Green Pigment Research Articles

Optimization of the Application of Walnut Green Peel Pigment in Wool Fiber Dying and Fixing Process under Microwave-assisted Condition

ABSTRACT In this paper, the response surface method was used to study the technology of dyeing wool fiber with walnut green peel pigment under the microwave-assisted method. The optimized pigment extraction process were: ethanol volume fraction 60%, extraction time 1 min, liquid-material ratio 24:1, microwave power 450 W, and the optimized mordant fixation process were: mordant fixation time 3 min, microwave power 270 W, amount of mordant fixing agent 7%, reducing agent dosage 22 g/L. The results showed that the use of microwave-assisted and new mordant fixing agent lanthanum chloride greatly improved the extraction efficiency of pigments, saved extraction costs, and significantly shortened the mordant fixation time, resulting in an environmentally friendly mordant fixation process.

Characterization of Green Paints in Ming and Qianlong Dynasties' Lin'xi Pavilion by Complimentary Techniques.

During conservation of the painted ceiling decoration of Lin’xi Pavilion in the Forbidden City, two distinct paint campaigns were isolated as a unique case study into architectural paint materials during both the Ming and Qing dynasties. Paint samples and cross sections from both paint generations were analyzed with SEM-EDX, time of flight-secondary ion mass spectrometry (ToF-SIMS), XRD, FTIR, and Raman spectroscopies. Similar organic and inorganic materials characteristic of these time periods were identified. The pigments of interest found in both paint generations were botallackite and atacamite polymorphs. This suggests a shift from natural mineral sources to synthetic copper-based pigments for these larger architectural projects.

Novel yellow to blackish green Ni-doped aluminium titanate ceramic pigments

Novel yellow to blackish green Ni-doped aluminium titanate (Al2TiO5) ceramic pigments were synthesized by solid-state reaction method at 1400 ?C. Effects of nickel doping content on phase composition, microstructure, optical properties and stability were studied. The results show that the higher content of Al2TiO5 phase and the reduction of the lattice distortion of aluminium titanate could be attributed to the entry of nickel ions into aluminium titanate lattice resulting in the formation of solid solution. Ni-doped aluminium titanate ceramic pigments show exceptional glaze colouring and are expected to be promising high-temperature pigments.

Polymorph identification in green Chinese architectural paints using Raman imaging and multivariate curve resolution

AbstractDistinguishing the polymorphs of basic copper chlorides is useful to inform how these materials were used as pigments in Western artworks. Raman imaging spectroscopy and multivariate curve resolution‐alternating least squares (MCR‐ALS) were employed to distinguish the minerals used in green pigments of several Chinese architectural paintings (12th–19th centuries). MCR‐ALS generated component spectra for the Raman datasets, which allowed the resolution of trace materials separated from background features. This method established the mixtures of atacamite and botallackite polymorphs and their relative ratios in five paint samples and identified the mineral azurite, a basic copper carbonate in one sample. These findings identify and suggest a shift to synthetic basic copper chloride pigments in Chinese architectural paints based on the spectroscopically resolved spectra of these mixtures. Thus, this methodology has successfully been applied to paint cross sections to distinguish components and to inform on the materiality and history of objects.

Antioxidant status of barley seedlings under conditions of excess manganese

The system of protection against the effects of heavy metals (TM) can differ not only in different species of plants, but also in different varieties. Manganese (Mn), as a biogenic element, is necessary for normal plant growth and development. However, in the case of concentrations exceeding the optimal level, it negatively affects both linear plant growth and physiological processes. The paper presents data on the assessment of the effect of excess manganese (II) ions (30, 60 and 90 mg/l of active substance) on barley seedlings of different varieties. Resistance of plants to ionic toxicity of manganese (II) was judged by the value of antioxidant activity (AOA) of superoxide dismutase (SOD), the content of low-molecular antioxidants (chlorophyll a and b, carotenoids and anthocyanins) in barley leaves. For most of the varieties studied, an increase in AOA of SOD, the content of anthocyanins indicating the activation of plant protective mechanisms, was noted. The amount of green pigments, as well as carotenoids, on the contrary, decreased, compared with the control, which indicated a violation of the processes of photosynthesis in them.

Chemical and Nutritional Compounds of Different Parts of Lemongrass (<i>Cymbopogon citratus</i> (DC) Stapf.) Cultivated in Temperate Climate of Poland

Lemongrass (Cymbopogon citratus (DC) Stapf.) is a perennial plant indigenous to semi-tropical regions of Asia and cultivated in other semi-tropical countries. The present study aimed to examine the key chemical constituents of various parts of lemongrass cultivated in the temperate climate of Poland. The content of essential oil and its composition were determined in 4 plant parts: leaves (part C), overground shoots (part B), underground shoots (part A), and roots (part R). Moreover, the content of dry weight, chlorophyll, polyphenols and macro- and microelements was determined in the edible parts (excluding roots). The essential oil from the aerial part predominantly contained neral (> 30%) and geranial (> 40%), which is consistent with the data reported in literature; the main component of essential oil (EO) from the underground part was elemol (65%); interestingly, such a high concentration of it was found for the first time. The concentration of chlorophyll was found to be higher in leaves, as compared to parts B and A. The highest level of potassium, magnesium, zinc and sodium was found in part A while of calcium and copper in leaves. The quality of lemongrass raw materials grown in temperate climates did not differ significantly from those obtained in warmer regions. The study findings confirmed the usefulness of leaves as a raw material for the preparation of infusions (higher concentration of pigments, polyphenols and EO) and of near-ground parts of a plant as a culinary material (a higher content of macroelements at lower concentrations of green pigments and dry weight).

Using endogenous pigments to recolour roasted green tea

Abstract Roasted green tea exhibits undesirable dark green that can seriously affect sensory quality, market price, and consumer acceptance. The aim of this work was to propose a method of improving the appearance of the roasted green tea. In this study, rehydration with freeze-drying (RFD) was used to recolour the tea leaves by redistributing the endogenous pigments. The results indicated that the colour of the roasted green tea changed from dark green to bright green after the RFD treatment, the values of L* and b* were significantly increased (P<0.05), and the value of a* was significantly decreased (P<0.05). In addition, the RFD treatment making the yellow–green pigments transfer onto the surface of the tea leaves also induced a change in pigment contents, including chlorophylls, carotenoids, and flavonoid glycosides. The well-defined optimum parameters for the rehydration process were moisture content of tea leaves at 35 per cent, water temperature 25 °C, and a standing time of 1.5 h.

Исследование пигментов и связующих красочных слоев росписей храма X–XIII вв. на плато Эски-Кермен

In 2018–2019, the excavations of an aisleless church dated from the tenth to thirteenth centuries and located in quarter II on the territory of a provincial Byzantine town atop of the plateau of Eski-Kermen discovered fragments of wall-plaster with polychrome painting. There are several shades of green, two shades of red, white (beige), yellow (ochre), and grey-brown colours. This paper presents the results of studies of the colour layer, determines pigments and cohesive colour components, and uncovers the features of the painting technique applied to the walls of the church. Four groups of samples were selected for the study featuring: 1 – white, 2 – yellow, 3 – red, and 4 – green colours. The elemental composition of the colour layer was studied by scanning electron microscopy combined with energy-dispersive X-ray microanalysis (SEM/EDX). The phase constitution of the samples was investigated by X-ray powder diffraction (XRD) method with the use of diffractometers operated in a transmission mode at the Kurchatov synchrotron radiation source. The chemical composition of colour layers was studied by infrared spectroscopy, and the study of cohesive colour materials was carried out by gas chromatography with mass spectrometry (GC/MS). The elemental composition and phase constitution of the white colour indicated the use of lime whitewash. Yellow ochre (goethite) was used as yellow colour. Red colour features the presence of hematite typical for the group of pigments united under the name of red soils. However, the discovery of 1% goethite typical for yellow ochres in the phase constitution of one sample allows the possibility that burnt yellow ochre was used as a red pigment. The green colour was green soil (glauconite and celadonite). It should be noted that none of the examined samples of red pigment contained traces of vermilion, which occurred in ancient paintings in the Crimea and was typical for Byzantine wall-paintings. In all the samples of pigments contained a significant degree of calcite (36-98%), possibly due to the presence of particles of undercolour in the measured samples of wall paintings, or diluting the pigment with lime water for the making of wall-painting featuring fresco technique. The use of the latter technique is also indicated by the presence of white lime colour. The traces of cohesive component in the form of fish glue and protein products from chicken eggs found in the red and green paint samples also suggests the use of the dry painting technique. Therefore, there are reasons to suppose that the painting of the quarter church of Eski-Kermen used two techniques, fresco and dry plaster paintings.

Harkton's Hundred or A Wind in the Minagaroons

33 ROBERT CLINTON Harkton’s Hundred or A Wind in the Minagaroons • I walked by Harkton’s Hundred where the froyn and the quirts are flowering, and I’ve never seen greener dewstein than what flows over Harkton’s pastures. The lazy and poignant froyn deploys in its tissues and twigs a scented air, distantly, faint copy of the flowers, but it says you come here and leads you to the southeast corner where it was pridefully set by Dissenters. Busily it spin-sings its grey and white flowers: froyn’s fragrance comes in a private coach. I felt scent-induced vertigo, standing so close. Quirts, or hackroot, a tough blooming hedge, has got Harkton’s Hundred onto its grid, bounding his fields in sharp straight lines. Quirts comes to spring in a scarlet coat of tiny odorless florets; the coat falls in May and here are the little quirts leaves, simple hearts of bright green, mint-smelling, liking well to be pruned in the fall: politely a fence. And the dewstein is deep and constant on Harkton’s lawns and pastures. It roars and rolls everywhere, burying tree stumps, over your doorsill and into the front hall, half masking the apple tree trunks. A bluegrass in color, but dewstein is bluer and grassier. It holds to the ground so close and floods our fields like thick green paint or billows of sea. 34 I walked by Harkton’s Hundred where the froyn and the quirts are flowering, and I’ve never seen dewstein so lush as what flows over Harkton’s pastures. I waited to see if Harkton was home—would he open the door with Good Morning, or was he down in the Hundred somewhere, recking with last fall’s pommeley briars that lock to your fence rails, at least till the phoebe wasps come and drain the new shoots—or was one of his herd of premiere bowhas not being correctly an animal—pails of songs instead of true syrup? It’s a rich-dirt farm but nobody home, Harkton or Lady Dame Harkton or the sons, still twins after all these years. A wind in the minagaroons, that hang their blue blooms from the rafters, and pink mandaleets sang through the trees. I hatted myself and took the north road. I’d spend a dime at Mrs. Dotspot’s for three of the jelliest ling-dings in town. I’m doing that, walking uphill with my dime. ...

ANALYTICAL STUDY AND TREATMENTS OF THE DECAYED MURAL PAINTINGS AT ATHRIBIS IN SHEIKH HAMAD TEMPLE, SOHAG GOVERNORATE, EGYPT

This article focuses on the identification of the building materials used at Athribis temple – Sohag and their most common degradation factors, and then assessing the most appropriate consolidants for the decayed wall paintings at the temple. The building materials were studied through XRD, SEM-EDX, FTIR spectroscopy and light optical microscope to identify chemical decompositions and physical failures. Soluble salts were detected in the building materials. White pigment is calcium carbonate, yellow pigment goethite, red pigment hematite, blue pigment Egyptian blue, green pigment Egyptian green, the paint medium is animal glue. Conservation treatments were achieved using Ethanol + PLM.I for injecting detached plasters, Sturgeon glue 1.5% as a filler for cracks, Syton x30 for pre-consolidation, EDTA poultices for cleaning, EDTA for salt extraction, Cidal 50 L50 as a biocide and Klucel G as a final consolidant.

Study on UV-aging performance of fluorinated polymer coating and application on painted muds

The UV-aging tests were carried out on synthetic fluorinated polymer coating (poly (methyl methacrylate)-poly (dodecafluoroheptyl methacrylate), FP) to study its UV-aging mechanism, UV-aging resistance and application on painted muds with calcium carbonate, azurite, haematitum, mineral green and cinnabar pigments. The UV-aging mechanism was studied by Fourier infrared spectroscopy attenuated total reflection technique (ATR-FTIR) and x-ray photoelectron spectroscopy (XPS). The UV-aging resistance of FP was characterized by field emission scanning electron microscope (SEM), CR-400 color difference meter and static contact angle (SCA). The FP was applied on the painted muds samples and the protective efficacy was evaluated by measuring the chromatic variations(ΔE) and water contact angles of samples after treatment. The results of ATR-FTIR and XPS shown that FP only had microphase separation without chemical change after 360h of aging. After 360h of aging, the SEM shown that there were just some bumps on the FP film surface and further proved the phenomenon of microphase separation; the color change of the FP film was no difference (ΔE = 0.46); the FP film could retain adequate hydrophobicity (101.0°). After the painted muds samples were treated by FP, the color change of the calcium carbonate and haematitum was just noticeable difference (ΔE = 0.80 ∼ 1.49), while the color change of the azurite, mineral green and cinnabar was fairly large difference (ΔE = 4.4 ∼ 6.3); all pigments could maintain hydrophobicity at the end of aging. All the results demonstrated that the FP has excellent UV-aging resistance and could provide adequate protective efficacy for calcium carbonate and haematitum, but the protection efficacy for the azurite, mineral green and cinnabar is not ideal. Thus, it is believed that the FP can be used as a suitable UV resistant protective coating for calcium carbonate and haematitum.

EU should not ban phthalo blue & green pigments for use in tattoo inks

EU should not ban phthalo blue & green pigments for use in tattoo inks

Chlorophyll does not reflect green light – how to correct a misconception

ABSTRACT Plant leaves are green because they contain the green photosynthetic pigments, chlorophylls a and b. Popular science literature, and sometimes even textbooks, state that the greenness is caused by reflection of green light by chlorophyll. In the present study, we compared the reflectance spectra of green leaves to yellow or white leaves of the same species. Chlorophyll-deficient leaves reflected green light more efficiently than green leaves of the same species, which conclusively refutes the misconception. The data show that the green colour of leaves is caused by preferential absorption of blue and red light by chlorophyll, not by reflection of green light by chlorophyll. The data suggest that the cellulose of the cell walls is the main component that diffusely reflects visible light within plant leaves.

Green antifungal waterborne coating based on essential oil microcapsules

There is a great concern about the indoor microbial colonization especially in places that should have high standards of environmental hygiene. Besides, due it shortened the useful life of the coating by discoloration and degradation. Currently this is a problem that must be solved in an innovative and eco-friendly way. In this sense, the aim of the work was to develop a green waterborne paint formulated with microcapsules containing essentials oil as biocide agent. This novel hygienic coating would be applied as to protect indoor surfaces from fungi. The microcapsules were synthesized by interfacial polymerization. Melamine-formaldehyde (MF) resin was used for the microcapsule shell wall, and Lavandin and Tea Tree essential oils (EOs) as core materials. The synthesized microcapsules were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and particle size analysis. Preparation of acrylic waterborne paint was performed and the microcapsules MF-EOs were dispersed into the original paint just before application on commercial gypsum boards. The stability of the MF-EOs in the paint was successfully achieved. Two control paints were used, one containing EOs in free form and other without biocide.The effectiveness of the microcapsules into paint film against spore suspension of Aspergillus fumigatus was evaluated by seeding the fungus on the painted surface. The fungal growth was evaluated according to ASTM D5590 standard specification. The score obtained from MF-Lavandin paint indicates just a trace growth onto the painted surface (<10 %). On the control and MF-Tea tree paints the growth was 70 %. The MF-Lavandin showed a high inhibition activity against fungal in the dry paint film compared with the one containing free form EOs paint.

Extraction Improvement of the Bioactive Blue-Green Pigment "Marennine" from Diatom Haslea ostrearia's Blue Water: A Solid-Phase Method Based on Graphitic Matrices.

The compound “marennine” is a blue–green pigment produced by the benthic microalgae Haslea ostrearia, with pathogenicity reduction activities against some bacteria and promising potential as a natural pigment in seafood industries. After decades of research, the chemical family of this compound still remains unclear, mainly because structural studies were impaired by the presence of co-extracted compounds in marennine isolates. To improve the purity of marennine extract, we developed a novel extraction method using a graphitic stationary phase, which provides various advantages over the previous procedure using tandem ultrafiltration. Our method is faster, more versatile, provides a better crude yield (66%, compared to 57% for ultrafiltration) and is amenable to upscaling with continuous photobioreactor cultivation. Our goal was to take advantage of the modulable surface properties of the graphitic matrix by optimizing its interactions with marennine. As such, the effects of organic modifiers, pH and reducing agents were studied. With this improvement on marennine purification, we achieved altogether the isolation of a fucoidan-related, sulfated polysaccharide from blue water. Characterization of the polysaccharides fraction suggests that roughly half of UV-absorbing compounds could be isolated from the marennine crude extracts. The identification of sulfated polysaccharides could be a major breakthrough for marennine purification, providing targeted isolation techniques. Likewise, the added value of Haslea ostrearia and the role of polysaccharides in previous marennine chemical characterization and bioactivity studies remain to be determined.

Green nanoceramic pigments based on cobalt chromite doped with Al: Synthesis, characterisation and colour performance

Nano-sized spinel cobalt chromite oxide CoCr2O4 and its substituted forms CoCr2−xAlxO4 (0 ≤ x ≤ 2) have been successfully synthesised by wet chemical route. The prepared powders were characterised by means of thermal analysis (DTA/TGA), X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Brunauer–Emmett–Teller analysis (BET), UV–visible techniques (UV–Vis) and colorimetric analyses (L* a* b*). The results show that the CoCr2−xAlxO4 (0 ≤ x ≤ 2) samples are in the crystalline phase at 900 °C with a particle size range of 20–200 nm. The colouration of the synthesised pigments is sensitive to the distribution of doping trivalent ions in the spinel lattice. The Al-enrichment leads to a colour shift from green to blue and the grains become more and more spherical and less agglomerated. Green cobalt chromite powders were substituted with 50% aluminium (CoCrAlO4), allowing the specific surface area of green nanometric powders to be increased from 7.4 to 12.4 m2/g.

Applications of Raman spectroscopy in art and archaeology

Applications of Raman spectroscopy in art and archaeology

Microscopic analysis of overglaze green pigment on Chinese famille rose porcelain from the Imperial Palace.

Famille rose porcelain made in the imperial workshop was one of the symbols of the highest manufacturing techniques in ancient China. It was very precious and only owned by the royals for a long time. Because of its complex making technology, overglaze green pigment painted on famille rose porcelain shows many variations. In this work, selected porcelain shards that were excavated at the Forbidden City were analyzed by using microscopy observation, micro-Raman spectroscopy, scanning electron microscopy, and energy dispersive X-ray spectrometer to obtain a deep understanding of overglaze green pigment technique on famille rose porcelain. The results revealed that four types of green pigment are used in the selected samples. With different recipes and combinative ways on green pigment and opaque white pigment, craftsmen can choose the using method of pigment to get the effect they want.

Evaluation of degradation of pigments formed during garlic discoloration in different pH

The specific chemical bond changes of green pigment formed in garlic discoloration were investigated in our study. Multiple analysis methods were used in the degradation of pigment, including ultraviolet–visible (UV–Vis) spectrophotometry, attenuated total reflection Fourier transform infrared (ATR-FTIR) and Fourier transform infrared near infrared (FT-NIR). Green pigments were treated at 40 °C for 7 days in the pH range of 5.0–8.0. Principal component analysis of the ATR-FTIR and FT-NIR spectra indicated the similarities and differences during pigment degradation. It was found that the degradation degree of green pigments in a solution with pH 5.0 was the lowest. Changes in the absorptions of CO, COO−, CN, CN, OCOCH, COC, COOH, and NH bonds vibrations are attributed to the decomposition of the pigments. The absorption at 5170 cm−1 (NH bond first overtone) and 4871 cm−1 (OCH stretching) correlated to pigment degradation were confirmed by FT-NIR spectra. One proposed pathway of the pigment decomposition was explored.

Nutritional quality and volatile flavor substances of “laba” garlic products produced by either soaking or fumigating with acetic acid

The quality of garlic (Allium sativum L.) is attributed to nutrients and organosulfur compounds. In this study, the quality of “Laba” garlic with the same degree of greening produced by soaking or fumigating with acetic acid was investigated using fresh garlic as the control. Garlic fumigated with acetic acid exhibited higher soluble solid, monosaccharide, and polyphenol contents. The flavor profiles were significantly distinguished without overlap using the linear discriminant analysis classification model. Thirty volatile compounds were detected in the garlic samples, of which 16 were common among the three garlic samples, while four and five unique compounds were identified in fresh and fumigated garlic, respectively. “Laba” garlic fumigated with acetic acid showed more varieties of allyic compounds and higher contents of thiocycloalka(e)nes than that soaked in acetic acid. In summary, “Laba” garlic produced by fumigation with acetic acid was of higher quality than that produced by soaking in acetic acid. Practical applications “Laba” garlic is made by pickling aged garlic in vinegar. However, green pigment, water-soluble vitamins (including vitamin B and C) and sugars might transfer from garlic to the soaking solution. Therefore, “Laba” garlic was prepared by dry processing, through fumigation with acetic acid. Clarification of quality difference between “Laba” garlic products produced by traditional and dry processing methods will provide useful information for the “Laba” garlic processing industry.