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Biodiesel is a fuel derived from renewable sources such as vegetable oils, animal fats, or residual oils. Although it is a potential source of energy, the efficiency of the production of this fuel depends on several factors, including variables associated with the stirring and mixing process of the reactions. The proper choice of these variables can avoid the formation of vortices, favor the flow direction and the homogeneity of the mixture, and, consequently, contribute to a higher yield of biodiesel. In this context, the present work investigated the effect of agitation and mixing on the production of soybean biodiesel from the analysis of parameters: impeller (blade - turbine), stirring speed (150 rpm – 300 rpm), and baffle (with-without). For this, a 2³ factorial experimental design was carried out for the methylic and ethylic routes. In the reactions, the oil: alcohol molar ratio, amount of catalyst, time, and temperature were fixed. Experimental results indicated higher yields for reactions via the methylic route (more than 93%). Through the statistical analysis, it was also verified that the presence of a baffle and the use of a turbine impeller were the variables of greater statistical significance for the methylic and ethylic routes, respectively. These results showed that the variables considered had a significant impact on the yield of the reactions, although the reaction conditions remained constant, which reinforces that only the control of stirring and mixing parameters can promote optimal yields of the reactions, reducing costs with reagents, operating time, or temperature control.

Made available in DSpace on 2022-04-28T19:42:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-08-12 This paper reports experimental results and thermodynamic modeling of the liquid-liquid equilibrium (LLE) of the system chicha biodiesel (Sterculia striata) + glycerol + ethanol. Binodal curves and tie lines were obtained at different temperatures (303.15, 318.15, and 333.15 K) and atmospheric pressure (101.3 kPa). The quality of the experimental data was evaluated using the criteria of Marcilla and co-workers. The nonrandom two-liquid (NRTL) and analytical solutions of groups (ASOG) models were used to correlate the LLE data. Both models well fitted the experimental data with root-mean-square deviations (rmsd) not greater than 1.5%. Laboratory of Separation Systems and Process Optimization (LASSOP) Center of Technology Federal University of Alagoas, Alagoas Department of Chemical Engineering Federal University of Parana, Paraná Engineering School of Lorena Department of Chemical Engineering University of Sao Paulo (USP), São Paulo Department of Energy Engineering Sao Paulo State University (UNESP), São Paulo Department of Energy Engineering Sao Paulo State University (UNESP), São Paulo

Interest on the use of lignocellulosic waste from second-generation (2G) ethanol industry has increased each year, where biochar and bio-oil production by pyrolysis is a relevant alternative. Biochar has high energy, adsorption capacity and soil enrichment potential, while bio-oil has applications for the pharmaceutical, chemical and fuel industries. Nonetheless, research on pyrolysis of this residue has not been reported, nor has the characterization of the bio-oil produced been profiled. Besides this, few studies on biochar and bio-oil produced from sugarcane bagasse have analyzed the effects of temperature and heating rate on yield. This work investigates the production and characterization of biochar and bio-oil by pyrolysis from this 2G waste. Temperature (500–700 °C) and heating rate (5–15 °C min−1) were the variables evaluated using a full factorial design (FFD), while biochar and bio-oil yields were the responses investigated. Characterization was carried out by thermogravimetric analysis, physical and chemical analyses, Fourier transform infrared spectroscopy, dispersive energy X-ray fluorescence spectroscopy (EDS) and gas chromatography–mass spectrometry (GC–MS). From FFD results, linear models were successfully fit to the responses. Maximum biochar and bio-oil yields of 40.3% and 39.0% were found for a set of temperature-heating rates of 500 °C-5 °C min−1 and 700 °C-15 °C min−1, respectively, in agreement with residue from first-generation ethanol process. The biochar presented low content of ash, volatile materials and moisture as well as high fixed carbon content and heating values, showing high energy potential. The bio-oil exhibited alternativity as source of phenols (53.2%) for industry based on the GC–MS results.

The activated biochar is a carbonaceous material obtained from thermal degradation of biomass with high adsorption potential. On the other hand, the high production cost has still limited its use in large-scale, so that low-cost raw materials derived from biomass have been encouraged. For instance, waste from palm oil industry, such as palm endocarp (Elaeis guineenses), has shown high potential to produce cheaper activated carbon since high amount of palm residues are annually generated worldwide. Moreover, as far as we know, Elaeis guineensis-biochar activated by ZnCl2 has not been tested as an adsorbent for methylene blue (MB) removal. In addition, optimization studies on activation variables focused on maximizing MB removal are still scarce. This work aims to investigate the adsorption capacity of the Elaeis guineensis-activated carbon for MB removal and to find optimized conditions. Thermo-chemical activation was carried out using ZnCl2. Temperature ( $$T$$ ), activation time ( $$t$$ ) and particle size ( $$PS$$ ) were the variables evaluated through a full factorial design. The optimal condition was obtained based on central composite design (CCD) and surface response methodology (RSM) techniques. Kinetic and equilibrium studies were also carried out. CCD and RSM predicted an optimal MB removal of 93.2% adopting 0.05 g of activated biochar, PS = 65 mesh, $$T\hspace{0.17em}$$ = 700 °C and $$t\hspace{0.17em}$$ = 3 h. Kinetic and adsorption equilibrium results agreed to pseudo second-order model and Langmuir’s model, respectively. Finally, Elaeis guineensis showed to be a promising feedstock to produce activated biochar aiming MB removal from water and wastewater.

To produce biodiesel, one of the most important factors is the quality of the oil used in the production. However, other factors such as price and availability should also be taken into consideration. Chicken wastes oil shows a very promising option for this sector, since it comes from a waste. The aim of the present study was a methodology for extraction and characterization of chicken wastes oil for production of biodiesel by ethylic transesterification, besides presenting the characterization and optimization of the process variables of the production of biodiesel, the applying of RSM involving CCD. The investigation was performed following evaluation of the characterization parameters for the oil: viscosity, density, acidity index, moisture of the sample, refractive index, and saponification index. For biodiesel, viscosity, density, acidity index and ester content were evaluated. An optimum point was reached for the production of chicken biodiesel where the concentration of the catalyst is 2.1% by mass, the oil/ethanol ratio is 1:5.5 and the reaction temperature of 30 ?C; at that point, a 95% conversion was achieved. At the optimum point obtained from the statistical technique for a p-value of 0.05 the results found for the physical- chemical characterization of biodiesel are found in the ANP standards.

A fitoterapia apresenta interesse medico e veterinario em âmbito mundial, sendo considerada confiavel e com abrangente aplicabilidade em populacoes tradicionais. Com objetivo de analisar a viabilidade de investir em pesquisas e desenvolvimento de produtos veterinarios contendo a planta “sambacaita” ( Hyptis pectinata) , vegetal com propriedades analgesica, anti-inflamatoria, antimicrobiana, anti-edematogenica e cicatrizantes; realizou-se um estudo prospectivo tecnologico atraves de levantamento de artigos cientificos e patentes depositadas que demonstram o interesse da ciencia relacionado ao tema cicatrizacao de feridas e Hyptis pectinata . Os resultados demonstram perspectiva de mercado aberto a este tipo de investimento tendo como publico-alvo os animais.

Dry rot of yam (Dioscorea spp.) caused by Scutellonema bradys and Pratylenchus spp. has restricted yam production in Brazil. Plant-based products can be useful reducing nematode damages. The objectives of this study were to evaluate the nematostatic and nematicidal in vitro activities of pyroligneous extracts from Cocos nucifera, Syagrus cearensis, S. coronata, and Wodetia bifurcata palms against S. bradys and to evaluate the effect of C. nucifera pyroligneous extract in the treatment of yam tubers infected by S. bradys and Pratylenchus sp. under greenhouse conditions. The pyroligneous extracts obtained at pyrolysis temperatures of 400, 500, 600, and 700 oC, and at different concentrations, were tested for nematode immobility and mortality in Kline slides. Cocos nucifera pyroligneous extract obtained at 400 °C and 1% concentration was tested on yam tubers, under different immersion periods. Six months after yam planting the nematode populations were evaluated. All pyroligneous extracts inhibited the mobility and caused mortality to S. bradys, however 100% inhibition of both variables was achieved at concentrations varying from 0.75 to 2%, depending on the pyrolysis temperatures. The reproduction factor was reduced in 43% by treating infected yam tubers with pyroligneous extract from C. nucifera.

Second-generation technology (2G) is currently the industrial route that is being developed with the potential to meet the demand for biofuels and bioproducts. The technology studied in the present work is based on the non-food processing of sugarcane straw, which is unlike the bagasse processing route (a lignocellulosic residue) that is commonly used in boilers for steam and electricity generation. In the last years, cellulosic ethanol plants worldwide include the utilisation of corn stover, sugarcane bagasse, wood waste and plant residues. Therefore, a communication based on industrial aspects using sugarcane straw is important in order to expand the knowledge regarding this promising technology. The main objective of this work included listing the results obtained in a cellulosic-ethanol production industry using sugarcane straw, located in the Northeast region of Brazil and taking into account the efficiency of pre-treatment, enzymatic hydrolysis and fermentation processes and comparing these results with data found in the literature regarding studies with similar efficiency. It was possible to observe that the production of ethanol from sugarcane straw at an industrial scale achieved a productivity of 200 l of ethanol per tonne of biomass, exhibiting 90, 70 and 85% of pre-treatment, hydrolysis and fermentation efficiency, respectively.

Petroleum is one of the top commodities in the world, which produces some of the most environmentally hazardous wastes, such as produced water. Thus, research on technologies capable of processing wastewater are important for promoting the treatment of this waste and reducing costs in the segment. Among the processes used to treat wastewater, flotation is one of the leading methods used in physical separation operations. The efficiency of this technique has a high influence on internal hydrodynamic flows. This paper proposes a mathematical modeling to fluid dynamics of oil-water separation in an airlift flotation column based on momentum and continuity balance equations. To simplify the modeling used, we considered only the drag force as the most relevant interfacial force in this phenomenon. The software Ansys CFX 13.0 was used to evaluate the data. Three columns were created, and all data were submitted to a simulated effluent, containing 1000 ppm of oil. By evaluating efficiency selection in three columns and observing the countercurrent design, we found 84.72% as the best result achieved. This result can be associated with a column model that allows better phase contact as an ideal turbulence in the recirculation zone. Despite the simplifications in the proposed model, it is possible to observe a good association between the results obtained in the simulations and the ones presented in the literature.

The use of renewable sources has been an alternative to decrease the negative environmental impacts of fossil fuels. In this context, bioethanol from sugarcane has proved to be a successful option to gasoline. However, bioethanol purification through conventional distillation requires high-energy demand. For this reason, energy balance calculations are very useful to estimate steam demand. As a result, simpler alternatives for estimation of steam consumption from spreadsheet calculations have been encouraged. In contrast, many efforts have focused to solve complex flowsheets including tear streams, which increases convergence complexity for each change on feed composition and additional components. In this work, mathematical models were fitted to bioethanol–water mixture property data and applied to energy balance calculations involved in the conventional process for hydrated bioethanol purification. Total steam consumption was obtained for volume percentages of bioethanol in the wine feed stream of 6, 8 and 10 °GL considering potential losses found in the industrial reality. The calculated data were compared to simulations carried out in the Aspen Plus® software. Similar values of total steam consumption were found comparing the two approaches, where the average absolute relative deviation was kept below 5%. Moreover, simulated temperature and composition profiles agreed to process data. Finally, mathematical models and energy balance calculations proved to be a simpler and faster alternative to estimate total steam consumption involved in the hydrated bioethanol purification from wine.

The use of biomass obtained by pyrolysis has received great attention due to its favorable characteristics to the improvement of soil quality for agricultural purposes, soil remediation against several types of contaminants and great potential for carbon sequestration. This study aimed to evaluate the physical–chemical characteristics of biochar produced from the endocarp of Syagrus coronata. It was determined the best operational conditions to obtain a biochar with good features to be used in soil as fertilizer. The thermal gravimetric analysis (TGA/DTGA), elemental analysis (EDX), scanning electron microscopy and infrared spectroscopy (FT-IR) techniques allowed the finding that the pyrolyzed at 400 °C was the one that presented a greater stability and more suitable characteristics, in comparison to the other materials. The material in that condition is more favorable to be used as a natural fertilizer to improve the ground standard and, consequently, to stimulate the agricultural productivity.

Currently, biodiesel is marketed with mineral diesel constituting blends of biodiesel in accordance with the National Program for the Production and Use of Biodiesel (Law 11,097/05) but depending on the composition of biodiesel/diesel blends, there will be the physico-chemical properties of the mixtures. Among the properties, the density and kinematic viscosity very significantly with the changes in the compositions of the mixtures and therefore deserve to be high lighted, besides representing two important parameters monitored by National Petroleum, Natural Gas and Biofuel Agency (ANP) resolutions. In this article, the biodiesel produced from chichá oil was mixed with diesel in different proportions where the viscosities and densities of the blends were analyzed at different temperatures. With the values obtained, a study of the influence of these variables was carried out and a model of a surface was proposed to adjust the curves that varied as a function of the biodiesel concentration and the temperature. The model was validated with an unused curve during its construction and showed good ability to represent the relationship between the variables. Experimental data showed that the density and viscosity of the mixture increase with increasing percentage of biodiesel in the mixtures and decreased with increasing temperature for all biodiesel mixtures studied. Keywords: Biodiesel, Chichá, Modeling, Viscosity, Density

This study aimed to analyze the influence of stirring and mixing on the production of soybean biodiesel. It was verified the influence of the baffle, different stirring speeds and two types of impellers (turbine and blade). The experiments were conducted by full experimental design 23 with the following fixed parameters: temperature (70 °C), oil/ethanol molar ratio (1/10), catalyst amount (1.5%), and reaction time (30 min). The independent variables were impeller type (turbine or blade), baffle (presence or absence), and stirring speed (150 or 350 rpm). Chromatographic analyses helped to determine the yield of biodiesel production at different operating times. The optimized parameters turbine impeller, absence of baffle, and stirring speed of 350 rpm provided high biodiesel yields within the first minutes of reaction. The analysis of the effect over time allows to verify in which period the variables had more influence on the biodiesel production and in which time there is no increase of the yield. Keywords: Optimization, Stirring, Biofuels, Production

Among the methods of controlling the spread of red ring disease, the use of pheromones associated with food traps has been shown to be very efficient in capturing the pest insect. The pheromone used is called Rincoforol and is available in microtubes. Studies are under development to apply the capture agent to solid matrices. In this context, the present work was carried out in order to evaluate the adsorptive capacity of the activated carbon of the palm oil endocarp in the incorporation of Rincoforol for controlled release of pheromone in the field. For this, a complete experimental planning (23) was carried out in order to evaluate the influence of the use of stabilizer with the pheromone, the granulometry of activated carbon and the number of holes in the sachet in the release process, obtaining in response to mass loss. It was found that the condition that favors the controlled release of the pheromone, when compared to the release made in eppendorf, was the use of formulated Rincoforol (with stabilizer) adsorbed on charcoal with smaller particle size (35

This study reports experimental data for the liquid–liquid equilibrium (LLE) for a {peanut biodiesel (1) + glycerol (2) + ethanol (3)} system at 303.15 K and 323.15 K at atmospheric pressure. Solubility (binodal) curves were obtained by a cloud-point method. The reliability of the experimental data was confirmed using the Hand and Othmer–Tobias correlations. The regression coefficients were above 0.97 for all data sets. The universal quasichemical model was successfully used to correlate LLE data, which showed root-mean-square deviations of 0.99%, indicating accuracy close to experimental uncertainties.

This work aims to produce activated carbon from the endocarp of Syagrus oleracea by vacuum pyrolysis and evaluate its potential as an adsorbent. The effects of pyrolysis temperature (400 °C, 500 °C, 600 °C, and 700 °C), particle diameter (0.467 mm, 0.267 mm, and lower than 0.234 mm), and activation agent (H2SO4, H2PO3, and KOH) on the potential for methylene blue adsorption were investigated. In addition, kinetics and adsorption equilibrium were evaluated. The best condition found was particle diameter

Produced water is a waste generated in the units of petroleum production having as main characteristics the high salinity with presence of emulsified oil, suspended solids, chemical additives, heavy metals and other contaminants. Considering that the inadequate disposal of this water causes environmental contamination, this work aimed to investigate the adsorption of emulsified oil present in the produced water, using sugarcane bagasse (an abundant by-product from sugar/ethanol production) as adsorbent, improving the treatment of this type of effluent. The adsorption reached equilibrium within 5 minutes of contact and more than 90% of the emulsified oil present in the mixture was removed when 0.1% adsorbent (m/v) was used at 30 °C and 110 rpm. Pseudo first-order and pseudo second-order models were applied to adjust the kinetic data. The best correlation was provided by the pseudo first-order kinetic model demonstrating that chemical sorption was the rate-limiting step, although intraparticle diffusion can not be neglected. From these results, it can be stated that the use of sugarcane residues as an adsorbent agent is an alternative for the efficient removal of the oil present in the produced water. Thus, two partial problems can be solved: wastewater treatment and agroindustrial residue disposal.

In this work, LDH-biochar composites were synthesized in different molar ratios of Mg:Al (2:1, 3:1 and 4:1) using co-precipitation method. The composites were applied to remove an organic dye from aqueous solutions by adsorption. The composites and the pure bovine bone biochars were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) measurements, thermogravimetric analysis (TG/DTG), dispersive energy spectroscopy (DES) and scanning electron microscopy (SEM). The methylene blue dye adsorption experiments were conducted in a finite bath. The results indicate that pH 12 is more suitable for dye adsorption process, with a removal >95% for all composites. The adsorption kinetic was best described by the pseudo-second order model, reaching the equilibrium in approximately 20 min. The Redlich-Peterson model fit the adsorption equilibrium isotherms satisfactorily. It was obtained a maximum adsorption capacity of 406.47 mg·g −1 at 40 °C. Negative values of ΔG indicate the spontaneity of the adsorption process. The positive value of ΔH (30.72 kJ·mol −1 ) indicates the physical nature of the adsorption and the positive value of ΔS (0.1863 kJ·mol −1 ) indicates that there was a change in the structure of the adsorbent and increased randomness during the fixing of the dye.

Biodiesel production consists of several processes, the reaction stage being the most important. However, after reaction, the biodiesel product undergoes separation involving an aqueous phase, henc...

In this work, agro-wastes coming from soursop (peel, seeds and pulp fiber) and sugarcane (bagasse) are used as low-cost biosorbents to remove methylene blue (MB) from aqueous media. Batch experiments are performed under different experimental conditions investigating the effects of biosorbent amount, dye concentration and stirring rate. The best results were found using soursop wastes for a MB concentration of 100 mg L−1, using 0.75 g of residue and a stirring rate of 110 rpm, removing a percentage above 90%. Theoretically, adsorption kinetic can be successfully described by the pseudo-second order model. Redlich-Peterson and Sips models are adopted to interpret the equilibrium adsorption of MB on sugarcane bagasse and soursop residue, respectively. Interestingly, the monolayer model with single energy derived by statistical physics theory is also applied for a deeper explanation of the adsorption mechanism of MB on both the adsorbents. The application of this model allows defining the adsorption geometry of the investigated adsorbate and provides important information about the interactions between the adsorbate and sorbents. In particular, the modelling analysis by statistical physics allows defining that the dye molecules are adsorbed in vertical position and the adsorption process is multi-molecular (i.e. n > 1). Finally, the estimation of adsorption energy suggested that MB adsorption on biosorbent is a physisorption process.

The objective of this work was to evaluate and compare the potential of polyurethane and kapok (Chorisia speciosa) residues as sorbent materials in the treatment of diesel spillage. To determine the sorption capacity, gravimetric tests were performed in static medium at room temperature and at different temperatures (10, 15 and 28 °C) and varying the time of contact between the sorbent material and diesel. It was observed that the sorption process occurs at a high velocity, with saturation point achieved in the first 5 minutes of contact, and the natural fiber presents higher sorption capacity compared to the polyurethane residue due to the low viscosity of diesel oil, that contributes to reduce de entrapment inside the porous foam. It has also been observed that the polyurethane residue exhibits an increase in sorption capacity with time and temperature increase. Scanning electron microscopy (SEM) analysis have shown that the main morphological property involved in smooth oil sorption was the high porosity associated with a small porous diameter. The kapok presented sorption capacity of 37 g/g in equilibrium demonstrating its great potential of application as a sorbent material for the treatment of diesel spillage. Keywords: Removal; Diesel; Natural Fiber; Polymer; Sorption.

The oil spill off the coast of the Brazilian Northeast region is one of the most significant global events regarding contamination and environmental impact in recent years. This work evaluates the effects of oil spills on the Northeast coasts between Alagoas and Sergipe states from October 2019 to January 2020. Analysis of some sampling points of seawater revealed the presence of Hg, Cd, Pb, and Cu in levels above the maximum concentration limits established by the Brazilian legislation. For water quality parameters, phosphorus, nitrite, and turbidity showed statistically different values. However, the chromatographic profiles of oil obtained from different beaches were quite similar. Seawater, fishes, and massunins (bivalve) presented the main polycyclic aromatic hydrocarbons: naphthalene, phenanthrene, fluoranthene, fluorene, and acenaphthalene. Therefore, the concentration of organic and inorganic contaminants determined in different environmental locations served as a subsidy to assess the effect of the preliminary oil spill on the Brazilian coast.

Aiming investigated the pyrolysis of the agricultural waste known as cassava stump, the portion of the plant to which the tuberous roots and aerial parts of the plant are attached, this study had as objective to produce biochars from cassava stump by conducting vacuum pyrolysis at 400, 500, or 600 °C. The biochars were characterized by proximate analysis, thermogravimetric analysis, Fourier-transform infrared absorption spectroscopy, X-ray diffraction, scanning electron microscopy, and nitrogen adsorption. Adsorption affinity tests were performed with four different dyes: methylene blue, basic fuchsin, acid fuchsin, and alizarin. Biochar obtained at 500 °C, heating rate of 20 °C.min−1, and 90 min of residence at the final temperature, had 22% higher fixed carbon content as compared to the other biochars and 3.16 times greater fixed carbon content than the original cassava stump. This biochar showed the best adsorption capacity (0.0679 mmol/g) and percentage of removal (87.6%) of methylene blue dye...

This work evaluates the application of Mytella falcata shells, discarded in large quantities in the state of Alagoas, Brazil, as adsorbent for methylene blue dye (MB). It was investigated how the amount of adsorbent (M), the average particle diameter (G), and the agitation speed (A) affected the adsorption. Kinetic and equilibrium studies were conducted, and the pseudo-second-order equation adequately represented the kinetic data and isotherms following Liu’s model (q max = 8.81 mg g−1 at 60 °C). The adsorption was spontaneous, favorable, and endothermic. Mytella falcata shell is a suitable adsorbent for MB and could potentially contribute to its removal from the environment.

Produced water is the largest liquid effluent in volume generated in petroleum production. It originates from natural wells or from water that was previously injected during the exploration process. The composition of produced water is complex, containing high salt concentration, emulsified oil, suspended solids, chemical additives used in the various stages of oil production, heavy metals, and other contaminants. Several technologies can be used in the treatment of produced water in order to meet the conditions specified in local legislations and the most used are phase separators, decanters, cyclones, and filters. The separation process mechanism of oil emulsions by coalescence in fibrous media has excellent results, though it is not fully understood and is frequently based on empirical, as well as on experimental, observations. This article presents a general overview on produced water, including origin, production, composition, environmental impact, treatment techniques, disposal, and legislation, as well as an updated discussion utilizing recent literature regarding the unit operation of coalescence: general aspects, kinetics, mechanisms, and factors that influence the coalescence process.

This work aims to produce activated carbon from the endocarp of Syagrus oleracea by vacuum pyrolysis and evaluate its potential as an adsorbent. The effects of pyrolysis temperature (400 °C, 500 °C, 600 °C, and 700 °C), particle diameter (0.467 mm, 0.267 mm, and lower than 0.234 mm), and activation agent (H

In this work the properties of activated carbon obtained from macauba endocarp were evaluated, an agro-industrial waste widely produced in Brazil. This material was applied to remove the herbicide atrazine, an emerging pollutant. The biochar it was produced by vacuum pyrolysis (temperatures of 400 °C and 600 °C; heating rates 10 and 50 °C min−1) and activated with K2CO3. The characterizations of materials were performed by elemental analysis (CNHO), immediate analysis, TG/DTG, density, FTIR, DRX, SEM and surface area analysis by the N2 adsorption and desorption method. Chemical reactivity of the atrazine molecule was investigated using DFT-based reactivity descriptors. For the kinetic profile and mechanism proposal, rate equations of pseudo-first-order, pseudo-second-order and intraparticle diffusion were considered. Activated carbons showed a typical amorphous structure, with an increase in the porous cavity after chemical activation process. Surface areas of 951–1002.5 m2 g−1 were obtained after activation with pores in the range of 1.70–2.67 nm. Activated carbons showed a high affinity with atrazine with a 90–98% removal percentage. The quantum chemical parameters calculated were the energy of the HOMO (EH = −6.4649) and LUMO (EL = −0.4558) orbitals, global chemical hardness (η = 3.0045), chemical potential (μ = 3.4603) and the global electrophilicity index (ɷ = 1.9926). In the kinetic study, the pseudo-second-order model was more predictive in adsorption tests. These results suggest that macauba endocarp activated carbon is efficient in atrazine removal, in addition to being a strategy for using agro-industrial waste.

Alternatives for the use of acai seed have been investigated to remove caffeine from aqueous solutions. The pyrolytic process was conducted under two temperatures and heating rates (400 °C, 10 °C min−1 and 600 °C, 50 °C min−1), with a vacuum pump coupled operating at 20 kPa and the biochar was activated with K2CO3, resulting in CA-SA 400/10 and CA-SA 600/50. Density, moisture, volatile and ash content were evaluated for biomass, as well as their activated carbons were characterized through elemental, thermogravimetric (TGA) analysis, N2 adsorption and desorption isotherms (BET/BJH), infra red spectroscopy with Fourier transform (FTIR), X-ray diffraction (DRX), scanning electron microscopy (SEM), dispersive energy spectroscopy (EDS) and by the pHZPC method. CA-SA 400/10 and CA-SA 600/50 showed high values of specific area (1150.4 and 929.3 m². g−1), average similar pore diameter (2.55 and 2.66 nm) and a mixture in the structure between amorphous phase and graphitic. The adsorptive study showed that the pseudo-second order model adjusted better to the kinetic data and that intraparticle diffusion is not the only step that limits the process. Quantum chemical parameters were evaluated for caffeine, based on the Density Functional Theory (DFT) calculations, in order to understand its chemical reactivity at the atomic level. The results showed that the use of activated charcoal from acai seed is a promising material for removing caffeine, and emerges as an innovation for using the tailings.

Aiming to evaluate how stirring procedures impact biodiesel production from castor oil, this work employed a fractional factorial design to study the influence of some parameters on the alkaline catalytic transesterification of castor oil for biodiesel production. Biodiesel was produced in a pilot plant equipped with a stirring tank reactor and a thermostatic bath. The study used a 27-2 factorial design. The variables were stirring rate, presence or absence of deflection, impeller type, oil/methanol molar ratio, reaction time, temperature, and catalyst type. Gas chromatography afforded the reaction yields. Analysis of each variables as well as evaluation of binary interactions helped to determine how the parameters affected biodiesel production. The best conditions for a yield of 99.3 % were: turbine impeller, absence of deflection in the reactor, stirring rate of 500 rpm, 1:7 oil/alcohol molar ratio, sodium hydroxide as catalyst, reaction time of 30 min, and temperature of 50 °C.

Biodiesel is an alternative to fossil fuels. Its industrial production relies on vegetable oil transesterification with a short-chain with ethanol using sodium hydroxide (NaOH) as the catalyst. The growing demand for biofuels has motivated studies on new vegetable oil sources. Sterculia striata (Chicha) seeds are particularly interesting in this sense—their mass consists of about 40% oil, so it is possible to convert them into biodiesel in high yield. Hence, this manuscript aimed to investigate how process variables affect biodiesel production from chicha oil. Application of a factorial design technique aided analysis of four process variables: temperature (30–70 °C), oil/alcohol molar ratio (1:6–1:10), catalyst amount (0.5–1.5% w/w), and reaction time (0.5–2.0 h). The resulting biodiesel met most of the standard requirements; however, its density lay above the values established by the Brazilian petroleum agency. Considering variables evaluated the best conditions were temperature = 30 °C, oil/alcohol molar ratio = 1:10, 1.5% catalyst in relation to oil (w/w), and reaction time = 30 min.

Fibers from silk-cotton tree were characterized by scanning electron microscopy, Fourier transform infrared, thermogravimetric analysis, photoluminescence excitation and applied in the sorption of diesel oil. Sorption oil capacity, kinetic behavior and dynamic retention potential were evaluated. To understand the functionalization contribution from surface, waxy contend was extracted and characterized by gas chromatography with mass spectrometry and the material was subjected again to sorption tests to measure the modified capacity. The results indicated that the fibers are composed by aliphatic and aromatic hydrocarbons which confers hydrophobic and oleophilic character, reaching more than 58.462 ± 6.733 g/g of diesel sorption in a rapid phenomenon, according to Fractal Like-Linear Driving Force model adjustment, ruled by absorption mechanisms. It has also been noted that the arrangement of fibers provides high retention stability with more than 85% of oil still trapped after agitation, and the extractive process has been proved that surface waxes influence the oleophilic character of the material, but do not reduce its sorption potential. Therefore, the material demonstrates outstanding environmentally friendly features due to its high availability, agricultural origin and light oil spill resource for its fast, high and stable sorption capacity.

O desenvolvimento de novos materiais e crescente ao longo das decadas, tendo como destaque os catalisadores, os quais exercem papel importante nos processos industriais atuando em reacoes como de transesterificacao e esterificacao na producao de diversos compostos, a exemplo, os biocombustiveis. Neste trabalho realizou-se o levantamento prospectivo tecnologico de catalisadores utilizados em reacoes de transesterificacao e esterificacao. A execucao das buscas de patentes e artigos ocorreu em diferentes bases de dados utilizando-se as palavras-chave catalyst AND transesterification AND esterification . Essa tematica tem atraido atencao no meio industrial e academico como observado no Scopus, com o numero de publicacoes de 719 documentos, com os paises lideres China e India; e no quesito numero de patentes depositadas conforme o Patent Inspiration , de 216, destacando-se os Estados Unidos e Japao. O Brasil apresenta crescente interesse nesse cenario por meio do desenvolvimento e aperfeicoamento de catalisadores.

The endocarp of Wodyetia bifurcata was used to produce biochar by vacuum pyrolysis as an alternative adsorbent for methylene blue (MB) removal. The influence of different pyrolysis temperatures, particle diameters and activation agents in the adsorption process was studied. Kinetics and adsorption equilibrium were also evaluated. Biochar obtained at higher pyrolysis temperatures and activated with H3PO4 showed the best adsorptive capacities, achieving 83% of MB removal. The experimental data fitted better with pseudo-second order model. Isotherms performed at 25, 40, 50 and 60 °C showed that the adsorption of MB onto the activated biochar had no concentration dependence in the range studied. Experimental isotherms fitted well with the Freundlich and Sips models and the thermodynamic parameters suggested a physical adsorption mechanism in a heterogeneous surface, spontaneous at all temperatures evaluated. In brief, the activated carbon obtained from Wodyetia bifurcata can be a promising material for MB removal from aqueous solutions.