Strong Color Research Articles

Development of Eco‐Friendly Food Packaging Films Using Bio‐Based Polyethylene and Natural Pigments

ABSTRACTIn this study, sustainable and environmentally friendly packaging films were developed using bio‐based polyethylene (BIO‐PE) and natural plant pigments. The pigments were obtained from Rubia tinctorum (madder), Punica granatum (pomegranate), Juglans regia (walnut), Reseda lutea (yellow mignonette) and Quercus infectoria (Aleppo oak), which are known for their strong colouring properties and are widely available in the rich flora of Turkey. These pigments were blended with BIO‐PE at a ratio of 10% in the form of composites. The packaging films were produced via blown film extrusion, and their optical, mechanical, frictional and blocking properties were systematically characterized. The results showed that natural pigments significantly improved the optical properties, especially the opacity, with films containing Reseda lutea reaching the highest value of 99.77%. In addition, Punica granatum–based films exhibited a tensile modulus of 246 MPa, which improved structural integrity. The addition of natural pigments reduced the blocking force to 440 gf/100 cm2, allowing the layers to separate more easily, while the coefficients of friction ranged from 0.15 to 0.27, improving the sliding properties. These results demonstrate the potential of BIO‐PE and natural pigments to create effective and sustainable packaging solutions.

Novel Colors in Packaging: Boosting Consumers Learning Through Greater Expectation Violation

ABSTRACTCompanies often change product packaging colors to drive innovation and boost sales. However, these changes may violate expectations, resulting in inconsistent associations between new colors and original labels. It remains unclear whether consumers can learn these new associations. This study delved into the effect of expectation violation on consumer learning of color–label (flavor/brand) associations by varying the degree of violation between colors (adjacent and complementary) and labels. To assess associative strength, we compared learning effects under strong (color–flavor) and weak (color–brand) associations. Experiment 1 demonstrated higher accuracy in the visual search for packaging with complementary colors after learning. It was supported in Experiment 2. Between experiments, weaker associations showed greater improvement in response times (RTs). Our results suggest greater expectation violation in packaging color enhances associate learning. However, entrenched strong associations may impede the formation of new ones. These findings advance expectation violation theories and guide companies in using packaging color changes to innovate. Taking complements violating expectations can facilitate consumer learning.

Ultra‐Bright Stimuli‐Responsive Photonic Crystals for High‐Performance Anticounterfeiting Coatings

AbstractPhotonic crystals (PCs) with unique light manipulation capability have attracted widespread attentions. However, weak photonic bandgaps, poor structural color saturation, and tedious preparation process restrict their further development and practical application. Herein, an ultra‐bright stimuli‐responsive PC film with excellent optical performance is prepared by assembly of cadmium sulfide@polyacrylic acid (CdS@PAA) core–shell nanoparticles into PCs through molecule‐mediated shearing‐induced assembly technique (MSAT), this fabrication process is fast and facile, the solid periodic micro/nano‐structures can be formed within 10 s, and a wide selection range of structural color can be obtained. The high refractive index of CdS guarantees high brightness of the PC films. The prerequisite of using MSAT for preparation of large‐sized ultra‐bright PC film is that the CdS@PAA nanoparticles possess appropriate thickness of PAA shell. Compared with conventional PCs, the ultra‐bright PC films present strong photonic bandgaps and high structural color saturation, the relative reflectance is up to 130% compared with a standard aluminum mirror, which is more than four times reflectivity of PS@PAA microspheres. In addition, the PC paint is prepared by mashing the ultra‐bright PC film and blending it with transparent polydimethylsiloxane (PDMS) matrix, the PC coating prepared by alkali treated ultra‐bright PC pigments can achieve good water response ability and anticounterfeiting effect.

Designing a Simple Quinoline-Based Chromo-Fluorogenic Receptor for Highly Specific Quantification of Copper (II) Ions: Environmental and Bioimaging Applications.

Many industries use copper metal ions (Cu2+ ions), and their salts are utilized as supplemental materials in both agriculture and medicine. Identifying and monitoring these Cu2+ ions in biological and environmental specimens is crucial due to their association with several health issues. In this investigation, we have designed a simple quinoline-based receptor (E)-3-(((2,4-di-tert-butyl-5-hydroxyphenyl)imino)methyl)-6-methoxyquinolin-2(1H)-one (QAP) containing imine functional groups to inspect its capability to identify metal ions in a semi-aqueous medium. The photophysical characteristics and structural confirmation of the receptor QAP were investigated using various spectroscopic techniques. Among various metal ions, the receptor QAP displayed an intense color shift from slightly yellow to strong yellow in the existence of Cu2+ ions, as visualized by the nude eye. Furthermore, the fluorescence spectral maximum wavelength at 485 nm and the strong cyan fluorescence color were quenched upon introducing Cu2+ ions. The alteration in the spectral and colorimetric features of QAP with Cu2+ ions is due to coordination complex formation. The present sensor shows the linear range from 3 to 69 μM, subsequent in a computed limit of detection as 3.16 nM, which is much lower than that of the maximum threshold of Cu2+ ions in drinking water set by WHO. Therefore, the receptor can respond to Cu2+ ions sensing in two ways: by changing color and by quenching fluorescence. The binding mode of the Cu2+ ions to the functional groups of the receptor QAP is a 1:1 stoichiometry, according to ESI-mass, Job's plot analysis, and density functional theory (DFT) computations. The practical utility of the fluorescent receptor QAP was applied for Cu2+ ions determination in environmental samples (drinking, tap, and dam water) and cancer cells (HeLa cells).

Perfect Resolution of Strong Conflict-Free Colouring of Interval Hypergraphs

The \(k\) -Strong Conflict-Free ( \(k\) -SCF colouring problem seeks to find a colouring of the vertices of a hypergraph \(H\) using minimum number of colours so that in every hyperedge \(e\) of \(H\) , there are at least \(\min\{|e|,k\}\) vertices whose colours are different from that of all other vertices in \(e\) . In the case of interval hypergraphs, we present an exact \({\mathsf{P}}\) -time algorithm for the \(k\) -SCF problem thus solving an open problem posed in 2014. We achieve our results by showing that for any hypergraph, a \(k\) -SCF colouring is a proper colouring of a related simple graph which we refer to as a co-occurrence graph . We then show that a co-occurrence graph is obtained by identifying an induced subgraph of a second simple graph that we introduce, which we refer to as the conflict graph . For interval hypergraphs, we show that each co-occurrence graph and the conflict graph are perfect graphs. This property plays a crucial role in our polynomial time algorithm. Second, we show that for an interval hypergraph, the \(1\) -SCF colouring number is the minimum partition of its intervals into sets such that each set has an exact hitting set (a hitting set in which each interval is hit exactly once).

Distinguishing Martin's axiom from its restrictions

We introduce an iteration of forcing notions satisfying the countable chain condition with minimal damage to a strong coloring. Applying this method, we prove that Martin's axiom is strictly stronger than its restriction to forcing notions satisfying the countable chain condition in all finite powers. Our method shows also the finer distinction, that Martin's axiom is strictly stronger than its restriction to forcing notions whose squares satisfy the countable chain condition.

MXene Bimetallic Coating Synergistic Enhanced Colorimetric-Raman Dual Signal-Based Immunochromatographic Assay for Advancing Detection Performance.

Herein, a three-dimensional thin film-like multifunctional MXene bimetallic coating material (Ti3C2@Au-Ag) with strong color intensity, high surface-enhanced Raman scattering (SERS) activity, and strong antibody affinity (1.00 × 108 M-1) was prepared. It was the first time that Ti3C2@Au-Ag-based colorimetric-SERS dual-signal immunochromatographic assay (ICA) was developed for the detection of dexamethasone, achieving the limits of detection of 0.0089, 0.14, and 0.084 μg/kg for milk, beef, and pork in colorimetric mode and 0.0015, 0.060, and 0.075 μg/kg in SERS mode. It was up to 200-fold more sensitive than the reported ICAs. The recoveries were 82.0%-112.6%, and the coefficients of variation were 1.4%-13.7%. The Ti3C2@Au-Ag-ICA was verified by LC-MS/MS in the application on 30 real samples with a correlation coefficient greater than 0.98. This study can provide efficient theoretical and practical value for the development of a colorimetric-SERS dual-signal immunoassay platform.

Electron-Deficient Indenofluorene-Based Systems: Multicolor and Visible-To-Near-Infrared (NIR) Electrochromism and OFF-OFF-ON Electrofluorochromism.

Multifunctional electrochromic systems with divergent functions are highly sought after but rare and challenging to develop. Here, we report the synthesis and multi-functional electrochromic behaviour (multi-colour modulation, visible-to-near IR absorption switching, and electrofluorochromism) of electron-deficient indenofluorene-based systems. The compounds (IF1-IF5) have been obtained via Knoevenagel condensation of indenofluorenone (IFK) with various nucleophiles (malononitrile, benzylcyanide, dimethyl malonate, methyl cyanoacetate, benzothiazole-2-acetonitrile). IF1-IF5 possess strong colours and absorb in the visible region (λmax=295-388 nm). These compounds are electroactive and exhibit two reversible reduction waves (-0.35--0.88 V and -0.65--1.30 V vs Ag/AgCl), generating radical anion and dianion systems. For the electrochromic studies, upon applying the one-electron reduction potential (-0.35 V vs Ag/AgCl), the absorption maximum of IF1 redshift from 382 nm to 1240 nm (IF1 -⋅), which subsequently blueshifts to 466 & 745 nm (IF1 2-⋅) upon increasing to two-electron reduction potential (-0.65 V vs Ag/AgCl). The color of the solution was switched from green to dark blue and further to light orange. The electrochromic behaviour is highly reversible and cycling. In addition, unlike the non-fluorescent (IF1 and IF1 -⋅), the two-electron reduced system (IF1 2-⋅) is red-emissive (λem=630 nm) due to the combination of radicals leading to the formation of antiaromatic quinoidal π-conjugated system (IF1 2-).

Silver-Platinum Hollow Nanoparticles as Labels for Colorimetric Lateral Flow Assay

Article Silver-Platinum Hollow Nanoparticles as Labels for Colorimetric Lateral Flow Assay Jinfeng Zhou 1, Shikuan Shao 1, Zhiyuan Wei 1 and Xiaohu Xia 1,2,* 1 Department of Chemistry, University of Central Florida, Orlando, FL 32816, USA 2 NanoScience Technology Center, University of Central Florida, Orlando, FL 32816, USA * Correspondence: xiaohu.xia@ucf.edu Received: 23 September 2024; Revised: 7 November 2024; Accepted: 12 November 2024; Published: 18 November 2024 Abstract: Colorimetric lateral flow assay (CLFA) has been a widely recognized point-of-care testing technology over the past few decades. Driven by the increasing demand in various biomedical applications, it is urgently needed to develop CLFAs with high sensitivities and low costs. In this work, we report a type of CLFA that relies on unique colorimetric labels—silver-platinum hollow nanoparticles (Ag-Pt HNPs). The Ag-Pt HNPs possess intrinsic enzyme-like catalytic activities, providing the Ag-Pt HNP-based CLFA with strong color signal and thus a high sensitivity. Meanwhile, the Ag-Pt HNPs have hollow interiors and are mainly composed of less expensive silver, making the Ag-Pt HNP-based CLFA cost-effective. Using prostate-specific antigen (PSA) as a model disease biomarker, the Ag-Pt HNP-based CLFA achieved a high sensitivity with a detection limit at the low picogram-per-milliliter level. Potential application of the CLFA in clinical diagnosis was demonstrated by detecting PSA from human serum samples.

Stabilization of PE with the natural antioxidant t-resveratrol: Interaction of the primary and the secondary antioxidant

The study focuses on the possibility of using resveratrol, a stilbenoid-type natural antioxidant, as a stabilizer in polyethylene. The experiments were carried out in two stages. First, the efficiency of the natural antioxidant was compared to that of a commercial product, and then polymer properties were determined as a function of additive content. Stabilization efficiency was determined by multiple extrusion experiments. Resveratrol proved a very efficient stabilizer, more efficient than the commercial hindered phenolic antioxidant. Resveratrol provides excellent processing stability and the residual stability of PE containing it is exceptional. Because of its large efficiency, 400–500 ppm additive is sufficient to achieve adequate stability for practice. Resveratrol interacts with the secondary phosphorous stabilizer used in the study, and the effect is antagonistic; resveratrol performs better alone than in combination with PEPQ. Accordingly, this unusual effect must be taken into account during formulation and the construction of the actual additive package. Resveratrol is used in other industries, thus it is available in large quantities and relatively cheap. Besides its advantages, the natural antioxidant has some drawbacks, like its high melting temperature, limited solubility in polyethylene, and strong color of its reaction products. Nevertheless, resveratrol has great potential as a stabilizer in certain products.

The application of Xinjiang safflower extract on Aidelaisi silk fabric

Purpose This study aims to explore the traditional plant dyeing of Xinjiang Atlas silk fabrics, providing references for the comprehensive utilization of plant dyes in intangible cultural heritage.Design/methodology/approach The focus of this study is on dyeing experiments of Atlas silk fabrics using safflower extracts, constrained by regional resources. Safflower dry flowers grown in Xinjiang were selected, rinsed with pure water and rubbed. Yellow pigments were removed by adding edible white vinegar. Red pigments from safflower were extracted using an alkaline solution prepared with Populus euphratica ash, a special product of Xinjiang. The extraction rate was analyzed under varying material-to-liquor ratios, pH values, times and temperatures. Direct dyeing process experiments were conducted to obtain different colorimetric L, a, b and K/S values for comparison. Samples with good color development were selected to test the impact of dyeing immersions on color development, and their color fastness, UV protection and antibacterial effects were verified.FindingsThe dyeing experiments on silk fabrics confirmed their UV protection capabilities and antibacterial properties, demonstrating effectiveness against E. coli and Staphylococcus aureus. As a major producer of safflower, Xinjiang underscores the significance of safflower as an essential plant dyes on the Silk Road. This study reveals its market potential and suitability for use in the plant dyeing process of Atlas silk, producing vibrant red and pink colors.Originality/valueThe experiments indicated that after removing yellow pigments, the highest extraction rate of red pigment from safflower was achieved at a pH value of 10–11, a temperature of 30°C and an extraction time of 40 min. The best bright red color effect with strong color fastness was obtained with a material-to-liquor ratio of 1:20, a temperature of 40°C and three immersions. The best light pink color effect with strong color fastness was a material-to-liquor ratio of 1:80, a temperature of 30°C and two immersions.

Unravelling the object-based nature of visual working memory: insight from pointers.

Visual working memory (VWM) plays a crucial role in temporarily storing and processing visual information, but the nature of stored representations and their interaction with new inputs has long been unclear. The pointer system refers to how VWM links new sensory inputs to stored information using specific cues. This study aimed to investigate whether the pointer system is based on spatial, feature-based, or object-based cues by employing the repetition benefit effect, where memory performance improves with repeated memory items. Across three experiments, we manipulated spatial positions, shapes, and colors as pointer cues to determine how these features affect VWM consolidation and updating. The results showed that while spatial location serves as a strong pointer cue, shape and color features can also effectively reestablish object correspondence in VWM. These findings support the view that the pointer system in VWM is flexible and object-based, utilizing various feature cues to maintain memory continuity. This study provides new insights into how VWM connects new inputs with stored information through the pointer system.

WITHDRAWN: Fermentative production, comparative characterization with carrots, and functional analysis of β-carotene produced from Rhodotorulla toruloids

Beta-carotene is the most widely demanded red-orange colored pigment having several applications in the food, cosmetic, and dying industries. Synthetic pigments pose serious side effects leading to the need for natural alternatives. In this study, β-carotene was extracted from fungi, and carrots. The confirmation and characterization of β-carotene was carried out via spectrophotometry, Thin Layer chromatography, and High-Performance Liquid Chromatography. Finally, the antimicrobial and antioxidant activities of the pigment were identified and its application as a dye was tested. The isolated yeast strain was identified as Rhodotorulla toruloids. Submerged fermentation of R. toruloids in YPD medium (wit 4% Dextrose) produced maximum biomass (0.6g/L) at 25°C. Using chloroform and methanol, 0.36g/L β-carotene yield was obtained. The R. toruloids extracted β-carotene showed the highest antibacterial potential against Salmonella sp. with 25.3±0.3 mm inhibition zones as compared to that of carrot extracted β-carotene i.e., 20.3±0.26mm. The DPPH analysis also revealed R. toruloids derived β-carotene as a strong antioxidant. The R. toruloids extracted β-carotene also cast a strong red color on cotton indicating it as a suitable candidate for organic dye. It is concluded from this study that β-carotene extracted from R. toruloids showed better antimicrobial and antioxidant potential along with its efficient ability to dye cotton as compared to the carrot's β-carotene. Hence, R. toruloids, being easily available and cost-effective production can prove better β-carotene source as compared to carrots.

JWST’s PEARLS: Resolved study of the stellar and dust components in starburst galaxies at cosmic noon

Dusty star-forming galaxies (DSFGs) significantly contribute to the stellar buildup in galaxies during “cosmic noon,” the peak epoch of cosmic star formation. Major mergers and gas accretion are often invoked to explain DSFGs’ prodigious star formation rates (SFRs) and large stellar masses. We conducted a spatially resolved morphological analysis of the rest-frame ultraviolet/near-infrared (∼0.25–1.3 μm) emission in three DSFGs at z ≃ 2.5. Initially discovered as carbon monoxide (CO) emitters by NOrthern Extended Millimeter Array (NOEMA) observations of a bright (S350 μm = 111 ± 10 mJy) Herschel source, we observed them with the James Webb Space Telescope/NIRCam as part of the PEARLS program. The NIRCam data reveal the galaxies’ stellar populations and dust distributions on scales of 250 pc. Spatial variations in stellar mass, SFR, and dust extinction are determined in resolved maps obtained through pixel-based spectral energy distribution fitting. The CO emitters are massive (Mstar ≃ (3 − 30)×1010 M⊙), dusty starburst galaxies with SFRs ranging from 340 to 2500 M⊙ yr−1, positioning them among the most active star-forming galaxies at 2 < z < 3. Notably, they belong to the ∼1.5% of the entire JWST population with extremely red colors. Their morphologies are disk like (Sérsic index n ≃ 1), with effective radii of 2.0–4.4 kpc, and exhibit substructures such as clumps and spiral arms. The galaxies have dust extinctions up to AV = 5–7 mag extending over several kiloparsecs with asymmetric distributions that include off-center regions resembling bent spiral arms and clumps. The near-infrared dust-attenuation curve in these sources deviates from standard laws, possibly implying different dust–star geometries or dust grain properties than commonly assumed in starburst galaxies. The proximity (< 5″) of galaxies with consistent redshifts, strong color gradients, an overall disturbed appearance, asymmetric dust obscuration, and widespread star formation collectively favor interactions (minor mergers and flybys) as the mechanism driving the CO galaxies’ exceptional SFRs. The galaxies’ large masses and rich environment hint at membership in two proto-structures, as initially inferred from their association with a Planck-selected high-z source.

UNCOVER NIRSpec/PRISM Spectroscopy Unveils Evidence of Early Core Formation in a Massive, Centrally Dusty Quiescent Galaxy at z spec = 3.97

We report the spectroscopic confirmation of a massive ( log(M⋆/M⊙)=10.34±0.070.06 ), Hubble Space Telescope–dark (m F150W − m F444W = 3.6) quiescent galaxy at z spec = 3.97 in the UNCOVER survey. NIRSpec/PRISM spectroscopy and a nondetection in deep Atacama Large Millimeter/submillimeter Array imaging surprisingly reveals that the galaxy is consistent with a low (<10 M ⊙ yr−1) star formation rate (SFR) despite evidence for moderate dust attenuation. The F444W image is well modeled with a two-component Sérsic fit that favors a compact, r e ∼ 200 pc, n ∼ 2.9 component and a more extended, r e ∼ 1.6 kpc, n ∼ 1.7 component. The galaxy exhibits strong color gradients: the inner regions are significantly redder than the outskirts. Spectral energy distribution models that reproduce both the red colors and low SFR in the center of UNCOVER 18407 require both significant (A v ∼ 1.4 mag) dust attenuation and a stellar mass-weighted age of 900 Myr, implying 50% of the stars in the core already formed by z = 7.5. Using spatially resolved annular mass-to-light measurements enabled by the galaxy’s moderate magnification ( μ=2.12±0.010.05 ) to reconstruct a radial mass profile from the best-fitting two-component Sérsic model, we infer a total mass-weighted reff=0.74±0.170.22 kpc and log (Σ1kpc[M⊙kpc-2])=9.65±0.150.12 . The early formation of a dense, low SFR, and dusty core embedded in a less attenuated stellar envelope suggests an evolutionary link between the earliest-forming massive galaxies and their elliptical descendants. Furthermore, the disparity between the global, integrated dust properties and the spatially resolved gradients highlights the importance of accounting for radially varying stellar populations when characterizing the early growth of galaxy structure.

K-means 알고리즘을 기반으로 한 야오족 자수 색상 추출 및 가상 캐릭터 의상디자인 응용

To promote the digital preservation and transmission of traditional cultural elements, this study focuses on Yao embroidery as a case study, combining digital technologies and algorithms to extract and analyze its color characteristics. These extracted color features were applied to the design of virtual character clothing. First, a bilateral filtering algorithm was used to preprocess the images of Yao embroidery, reducing noise while preserving intricate details. Subsequently, Euclidean distance was calculated in the Lab color space, and the OSTU adaptive binarization method was employed to separate the image from its background. Additionally, K-means clustering was applied multiple times to the color data, and the optimal result was achieved when the number of clusters was set to eight. Through this process, eight major colors of Yao embroidery were extracted. Based on these extracted colors, 3D point cloud analysis was conducted to study the three-dimensional spatial distribution of color points, and a color combination model based on hue, brightness, and saturation was constructed. The results revealed that the color composition of Yao embroidery predominantly consists of high-saturation colors, with strong color contrasts and distinct ethnic characteristics. Ultimately, this study demonstrated the applicability of integrating the color model and design patterns of Yao embroidery into virtual character clothing design, showcasing the potential for incorporating traditional embroidery into digital design. This contributes to the preservation and promotion of intangible cultural heritage and serves as a valuable reference for further research on the color systems of traditional ethnic costumes.

Integrated Sensing Platform Validated for the Efficient and On-Site Screening of Amine-Containing Illicit Drugs.

Efficient and reliable technologies for the on-site detection of illicit drugs are important in drug-facilitated crime investigations. However, the development of such technologies is challenging. Based on the synthetic optimization, introducing a boron ester functional group to the two furanic indicators endows the stimulus-responsive properties synergistically. The ring-opening reaction of the indicators in the presence of amine-containing illicit drugs generated well-known donor-acceptor Stenhouse adducts, accompanied by strong color changes. A small-size and lightweight laminated sensor was integrated based on the outstanding ratiometric variations of the two active furanic indicators. A prototype platform was fabricated equipped with a circuit control, a mini pump, and a signal processing system. A user-friendly detection and efficient screening of amine-containing illicit drugs, including phenethylamines, amphetamines, cathinones, and tryptamines in the liquid states were conducted. The ratiometric response of the sensor was linear in the concentration range of 2.1-10.6 μg·mL-1 for methamphetamine·HCl and methcathinone ·HCl. The detection limits for the two illicit drugs at the sublevel (ng·mL-1) were found to be 8.4 and 9.0 ng·mL-1, respectively. Double-blind field tests and different illicit drugs were evaluated with good screening capability. Successful trials showed the potential applications of the developed prototype platform for efficient and on-site analytical determination.

Initial development of a rapid, portable, stall-side ELISA for the measurement of equine adrenocorticotropic hormone.

Pituitary pars intermedia dysfunction (PPID) is a neurodegenerative disease of senior horses. Loss of dopaminergic inhibition of the melanotropes of the pars intermedia leads to increased concentrations of pro-opiomelanocortin (POMC)-derived peptides. Diagnosis is challenging due to pre-analytical variables, such as sample storage, handling, and time to analysis. Our objective was to develop an ELISA for ACTH measurement, which could ultimately form the basis for a stall-side equine ACTH test. We selected 2 ACTH-specific monoclonal antibodies, CBL57 and EPR20361-248, based on the recognition of separate epitopes, strong and rapid color change, and minimal background interference, including no cross-reactivity with themselves, each other, and the test reagents. CBL57 was chosen as the detection antibody (or secondary antibody). EPR20361-248, functionalized on superparamagnetic iron oxide beads, was chosen as the capture antibody (or primary antibody) to bind ACTH in plasma. The incorporation of magnetic beads marks the initial stage in establishing a platform that could potentially be utilized in the field, similar to other stall-side tests. The concentrations of antibodies, magnetic beads, and incubation durations were optimized. Our immunoassay detected unglycosylated rat recombinant ACTH. Further studies are ongoing to optimize and validate our assay using equine plasma and serum samples.

Formulation and analysis of acrylic emulsion coatings with chrome yellow, phthalocyanine blue, and red oxide pigments using high speed disperser and bead mill techniques

A major commercial problem is achieving stable and fine particle pigment dispersion, especially for aqueous pigment dispersions. It is essential to optimize dispersants in order to moisten, disperse, and stabilize pigments throughout the milling process. This study focuses on formulating acrylic emulsion coatings using chrome yellow, phthalocyanine blue, and red oxide pigment concentrates. The formulations were developed using both high-speed dispersers (HSD) and bead mills. A quality evaluation of the products from the two milling techniques was carried out. Formulations made with chrome yellow, phthalocyanine blue, and red oxide pigment concentrates in a water-based, binder-free system using bead mills, Tween-80, SLS, and cocosulphosuccinate surfactants showed narrower particle size distributions and stronger color than those made with HSD. Specifically, formulations prepared with bead mills and the aforementioned surfactants demonstrated superior color strength compared to those prepared with HSD. The color shade of acrylic emulsion coatings formulated with phthalocyanine blue and red oxide pigment concentrates, along with Tween-80 and cocosulphosuccinate surfactants using HSD, matched the standard color shade formulations prepared in bead mills. However, formulations using phthalocyanine blue pigment concentrates with SLS and oleylsulphosuccinate surfactants in HSD did not match the standard color shade prepared in bead mills.

Kinetic Study of the Water Quality Parameters during the Oxidation of Diclofenac by UV Photocatalytic Variants

Diclofenac (DCF, C14H11Cl2NO2) is a widely used non-steroidal anti-inflammatory drug, with a significant occurrence in waste effluents. DCF is especially persistent and difficult to degrade, with numerous toxic effects on aquatic fauna and humans. In 2015, DCF was identified as a priority pollutant (EU Directives on water policy). In this work, UV irradiation and its combination with hydrogen peroxide only or catalyzed by iron salts (photo-Fenton) are analyzed to find the most efficient alternative. DCF aqueous solutions were treated in a stirred 150 W UV photocatalytic reactor. Depending on the case, 1.0 mM H2O2 and 0–5.0 mg/L Fe2+ catalyst, such as FeSO4, was added. During the reaction, DCF, pH, turbidity, UVA at 254 and 455 nm, dissolved oxygen (DO), and TOC were assessed. The degradation of DCF yields a strong increase in aromaticity because of the rise in aromatic intermediates (mono-hydroxylated (4-hydroxy-diclofenac and 5-hydroxy-diclofenac) and di-hydroxylated products (4,5-dihydroxy-diclofenac), which subsequently generate compounds of a quinoid nature), which are very stable and non-degradable by UV light. Thus, only if H2O2 is added can UV completely degrade these aromatic colour intermediates. However, adding ferrous ion (photo-Fenton) the aromaticity remains constant due to iron com-plexes, that generates maximum colour and turbidity at an stoichiometric Fe2+ : DCF ratio of 3. As a result of the study, it is concluded that, with UV light only, a strong yellow colour is generated and maintained along the reaction, but by adding H2O2, a colourless appearance, low turbidity (&lt;1 NTU), and [DO] = 8.1 mg/L are obtained. Surprisingly, photo-Fenton was found to be unsuitable for degrading DCF.