Novel environmentally friendly inorganic red pigments based on calcium bismuth oxides

Novel environmentally friendly inorganic red pigments based on calcium bismuth oxide Ca3(Bi1-xREx)8O15(0≤x≤0.09;RE=Sc^(3+),Er^(3+),Y^(3+),Ho^(3+)and Dy^(3+)),were successfully synthesized and the color properties were characterized.The color of these pigments depended on the composition and the synthesis condition,and the most vivid red color was obtained for the Ca3(Bi0.93Y0.07)8O15 sample calcined thrice at 800℃for 2 h.The L*and a*values corresponding to brightness and red chromaticity for this pigment were 45.6 and+30.6,respectively,which were greater than those of a commercially available Fe2O3 pigment(L^(*)=38.4,a^(*)=+29.5).Since the present pigment is composed of nontoxic and safe elements,it should be an attractive alternative to the conventional Fe2O3 pigment.

Isolation of a Prodigiosin-producing Strain and Analysis of It's Pigments

[Objective] The aim was to isolate a prodigiosin producing strain and study its pigment fractions.[Method] Red pigment-producing bacteria was identified by physiological and biochemical characteristics after isolation in plate.By using column chromatography and thin-layer chromatography,pigment fractions were separated and purified from the extractives of the strain after fermentation in flask,and then pigment fractions were analyzed via UV-Vis and LC/MS.[Result] A red pigment-producing Serratia marcescens strain NS-17 sampled from soil of Nanchang was isolated and identified.2 pigment fractions showing similar UV-Vis and LC/MS characters were separated and purified,the characters of fraction 1 were identical to those of prodigiosin,while fraction 2 showed a special UV-Vis absorption spectrum that had not been reported.[Conclusion] A prodigiosin-producing Serratia marcescens strain NS-17 and its 2 pigment fractions were isolated.

Preliminary Identification of Red Pigment and Positive Correlation between the Contents of Red Pigment and Total Saponins of Panax notoginseng Fruits

[Objective] This study aimed to identify red pigment of Panax notoginseng fruits and explore the correlation between pigment content and total saponins of the fruits. [Method] The red pigment of Panax notoginseng fruits was preliminarily identi- fied with specific color reactions and UV-vis spectra, and the contents of the pigment and total saponins were determined via spectrophotometry. [Result] The red hues of the fruits were contributed by anthocyanins and/or the anthocyanidins. The contents of anthocyanins and total saponins of the fruits both decreased along with thinning of the red hues. The content difference of the anthocyanins in fruits with different red hues reached extremely significant level, but that of total saponins just reached significant level. [Conclusion] The red pigment of P. notoginseng fruits is anthocyanins which are of extremely significant positive correlation with total saponins in contents.

Purification of specularite by centrifugation instead of flotation to produce iron oxide red pigment

This study used specularite, a high-gradient magnetic separation concentrate, as a raw material in reverse flotation.An iron concentrate with a grade of 65.1 wt% and a recovery rate of 75.31% were obtained.A centrifugal concentrator served as the deep purification equipment for the preparation of iron oxide red pigments, and its optimal rotating drum speed, feed concentration, and other conditions were determined.Under optimal conditions, a high-purity iron oxide concentrate with a grade of 69.38 wt% and a recovery rate of 80.89% were obtained and used as a raw material for preparing iron oxide red pigment.Calcining with sulfuric acid produced iron red pigments with different hues.Simultaneously, middlings with a grade of 60.20 wt% and a recovery rate of 17.51% were obtained and could be used in blast furnace ironmaking.High-value utilization of specularite beneficiation products was thus achieved.

Research and Development of Cadmium Sulphoselenide Red Pigment

Cadmium sulphoselenide was synthesized continuous substitution solid solution and the only known pigment to yield bright red color on ceramic decoration. Encapsulated cadmium sulphoselenide pigments could yield abundant hues from yellow to red with high opacity at high temperature. The color generation has a linear function relation with the substitution rate. The encapsulation formation process of zirconium silicate encapsulated cadmium sulphoselenide was shown. Insuffi cient encapsulation effi ciency and potential hazard to human and environment had limited the industrial application of cadmium sulphoselenide red pigment. Ink-jet printing decoration required fi ne size cadmium sulphoselenide red pigment on ceramic decoration. The review mainly focused on the synthesis techniques and industrial application of cadmium sulphoselenide red pigment.

Preparation of Cr-Doped YAlO3 Red Ceramic Pigment and the Coloration Mechanism

The red ceramic pigment is widely used in industrial production, but the pigments with pure color and bright red performance are rare. Therefore, it is important to study and develop new red ceramic pigment with perfect color performance. This paper reports the preparation of Cr-doped YAlO_3 red ceramic pigment rendering by sol-gel method with high temperature resistance, good color and proposed color mechanism. The prepared samples were characterized by XRD, SEM, EDS and UV-vis, and the effects of Cr on the crystal structure, color rendering properties and color mechanism were discussed. The results showed that the optimum concentration of coloring agent（Cr） in Cr：YAlO_3 red ceramic pigment was 3 at.%. The main color mechanism was also discussed. Compared with the solid phase sintering and precipitation methods for the synthesis of red ceramic pigment, the sol-gel method possessed obvious advantages, such as perfect mixing of the raw materials, uniform dispersion of doping ions and the pure color.

Construction of high-density genetic linkage map of Pyropia yezoensis(Bangiales,Rhodophyta)and identifi cation of red color trait QTLs in the thalli

Pyropia yezoensis is an important macroalga because of its extensive global distribution and economic importance.Color is an important trait in the thalli of P.yezoensis,it is also an effective marker to identify the hybridization in genetic breeding.In this study,a high-density genetic linkage map was constructed based on high-throughput single nucleotide polymorphism(SNP)markers,and used for analyzing the quantitative trait loci(QTLs)of red color trait in the thalli of P.yezoensis.The conchospore undergoes meiosis to develop into an ordered tetrad,and each cell has a haploid phenotype and can grow into a single individual.Based on this theory,F1 haploid population was used as the mapping population.The map included 531 SNP markers,394.57 cM long on average distance of 0.74 cM.Collinear analysis of the genetic linkage map and the physical map indicated that the coverage between the two maps was 79.42%.Furthermore,QTL mapping identified six QTLs for the chromosomal regions associated with the red color trait of the thalli.The value of phenotypic variance explained(PVE)by an individual QTL ranged from 4.71%-63.11%.And QTL qRed-1-1,with a PVE of 63.11%,was considered the major QTL.Thus,these data may provide a platform for gene and QTL fine mapping,and marker-assisted breeding in P.yezoensis in the future.

Preparation of Novel Scorzalite Imitated Phosphate Pigments

Novel phosphate pigments imitated with Scorzalite,FeAl2(PO4)2(OH)2,were prepared from iron and aluminum nitrate solutions,ascorbic acid,and phosphoric acid with pH adjustments(pH 5,7,9).The obtained precipitates were heated at 300,500,and 700°C for 1 h.The precipitates and their thermal products were estimated with X-ray diffraction(XRD),Infrared(IR)spectra,ultraviolet-visible(UV-Vis)reflectance spectra,and L*a*b*color space.The precipitated sample was not clearly colored,but it turned orange to red when heated.Samples prepared at low pH showed higher whiteness than samples prepared at high pH.The theoretical amount of ascorbic acid was sufficient to completely reduce iron during the adjustment.This study showed the possibility of novel inorganic phosphate red pigment.

Culture medium optimization for pigment production with RSM method

Response surface methodology was used to optimize a medium for a red-pigmented marine bacterium S-9801 strain （Flavobocterium sp.）. In the first optimization step the influence of yeast extract, peptone, glucose and sodium chloride on pigment production was evaluated using a fractional factorial design. Pigment production was positively influenced by glucose and sodium chloride while other components had no significant effect. In the second step the path of steepest ascent was used to approach the optimal region of the medium composition. In the third step the optimal concentration of glucose and sodium chloride was determined by a central composite design and response analysis. The optimized medium allowed pigment production （A 535-650） to be increased from 0.137 to 0.559, being 320% higher than the original medium.

Continuous-flow synthesis and crystal modification of Pigment Red 53

In this study,a continuous-flow procedure containing four steps has been developed to synthesize Pigment Red 53 and modify its crystal structure.This process avoided the problems of conveying highly insoluble reaction intermediates by removing intermediate operating steps.After optimization,the overall yield of Pigment Red 53:1 reached 97.1%in the total residence time of 80 s by this diazotizationcoupling-laking-crystal transition process.From batch to continuous flow,the purity of products increased from 97.1%to 98.2%and the median diameter of pigment particles decreased from 14μm to 1.9μm.This process achieved a similar crystal transition effect in 18 s as in batch,producingα,δandνcrystals of Pigment Red 53:2 as expected.In conclusion,this continuous-flow procedure displays advantages in both synthesis and crystal transition,indicating another potential use for industrial application.

Preparation of SiO_2 coated Ce_2S_3 red pigment with improved thermal stability

SiO2 coated Ce2S3 red pigment was prepared in ethanol/H2O system via sol-gel method and TEOS were used as silica sources. X-ray diffraction （XRD）, scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDX）, UV-visible spectro-photometer and automatic colorimeter were used to investigate the properties of the samples. The results showed that the compact SiO2 film formed on the surface of Ce2S3 pigment at a cerium silicon molar ratio of 2. The thermal stability temperature of Ce2S3 pigment was improved to 450 oC after SiO2 coating. In addition, the color of Ce2S3 pigment was not affected significantly through coating colorless and transparent SiO2 and it could be used as safe red pigment in higher temperature fields.

Preparation and properties of rare earth luminous fiber containing red organic fluorescent pigment

Rare earth luminous fiber was prepared by method of melt spinning. X-ray diffraction （XRD）, scanning electron micros-copy （SEM）, and fluorescence spectrophotometer as well as afterglow brightness tester were used to characterize the resulting sam-ples. Results from XRD and SEM demonstrated that the phase of SrA12O4：Eu2＋,Dy3＋in the fiber was not destroyed in the manufac-turing process and the as-formed luminous fiber consisted of irregular particles. Under ultraviolet excitation, the luminous fiber exhib-ited a yellow-green and orange-red emission band with a maximum at 520 nm and around 600 nm originating from SrAl2O4：Eu2＋, Dy3＋and red organic fluorescent pigments. The energy transfer process was further studied. Furthermore, the emission colors of lu-minous fibers could be tuned from yellow-green to orange-red easily by doping red organic fluorescent pigment, making the materials have potential application in many areas.

Dual-enhancement of chromaticity and thermal stability:In-situ synthesis of core-shell γ-Ce_(2)S_(3) @CePO_(4) configuration

Non-toxic rare earth(RE) composite materials are promising and active in optoelectronic fields,such as pigment.In this work,Na ions doped γ-Ce_(2) S_(3) pigments were synthesized by solid-phase vulcanization and followed by in-situ synthesis to prepare an outer layer of CePO_(4) film.The characterizations of X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),solid state nuclear magnetic resonance(NMR) indicate that Na-dopedγ-Ce_(2) S_(3) and CePO_(4) uniformly and tightly coated core-shell structure was successfully synthesized.The thermogravimetric analysis(TG) and reflection spectrum(RS) reveal that the CePO_(4) coating significantly improves the colorant and thermal stability performance of γ-Ce_(2) S_(3) .The excellent color quality of γ-Ce_(2) S_(3) @CePO_(4)(L*=45.16,a*=55.94.b*=44.53) is achieved and the red color(L*=43.82,a*=49.79,b*=38.04) is still retained even if the sample is heated in air at 400℃ for 30 min.