Search Results (53)

This study aimed to evaluate the impact of low- and high-temperature bleaching processes on the quality parameters of pumpkin seed oil. The research focused on optimizing the process to improve the oil’s physicochemical properties while reducing losses of valuable bioactive components. The bleaching process was carried out using 12 adsorbents in four technological variants, differing in temperature and adsorbent amount (30 °C/2% w/w, 30 °C/5%, 90 °C/2%, and 90 °C/5%). The scope of the analyses included, among others, the determination of acid (AV), peroxide (POV), and anisidine values (AnV), as well as the characterization of the fatty acid profile and the content of phytosterols and tocopherols. The data obtained were subjected to principal component analysis (PCA) to correlate the type of adsorbent with the process effects. It was shown that bleaching partially improves the oil’s quality parameters, though it is associated with a reduction in tocopherol and carotenoid content. Aluminum oxides are very poor adsorbents of vegetable oil components. Finely divided activated carbons exhibit the broadest spectrum of adsorbed components. Furthermore, bleaching earths have different effects on oil components depending on their composition and process temperature. Full article

With the increasing emphasis and protection on forest resources worldwide, the development of non-wood plant fiber raw materials has become a key path to promote the green and sustainable development of China’s pulp and paper industry. In this study, Super-Arundo donax, a new non-wood fiber raw material, was systematically investigated for its applicability in the bleaching process. Firstly, by adjusting key bleaching technical variables such as alkali dosage, time, oxygen pressure and temperature, the oxygen delignification process of the Super-Arundo donax kraft pulp was optimized. The data revealed that under the experimental conditions of 3.0% alkali dosage, 60 min bleaching time, 100 °C bleaching temperature, 0.6 MPa oxygen pressure and 0.6% MgSO₄ dosage, the bleached pulp yield reached 91.58%, the brightness was 42.04% ISO, and its tensile index was 60.92 N·m/g, bursting index was 4.16 kPa·m²/g, and tear index was 5.45 mN·m²/g, respectively. To further enhance the bleaching effect, the study introduced the H₂O₂ enhanced oxygen delignification process. The alkali dosage, bleaching temperature and H₂O₂ dosage were selected as the process parameters, with the pulp yield and brightness as the response indicators. A central composite design was adopted to construct a response surface model, and the interaction effects among various factors were analyzed. The optimized optimal process conditions are as follows: pulp concentration 10%, alkali dosage 2.84%, bleaching temperature 105 °C, H₂O₂ dosage 4.85%, bleaching time 60 min, MgSO₄ dosage 0.6%. Under these conditions, the pulp yield was 89.76% and the brightness reached 53.85% ISO. Therefore, Super-Arundo donax possesses excellent pulp-making and papermaking properties, and is expected to serve as a high-quality non-wood fiber raw material to alleviate the pressure on traditional papermaking raw materials and contribute to the green, sustainable and low-carbon transformation of the pulp and paper industry. Full article

Titanium dioxide (TiO₂) thin films were deposited by DC magnetron sputtering and subsequently treated in hot water at 50, 70, and 95 °C for 72 h to investigate the influence of low temperature on their structural optical and functional properties. XRD analysis revealed a progressive transformation from amorphous to anatase phase with increasing treatment temperature, accompanied by an increase in crystallite size from 5.2 to 15.1 nm. FT-IR spectroscopy confirmed enhanced surface hydroxylation and contact angle measurements showed a decrease from 77.4° to 19.7°, indicating a significant improvement in superior wettability. The transmittance spectroscopy revealed a slight narrowing of the optical band gap from 3.34 to 3.21 eV, consistent with improved visible-light absorption. Photocatalytic tests using the Resazurin indicator demonstrated that the film treated at 95 °C exhibited the highest activity, achieving a bleaching time of 245 s three times faster than treated at 50 °C and twice as fast as treated at 70 °C. Under low-intensity solar irradiation, the same sample achieved complete E. coli inactivation within 90 min. These improvements are attributed to increased crystallinity, surface hydroxyl density, and enhanced ROS generation. Overall, this study demonstrates that mild hot-water treatment is an effective, substrate-friendly route to enhance TiO₂ film wettability and multifunctional performance, enabling the fabrication of self-cleaning and antibacterial coatings on fragile materials such as plastics and textiles. Full article

Two amide-preformed aromatic diamine monomers, N,N-bis(4-(3-aminobenzamido)phenyl)-N’,N’-bis(4-methoxyphenyl)-1,4-phenylenediamine (m-6) and N,N-bis(4-(4-aminobenzamido)phenyl)-N’,N’-bis(4-methoxyphenyl)-1,4-phenylenediamine (p-6), were synthesized and utilized to prepare two series of electroactive poly(amide-imide)s (PAIs) through a two-step polycondensation reaction with commercially available aromatic tetracarboxylic dianhydrides. The obtained polymers exhibited solubility in various polar organic solvents, and most of them could form transparent, flexible films via solution casting. Thermal analysis indicated glass transition temperatures (T_g) ranging from 250 °C to 277 °C, as measured by DSC, with no significant weight loss observed before 400 °C in TGA tests. Cyclic voltammograms (CV) of the polymer films on ITO-coated glass substrates revealed two reversible oxidation redox pairs between 0.67 and 1.04 V vs. Ag/AgCl in an electrolyte-containing acetonitrile solution. The PAI films showed stable redox activity with high optical contrast both in the visible and near-infrared regions, transitioning from colorless in the neutral state to green and blue in the oxidized states. Furthermore, the polymer films retained good electrochemical and electrochromic stability even after more than 100 cyclic switching operations. The PAIs displayed outstanding electrochromic performance, including high optical contrast (up to 95%), rapid response times (below 4.6 s for coloring and 5.7 s for bleaching), high coloration efficiency (up to 240 cm²/C), and low decay in optical contrast (less than 5% after 100 switching cycles for most PAIs). Full article

To address the challenges in preventing and controlling mastitis caused by Escherichia coli and Staphylococcus aureus in large-scale dairy farms, as well as the issues of traditional disinfection protocols relying on experience and exhibiting significant efficacy fluctuations, this study aimed to systematically explore optimal disinfection strategies adapted to different scenarios and seasons. Five common commercial disinfectants in China were selected to target the two aforementioned pathogenic strains. Experiments were conducted under three typical scenarios—bacterial suspension, stainless steel carriers (simulating milking equipment), and cow dung cubicle bedding—and three temperature conditions (4 °C, 25 °C, 37 °C, simulating seasonal temperatures). A series of tests were performed, including neutralizer identification tests, determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), quantitative suspension and carrier spray disinfection tests, and monitoring of bacterial growth and decline in cow dung cubicle bedding. These tests were used to quantitatively analyze the regulatory mechanisms of disinfectant concentration, action time, and environmental temperature on disinfection efficacy. The Compound Glutaral Solution (CGS) exhibited the best overall performance, with strong temperature stability across all scenarios and high-efficiency bactericidal activity even at low concentrations. Additionally, the combined system of the CGS and bleaching powder (BP) achieved the optimal effect in controlling bacterial rebound in the cow dung cubicle bedding scenario. This study clarified the scenario-specific adaptation rules of different disinfectants and established a scenario-specific precision disinfection strategy for dairy farms. It provides a scientific basis for improving the level of mastitis prevention and control and optimizing biosafety systems, while also offering references for the disinfection of hard surfaces in fields such as healthcare and food processing. Full article

Pectins are high-value plant cell-wall polysaccharides with extensive applications in the food, pharmaceutical, textile, paper, and environmental sectors. Traditional extraction and processing methodologies rely heavily on harsh acids, high temperatures, and non-renewable solvents, generating substantial environmental and economic costs. This review consolidates recent advances across the entire Bacillus–pectinase value chain, from green pectin extraction and upstream substrate characterization, through process and statistical optimization of enzyme production, to industrial biocatalysis applications. We propose a practical roadmap for developing high-efficiency, low-environmental-footprint enzyme systems that support circular bioeconomy objectives. Critical evaluation of optimization strategies, including submerged versus solid-state fermentation, response surface methodology, artificial neural networks, and design of experiments, is supported by comparative data on strain performance, fermentation parameters, and industrial titers. Sector-specific case studies demonstrate the efficacy of Bacillus pectinases in fruit-juice clarification, textile bio-scouring, paper bio-bleaching, bio-based detergents, coffee and tea processing, oil extraction, animal feed enhancement, wastewater treatment, and plant-virus purification. Remaining challenges, including enzyme stability in complex matrices, techno-economic scale-up, and structure-guided protein engineering, are identified. Future directions are charted toward CRISPR-driven enzyme design and fully integrated circular-economy bioprocessing platforms. Full article

Electrochromic devices have garnered significant interest owing to their promising applications in smart multifunctional electrochromic energy storage systems (EESDs) and their emerging next-generation electronic technologies. Tungsten oxide (WO₃), possessing both electrochromic and pseudocapacitive characteristics, offers great potential for developing multifunctional devices with enhanced performance. However, achieving an efficient and straightforward synthesis of WO₃ electrochromic films, while simultaneously ensuring high coloration efficiency and energy storage capability, remains a significant challenge. In this work, a low-temperature hydrothermal approach is employed to directly grow hexagonal-phase WO₃ films on FTO substrates. This process utilizes sorbitol to promote nucleation and rubidium sulfate to regulate crystal growth, enabling a one-step in situ fabrication strategy. To complement the high-performance WO₃ cathode, a composite PB/SnO₂ film was designed as the anode, offering improved electrochromic properties and enhanced stability. The assembled EESD exhibited fast bleaching/coloration response and a high coloration efficiency of 101.2 cm² C⁻¹. Furthermore, it exhibited a clear and reversible change in optical properties, shifting from a transparent state to a deep blue color, with a transmittance modulation reaching 81.47%. Full article

Light is considered an important co-factor in causing thermal bleaching in photosymbiotic corals. To quantify the effects of light strength on thermal bleaching, colonies of the stony coral Stylophora pistillata were experimentally subjected to a gradual increase in temperature (1 °C per 4 days) under two irradiance levels: 100 and 500 µmole quanta m⁻² s⁻¹. Corals kept under the same irradiance levels at a constant temperature of 26 °C were used as controls. The apparent photochemical yield ΔF/Fm′ of Photosystem II of the coral symbionts was monitored daily as an indicator for the onset of thermal bleaching, the onset of bleaching being defined as a steep decrease in ΔF/Fm′. In heat-treated corals incubated under the high irradiance of 500 µmole quanta m⁻² s⁻¹, the onset of bleaching occurred 26 days after the start of the heat ramp, at a temperature of 33 °C. ΔF/Fm′ in corals incubated under the low irradiance of 100 µmole quanta m⁻² s⁻¹ started to drop 1 day later at the same temperature. Before and after the observed drop in ΔF/Fm′, coral samples were taken for analysis of symbiont densities and levels of chlorophyll-a. At the onset of bleaching, symbiont densities and chlorophyll-a levels in heat-treated corals were not different from those of corals kept under control conditions. Three days after the onset of bleaching, symbiont densities and levels of chlorophyll-a in heat-treated corals had substantially decreased in comparison to controls. Under low irradiance, symbiont density and chlorophyll-a content were 84% and 76% lower than controls, respectively, whereas under high irradiance, symbiont density and chlorophyll-a content were 41% and 46% lower. These data suggest that damage to the photosystem in coral symbionts is the root cause of thermal bleaching in symbiotic corals, followed later by a collapse of the symbiosis. The role of light in augmenting thermal bleaching was only moderate, with a five-fold reduction in irradiance causing only a 1-day delay in bleaching. These results suggest that temperature is the main driver of bleaching in the studied coral. Full article

The corrosion behaviour of lean duplex S32101 (1.4162—X2CrMnNiN21-5-1) stainless steel was assessed in various corrosive environments relevant to the pulp and paper industry. Electrochemical techniques, including open-circuit potential measurements and cyclic polarisation, were used to evaluate the corrosion resistance of S32101 stainless steel in various acidic, saline, and industrial liquors such as black, green, and white liquors, as well as dissolved chlorine dioxide bleaching solutions. To evaluate the extent of damage and corrosion mechanisms, post-exposure surface analysis was conducted using scanning electron microscopy (SEM). The results showed that S32101 experienced pitting corrosion in chloride-containing solutions, particularly in salt and acidified-salt environments. Corrosion rates increased with rising temperatures across all solutions. The highest corrosion rate of 3.17 mm/yr was observed in the highly alkaline white liquor at 50 °C, whilst chlorine dioxide induced the least aggressive effects at all temperatures. The suitability of S32101 stainless steel in handling pulp and paper liquors is shown in its corrosion resistance against the bleaching medium and low-temperature saline solutions, but it is not recommended for prolonged exposure to high alkaline liquors or chloride-rich solutions. Full article

Luminescence techniques, especially thermoluminescence (TL) and optically stimulated luminescence (OSL), are essential for dating materials in Cultural Heritage. TL is effective for dating bricks by determining their last heating event, but brick reuse can introduce inaccuracies. OSL enhances accuracy by dating the last light exposure of quartz grains in mortars, a material that is coeval with the construction of the building. However, partial bleaching of quartz grains can lead to overestimated ages. A promising solution involves dating the carbonate fraction of mortars, as calcium carbonate experiences bleaching during mortar preparation. This study investigates the feasibility of isolating signals from quartz and calcite in a composite material. Initially, TL signals for quartz and calcite were characterized separately. A laboratory mixture, comprising 75% quartz and 25% calcite, was irradiated to simulate partial bleaching. TL curve deconvolution revealed distinct peaks: quartz displayed four peaks, while calcite had three, notably lacking a low-temperature peak. The mixed sample exhibited peaks at 527 K, 573 K, 618 K, and 690 K, with the first peak being exclusively quartz, the second primarily quartz with minor calcite, and the third showing contributions from both. Dose-response curves indicated that the quartz peaks aligned with the expected 41.40 Gy dose, and the calcite signal matched 10.40 Gy. This confirms the feasibility of separating TL signals from quartz and calcite in mixed samples, offering a potential method for accurately dating the carbonate fraction in mortars and addressing partial bleaching issues. Future work will focus on optimizing detection parameters and applying this method to historically significant mortars to assess its effectiveness. Full article

This study explores the potential use of mould biomass and waste fibres for the production of agrotextiles. First, 20 mould strains were screened for efficient mycelium growth, with optimized conditions of temperature, sources of carbon and nitrogen in the medium, and type of culture (submerged or surface). A method was developed for creating a biocomposite based on the mould mycelium, reinforced with commercial bleached softwood kraft (BSK) pulp and fibre additives (cotton, hemp). The best properties, including mechanical, water permeability, and air permeability, were shown by the biocomposites containing 10–20% Cladosporium cladosporioides mycelium grown in surface or submerged cultures, milled with BSK pulp, cotton, and hemp (10–20%). The mould mycelium was refined with cellulosic fibrous material, formed, pressed, and dried, resulting in a biomaterial with good mechanical parameters, low water permeability, and high air permeability. The biocomposite was fully biodegradable in soil after 10 days in field conditions. The use of the biocomposite as a crop cover shortened the germination time and increased the percentage of germinated onion, but had no effect on parsley seeds. This study shows the potential of using mould mycelium for the production of biomaterial with good properties for applications in horticulture. Full article

Of the three types of waste generated in beer processing, brewer’s spent grain (BSG) is the most abundant and has a high potential for valorization. In this work, defatted BSG (DB) was subjected to an extraction process with subcritical water at different temperatures to obtain extracts rich in phenols and the cellulosic fractions, which were also purified by using hydrogen peroxide (H₂O₂). The results showed that the dry extracts obtained at 170 °C were richer in phenolics (24 mg Gallic Acid Equivalent (GAE) g⁻¹ DB), but with lower antioxidant capacity (71 mg DB·mg⁻¹ 2,2-diphenyl-1-pikryl-hydrazyl). This extract also showed the highest antibacterial potential against L. innocua (80 mg·mL⁻¹) and E. coli (140 mg·mL⁻¹) than those obtained at lower temperatures. The purification of cellulose from the treated residues, using hydrogen peroxide, revealed that DB is a limited source of cellulose material since the bleached fractions showed low yields (20–25%) and low cellulose purity (42–71%), even after four bleaching cycles (1 h) at pH 12 and 8% H₂O₂. Despite this, the subcritical water extraction method highlights the potential of a simple process as a technological option to convert underutilized side streams like beer bagasse into added-value, potential ingredients for innovative food and pharmaceutical applications. Full article

This study highlights the adsorption efficiency of A. erioloba Seed Nanoparticles (AESNs) in the removal of ibuprofen from water. Ibuprofen is one of the most commonly used drugs in the world and often makes its way into aquatic resources through improper disposal. The AESNs (adsorbents) were extracted from the A. erioloba seed pod via dewaxing, alkali treatment, bleaching, and acid hydrolysis to obtain nanoparticles. These nanoparticles were characterized by scanning electron microscopy (SEM) analysis. An ibuprofen solution model was prepared via the dissolution of water–methanol at a ratio of 9:1. A calibration curve was prepared with a standard solution of the ibuprofen in a concentration range of 0.001–0.010 mg/L. The effect of dosage, pH, time, and temperature in each of the prepared ibuprofen concentrations was determined. Fourier–transform infrared spectroscopy (FTIR) was used to determine functional groups, and SEM was used to study the morphology, size, and surface structure of the nanoparticles. UV spectroscopy determined the concentration of ibuprofen after the interaction with the AESN in different parameters, and X-ray diffraction (XRD) was used to determine the crystal structure of the AESN. The Langmuir and Freundlich isotherm models, as well as Brunauer–Emmett–Teller (BET) methods, were applied to optimize the conditions for maximum adsorption and elucidate the surface area of AESNs and the behaviour of AESN as an adsorbent. The BET results indicate that the surface area was found to be 0.7313 m²/g and the pore size was 0.001148 cm³/g. The R² of 0.77 and 0.3710 results indicate that they do not favor both Langmuir and Freundlich isotherm models. The use of a low ibuprofen concentration, i.e., a low dosage, in this study resulted in positive results. Full article

The paper presents the new eco-friendly method of bleaching process of the cellulose fibre materials. Cellulose materials were bleached using hydrogen peroxide (both in aqueous solution, vapours, ozone and by the combined action of gaseous hydrogen peroxide and ozone. The method using hydrogen peroxide in aqueous solution presents the standard procedure and was used as the comparison technique. The bleaching processes using gaseous oxidants were carried out in a prototype device for dry, low-temperature treatment of fibrous materials with the use of oxidising agents in the gas phase. The influence of the innovative gas-phase bleaching method on the cotton samples’ properties was analysed by Scanning Electron Microscopy (SEM), evaluation of the colour and whiteness, assessment of the polymerisation degree (DP), analysis of the mechanical properties and sorption capacity as well as microbiological assessment against colonies of Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The comparison of the obtained results led to the conclusion that the bleaching processes using gas-phase agents—vaporised hydrogen peroxide, ozone or their combination—are non-invasive. The applied bleaching processes resulted in a slightly lower whiteness parameters than standard bath bleaching. After the bleaching processes with ozone and vaporised hydrogen peroxide separately, the decrease in the DP and tensile strength was similar to that observed after the bleaching with aqueous H₂O₂. When both processes were used together, a higher reduction in DP and tensile strength was noticed. Both oxidising agents showed a strong biocidal effect against bacteria. Gas-phase bleaching procedures, due to the lower temperature (35 °C vs. 98 °C) and minimal water consumption, have economic and environmental advantages, which allows their use in semi-industrial applications. It has been shown that the treatment of cotton fabrics using ozone and hydrogen peroxide in the gas phase allows to simultaneously obtain the bleaching and disinfection effect. Full article

Sulfur dioxide (SO₂)-generating pads associated with perforated plastic liners are often used to control gray mold in table grapes during cold storage; however, SO₂ may cause bleaching, shattered berries, and an unwanted taste. To overcome this difficulty, a field ultrafast SO₂-generating pad was designed to be used for a few hours before packaging grape bunches as an alternative for eradicating spores of fungi from berry skin. This study aimed to assess the postharvest conservation and shelf life of ‘Italia’ table grapes packaged in plastic clamshells and perforated plastic liners using the field ultra-fast SO₂-generating pads before packaging, associated with or without slow- or dual-phase SO₂-generating pads during cold storage. The packaged grapes were cold stored (1.0 ± 1.0 °C; 95% relative humidity), and after 45 d, grapes were placed at room temperature (22.0 ± 1.0 °C) without plastic liners and SO₂-generating pads for 3 d. Before and after the grapes had been subjected to the field ultra-fast SO₂-generating pads, the quantification of filamentous fungi on the surface of the berries was assessed. The use of field ultra-fast SO₂-generating pads before packaging, associated with slow- or dual-phase SO₂-generating pads during cold storage, resulted in a lower incidence of gray mold after 45 d of storage, with low weight loss and shattered berries, good preservation of stem freshness, and no impairment in the color and firmness of the berries. Additionally, a significant decrease in disease incidence was observed when using only the dual-phase SO₂-generating pads in cold storage, with good maintenance of bunch quality. Full article