Cork Powder Research Articles

Anti-photoaging Cream using a Quercus Suber Extract

This work aims at developing a new chemical product, which involves all the product design stages, starting from the evaluation of market needs, generation of ideas, selection of the selected idea and finally, the decision of the manufacturing process.During this analysis, it was decided to use the ellagic acid extracted from cork powder, a cork industry waste, to create our final product: an anti-photoaging cream free of parabens and fragrances. This decision results from the protective role of ellagic acid against UV-B-induced oxidative stress, reducing wrinkles and sun inflammation consequences. A rough economic feasibility analysis was carried out based on an industrial showcase, in which it was calculated the Net Present Value of 1.6 M€, so the project was considered viable. It was also determined the Internal Return Rate - value of 85 %, and the Payback Time was set at 3.3 years.

Can statistical methods optimize complex multicomponent mixtures for sintering ceramic granular materials? A case of success with synthetic aggregates

The relationship between the proportions of multicomponent mixtures with the technological properties of ceramic granular materials (synthetic aggregates) has been studied using statistical methods. The four phases involved in the formulations have been: kaolin (K) as aluminosilicate source; cork powder (C) as organic carbon source; sodium carbonate (N) as flux and pyrite (P) as source of iron and sulfur. The Mixture Experiments - Design of Experiments (ME-DOE) has been the statistical methodology applied from the initial configuration of the 36 starting formulations to the final validation of the models and optimums. After granulation, artificial aggregates have been obtained by sintering in a rotary kiln, and their main technological properties have been determined. Bloating index (BI), particle density (ρrd), water absorption (WA24) and crushing strength (S) were selected as the four key characteristics to be modeled and optimized, using response surface and effect plots to assess the effect of K, C, N and P on such properties. 32 out of 36 starting varieties met the density criteria for lightweight aggregates. In the optimum formulations obtained, the minimum percentage of K was 83 wt%, so that the variations in the percentages of P, C and N were the critical variables for determining the final properties of the aggregate. The contrast between experimental and estimated data has shown that the models fit adequately, indicating that this type of approach may have enormous potential for future research on artificial aggregates and other ceramic materials.

Expanding the use of cork as biosorbent through the determination of new psychoactive substances in postmortem blood samples

This study aimed to investigate the applicability of cork in a solid phase-based extraction method coupled to a 96-deepwell plate for LC-MS/MS determination of new psychoactive substances and other drugs of abuse in blood. Nowadays, there is a concern in developing new analytical methods that follows the principles of “green analytical chemistry”. These include the miniaturization of methods, utilization of minimal sample and solvent volumes, development of greener solvents and sorbents, among others. Regarding sorbents, natural compounds such as cork can be a great choice to be employed as extraction phase due to its large availability and low cost. Nevertheless, these new materials can help overcome analytical challenges related to postmortem analysis. Regarding sample preparation, blood samples were primarily submitted to protein precipitation by mixing 200 μL of blood, 250 μL of water, 250 μL of zinc sulfate and 50 μL of NaOH, followed by agitation and centrifugation. An aliquot of 500 μL of the supernatant was added to a 96-deepwell plate containing 30 mg of cork powder with particle size ≤ 250 μm. Extraction was performed by agitation for 15 minutes in an orbital shaker at 300 rpm, with consecutive removal of the aqueous phase. Desorption was performed by the addition of 1150 μL of acetonitrile with further agitation at 300 rpm for 2 minutes. The organic layers were recovered and dried under nitrogen stream, reconstituted in 30 μL of methanol and 2 μL was injected in the analytical system. Sample preparation parameters were optimized through univariate and multivariate strategies with the software Statistica 8.0 (Statsoft, Tulsa, USA). A Nexera UFLC system coupled to a LCMS-8045 triple quadrupole mass spectrometer (Shimadzu, Japan) was used for the analysis. Separation was performed on an Acquity UPLC® BEH C18 (1.7 μm, 2.1 × 50 mm) column (Waters, USA) using water (A) and acetonitrile (B) both containing 0.1% formic acid as mobile phases. Total run time was 7.5 minutes. The method was validated according to ANSI/ASB Standard 036 for the following parameters: lower limit of quantification (LLOQ), linearity, carryover, selectivity, precision, bias and dilution integrity. To verify the applicability of the method, three real postmortem blood samples were analyzed. The optimization of extraction parameters was carried out for the following items: choice of cork conformation (powder or sheet), cork particle size, cork mass, extraction time, desorption time, solvent type and solvent volume. The best parameters values are described in “Methods” session. LLOQs ranged between 0.5 and 5 ng/mL. Calibration curves were linear through the ranges of 0.5–85 ng/mL for ethylone, MDA, MDMA, N-ethylpentylone, 25B-NBOMe, 25C-NBOMe, 25I-NBOMe, fentanyl, pentylone and LSD; 1–85 ng/mL for cathinone, mephedrone and PCP; and 5–100 ng/mL for 25-NBOH, with determination coefficient (r2) > 0.99 and absence of carryover effects. Bias, within-run and between-run precision and dilution integrity results were within the acceptable values. The three samples were positive for the presence of MDA and MDMA with concentrations ranging between 23.11–26.59 ng/mL and 79.21–198.13 ng/mL, respectively. Sample preparation optimization was found to be relevant for the achievement of better analytical responses. Additionally, the use of the 96-deepwell plate allows simultaneous processing of multiple samples, with further possibility of automation. This study demonstrate that cork can be employed as a biosorbent for the determination of NPS and other drugs of abuse in postmortem blood through proper optimization, validation and application of the methodology. Therefore, it can be an alternative extraction phase to be considered in method development for toxicological purposes.

Air-Depleted and Solvent-Impregnated Cork Powder as a New Natural and Sustainable Fining Agent for Removal of 2,4,6-Trichloroanisole (TCA) from Red Wines.

Trichloroanisole (TCA) in wine results in a sensory defect called “cork taint”, a significant problem for the wine industry. Wines can become contaminated by TCA absorption from the atmosphere through contaminated wood barrels, cork stoppers, and wood pallets. Air-depleted solvent-impregnated (ADSI) cork powder (CP) was used to mitigate TCA in wines. The ADSI CP (0.25 g/L) removed 91% of TCA (6 ng/L levels), resulting in an olfactory activity value of 0.14. A Freundlich isotherm described ADSI CP TCA adsorption with irreversible adsorption and a KF = 33.37. ADSI CP application had no significant impact on the phenolic profile and chromatic characteristics of red wine. Using headspace sampling with re-equilibration, an average reduction in the volatile abundance of 29 ± 15%, 31 ± 19%, and 37 ± 24% was observed for the 0.10, 0.25, and 0.50 g/L ADSI CP, respectively. The alkyl esters and acids were the most affected. The impact observed was much lower when using headspace sampling without re-equilibration. Isoamyl acetate, ethyl hexanoate, ethyl hexanoate, and ethyl decanoate abundances were not significantly different from the control wine and 0.25 g/L ADSI CP application. Thus, ADSI CP can be a new sustainable fining agent to remove this “off-flavor” from wine, with a reduced impact on the wine characteristics.

Efficiency of the removal of tetraethyl pyrophosphate (TEPP) pesticide in water: use of cork granules as a natural adsorbent on acetylcholinesterase activity in neuronal PC12 cell

Tetraethyl pyrophosphate (TEPP) is an organophosphate pesticide that irreversibly inhibits acetylcholinesterase (AChE). Cork powder or granules have been recommended as a sustainable sorbent to remove pesticides from water. In the present study, we evaluated the effectiveness of removing TEPP from water using wine corks to obtain cork granules as natural adsorbent, analyzing the TEPP effects on AChE activity in commercial enzyme from Electrophorus electricus and secreted by neuronal PC12 cells. TEPP inhibited AChE activity in a concentration-dependent manner. For the first time, we showed that different concentrations of TEPP diluted in water after adsorption experiments using cork granules decreased TEPP's inhibitory effects on AChE activity in commercial enzyme and neuronal PC12 cell culture medium. Our results suggest that the optimum removal of TEPP from water by corks was 91.4 ± 4.0%. Overall, the findings support the hypothesis that cork granules can be used to remediate pesticide-contaminated environments, such as those contaminated by organophosphate pesticides, and demonstrate a new application of a biochemical assay on AChE activity using a commercial enzyme or secreted by neuronal PC12 cells in culture as a possible methodologic strategy for evaluating the success of TEPP removal from water.

Quercus suber: A Promising Sustainable Raw Material for Cosmetic Application

There is a drive within the cosmetic industry towards the development of more sustainable products, supported by consumer awareness of the environmental footprint. The cosmetic industry is rising to meet consumer demand by following practices, such as the use of by-products from agro-industrial waste. Quercus suber is a tree prevalent in the Mediterranean basin. The extraction of cork is considered sustainable, as this process does not harm the tree, and the amount of cork produced increases with the number of extractions. Beyond this, the cork industry produces by-products that are used to sustain the industry itself, such as cork powder, which is reused for generating energy. Additionally, cork and cork by-products contain bioactive compounds mainly with antioxidant activity that can be of use to the cosmetic industry, such as for antiaging, anti-acne, anti-inflammatory, and depigmenting cosmetic products. We provide the reader with an overview of the putative cosmetic applications of cork and its by-products as well as of their bioactive compounds. It is noteworthy that only a few cork-based cosmetic products have reached the market, namely antiaging and exfoliant products. Clearly, the use of cork upcycled cosmetic ingredients will evolve in the future considering the wide array of biological activities already reported.

Cassava-based materials for matrix solid phase dispersion: An alternative for sample preparation in food analysis

Cassava-based food ingredients were evaluated as candidate materials to be used as matrix solid phase dispersion (MSPD) for sample preparation. Cassava starch, tapioca, and tapioca pearls (TP) were applied in MSPD sample preparation of several food matrices such as mussels, fish, cooked ham, sausages, and animal feed (laying mash) for the determination of pharmaceuticals, preservatives, and polycyclic aromatic hydrocarbons by liquid chromatography coupled to tandem mass spectrometry or capillary electrophoresis. The performance of the new cassava-based solid phases was compared to other materials, such as diatomaceous earth, cellulose, cork powder, and a commercial polymer (Q-matrix® Hydra). The following parameters were used to select the most appropriate solid phases for each assay: fat removal, accuracy for certified reference material analysis, interferents presence in blank samples extract, signal to noise ratio, signal enhancement, and signal suppression. Best results were observed for cassava starch, except for nitrite and nitrate analysis, where the use of cellulose have led to the best sample preparation performance. Electronic microscopy of the materials and the mixture matrix and solid phase confirmed the adequate dispersion of the matrix on cassava starch. In conclusion, cassava-based solid phases were suitable for MSPD, allowing cheaper, greener, and abundant alternatives to sample preparation.

Removal of methylene blue from aqueous solutions with hybrid bioprocess: biosorption on modified cork powder and soluble turnip peroxidase

<p>Methylene blue (MB) removal from aqueous media using hybrid bioprocess: biosorption on modified cork powder (SDS-cork) and soluble turnip peroxidase (STP) was investigated. Cork powder was modified with sodium lauryl sulphate (SDS). Chemical composition of the biosorbent were characterized by infrared before and after biosorption. The hybridization was carried out under the optimal conditions of the two processes: pH=7, T=40 °C, [H2O2]=10 mM for enzyme activity(EA)=7 U mL-1 witch it was in excess for the EA= 5 and 3 U mL-1, [H2O2] = 15 mM for EA= 9 U mL-1 and [H2O2]=15 mM for EA= 11 U mL-1 with a treatment time that equals the sum of two optimal treatment times, and a mass of SDS-cork 0.04 g with a diameter <0.16 mm. The feasibility and performance of this hybridization was tested according to two parameters the initial concentration of MB which varied between 200 and 500 mg L-1 and the enzymes activities which has varied between 3 and 11 U mL-1. The minimum removal percentage of MB was satisfactory according to 93% for [MB] = 500 mg/L and an EA of 3 U mL-1, otherwise the maximum removal percentage was very satisfactory being in the order of 99.9% for a [MB] = 200 mg L-1 and EA= 11 U mL-1.</p>

Effect of the addition of organic wastes (cork powder, nut shell, coffee grounds and paper sludge) in clays to obtain expanded lightweight aggregates

Four organic solid wastes (coffee grounds, ground nut shell, paper money sewage sludge and cork powder) have been investigated as bloating inducing agents in lightweight aggregate (LWA) manufacturing when mixed in small proportions (2.5wt.%) with three types of clays. The pellets obtained were fired in a rotary kiln at the maximum feasible temperature for 4min. A similar impact was observed both in the working conditions and in the properties of the LWAs, showing that the differences between said residues are not as decisive as those of the clays to which they are added. The organic wastes have played a crucial role in achieving reducing conditions inside the aggregate. Thus, their addition has led to substantial improvements both from an operational point of view, lowering the working temperature, and from a technological perspective, favoring bloating and the development of a highly porous and lightweight structure. Leachate studies have shown that the LWAs meet the regulatory limits. The outcomes of this investigation show that, in line with the precepts of the Circular Economy, the recovery of organic wastes of different nature can have a place in the production of environmentally friendly LWAs.

Innovative liner concept using friction powder for increasing of broadband noise absorption. Applications for broadband noise absorption in fan duct

This paper presents research related influence of friction powders on enlarging the absorption band of acoustic liners used for reduction of tonal noise in fan duct of aero-engine. Kundt tube measurements done at COMOTI using fine powders (granules) made of various light-weight materials placed in the honeycomb cells of SDOF liners have shown a considerable broadening of the absorbed band of frequencies without a significant decreasing of absorption at the resonance frequency. Although the phenomenon is generally present for any type of powder, it was observed that for some powders the absorption is higher than for others. On the other hand, it was observed that the effect of the filling percentage of the cavity is important. Then, experiments done at the grazing flow facility of CNRS-Le Mans University have shown that the phenomenon is also present for high acoustic incident levels (up to 140dB) and M=0.13 while it still depends by the nature of powder material. The best results were obtained for the cork powder when the honeycomb is filled with powder at 66% of its height. For this material, the broadening of the transmission loss well was maximum. This phenomenon could be explained by the apparition of friction between powder granules which are taking place at very low scale consuming the noise power on a broader range of frequencies. It is supposed that the friction between the particles of powder have major influence because the best noise absorption was obtained for powders with a large distribution of particles’ dimensions while for particles with a small dimensional distribution (expanded polyester balls, for example) the transmission well broadening was smaller. The friction powders technology is simple and can be easily adapted to existing acoustic liner technologies with small manufacturing costs. This feature is conferred by the fact that powders can be easily poured in the honeycombs at the required height. The friction powder technology can be applied not only for the fan duct. In future, it could also be applied for reduction of jet noise reflected by pressure side of wing and for cabin noise reduction.

Polymer Composites with Cork Particles Functionalized by Surface Polymerization for Fused Deposition Modeling.

Cork powder received as a byproduct from local industries is valorized through the development of composite materials suitable for fused deposition modeling (FDM). For this purpose, a polymeric matrix of acrylonitrile–styrene–butyl acrylate (ASA) is used due to its good mechanical resistance and weather resistance properties. Prior to the manufacturing of the composites, the cork particles are characterized and modified by surface polymerization, creating a layer of poly(butyl acrylate) (PBA). Then, filaments for FDM are prepared by solvent casting and extrusion from ASA and composites with unmodified cork (ASA + C) and PBA-modified cork (ASA + Cm). PBA is one of the polymers present in the structure of ASA, which increases the compatibility between the cork particles and the polymer matrix. This is evidenced by evaluating the mechanical properties of the composites and examining their fracture surface by scanning electron microscopy. The analysis of the thermal properties shows that the developed composites also present enhanced insulating properties.

Characterization, Concentration of Biochar and Titanspheres and Heavy Metals Assessment of Quercus Suber Cork Powder Fly Ash Fractions

Cork powder is categorized in the group of the biodegradable fraction of products and waste. In Portugal, the cork powder production ranges between 32 000 and 37 000 tons/year and is used as fuel, which generates ash. For this ash characterization and possible recycling, sieving (dry and wet) and pre-treatments (ultrasounds and polycarboxylate) were tested in order to concentrate biochar, titanspheres and assess the fractions more suitable for fertilizer material. The samples were characterized via a combination of techniques: SEM/EDS, RLM, XRF, MRS and ICP-MS. For size-fractionation of cork powder fly ash, dry sieving is not an efficient method, however, improved efficiency, especially in the <25 μm size-fraction, can be attained by preceding wet sieving with a combined pre-treatment of ultrasounds and polycarboxylate. A sequence method was applied for biochar concentration and purification, however the amount of final biochar obtained is very low (1%wt.). The ICP-MS results indicate that the use of cork powder ash as fertilizer material in plant crops intended for human and animal consumption is not recommended, whereas other uses in soils are possible.

Surface properties of cork: Is cork a hydrophobic material?

Knowledge of the surface tension of cork and its hydrophobicity is of critical importance in many applications of this material at the interface with solid or liquid phases. The conventional technique based on contact angle measurement by sessile drop is not adapted to this naturally textured material and does not allow to accurately determine its hydrophobic character. A study based on capillary rise measurement is reported. A statistical distribution of the surface tension of cork is obtained, based on experiments performed on cork powder with various liquids and using a specific data processing to take into account the intrinsic heterogeneity of cork. This gives a surface tension of 22.6 (±1.2) mN·m−1, with a polar component at 5.2 (±0.5) mN·m−1 and a dispersive component at 17.4 (±1.6) mN·m−1. With a water contact angle of around 90°, cork shows an intermediate hydrophobic/hydrophilic behaviour. Locally, the specific surface texture and chemical composition can reinforce either the hydrophobic or the hydrophilic character. This critical analysis invites reflection on the notion of surface hydrophobicity as it can be determined macroscopically by a contact angle measurement and as defined at the molecular level by the free enthalpy of sorption of water.

Effect of Harsh Environmental Conditions on the Impact Response of Carbon Composites with Filled Matrix by Cork Powder

Composites are used in a wide range of engineering applications, as a result, exposure to hostile environments is rather common and its mechanical properties degradation is unavoidable. It is necessary to have a complete understanding of the impact of hostile environments on mechanical performance, namely critical solicitations as low velocity impacts. Therefore, this work intends to analyse the low velocity impact response of a carbon fibre/epoxy composite, and a similar architecture with an epoxy matrix filled with cork, after immersion into different solutions: diesel, H2SO4, HCl, NaOH, distilled water, seawater, and seawater at 60 °C. These solutions significantly affected the impact properties. In this context, the maximum load, maximum displacement, and restored energy behaviour were studied to understand the influence of exposure time. It was possible to conclude that such impact parameters were significantly affected by the solutions, where the exposure time proved to be determinant. The benefits of cork on the perforation threshold were investigated, and this parameter increased when the epoxy matrix was filled with cork. Finally, cork filled epoxy laminates also show less variation in maximum load and recovered energy than carbon/epoxy laminates.

Efficient anionic surfactant treatment of cork for cationic dye removal from aqueous media

<p>Sodium dodecyl sulfate sulfate modified Algerian cork powder (SDS-ACP) with interesting biosorption capacity was prepared for dye removal from aqueous media. The decolorization performance of SDS-ACP was studied using methylene blue (MB) as a model dye. Experiments were conducted in batch sysytem. The effects of initial pH, biosorbent dose, dye concentration, contact time and temperature were investigated. The kinetic modelling study showed that the experimental data are perfectly adjustable to the pseudo-second order model, with regression coefficients close to the unity and the intraparticle diffusion is not only the key controlling-step in the biosprption process. Langmuir isotherm was the most suitable model for describing the biosorption equilibrium results, which confirm the monolayer coverage and the maximum biosorption uptake of SDS-ACP was 117mg/g. Thermodynamic parameters such as Gibbs free energy, entropy and enthalpy were also evaluated showing that the biosorption process was spontaneously feasible and exothermic in nature. The application treatment has shown that SDS-ACP is a suitable lignocellulosic-type biosorbent for the decolorization of MB-colored solutions</p>

Comparison between a Traditional (Horse Manure) and a Non-Conventional (Cork Powder) Organic Residue in the Uptake of Potentially Toxic Elements by Lettuce in Contaminated Soils

The use of natural organic correctives is a current agricultural practice that may have advantages for the production of plants in contaminated soils. Cork powder is a natural sub-product of the cork industry that has several potential benefits compared to more commonly used soil amendments. In this work, an evaluation was performed of the use of cork powder (a non-conventional organic residue) and horse manure (traditionally used in agriculture) to control the availability of potentially toxic elements in artificially contaminated soils. Four concentrations were used for each element: Cr (100 to 800 mg kg−1), Ni (37.5 to 300 mg kg−1), Zn (150 to 1200 mg kg−1), Cd (1.5 to 12 mg kg−1) and Pb (150 to 1200 mg kg−1). The accumulation of these elements in lettuce plants grown in pots under controlled conditions was evaluated. With the exception of Cd, no significant differences were detected in the absorption of the different elements by lettuce plants at the studied amounts of correctives applied (1% for cork powder and 0.5% for horse manure). Cadmium was the element that accumulated most in lettuce. Cork powder was shown to be less effective than horse manure in controlling the bioavailability of these elements in the soil. Further tests with chemically modified cork products could improve its efficiency.

Cork powders wettability by the Washburn capillary rise method

The applicability of Washburn capillary rise (WCR) method on cork powders wettability was investigated. An adapted sample preparation method was also developed to guarantee measurements accuracy and reproducibility. The processing of cork powders by 3D Printing (3DP) presents a clear challenge related to cork wettability. The common liquid binders used in 3DP printers are composed mainly by water (95% w/w).Two sets of cork powders with different particle size distributions (PSD) were prepared and studied, namely Full Range powder with a wider distribution (20–100 μm) and Coarse powder with a narrow distribution (63–80 μm). Among the studied wetting liquids, hexane revealed to be the wetting liquid with higher ability to completely wet cork powders in a short period of time (14–18 s). Coarse powder exhibited higher packing ability based on the calculated parameter C values. Contact angles between a commercial binder and Full Range and Coarse powders were estimated as 86.1 ± 2.1° and 87.3 ± 1.5°, respectively. The obtained results showed that WCR method can successfully describe the wettability behaviour of cork powders.

Cork-derived hierarchically porous hydroxyapatite with different stoichiometries for biomedical and environmental applications

Hierarchically porous hydroxyapatite derived from cork powder shows excellent performance in biomedicine (low cytotoxicity) and environmental remediation (high Pb2+ removal).

Enhanced performance of rosin-based epoxy composites mixed with carbon nanotubes and cork powders from oriental oak bark

Rosin-based epoxy composites with high-impact toughness, tensile strength, modulus, and excellent flame retardance were prepared through a simple and effective approach. In this study, rosin-based epoxy resin (acrylopimaric diglycidyl ester, APA-ER) was synthesized from rosin, and the chemical structures of the products were determined by 1H NMR and FT-IR. The multiwalled carbon nanotubes (MWCNTs) and cork powders were introduced to the APA-ER to enhance the mechanical and thermal properties of epoxy composites. For the first time, cork powder was used to reinforce the modified rosin-based epoxy resin. Testing results of the mechanical properties indicated that the impact toughness of epoxy composite with 1.5 wt% MWCNTs and 3 wt% cork powders (100–200 mesh) had the highest value (12.34 and 12.04 kJ m−2), which was increased by 324% and 314%, respectively, compared to pure resin (2.91 kJ m−2). The composites with 1.5 wt% MWCNTs displayed better flexural and tensile performance compared to APA-ER/Cork. Moreover, the DMA, TG, and cone calorimeter results showed that APA-ER/Cork had a better performance in thermal stability and flame retardance than APA-ER/MWCNTs. Additionally, the flame retardance of rosin-based epoxy resin was further improved by adding MWCNTs and cork powder simultaneously. These results showed that the rosin-based epoxy resin could be toughened and strengthened effectively, and the thermal performance was improved by MWCNTs and cork powders. In conclusion, the value-added development of rosin and cork products was increased and applied in the field of functional materials.

Studies on the Compacting Behavior of Cork, Cytisus, Cistus and Eucalyptus Powders

The compacting behavior of biomasses of cork, Cytisus, Cistus and Eucalyptus and some of their mixtures were studied by uniaxial compression simulating the pelleting process. The obtained compression data were evaluated with some classic mathematical compression models. The estimates of two of these models complement each other, in such a way that a combination of both models was suggested and adopted in the present study. This new combined equation establishes a proportionality relation between the pellet's density and volume ratio, leading to a powder ranking according to the compressibility of the biomass powders under study. Furthermore, a three-entry abacus relates the density and relative volume of the pellet with volume reduction of the material, being compressed. It proves to be an interesting tool for selecting biomasses, from the point of view of their compressibility.