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A novel process for the purification and recycling of CO2 (PRCO2) in a pilot scale unit was implemented and validated. The system is a 4-cycle pseudocontinuous process composed of on-line supercritical fluid extraction integrated with fractionation of extracts in three separation vessels, followed by purification of CO2 in adsorption column at subcritical conditions, and subsequent recycling of the purified CO2 with the aid of a storage tank. Turmeric and annatto were the plant matrices used for extraction and oat bran was used as adsorbent. The PRCO2 reduced the consumption of CO2 in 85.24% for annatto and 74.27% for turmeric, representing monetary savings of USD 186.40 and USD 111.83, respectively. Economical evaluation showed that the increasing of the number of cycles decreased the cost of manufacture from USD 349.60/kg to 122.67/kg for the processing of annatto and USD 91.31/kg to USD 36.56/kg for the processing of turmeric.

The use of supercritical CO2 (SC–CO2) antisolvent for micronization, coprecipitation, and fractionation of high-value products for biorefining of plant matrices into marketable products has been a promising and increasing research topic. These SC–CO2 antisolvent processes are able to microencapsulate many materials that are difficult to treat with conventional techniques. In addition, the control of the morphology of materials by adjusting nucleation and growth during particle production is provided. The use of supercritical antisolvent processes is advantageous when compared with other methods like freeze-drying, drying at high temperatures and spray-drying such as uniform particle size distribution in the products and high efficiency to obtain nano or microparticles. The optimization of the process on the yield and quality of obtained particles properties depend mainly on the operational conditions such as pressure, temperature, and concentration of the bioactives solution, in terms of extract and polymer. Thus, this chapter provides some insights about the fundamentals and effects of operational conditions of these SC–CO2 antisolvent processes.

The use of supercritical CO2 (SC–CO2) as a solvent for the extraction of vanillin from organosolv media was proposed and evaluated. The use of sugarcane bagasse as a biomass source to product diversification has been gaining much attention recently and it is a very promising research topic. From sugarcane bagasse, it is already produced fuels as 2G ethanol and others are being investigated as methanol, SNG. Also, different bioproducts as PET area already in the market and bioproducts as xylitol, vanillin, etc. are under study or investigated in pilot plants. Thus, in this chapter, some perspectives on vanillin production from sugarcane bagasse lignin using supercritical CO2 as a solvent in a novel integrated second-generation ethanol biorefinery are presented.

This chapter proposes an innovative biorefinery conceptual process for the production of carotenoids from microalgae using lignocellulose-based biorefinery products and/or by-products and pressurized fluids. The extraction process, which can be done also with microalgal biomass with high content of moisture avoiding high-cost downstream processes, involves the use of ethanol and 2-MethylTetraHydroFuran (2 MTHF) mixed or in a sequential form for selective extraction of carotenoids. 2 MTHF is obtained from furfural, which is produced as a by-product during lignocellulosic biomass (sugarcane bagasse, wood, corn stover, rice straw, etc.) pretreatment for ethanol production, for example. The solvent recovery step involves the use of CO2, which is obtained from ethanol fermentation as a by-product. Specific conditions for CO2 for temperature and pressure to achieve supercritical conditions would be applied in order to besides high solvent recovery and recycling provide a desirable selective carotenoid purification and encapsulation if a coating material is added. The two-step process can be converted in a one-step process minimizing carotenoid degradation if the extraction process is performed under higher pressure than that performed during extract precipitation. In addition, the proposed processing route can be well integrated into conventional existing biofuels production (gasification, combustion, etc.) scenarios using the solids recovered after carotenoids production as feedstock.

This chapter discusses the recent (2013–2018) applications on the use of supercritical CO2 (SC–CO2) antisolvent for micronization, coprecipitation, and fractionation of high-value products for the food, cosmetic, and pharmaceutical industries, most focusing on the applications of integrated techniques on the biorefining of plant matrices into marketable products using supercritical carbon dioxide as an antisolvent. The concept of the biorefinery is defined as sustainable processing of feedstocks for bioenergy and biochemical purposes resulting in various marketable products, such as natural dyes, antioxidants, proteins for food and feed, lipids for biodiesel, and carbohydrates as feedstock for bioethanol production

This work investigates a novel approach for turmeric rhizomes valorization for the obtaining of microparticles composed of curcuminoids ethanolic extract and fractionated volatile oils, using compressed carbon dioxide as an antisolvent and the recovery of phenolic compounds and carbohydrates with pressurized hot water. In addition, a cheap and versatile method for the quantification curcuminoids using thin-layer chromatography coupled to image processing analysis was applied to the solid wastes and liquid extracts from turmeric, derived from extraction processes which employed supercritical CO2 and pressurized liquid ethanol. Coprecipitation of PEG with compressed CO2 resulted in the formation of spherical particles and blocks of aggregates. The reaction with vanillin-sulfuric acid reagent favored the detection of curcuminoids with a reasonable sensibility and wide linear range and mean recoveries between 92 and 104%.

It is presented a technical and economic analysis of ammonia borane confined in silica aerogel using carbon dioxide at subcritical conditions. The process was simulated in Aspen Plus software and an economic analysis was carried. The results showed that it is possible to produce 4795 kg/year of products with a total investment of 1.32 MUSD and a cost of manufacturing per mass of product of 183 USD/kg fixing the ageing time to 5 days. The results indicated that microparticles residence time is a restrictive factor of the process as it limits the number of process cycles in a year. According to new experiments, it is possible to reduce time from 5 days to 2 days. This implies the decrease in the cost of manufacturing to 87 USD/Kg with the same total initial investment and a rise in the annual productivity to almost 12 t/year.

The present study evaluates a sugarcane biorefinery producing ethanol through juice fermentation and methanol via gasification of sugarcane lignocellulosic residues and liquid fuel synthesis. Two technologies of gasification named entrained flow and circulating fluidized bed are compared. Flowsheet modeling and thermo-economic analysis methods are applied, followed by a multi-objective optimization based on a genetic algorithm. The optimum Ethanol–Methanol biorefinery design options are compared with other previously studied sugarcane biorefineries. The results show that the biorefinery's energy efficiency increases significantly with the integration of a methanol production plant in a conventional ethanol distillery. The configuration using an entrained flow gasifier presents lower conversion efficiency than the one using a circulating fluidized bed gasifier. However, for the entrained flow gasifier configuration, the size of the methanol production process could be bigger since more heat is available for the ethanol process favouring the integration with the ethanol plant. Higher energy efficiency due to increase of methanol production leads to a higher total investment for both gasification technologies. The cost analysis shows that the calculated methanol production cost is 30% higher than its current market price. Environmental incentives for biofuels could change this scenario but are not in the scope of this study.

Quercetin is an antioxidant compound with promising activity against a wide variety of diseases. However, a major limitation for the clinical application of quercetin is its low bioavailability, due to its low solubility in water. One way to increase the bioavailability of quercetin is to precipitate it in sub-micrometricscale, encapsulated by a surfactant material, using the Supercritical Fluid Extraction of Emulsions (SFEE) method. The objective of this work is to study the scale-up of a semi-continuous SFEE process for the production of microencapsulated quercetin. An experimental study of the encapsulation of quercetin in soy-bean lecithin–Pluronic L64®surfactants was performed in order to evaluate the variation of product characteristics with significant parameters, such as duration of SFEE, density of CO2 medium, used CO2/L of emulsion (kg/L), and thus determine the suitable conditions for scale-up. In addition, a themo-economic evaluation was done in order to identify bottlenecks during scale-up and promote solutions. According to the thermo-economic evaluation, the decrease of CO2 flow demonstrated to be the main parameter to decrease the energy demand and cost of manufacturing of the SFEE process. Thus further experimental studies should be done towards optimization of this parameter.

Chitosan is a natural polymer largely studied for heavy metal adsorption applications, since the amino and hydroxyl groups present in its structure can act as chelation sites. However, this material presents some drawbacks as adsorbent due to its low mechanical strength. Studies have shown that the use of immobilized chitosan on glass beads can improve the mechanical strength of adsorbent and enhance mass transfer properties. For this reason, stirred batch experiments of copper adsorption on chitosan immobilized onto glass beads were performed to estimate the surface diffusion coefficient and the chitosan film thickness, considering an inert solid glass core. The kinetic data were modelled by a surface diffusion model incorporating the external film mass transfer resistance. Column experiments were also performed for copper solution at different flow rates and a film-surface diffusion model was used to describe the breakthrough adsorption experiments, using the chitosan film thickness estimated from the batch experiment (ϕ = 2.5 µm). The input parameters for this model were determined by batch experiments or estimated from correlations available in the open literature. The surface diffusion coefficients (0.98-1.72 × 10−10 cm2 min−1) of copper in the chitosan film for different flow rates were estimated. The experimental data and the model agreed, indicating that the film thickness and the mass transfer parameters were well predicted. This article is protected by copyright. All rights reserved

High Turbulence Extraction Assisted by Ultrasound combined with Supercritical Antisolvent Fractionation (SAF) was done to intensify the recovery of bixin and phenolic compounds from semi-defatted annatto seeds. Annatto seeds are extensively used due to its colorant properties and bioactive potential in human health. Modifications were performed in the SAF experimental apparatus in order to prevent losses of product. Results show that supercritical fractionation resulted in particle yields between 72.2–80.5%, 20–50% phenolics, and 66% bixin.

Surfactants are widely used in the food industry to form and stabilize emulsion-based food and beverage products. The use of natural surfactant to replace the synthetic ones is a recent demand in industries. In this work, first it was evaluated the influence of hydrostatic pressure levels (up to 10 bars applying nitrogen), oily phase type and surfactant type. In addition, we propose a novel surfactant for the formulation of emulsions constituted of concentration of saponin-enriched extract. The extract containing saponins was obtained from pressurized hot water extraction of Brazilian Ginseng (Pfaffia glomerata) roots. The emulsions containing saponin extract were used for further processing by Supercritical Fluid Extraction of Emulsions (SFEE), using an oily bixin-rich extract from annatto seeds (Bixa orellana L.) as core material (extracting solution from hot ethyl acetate pressurized extraction). Since, the final product of SFEE achieved a low residual ethyl acetate concentration (9.4 ppm). Regarding droplet size similar results were obtained for the emulsion (549 nm) and the produced suspension (569 nm), which were 24.74% lower than the droplet size obtained in process not assisted with pressurized nitrogen atmosphere (730 nm). This work proposed the use of this alternative biosurfactant and the process that we named Ultrasound Emulsification Assisted by Nitrogen Hydrostatic Pressure (UEANHP), during the emulsification preparation step of the SFEE process.

The objective of this study was to investigate the technical-economic feasibility of supercritical antisolvent (SAS) technique for the precipitation of a vitamin complex containing riboflavin, δ-tocopherol and β-carotenein zein microcapsules. First, the following parameters were investigated for the precipitation of pure zein: pressure (7.0–16.0 MPa), anti-solvent flow rate (20–60 g/min), solution flow ratio (0.5–1.5 mL/min) and concentration of zein in an aqueous ethanol solution (0.02–0.04 g/mL). Then, at optimized SAS condition for zein precipitation (pressure of 16 MPa, temperature of 313 K, zein concentration of 0.02 mg/mL, solution flow rate of 1 mL/min and anti-solvent flow rate of 60 g/min) was performed the co-precipitation of the vitamins with zein. The results showed that the mean particle size of the microcapsules varied from 8 to 18 μm, depending on the vitamins encapsulated, being its morphology spherical, meanwhile the precipitation yield was within the range of 41–82 g/100 g.

The formulation of clove essential oil as an emulsion using nonpurified aqueous extract from Pfaffia glomerata roots as surfactant has been experimentally demonstrated. Firstly, a commercial surfactant (OSA-modified starch) was used to evaluate the formulation of nano-emulsions in our devices. Results show that, the method of emulsification and its duration had an insignificant influence on all response variables. On the other hand, the influence of OSA-modified starch concentration was very significant (P

Anthocyanins are one of most important group of water-soluble and vacuolar pigments in nature. This phytochemical has attracted great interest to the food industry due to the wide range of biological activities including antioxidant and anti-inflammatory activities. However, the introduction of anthocyanins into food and/or medical fields has proved to be a major technological challenge since these compounds have low stability to environmental conditions during processing and storage. In this context, the present study evaluates the encapsulation of anthocyanin extract obtained from jabuticaba ( Myrciaria cauliflora ) skins in Polyethyleneglycol using supercritical CO 2 as solvent and ethanol as co-solvent. For comparison, a conventional method, ionic gelification, was employed to produce encapsulated particles by entrapment in Ca-alginate beads. The encapsulation efficiency of the extract in Ca-alginate beads was higher (98.67%) than those obtained by Rapid Expansion of Supercritical Solution (RESS) process (79.78%). Encapsulated particles made by RESS at different pressures, and temperatures, retained the extracts' biological activity. The best operating RESS process condition for anthocyanin extract encapsulation was determined as 313.15 K and 20 MPa. The degradation studies indicated that both encapsulated systems were more stable to light and temperature than the free extract. Ca-alginate encapsulated Anthocyanin extract release in acid buffer solution was incomplete and slower than when the extract was encapsulated by PEG. Both systems increased the stability of anthocyanin, although presenting different characteristics.

The effects of supercritical carbon dioxide (CO2) on waste banana peels for copper adsorption were evaluated. Supercritical CO2 was employed both in a solvent extraction for antioxidant compound recovery and in an emerging biomass treatment to increase the subsequent heavy metal-removal step; the latter is termed “explosion with supercritical CO2”. This lignocellulosic biomass was analyzed before and after being subjected to both processes by scanning electron microscopy and X-ray patterning. Thermal gravimetric and differential scanning calorimetry analyses were performed to understand the different effects of supercritical carbon dioxide employed in these two processes on banana peels. The explosion with supercritical CO2 process resulted in a more pronounced effect on the vegetable structure. Nevertheless, no increase in the copper-removal capacity was achieved. The adsorption studies showed similar behaviors for fresh and extracted samples, demonstrating that banana peels previously extracted with supercritical CO2 retained their adsorption capacity for subsequent heavy metal removal.

BACKGROUND: Green chemistry, also known as sustainable chemistry, refers to environmentally friendly chemicals and processes that result in reduced waste, elimination of costly end-of-the-pipe treatments; safer products, and reduced use of energy and resources. In this context this study aims to evaluate a novel green sensitizer support for photochemistry use. For this propose, Rose Bengal (RB) and juglone production were chosen as a model sensitizer and a model photoreaction, respectively. RESULTS: The results showed that the RB-alginate beads prepared using a solution of 20% CaCl2 had better stability in the solvent t-amyl alcohol.Comparing all the immobilized systems a larger reaction yield (57.5%)was obtained when the proportion of the beads in the photoreactor flaskwas 5% (v/v). Although when using suspended RB the reaction yield was better (62%) the environmental friendly attributes and economical advantages of immobilized systems overcome it. CONCLUSIONS: The potentiality of this new kind of sensitizer immobilization was demonstrated and a mechanism based on immobilization of cells was proposed. Furthermore the use of this novel green support presents a greater efficiency and potentially lower costs than the commercial supported RB Sensitox.

Chitosan, a natural polymer obtained from the de-acetylation of chitin, has been extensively studied in adsorption applications because its amino and hydroxyl groups can act as chelation sites. However, this material is rarely used as an adsorbent, mainly because of mechanical strength limitations. A possible means of making its use viable is the immobilization of chitosan onto solid matrices using particle-coating techniques. Studies have shown that the use of immobilized chitosan not only improves the mechanical strength of the adsorbent, but also enhances its mass-transfer properties. In this context, the present study has investigated the adsorption application of chitosan coated onto glass beads in batch and dynamic systems for the removal of copper ions from aqueous solution. The adsorption equilibrium properties were measured at different temperatures (25, 40, 50 and 60 o C) and the Langmuir, Freundlich and Langmuir–Freundlich models were used to fit the equilibrium data. Kinetic studies showed that adsorption equilibrium was attained after 10 h. The pseudo-first-order and pseudo-second-order kinetic models in both linear and non-linear forms together with the intra-particle diffusion model were used to fit the adsorption kinetics data. The best fit was obtained with the pseudo-second-order kinetic model, thereby suggesting that the limiting factor to mass transfer was chemical adsorption. The results indicate that chitosan immobilized onto glass beads demonstrate a good adsorption performance, with similar or even better results relative to other chitosan-based materials. Dynamic adsorption studies using the coated beads in a fixed bed system demonstrated the viability of their use for wastewater treatment.

This study provides a preliminary contribution to the development of an industrial process for the UV/TiO2 water treatment by introducing a novel support for TiO2 immobilization. For the following study, Methylene Blue (MB) was chosen as the model dye to evaluate this novel immobilization system. The results showed that TiO2 immobilized in a Ca–alginate bead retained its photoactivity during all of the experiments and the TiO2-gel beads presented good stability in water for maintaining its shape after several uses. When a proportion of 10% (v/v) of these beads was used, the configuration system demonstrated an improved mass transfer and consequently enhanced degradation efficiency. Experiments were also performed using ‘recycled’ beads. The results showed an increase in the degradation efficiency when the beads were reused, with an eventual ‘self-destructive’ effect. These studies showed great promise regarding the recyclable reagents with a reduction in waste at no greater cost or reduction in efficiency. Therefore, the potential of TiO2-gel beads as a simple and environmentally friendly catalyst for continuous use was developed.