Winery Waste Research Articles

Experimental evaluation of temperature, nutrients, and initial concentration on medium-chain carboxylic acids production from winery wastes.

In the wine industry, grape processing is accompanied by waste generation, such as grape stalks, winery wastewater, and grape pomace (GP). GP can be used to produce value-added compounds such as medium-chain carboxylic acids (MCCA). This work aimed to determine the operational conditions (temperature, addition of nutrients, and initial waste concentration) to improve MCCA production using waste GP from the winery industry as a substrate. The electron donor (ethanol) and electron acceptor (acetate) were directly generated from the GP and consecutively used to produce MCCA. The treatment with high concentration, temperature, and nutrient addition promotes caproic acid's maximal yield and concentration (0.11 ± 0.02 g MCCA/g TS). Nutrients' presence and temperature significantly affected electron acceptor production. The addition of nutrients and 30 °C leads to elevated acetate production. However, at 37 °C, butyrate and MCCA were mainly produced without adding nutrients, and high ethanol consumption was observed. A higher metabolic diversification was observed at 37 °C than at 30 °C. Temperature and nutrient availability significantly affected the metabolic pathway and the type of carboxylic acid produced.

Green Synthesis of Iridium Nanoparticles from Winery Waste and Their Catalytic Effectiveness in Water Decontamination.

An environmentally friendly procedure was adopted for the first time to prepare green iridium nanoparticles starting from grape marc extracts. Grape marcs, waste of Negramaro winery production, were subjected to aqueous thermal extraction at different temperatures (45, 65, 80, and 100 °C) and characterized in terms of total phenolic contents, reducing sugars, and antioxidant activity. The results obtained showed an important effect of temperature with higher amounts of polyphenols and reducing sugars and antioxidant activity in the extracts with the increase of temperature. All four extracts were used as starting materials to synthesize different iridium nanoparticles (Ir-NP1, Ir-NP2, Ir-NP3, and Ir-NP4) that were characterized by Uv-Vis spectroscopy, transmission electron microscopy, and dynamic light scattering. TEM analysis revealed the presence of very small particles in all samples with sizes in the range of 3.0-4.5 nm with the presence of a second fraction of larger nanoparticles (7.5-17.0 nm) for Ir-NPs prepared with extracts obtained at higher temperatures (Ir-NP3 and Ir-NP4). Since the wastewater remediation of toxic organic contaminants on catalytic reduction has gained much attention, the application of the prepared Ir-NPs as catalysts towards the reduction of methylene blue (MB), chosen as the organic dye model, was evaluated. The efficient catalytic activity of Ir-NPs in the reduction of MB by NaBH4 was demonstrated and Ir-NP2 was prepared using the extract obtained at 65 °C, showing the best catalytic performance, with a rate constant of 0.527 ± 0.012 min-1 and MB reduction of 96.1% in just six min, with stability for over 10 months.

Use of distillery by-products asTenebrio molitor mealworm feed supplement

Agricultural and industrial waste represent valuable starting materials to create novel products with economic value added. Winery industry represents an important economic sector in Italy, which produces tons of by-products every year. Global warming and the increasing demand for food and feed led us to analyse the nutraceutical properties of distillery by-products as possible supplements to feedTenebrio molitor larvae (TML). Grape pomace (GP) and grape marcs (GM), grape skin pulp, grape seeds and winery waste sludge were analysed for their antioxidant activity and fatty acid (FA) profile. Even if subjected to multiple processing, by-products had an important content of antioxidant compounds, in particular polyphenols, flavonols, flavonoids and condensed tannins. Moreover, the high amount of polyunsaturated fatty acids and the low percentage of saturated fatty acids found make them useful feed supplements. Herein has been disclosed that their use as TML feed material was well tolerated over TML development, with a significant mean weight gain respect to control of about 25% and no effect on survival rate. Interestingly, total antioxidant activity and FA profile ameliorate significantly, suggesting that distillery by-products can be used to extend the shelf-life of TML and ameliorate their nutraceutical properties, with possible application in controlled dietary regimens. This work confirmed that by-products largely produced in Europe can be used as TML feed materials, simplifying waste management and reducing rearing costs.

Effect of winery waste composted with biochar on seedling and plant growth of organic Brassica spp. crops

Effect of winery waste composted with biochar on seedling and plant growth of organic <i>Brassica</i> spp. crops

Towards a more sustainable feed for New Zealand farmed abalone: Inclusion of insect meal and grape pomace as alternative ingredients

Abalone, locally called pāua, is a valuable export product in New Zealand, contributing between NZD $50-60 million annually towards the country’s export economy [1]. Generally, one of the most significant bottlenecks of land-based abalone aquaculture is the high cost of the feed, which can be up to 50% of the production cost [2]. The high price has been attributed to fish meal, which is a key ingredient used in aquaculture feeds due to its excellent amino acid profile and palatability. However, fish meal use has been questioned due to the utilisation of wild fish to feed farmed fish and the exacerbation of overfishing marine resources [3]. Alternative ingredients, such as insects and winery waste products, are potential candidates as protein replacements due to their suitable nutritional profile and more sustainable production. This study aims to 1) develop and characterise alternative formulated feed for pāua (Haliotis iris) using insect meal and grape pomace and 2) evaluate the nutritional and growth alterations in juvenile pāua receiving different formulated feeds for 6 months. Proximate analysis is used to identify nutritional variations in body and faecal matter, and liquid/gas chromatography–mass spectrometry (LC/GC–MS) analyses are utilised to characterise amino acid and fatty acid profiles in tissue samples. Results show a high animal survival rate of 95% and increased seawater stability of experimental diets compared to a commercial feed. Nutritional analyses show no significant variations in animal tissues in terms of protein proportions and amino acid profiles, but differences were found in the lipid proportions and fatty acid profiles. This research will present the evidence to support the potential use of insect meal and grape marc as fishmeal replacements in abalone feeds, leading to a more sustainable aquaculture.

A Tamarind Local Variety from Garoua, Cameroon: Physicochemical Characterization, Fruit Pulp Fermentation and Extraction of Tartaric Acid from the Fruit Pulp Winery Waste

Objective: Tamarind is known for the tart taste that is characteristic of Tartaric acid. The fruit pulp is in high demand in both the domestic and industrial settings due to its high food value. It contains fatty acids, vitamins, roughage, phytosterols and many other phytochemicals necessary for good health. To the best of our knowledge, very little has been reported on the processing of this nutritional fruit and the results reported so far show variability as a function of the botanical origin of the plant. No literature exists on the Tamarind variety from Cameroon and no study combining wine production and extraction of Tartaric acid from the waste residue has so far been reported. We are taking this advantage to explore wine fermentation from Tamarind fruit pulp by focusing on the effects of different parameters such as time of treatment for juice extraction, yeast inoculate for wine fermentation and secondary fermentation on wine quality, and to extract Tartaric acid from the winery solid waste residue. Methods: The main fermentation was done at 2°C in 13d and 1w secondary fermentation was done in 1 week. The wine was characterized for alcoholic content, pH, titratable acidity, soluble dry matter and consumer acceptability. The winery solid waste residue (potassium bitartrate precipitate) was used to extract crystalline L-Tartaric acid which was characterized by Fourier transform infrared spectroscopy, melting point and crystallinity by powder X-ray diffraction. Results: The Tamarind pulp wine produced was of acceptable quality. It was clear, sweet, sparkling, smooth and well-flavored. The drink had a pH of 3.04 and an alcohol content of 16%. The Tartaric acid was crystalline, and it reflected all characteristic functional groups of Tartaric acid, with a melting point of 189.8-196.4°C (laboratory grade). Conclusion: It is very possible to couple Tamarind fruit pulp wine production with chemical synthesis of pure crystalline Tartaric acid using solid winery waste from Tamarind fruit pulp. The method used in this study is simple, straightforward, ecofriendly and cost effective.

Multi-feedstock biorefinery concept: Valorization of winery wastes by engineered yeast

The wine industry produces significant amounts of by-products and residues that are not properly managed, posing an environmental problem. Grape must surplus, vine shoots, and wine lees have the potential to be used as renewable resources for the production of energy and chemicals. Metabolic engineering efforts have established Saccharomyces cerevisiae as an efficient microbial cell factory for biorefineries. Current biorefineries designed for producing multiple products often rely on just one feedstock, but the bioeconomy would clearly benefit if these biorefineries could efficiently convert multiple feedstocks. Moreover, to reduce the environmental impact of fossil fuel consumption and maximize production economics, a biorefinery should be capable to supplement the manufacture of biofuel with the production of high-value products. This study proposes an integrated approach for the valorization of diverse wastes resulting from winemaking processes through the biosynthesis of xylitol and ethanol. Using genetically modified S. cerevisiae strains, the xylose-rich hemicellulosic fraction of hydrothermally pretreated vine shoots was converted into xylitol, and the cellulosic fraction was used to produce bioethanol. In addition, grape must, enriched in sugars, was efficiently used as a low-cost source for yeast propagation. The production of xylitol was optimized, in a Simultaneous Saccharification and Fermentation process configuration, by adjusting the inoculum size and enzyme loading. Furthermore, a yeast strain displaying cellulases in the cell surface was applied for the production of bioethanol from the glucan-rich cellulosic. With the addition of grape must and/or wine lees, high ethanol concentrations were reached, which are crucial for the economic feasibility of distillation. This integrated multi-feedstock valorization provides a synergistic alternative for converting a range of winery wastes and by-products into biofuel and an added-value chemical while decreasing waste released to the environment.

Recovery of phenolic compounds from wine lees using green processing: Identifying target molecules and assessing membrane ultrafiltration performance

Winery wastes are rich in polyphenols with high added value to be used in cosmetics, pharmaceuticals, and food products. This work aims at recovering and purifying the polyphenolic fraction occurring in the malolactic fermentation lees generated during the production of Albariño wines. Phenolic acids, flavonoids, and related compounds were recovered from this oenological waste by green liquid extraction using water as the solvent. The resulting extract solution was microfiltered to remove microparticles and further treated by ultrafiltration (UF) using membranes of 30 kDa and 5 kDa molecular weight cut-offs (MWCOs). The feed sample and the filtrate and retentate solutions from each membrane system were analyzed by reversed-phase liquid chromatography (HPLC) with UV and mass spectrometric (MS) detection. The most abundant polyphenols in the extracts were identified and quantified, namely: caftaric acid with a concentration of 200 µg g−1 and trans-coutaric acid, cis-coutaric acid, gallic acid, and astilbin with concentrations between 15 and 40 µg g−1. Other minor phenolic acids and flavanols were also found. The UF process using the 30 kDa membrane did not modify the extract composition, but filtration through the 5 kDa poly-acrylonitrile membrane elicited a decrease in polyphenolic content. Hence, the 30 kDa membrane was recommended to further pre-process the extracts. The combined extraction and purification process presented here is environmentally friendly and demonstrates that malolactic fermentation lees of Albariño wines are a valuable source of phenolic compounds, especially phenolic acids.

Use of Winery and Animal Waste as Fertilizers to Achieve Climate Neutrality in Non-Irrigated Viticulture

There is a growing interest globally in reducing the environmental impacts of farming by reusing agricultural waste and reducing agricultural greenhouse gas (GHG) emissions. In this work, the potential of Mediterranean viticulture for GHG emissions mitigation and Carbon (C) storage in biomass and soil is examined. In a field experiment, synthetic fertilizer use was reduced by 50 and 100% after applying a winery waste-based biofertilizer, and the C balance was determined at the vineyard level. The Vineyard Carbon Tool (VCT) for GHG emissions estimation in vineyards was developed by tailoring to vineyards the widely used Cool Farm Tool (CFT). Our results show that existing conventional viticulture could be easily transformed into zero-emissions by reducing nitrogen (N) fertilizers, lowering tillage frequency, using less fuel, and maintaining field margin vegetation at the farm level. Use of Life Cycle Analysis (LCA) showed that farm input reductions lead to a vineyard lifetime C storage equal to 25,124 kg CO2-eq ha−1 or 837 kg CO2-eq ha−1 year−1. This approach could be used for the design of eco-schemes related to C farming under the new Common Agricultural Policy (CAP).

Insights into rhamnolipid amendment towards enhancing microbial electrochemical treatment of petroleum hydrocarbon contaminated soil

Environmental pollution by hydrophobic hydrocarbons is increasing, notably nowadays due to a large amount of industrial activity. Microbial electrochemical technologies (MET) are promising bio-based systems which can oxidize hydrophobic hydrocarbon pollutants and produce bioelectricity simultaneously. However, MET faces some issues in terms of soil remediation, including low mass transfer, limited electro-activity of anodes as electron acceptors, low bioavailability of hydrocarbons, and the limited activity of beneficial bacteria and inefficient electron transport. This study aims to investigate the role of the addition of rhamnolipid as an analyte solution to the MET to enhance the efficacy and concurrently solve the abovementioned issues. In this regard, a novel long chain of RL was produced by using low-cost carbon winery waste through non-pathogenic Burkholderia thailandensis E264 strains. Different doses of RL were tested, including 10, 50, and 100 mg/L. A maximum enhancement in the oxidation of hydrophobic hydrocarbons was found to be up to 72.5%, while the current density reached 9.5 Am-2 for the MET reactor having a dose of 100 mg/L. The biosurfactants induced a unique microbial enrichment associated with Geobacter, Desulfovibrio, Klebsiella, and Comamona on the anode surface, as well as Pseudomonas, Acinetobacter, and Franconibacter in soil MET, indicating the occurrence of a metabolic pathway in microbes working with the anode and soil bioelectrochemical remediation system. According to cyclic voltammetry analysis, redox peaks appeared, showing a minor shift in redox MET-biosurfactant compared to the bare MET system. Furthermore, the phytotoxicity of polluted soil to L. sativum seeds after and before MET remediation shows a decrease in phytotoxicity of 77.5% and 5% for MET-biosurfactant system and MET only, respectively. With MET as a tool, this study confirmed for the first time that novel long-chain RL produced from non-Pseudomonas bacteria could remarkably facilitate the degradation of petroleum hydrocarbon via extracellular electron transfer, which provides novel insights to understand the mechanisms of RL regulating petroleum hydrocarbon degradation.

H2-rich gas production from steam gasification of a winery waste and its blends with industrial wastes. Effect of operating parameters on gas quality and efficiency

A winery waste and its blends with industrial wastes were gasified by steam via a two-step process, employing a fixed bed reactor and a thermal analysis-mass spectrometer unit. Solid materials were characterized in terms of elemental analysis, heating value, internal structure and chemical functional groups, whereas bio-oil, pyrolysis gas and syngas were quantitatively analysed. The effect of temperature, steam-to-biomass ratio and fuel composition on carbon conversion, cold gas efficiency, energy recovery, reaction rate, gas composition and quality were determined and kinetic analysis was performed. When industrial wastes waste wood shavings and refused derived fuel were blended with grape husks and curls at ratios 30:70, upgraded fuels were produced. At 850 °C organic matter was almost completely converted to syngas upon steam gasification. A first-order kinetic model fitted the experimental results successfully, with activation energy values ranging between 54.3 kJ/mol and 143.5 kJ/mol. An increase in steam-to-biomass ratio from 0.5 to 3 resulted in a higher concentration of hydrogen in product gas, while excess steam enhanced hydrogen yield up to 74%. Energy recovery from all fuels was high, cold gas efficiency reached a value of 66% and the higher heating value of syngas ranged between 9.6 and 11.4 MJ/m3.

Innovative Use of Olive, Winery and Cheese Waste By-Products as Functional Ingredients in Broiler Nutrition.

The purpose of this study was to evaluate the dietary use of novel silage that was created by combining three agro-industrial wastes produced in bulk, i.e., olive mill wastewater, grape pomace, and deproteinized feta cheese whey, in the diets of broiler chickens. A total of 216 one-day-old male Ross-308 chicks were randomly allocated to three treatment groups with six replications (12 chicks per pen). Three isocaloric and isonitrogenous diets were formulated to include the examined silage at 0%, 5%, or 10%. Commercial breeding and management procedures were employed throughout the trial. At the end of the trial (day 35), tissue samples were collected for analysis. Feeding 10% silage resulted in increased (p ≤ 0.001) final body weight (p ≤ 0.001) and feed intake. Jejunum and cecum microflora, as well as breast and thigh meat microflora, were modified (p ≤ 0.05) by the dietary inclusion. Thigh meat oxidative stability was improved (p < 0.01) by the silage supplementation. In addition, breast and thigh meat fatty acid profiles were different, respectively, (p < 0.05) in the supplemented treatments compared to the control. The examined silage was successfully tested in broiler diets with potential benefits for their performance and meat quality.

Next Generation Ingredients Based on Winemaking By-Products and an Approaching to Antiviral Properties

Management of waste and use of winemaking by-products plays an important role in the development of new ingredients, especially with antiviral properties. Although the richness of bioactive compounds from wine waste is known, less is known about potential antiviral action. Bioactive compounds and health-enhancing effects of winery by-products make them potential candidates for use in antiviral ingredients. The design of new formulations by using nano-microencapsulation techniques will be necessary to successfully control diseases produced by viruses. Outcomes about the use of winery by-products, bioactive compounds found in winery wastes, green extraction techniques to concentrate these compounds, and development of formulations to obtain new ingredients were extracted from research around the world to be discussed and updated in this manuscript. The evidence collected in this review aims to encourage transfer of in vitro and in vivo knowledge to a new step for the development of antiviral and treatments.

By-Product Revalorization: Cava Lees Can Improve the Fermentation Process and Change the Volatile Profile of Bread

Wine lees are a by-product that represents a 25% of the total winery waste. Although lees are rich in antioxidant compounds and dietary fiber, they have no added value and are considered a residue. The aim of this study was to evaluate the effect of Cava lees (0 and 5% w/w) on microbial populations during sourdough and bread fermentation and the volatile fraction of the final bread. The results showed that 5% Cava lees promoted the growth of both lactic acid bacteria (LAB) and yeast in short fermentations (bread) but did not improve microbial growth in long fermentations (sourdough). Regarding volatile compounds, the addition of Cava lees increased the concentration of volatiles typically found in those products. Also, some compounds reported in sparkling wines were also identified in samples with Cava lees adsorbed on their surface. To sum up, the addition of Cava lees to sourdough and, especially, bread formulation may be a new strategy to revalorize such by-product.

A green approach to phenolic compounds recovery from olive mill and winery wastes

The aim of this study was to evaluate the recovery of phenolic compounds from olive mill and winery wastes by conventional solid-liquid extraction (SLE) using water as the extraction solvent. The studied variables were extraction time (5–15 min), temperature (25–90 °C), solid-to-liquid ratio (1:10–1:100 (kg/L)), pH (3−10) and application of multiple extractions (1–3). The extraction efficiency was evaluated in terms of total phenolic content (TPC), determined by high performance liquid chromatography (HPLC-UV), but also from the recovery of some representative phenolic compounds. The optimized conditions were one extraction step, 10 min, 25 °C, 1:30 (kg/L), pH 5 for olive pomace, and one extraction step, 10 min, 70 °C, 1:100 (kg/L), pH 5 for winery residues. The extraction method is simple and suitable for scaling-up in industry, and the aqueous extracts are fully compatible with further purification schemes based on the use of membranes or resins. The optimized technique was applied to a set of different representative residues from olive mill and winery industries, to assess their suitability as sources for phenolic compounds recovery. The phenolic content in the extracts was evaluated by chromatographic analysis and by the Folin–Ciocalteu assay (FC). Furthermore, the antioxidant capacity was determined by 2,2-azinobis-3-etilbenzotiazolina-6-sulfonat (ABTS), 2,-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Because of their high contents in phenolic compounds and great antioxidant capacity, olive pomace and lees filters were identified as especially suited sources for phenolic compounds recovery.

Winery waste valorisation as microalgae culture medium: A step forward for food circular economy

Wastewater is one of the critical environmental problems worldwide. In this study, the circular economy concept was applied to winery wastewater that has been considered as a rich source of nutrients for growing edible microalgae to produce a high value protein product. To this end, Chlorella vulgaris and Arthrospira platensis were co-cultured. The effects of processing parameters on the microalgae yield and protein recovery were examined. Different microalgae growth systems: open pond, column and tubular photobioreactor were used for obtaining more than two grams of dry weight biomass per liter. The protein fraction was extracted and recovered by ultrasound-assisted extraction. The image analysis shows that wastewater strongly affected the intracellular components concentration, cell morphology, and resistivity to cell rupture. The results of our study demonstrate that it is viable to use microalgae to substantially reduce the pollutant impact of the wastewater and produce high value products such as proteins.

Pretreatment/fractionation and characterization of winery waste streams within an integrated biorefinery concept

The aim of this work was the characterization of the main winery wastes, e.g. vineyard prunings, grape stalks, grape pomace and wine lees, and the utilization of the hydrothermal pretreatment towards selective fractionation and recovery of hemicellulose (and related sugars, furans and acids), increased cellulose enzymatic hydrolysis, and isolation of “surface” and hydrothermal/acid hydrolysis lignin, discussing also the potential valorization of each stream into value-added chemicals. Two varieties from Greece were investigated, i.e. Grenache Rouge (Vitis vinifera L. cv. Grenache Rouge) and Malagouzia (Vitis vinifera L. cv. Malagouzia). Three hydrothermal pretreatment severities were applied, i.e. logRo 3.24, 4.32 and 4.71 (corresponding to 170oC-15 min, 170oC-180 min, and 220oC-15 min), all leading to enhanced enzymatic hydrolysis of cellulose in the vine prunings to glucose. The composition of the recovered aqueous product contained mainly glucan and xylan, which were converted to monomeric sugars and eventually to furans (furfural, HMF) and organic acids (formic, lactic) at more intense conditions. The grape stalks and mainly the grape pomace which comprises of grape skins and seeds, contained less carbohydrates compared to vine prunings, but can be considered as an abundant source of lignin that can provide fast pyrolysis oils enriched in phenolic compounds. Similarly, the extracted surface lignin from the hydrothermally pretreated vine prunings may offer highly phenolic/aromatic bio-oils. The extractives of the parent lignocellulosic wastes (15–50 wt%) contain water soluble sugar monomers and oligo-saccharides and ethanol soluble fatty acids (palmitic, tridecanoic, a-linoleic, oleic, stearic acids). The wine lees can be considered as a source of value-added polyols and phenyl alcohols, such as glycerin (1,2,3-propanotriol), 2,3-butanediol and phenylethyl alcohol.

Integration of Nanofiltration and Reverse Osmosis Technologies in Polyphenols Recovery Schemes from Winery and Olive Mill Wastes by Aqueous-Based Processing.

More sustainable waste management in the winery and olive oil industries has become a major challenge. Therefore, waste valorization to obtain value-added products (e.g., polyphenols) is an efficient alternative that contributes to circular approaches and sustainable environmental protection. In this work, an integration scheme was purposed based on sustainable extraction and membrane separation processes, such as nanofiltration (NF) and reverse osmosis (RO), for the recovery of polyphenols from winery and olive mill wastes. Membrane processes were evaluated in a closed-loop system and with a flat-sheet membrane configuration (NF270, NF90, and Duracid as NF membranes, and BW30LE as RO membrane). The separation and concentration efficiency were evaluated in terms of the total polyphenol content (TPC), and by polyphenol families (hydroxybenzoic acids, hydroxycinnamic acids, and flavonoids), using high-performance liquid chromatography. The water trans-membrane flux was dependent on the trans-membrane pressure for the NF and RO processes. NF90 membrane rejected around 91% of TPC for the lees filters extracts while NF270 membrane rejected about 99% of TPC for the olive pomace extracts. Otherwise, RO membranes rejected more than 99.9% of TPC for both types of agri-food wastes. Hence, NF and RO techniques could be used to obtain polyphenol-rich streams, and clean water for reuse purposes.

Vine Shoots as a Source of Trans-Resveratrol and ε-Viniferin: A Study of 23 Italian Varieties.

Stilbenes are a family of phenolic secondary metabolites that are known for their important roles in plant protection and human health. Numerous studies show that vine shoots, one of the most abundant winery wastes, could be used as a source of bioactive compounds such as stilbenes. The predominant stilbenoids in vine shoots are trans-resveratrol (Rsv) and ε-viniferin (Vf), whose content varies depending on numerous intrinsic and extrinsic factors. The present work investigates the influence of pre-treatment and variety on stilbene concentration in vine shoots. Vine shoots of the Primitivo and Negroamaro varieties were submitted to four different trials before stilbene extraction (untreated, dried at 50 °C for 24 h, dried at 70 °C for 15 min, and dried at 80 °C for 10 min). The results showed that the heat pre-treatments had a slight impact on the total phenol and stilbene content. In contrast, the variety variable had a stronger impact on stilbene concentration, ranging from 2700 to 6400 mg kg−1 DW for untreated vine shoots of 23 Italian varieties. In all vine shoots, the most abundant stilbene compound was Rsv and the highest content was found in vine shoots of the Nero di Troia (5298.1 mg kg−1 DW) and Negroamaro (5249.4 mg kg−1 DW) varieties.

The effect of chemical and thermal modifications on the biosorption of uranium in aqueous solutions using winery wastes

Biosorbents from winery wastes were tested for the removal of U(VI) after chemical and thermal modifications which led to significant improvement of the properties and the sorption capacity of the raw material. Batch experiments in aqueous solutions were undertaken to examine the influence of various parameters (pH, dosage, contact time, temperature, initial concentration, and ionic strength). Isotherms and kinetics obtained at pH3 and 4 (Cinitial:5–300 mgL−1,) were fitted by the Langmuir, Freundlich, pseudo-first- (PFO) and pseudo-second-order (PSO) equations respectively. Characterization techniques (SEM-EDS, XRD, FTIR and XPS) were used to explore the mechanism of U(VI) adsorption which seems to include dipol-cation interactions and formation of surface complexes as well as ion exchange and surface-supported reduction of U(VI) to U(IV), which most probably results in the surface precipitation of the very low soluble U(OH)4. Desorption tests were performed and showed the safe disposal of the loaded sorbents. It was demonstrated that a simple and low-cost chemical modification results in significant improvement of the sorption capacity of the raw material (from 58 to 250 mg g−1) due to presence of functional groups while thermal modification enhances the stability of the material offering lesser improvement (qmax:100 mg g−1)