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•Biorenewable DES efficiently extract polyphenolic antioxidants from orange waste.•ChCl:EG 1:4 provides the highest polyphenolic content and antioxidant potential.•Ferulic acid is the ...main antioxidant present in the polyphenolic extracts.•Structural analysis suggests DES efficient solvent for biomass pretreatment.•Novel orange waste valorization strategies can be developed based on sustainable DES.
Extraction of polyphenolic compounds from orange peel (OP) via solid-liquid extraction (SLE) using deep eutectic solvents (DES) was investigated in this work as a means to develop sustainable separation processes to recover natural antioxidants from food waste biomass. In particular, choline chloride-based DES paired with glycerol and ethylene glycol were explored as potential extractants to evaluate the effect of the solvent structure (i.e. number of hydroxyl groups and hydrogen bond acceptor/donor ratio) on the polyphenol extraction efficiency. Afterwards, the effect of different operating parameters (i.e. solvent concentration, temperature, time and solid/liquid ratio) were further evaluated to determine the optimal extraction conditions for polyphenols recovery in terms of total phenolic content (TPC) and antioxidant activity based on DPPH radical scavenging method. Under optimum conditions (DES 10 wt.% water, temperature of 333.15 K, 1:10 solid/liquid ratio and extraction time of 100 min), choline chloride-based DES outperformed the benchmark solvent (aqueous (aq.) ethanol 30 wt.% water) for the extraction of polyphenolic compounds from OP, with ChCl:EG 1:4 providing the highest TPC (3.61 mg gallic acid equivalent per gram of orange peel (GAE/g OP) and antioxidant potential (30.6 µg/ml). Although ethylene glycol (EG) has provided the highest TPC (5.84 mg GAE/g OP), DES have proved more selective towards target polyphenolic compounds. Additionally, Scanning Electron Microscopy (SEM) was performed to illustrate the structural modifications occurred on the biomass before and after the extraction process, supporting DES as efficient solvents for cell wall dissolution. Lastly, characterization and quantification of individual polyphenolic profiles in the extracts were completed via high performance liquid chromatography (HPLC), displaying ferulic acid as the most abundant compound followed by ρ-coumaric acid and gallic acid.
Extraction processes are widely used in biorefinery applications to recover target products from biomass, and their comprehensive evaluation is key to improving their economic and environmental ...sustainability. This paper applies a systematic methodology that combines a rigorous process design, techno-economic analysis, and life cycle assessment to evaluate the sustainability performance of solvent extraction-based processes, with a focus on downstream activities. The methodology, which consists of seven iterative steps that combine process simulation and economic and environmental sustainability assessment tools, is demonstrated using a biodiesel production process from algae biomass, with hexane as the lipid extraction solvent. The minimum biodiesel selling price is estimated at U.S. $8.95 per U.S. gal, using the discounted cash flow rate of return. This is 3.5 times the average price of fossil diesel, mostly due to the cost of algae biomass and lipid recovery capacity of the solvent. Eighteen environmental impact categories are estimated from cradle to grave using the ReCiPe v1.1 method. For example, the climate change and primary energy demand are calculated at 95 g CO2 eq./MJ and 1.52 MJ/MJ biodiesel, which are 5 and 24% higher compared to fossil diesel, respectively. Lipid extraction is identified as the hotspot of the downstream processing stages for all impact categories (52–97%) and an opportunity for improving the overall sustainability performance of algae biodiesel, e.g., solvent selection. These findings provide a benchmark for future improvements to biodiesel production from algae biomass, with focus on the interactions between biomass and the solvent, e.g., phase equilibrium thermodynamics.
Lipid extraction and biodiesel production from algae biomass rely on volatile organic solvents obtained from fossil resources such as hexane, whose use involves high energy consumption for recovery ...and negative environmental impacts due to their volatile and hazardous nature. This study presents a techno-economic and environmental analysis of using alternative lipid extraction solvents in algae biodiesel production in an effort to understand how they may affect the performance of the process. Lipid recovery (LR), minimum biodiesel selling price (MBSP), solvent intensity (SI), energy intensity (EI), and water consumption (WC) are considered here as performance indicators at process and downstream processing levels. The studied solvents are limonene, ethyl tert-butyl ether (ETBE), and cyclohexane, which were screened in a previous study by the authors, and hexane for reference. The assessment is carried out using data sourced from the literature (upstream processing), while downstream processing data is generated in this study using the COnductor-like Screening MOdel for Real Solvents (COSMO-RS) method and process simulation tools in the absence of experimental data for the solvents. The results indicate that while there is no single candidate solvent that outperforms hexane in every criteria considered here, ETBE and limonene are promising alternative solvents for lipid extraction and should be explored further. For example, ETBE presented the highest LR (95.5%) and lowest MBSP (8.58 $/US gal), while limonene has a SI that is 35% lower than hexane. In terms of EI and WC, ETBE is the best performing solvent after hexane with a 4% difference. The MBSP of ETBE is still around 3.5 times the selling price of fossil diesel, and further efforts to improving the economic viability of algae biodiesel production are still needed. Besides from decreasing algae biomass costs (upstream processing), other improvement opportunities worth exploring in downstream processing includes alternative cell disruption technologies, as this is the most energy intensive stage in lipid extraction. While the use of biobased and less hazardous solvents can help improve the environmental performance of downstream processing in algae biodiesel production, it is recommended that their environmental impacts are quantified on a life cycle basis, i.e., solvent production and disposal.
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•Natural antioxidants as phenolic compounds are present in food by-products.•Extraction of phenolic compounds promotes food processing waste valorization.•Neoteric solvents can ...replace conventional organic solvents for extraction.•Ionic liquids, eutectic solvents and bio-solvents are promising extractants.
The loss and waste of food is a matter of great concern, leading to a multifaceted problem with negative economic, social, and environmental impacts as addressed in the UN Sustainable Development Goals number 2: zero hunger. The wine, fruit juice and vegetable oil processing industries generate significant amounts of wastes and side streams containing potentially valuable bioactive compounds. Some of them are plant secondary phenolic metabolites that offer remarkable health benefits (as antioxidants and anti-inflammatory compounds). One of the current challenges is the recovery of such bioactive compounds from residual matrices for further applications in food, pharmaceutical and cosmetic industries. Within this framework and in the scope of the Green Chemistry concept, one of the current challenges is to find eco-efficient techniques for the recovery of bioactive compounds. In this context, neoteric solvents are considered a greener alternative to traditional solvents, as the latter are more harmful to human and animal health, and environment. This overview focuses on recent advances in the use of hydrophobic neoteric solvents, i.e. ionic liquids, eutectic solvents, and bio-based solvents, for liquid–liquid extraction of phenolic compounds from liquid agri-food matrices.
Solvents play a primary role in the chemical industry, with an increasing regulatory pressure urging to find more benign replacements for conventional fossil-derived solvents. Efficient methods for ...rational screening, considering the wide variety of green solvent alternatives, are key to promote sustainable processes based on neoteric solvents. This paper summarizes recent advances on green solvent screening using computer-aided methods focused on macroscale modeling of phase equilibrium properties. Particular attention is paid to quantum chemistry methods based on Conductor-like Screening Model (COSMO) as a tool for guiding solvent selection from thermodynamic performance indicators. Integrated methods based on COSMO-derived molecular descriptors combined with molecular and large data-based methods are revised as significant approaches for multiobjective problems. Relevant solvent screening applications for separation operations, reactive systems, and environmental and health properties estimation are reviewed. Future prospects for the design of sustainable industrial systems based on green solvents using in silico strategies are discussed.
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•Hydrophobic eutectic solvents with ammonium salts and natural compounds were formed.•Liquid-liquid extraction of wine-derived phenolic antioxidants was optimized.•Extraction ...efficiencies were determined by spectrophotometric methods and HPLC.•N8881Cl-based HESs can efficiently recover wine-derived phenolic antioxidants.•Hydrophobic eutectic solvents are promising for winery wastewater treatment.
Global food waste is a far-reaching problem, where the recovery of high-value compounds from agri-food effluents using green solvents is an attractive valorisation strategy. Wine industry is an important business sector which generates significant volumes of wastewater, with negative economic and environmental implications. However, winery wastewater can be exploited as a rich source of phenolic antioxidants for food and fine chemical applications. For that purpose, the main goal of this work is the recovery of wine-derived phenolic compounds from liquid effluents using hydrophobic eutectic solvents (HESs). In particular, HESs composed of ammonium salts, DL-menthol and fatty acids, were prepared and evaluated for liquid–liquid extraction of phenolic compounds from synthetic winery wastewater. To achieve optimum extraction performance, the experimental conditions were optimized, including extraction time, solvent to feed volume ratio, dilution factor and type of HESs. The extraction method developed was used for the efficient extraction of natural antioxidants from wine-derived samples and gallic acid from aqueous solutions. The extracted phenolic compounds were quantified and determined by spectrophotometric methods and high-performance liquid chromatography (HPLC). The experimental results showed satisfactory recoveries of the target compounds within the range of 64.14–84.10% from winery wastewater and recoveries between 74.86 and 92.31% from gallic acid solutions. Chloride ammonium salts-based HESs, especially N8881Cl-DL-Menthol and N8881Cl-Octanoic acid, proved the highest potential for phenolic compounds recovery from winery wastewater matrices and aqueous solutions. Finally, the antioxidant capacity of the extracts was confirmed.
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•Green solvents were coupled with liquid membrane separation technology.•Biomolecules recovery was archived using supported green liquid membranes.•An activity-based approach is ...implemented to improve the SLM process description.•A novel SLM countercurrent cascade extraction process design method is given.
Supported liquid membranes (SLMs) containing novel green solvents are proposed as a sustainable alternative separation process in the recovery of biomolecules. In this work, succinic acid has been successfully extracted from model fermentation broths through a stripping phase-facilitated transport mechanism with four different green supported liquid membranes: two eutectic solvents (DL-menthol:OctA and N4444Cl:OctA), the bio-based solvent eucalyptol and the ionic liquid C4pyrrTf2N. A permeability activity-based model that takes into account for the first time solute-phase affinities has been developed using the quantum chemical COSMO-RS method; the model corrects the mass transfer driving force and allows extraction predictions beyond the concentration equilibrium. The best recovery has been achieved experimentally for the eucalyptol-based SLM (concentration factor of 1.4) using an alkaline aqueous solution (0.5 M NaOH) as the stripping phase. A countercurrent cascade extraction process design is proposed, and a graphical method to determine the stage number, interstage concentrations as well as mass transfer area requirements is presented. This new tool, the Permeability Activity-Based Linear Operation (PABLO) method, will substantially enhance the process design of SLMs technology for the biorefinery industry.
The presence of bioactive compounds in winery waste streams represents a great opportunity to revalue these effluents that constitute a challenging environmental and economic problem. The main ...objective of this research is to develop an efficient and environmentally friendly liquid-liquid extraction process for the recovery of phenolic antioxidants from winery wastewater. Two bio-based solvents, 2-methyltetrahydrofuran (2-MeTHF) and cyclopentyl methyl ether (CPME), were evaluated as potential extractants along with ethyl acetate (EA) as benchmark organic solvent. Extraction efficiencies were maximized by testing several operation factors such as stirring time, solvent to feed ratio, concentration and alcohol effect. Subsequently, the extracted phenolic compounds were quantified by spectrophotometric (using the Folin-Ciocalteu assay, the flavonoid-aluminum chloride complexation assay and the DPPH free radical assay) and chromatographic (HPLC-DAD) methods. Overall, 2-MeTHF showed the highest extraction efficiency of target antioxidants, yielding up to 96.46% for gallic acid, 87.44% for protocatechuic acid, 80.82% for 4-hydroxybenzoic acid, 92.24% for caffeic acid, 75.18% for vanillic acid and 38.19% for syringic acid. In the interest of full sustainability, the isolation of the phenolic compounds as a solid fraction from the extraction solvent was efficiently accomplished, while the recyclability of 2-MeTHF was successfully demonstrated.
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•Sustainable recovery of antioxidants was proposed for winery wastewater valorization.•Bio-based solvents extracted target phenolic antioxidants from winery effluents.•2-MeTHF showed the highest extraction yield over the conventional solvent.•LLE optimization was performed using spectrophotometric/chromatographic methods.•2-MeTHF was efficiently recycled and reused in the extraction process.
Lipid extraction is regarded as a major bottleneck in an industrial-scale production of algae biodiesel because of the use of hazardous solvents and energy-intensive operations for cell disruption ...and solvent recovery. This study uses life cycle assessment (LCA) to evaluate the environmental impacts and primary energy demand (PED) of algae biodiesel production from “cradle to grave”, focusing for the first time on alternative solvents used for lipid extraction and to identify opportunities for process design improvements. Limonene, ethyl tert-butyl ether (ETBE), and cyclohexane are investigated alongside the benchmark solvent, hexane. The ReCiPe method is used to estimate 18 midpoint environmental impacts of “the production and combustion of 1 MJ of algae biodiesel”. Results show that the climate change (CC) and PED of algae biodiesel range from 94 to 101 g CO2 eq./MJ and 1.59 to 1.65 MJ/MJ, with hexane having the lowest CC and PED and limonene the highest. Lipid extraction is identified as the main hotspot in downstream processing due to the high energy consumption for cell disruption (i.e., high-pressure homogenization) and solvent recovery. The use of an acid pretreatment for cell disruption prior to lipid extraction reduces 11 out of 18 environmental impacts and PED of algae biodiesel for all solvents, including hexane. Overall, this study highlights the critical role of lipid extraction in algae biodiesel production and the need for improvements in solvents and process design. Moreover, the findings provide valuable insights that can be applied to improve the environmental sustainability of other extraction applications.
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