2018 Category: Chemistry Source Type: research