Color Degradation Research Articles

COD removal and colour degradation of textile dye effluents by locally isolated microbes

ABSTRACT Textile industry has been rapidly progressing over the years, leading to an increasing volume of water usage that contributes to the large production of textile wastewater. Biological treatment processes have been proven to be the most environmentally friendly, cost-effective and requiring reduced production treatment by-products. In this study, using microbial treatment was applied. Three potential local isolates of micro-organism had been isolated from textile wastewater. The treatment processes were studied under two conditions, namely aerobic and anaerobic. Decolourization of seven commercial textile dyes, namely Crystal Violet 3, Acid Black 1, Basic Blue 8, Acid Blue 147, Congo R, Chrysoiodine R and Yellow 2 G were studied. After seven days of incubation, a significant reduction of 92% for Yellow 2G (Y) and 73.73%for Chrysoiodine R was observed, indicating a high capability of the bacterial isolates indye-degrading activities. Highest chemical oxygen demand (COD) removal was achieved byisolate C3K (93.93%), followed by isolate C3W (90.5%) and isolate C1 (89.173%) in nineincubation days, highlighting the ability of these microbial isolates in removing COD from the individual textile dyes.

Effect of vacuum-steam pulsed blanching (VSPB) on drying characteristics and quality properties of garlic slices

To explore the effects of vacuum-steam pulsed blanching (VSPB) on drying characteristics and quality attributes of garlic slices, the surface color, texture, peroxidase (POD) activity, total phenolic content, antioxidant capacity (DPPH and FRAP), rehydration ratio and thiosulfinate content under various blanching cycle of times (2, 3, 4, and 5 times) and atmospheric pressure duration (20, 30, 40, and 50 s) were investigated. Results indicated that VSPB treatment can inactive POD completely under all VSPB conditions. The hardness of garlic cloves was reduced after VSPB treatment, while hot air drying increased the firmness of garlic slices. The porosity of the garlic surface evidently declined after VSPB treatment, which hindered the moisture diffusion and thus prolonged the drying time from 3 h to 9 h. The total phenolic content, DPPH and FRAP values of blanched garlic cloves were significantly (p < 0.05) lower than those of the raw garlics. VSPB treatment resulted in undesirable color degradation and thiosulfinate degeneration. The highest rehydration ratio was found for the sample blanched at atmospheric pressure duration of 30 s with the blanching cycle times of 3. The findings in the current work will enhance the better understanding of the effect of VSPB on drying behavior and quality attributes of garlic and may provide clues about on selecting suitable blanching methods for garlic.

Skin colour, carotenogenesis and chlorophyll degradation mutant alleles: genetic orchestration behind the fruit colour variation in tomato.

The genetics underlying the fruit colour variation in tomato is an interesting area of both basic and applied research in plant biology. There are several factors, like phytohormones, environmental signals and epistatic interactions between genes, which modulate the ripe fruit colour in tomato. However, three aspects: genetic regulation of skin pigmentation, carotenoid biosynthesis and ripening-associated chlorophyll degradation in tomato fruits are of pivotal importance. Different genes along with their mutant alleles governing the aforementioned characters have been characterized in detail. Moreover, the interaction of these mutant alleles has been explored, which has paved the way for developing novel tomato genotypes with unique fruit colour and beneficial phytonutrient composition. In this article, we review the genes and the corresponding mutant alleles underlying the variation in tomato skin pigmentation, carotenoid biosynthesis and ripening-associated chlorophyll degradation. The possibility of generating novel fruit colour-variants using different combinations of these mutant alleles is documented. Furthermore, the involvement of some other mutant alleles (like those governing purple fruit colour and high fruit pigmentation), not belonging to the aforementioned three categories, are discussed in brief. The simplified representation of the assembled information in this article should not only help a broad range of readers in their basic understanding of this complex phenomenon but also trigger them for further exploration of the same. The article would be useful for genetic characterization of fruit colour-variants and molecular breeding for fruit colour improvement in tomato using the well-characterized mutant alleles.

Quality Assessment and Application of Red Natural Dye from Beetroot (Beta Vulgaris)

| Beet root (Beta vulgaris) is an excellent source of natural red colorant. In the present work red beet root dye was prepared in the powder form and then candies were prepared using this red beet root dye as food color. The stability studies of both, the prepared red beet dye and candies were performed at different storage conditions 4oC, 25oC, 45oC for eight weeks. Betanin content (%) was measured to evaluate the stability of color which showed the maximum retention of betanin content in red beet dye and candies stored at 4°C while lowest %age of betanin content was observed at 45°C showing that at higher temperatures the color is deteriorated. Stability in pH of red beet dye was also monitored at three different temperatures (4°C, 25°C and 45°C). Increase in pH was observed with increasing storage temperatures. Maximum stability of the color was observed at 4°C at most stable acidic pH and color degradation was observed with gradual increase in pH at 45°C. Microbiological analysis of candies and beet powder at 4°C and 25°C ensure that they are safe for consumption at both storage temperatures.

Effect of Radio Frequency Low Pressure Cold Plasma on Total Phenol, Antioxidant Activity and Colour Degradation Kinetics of Red Chilli Pepper Powder

The study was aimed to analyse the effect of low pressure cold plasma treatment [operated at 60.8 kPa on the quality parameters of red chilli pepper powder (RCPP)]. The experiments were conducted at two radio frequency power levels (60 W, 120 W) over a time range from 0 to 10 min. Total phenols, antioxidant activity, colour, and moisture content were determined. Results showed that radio frequency operating power and treatment time had significant negative effects (p &lt; 0.05) on the quality parameters analysed. Cold plasma treatment reduced the redness, total phenol content, moisture content, and increased the antioxidant activity of the RCPP. Changes in the quality of the treated samples, especially the colour degradation were significant after 4 min of treatment. Degradation kinetics was determined for parameters studied to ascertain their order of reaction during cold plasma treatment. The order of reaction was decided from best fit models with the highest R2, minimum bias, and error sum of squares. Total phenol followed a zero-order, whereas antioxidant activity and colour followed first-order reactions. The study explored the possibilities and impact of using cold plasma for powdered food materials.

Ekstraksi dan Uji Stabilitas Zat Warna Alami dari Bayam Merah (Alternanthera amoena Voss)

Research on the extraction and stability test of natural dye from red spinach (Alternanthera amoena Voss) has been carried out. This study aims to determine the effect of pH and length of sun exposure on the stability of the dye from red spinach. Extraction using the maceration method with ethanol solvent and measurement using a UV-Vis spectrophotometer. Stability testing is carried out at pH 2-5 and sun exposure for 1-4 hours using a dark and light container. The results obtained, at pH 2 and pH 3, anthocyanins were more stable, compared to pH 4 and 5 which had greater color degradation. In exposure to sunlight, dark containers with a degradation percentage of 31.70% were better than clear containers with a percentage of 48.78%.&#x0D; Keywords: Anthocyanin, red spinach, natural dyes stability.

Electro-Fenton, solar photoelectro-Fenton and UVA photoelectro-Fenton: Degradation of Erythrosine B dye solution

The treatment of Erythrosine B, selected as a model compound, has been comparatively studied by electrochemical advanced oxidation processes (EAOPs) such as electro-Fenton, UVA photoelectro-Fenton and solar photoelectro-Fenton at constant current density. Experiments are performed in a one-compartment cell with a BDD anode, and a commercial carbon felt cathode at pH = 3, treating a volume of 0.3 L in each test. The irradiation plays a crucial role in the increasing of hydroxyl radical production and in the recover of iron catalyst. A faster colour and COD removal degradation are achieved under the light application. UVA photoelectro-Fenton and solar photoelectro-Fenton processes allow degrading COD entirely in 90 min, while a conventional electro-Fenton does not reach 90% COD removal after 2 h. Energy consumptions are a substantial factor in process selection. Photo electro-Fenton with a UVA-100 W lamp has one of the best removal performance, but it becomes not suitable for application due to high energy demand, up to 515.6 kWh m−3, and the UVA system requires the main fraction of this energy. Possible alternatives are proposed to contain costs: the first is the reduction of UVA lamp power to 25 W, maintaining a high-performance removal with an Ec decreasing to 187.9 kWh m−3. Nevertheless, the lowest and competitive energy demands is obtained working with a solar photoelectro-Fenton system, where energy consumption are only related to the electrochemical process (20.9 kWh m−3), and removal is complete.

Analysis of Thermal Degradation in the Annealing Process of Colored Parts Built by Extrusion-Based 3D Printing

With the ever-increasing request of light materials, poly lactic (acid) PLA, have got much in consideration. Low-cost PLA materials have risen its use. Those possess some benefits but nevertheless insufficient mechanical strength. The printed PLA objects have a stumbling block for practical applications. Thus, annealing is an interested alternative to make 3D printed objects strong. This thermal treatment can significantly develop investigational studies and offer technical data. Hence the purpose of this paper is study and discuss how to increase the flexural strength through annealing process. Geometry distortions and color degradation will be analyzed. Differential Scanning Calorimetry, Taguchi Method (TM) and variance (ANOVA) were applied as part of the design experiments and analysis. Twenty-seven printed specimens were tested and factors as temperature, time and color were selected.

Influence of photodegradation on the removal of color and phenolic compounds from palm oil mill effluent by Arthrospira platensis

Palm oil mill effluent (POME) released from conventional treatment systems poses severe environmental problems due to its dark color, its high chemical oxygen demand (COD), and high content of phenolic compounds. However, the possible biodegradation of phenolic compounds and color by microalgae was not well explored. This research aimed to reveal optimal conditions for pollutant removal through biodegradation by the cyanobacterium Arthrospira platensis. This species was grown under a range of POME fractions and environmental conditions (irradiance, salinity, nutrients) during which growth, final biomass, color, COD, and phenolic compound levels were followed. POME fractions influenced A. platensis growth rate, final biomass, COD, and color removal. The optimization of phenolic compound removal by using central composite design (CCD) response surface methodology (RSM) showed that low light and high initial phenolic compounds promoted the activity of A. platensis to degrade phenolic compounds. The combination of high initial phenolic compounds and high light intensity increased the growth rate up to 0.45 days−1 and final biomass up to 400 mg L−1, while total phenolic compounds were almost completely (94%) removed. Finally, this study showed that phenolic compounds and color degradation from POME were dominated by the activity of photodegradation at high irradiance, while the activity of A. platensis dominated at low light intensity.

Correlated Functional Models with Derivative Information for Modeling Microfading Spectrometry Data on Rock Art Paintings

Rock art paintings present high sensitivity to light, and an exhaustive evaluation of the potential color degradation effects is essential for further conservation and preservation actions on these rock art systems. Microfading spectrometry (MFS) is a technique that provides time series of stochastic observations that represent color fading over time at the measured points on the surface under study. In this work, a reliable and robust modeling framework for a short and greatly fluctuating observation dataset collected over the surfaces of rock art paintings located on the walls of Cova Remigia in Ares del Maestrat, Castellón, Spain, is presented. The model is based on a spatially correlated spline-based time series model that takes into account prior information in the form of model derivatives to guarantee monotonicity and long-term saturation for predictions of new color fading estimates at unobserved locations on the surface. The correlation among the (spatially located) time series is modeled by defining Gaussian process (GP) priors over the spline coefficients across time series. The goal is to obtain a complete spatio-temporal mapping of color fading estimates for the study area, which results in very important and useful information that will potentially serve to create better policies and guidelines for heritage preservation and sustainable rock art cultural tourism.

Synergistic effect of TiO2 /chitosan/glycerol photocatalyst on color and COD removal from a dyeing and textile secondary effluent

In this study, the optimum conditions and the synergistic effects of TiO2/chitosan/glycerol photocatalyst (TCGB) in color and COD removal from Azo dye and a secondary effluent of dyeing and textile wastewater were investigated. In order to optimize conditions of the dye photocatalytic degradation of TCGB, acid blue 193 (AB 193) was used as an indicator for experiments based on statistical methods developed by Taguchi and ANOVA analysis. The optimum conditions for AB 193 degradation were TiO2/chitosan ratio of 2% (w/w), irradiation time of 90 min at pH 4.5, initial dye concentration of 10 mg/L and TCGB loading of 0.2 g/mL. The polynomial regression model of AB regression was performed with R squared of 93.33%. After optimizing, the photocatalytic experiments with the real secondary effluent were carried out. In the presence of glycerol in TiO2/chitosan beads significantly enhanced the color degradation yield of AB193 (85%) and secondary effluent (72%) under the optimal parameters. The synergistic rate of TCGB compared to separate part (chitosan, TiO2, glycerol) were 60%–120% and 70%–105% for AB193 removal and secondary effluent, respectively. A kinetic study of photocatalytic degradation of TCGB composite on various initial AB193 concentrations was found to fit with the pseudo-first-order model.

Whey protein improves the stability of C-phycocyanin in acidified conditions during light storage

C‐phycocyanin is a bright blue natural colorant used in food and beverage applications. However, its color stability is poor in acidic conditions under exposure to light. In this work, we study the use of whey protein isolate (WPI) to protect C‐phycocyanin from color degradation. Low concentration (0.05–0.1%) WPI addition delayed (~2 days) the color degradation of C‐phycocyanin at pH 3.0 over 5-day storage in light. However, the color degradation was aggravated adversely during 5-day light storage when C‐phycocyanin mixed with a higher concentration (~1%) of WPI degraded after heat-treatment. The Fourier transform infrared and fluorescence spectroscopy confirmed that structural changes (e.g., alpha-helix protection and transformation from alpha-helix to beta-sheet) of C‐phycocyanin due to interaction with WPI. These results, along with quartz crystal microbalance with dissipation technology outcomes, suggest that a low concentration of WPI may help protect C-phycocyanin’s secondary structure from becoming damaged during light storage, preventing its color degradation.

Impact of processing and storage conditions on color stability of strawberry puree: The role of PPO reactions revisited

The effect of pre-heating fresh strawberries (hot break) and the use of refrigerated temperatures prior to pasteurization on the stability of anthocyanins, vitamin C, color and polyphenol oxidase (PPO) activity during storage (42 days at 35 °C) of strawberry puree was studied. Hot break resulted in 20% residual PPO activity and caused 10% anthocyanin degradation, whereas vitamin C was unaffected. After mashing, purees were stored at 4 °C and 25 °C for 3 h. During this period, anthocyanins and PPO activity remained constant independently of the processing history but ascorbic acid was oxidized faster at 25 °C. Pasteurization caused complete inactivation of PPO, reduction of anthocyanins (25%), of a* value (6%) and of vitamin C (50%). Neither partial inactivation of PPO early in the processing (hot break) nor the use of refrigeration prior to pasteurization had a positive effect on color and anthocyanin stability of strawberry puree during subsequent storage, suggesting that PPO-derived reaction products formed during processing have a very limited impact on color degradation during shelf-life. • Different strawberry puree manufacturing processing conditions were evaluated. • Hot break did not improve color stability during further processing and storage. • Refrigeration prior to pasteurization prevented ascorbic acid oxidation. • PPO reactions before pasteurization do not affect color degradation during storage. • “Impact of processing and storage conditions on color stability of strawberry puree: the role of PPO reactions revisited”.

Ingredient photostability as affected by iron: Colorant degradation

Understanding factors that affect food chemical stability is important for optimizing product quality and shelf life. The objective of this project was to investigate the role of iron and ultraviolet (UV) light on chemical stability by determining the degradation rate constants of Brilliant Blue, tartrazine, and Allura Red in pH 3 solutions of various compositions stored in the presence and absence of UV light. The storage of solutions in darkness at 30°C resulted in no observable loss of any colorant. Exposure to UV light significantly (p < .05) increased the degradation rate constants. Colorant degradation was fastest in the presence of citrate, iron, and UV light. Iron–citrate complexes are likely forming hydroxyl radicals upon UV exposure, which enhance colorant degradation. Photodegradation of food ingredients increases in the presence of iron and citrate buffer, resulting in a loss of shelf life. Practical applications The adverse effect of UV light on food chemical stability is enhanced by the presence of iron. Solutions containing iron and citrate buffer become decolorized rapidly when exposed to UV light. Thus, beverages packaged in light-permeable materials should not contain iron as a contaminant. Beverages fortified with iron should be placed in light-protective packaging to improve the storage stability of colorants and other ingredients.

Photocatalytic degradation of organic pollutants using Trianthema Portulastrum leaf extract based CeO2 nanoparticles.

Comparison of bio CeO2-Nps prepared using Trianthema Portulastrum leaf extract with chemical CeO2-Nps is of interest. The ultraviolet - visible, x-ray diffraction, HR - TEM, FT - IR, and photoluminescence studies were conducted with CeO2-Nps. UV-Maximum absorptionat 292 nm was completed using UV-visible spectrum. The HR–TEM images showed 38 nm bio CeO2-Nps with spherical morphology. This showed the polycrystalline character of CeO2-Nps similar to XRD data. The presence of metal oxide is confirmed by FT - IR analyses. The CeO2-Nps showed the potential photocatalytic activity for Acid black 1 color degradation after exposure to sunlight. Chem and bio CeO2-Nps have a degradation rate of 86.66 and 94.33%, respectively for acid black 1 dye. The synthesized CeO2-Nps are also evaluated for antibacterial and antioxidant activity. The bio CeO2-Nps has antibacterial activity for Pseudomonas aeruginosa (17 ± 0.56 mm) and Staphylococcus aureus (16 ± 0.24 mm) at low concentrations of 100 µl. The CeO2-Nps bio showed high inhibition of radical DPPH IC50 µg/ml, at 95.17 ± 21. Thus, we show that CeO2-Nps have environmentally friendly properties that are useful for dye degradation with antimicrobial and antioxidant activities.

Weathering performance of dyed bamboo fiber composites

Flattened and crushed fiber-bundles of moso bamboo (Phyllostachys pubescens) were dyed with a water or alcohol-based dye at 20 °C, 75 °C or 90 °C for 72 h, followed by drying and coating with PF resin. Hot-pressed bamboo fiber composites (BFC) were manufactured, and the weathering performance of the composites made from dyed and natural bamboo material were tested over 90 days of the Autumn/Winter season in Beijing. Dye was able to penetrate the bamboo tissue to create a rich red color that degraded in color faster than BFC made from un-dyed bamboo. BFC made from un-dyed tissue remained a lighter but more consistent color over the weathering period. Dying the bamboo in ethanol-based dye was effective at pigmenting the product, but made it more susceptible to color degradation as well as greater mass and thickness loss due to the chemical degradation of the lignin caused by ethanol. Higher temperature of water dying treatment (90 °C) gave the greatest resistance to mass and thickness loss during outdoor exposure, and the bamboo may have benefitted from the longer period of ‘heat treatment’ during dyeing. Further work is needed to quantify dye leaching from bamboo tissue and to develop more water-tight and color-fast, weather resistant dyes for bamboo products.

Degradation of Rhodamine B in water alone or as part of a mixture by advanced oxidation processes

Degradation of a dye in water alone or as part of a mixture was studied under different advanced oxidation processes in order to elucidate possible competition or interference between dyes. For this purpose, color degradation of aqueous solutions of Rhodamine B alone or mixed with Indigo Carmine was evaluated under ultrasound, ultraviolet radiation and under their combined effect, in the presence or absence of catalyst, which was either TiO2 (Degussa P-25) or a mixed catalyst TiO2-ZrO2 prepared by sol gel method. Regardless of the oxidation process used, results suggest that Rhodamine B discoloration was negatively affected by the presence of Indigo Carmine, which was degraded preferentially. Concerning the oxidation processes, synergy was observed for the combined operation of ultrasound and ultraviolet radiation in the presence of TiO2 catalyst, for both dyes when treated individually, however, for a mixture of dyes synergetic degradation was observed only for Indigo Carmine. It appears that competition exists between individual components in a mixture for the access to catalyst reaction sites and interaction with hydroxyl radicals, and which seem to ease the degradation of some components in detriment of others. Photosonocatalytic degradation of these dyes was not improved by the presence of mixed TiO2:ZrO2 catalysts as compared with Degussa P-25 catalyst. However, for the case of Rodamine B, the yield of decolorized dye converted into mineralized products appears to be enhanced for the mixed catalyst.

Color degradation mapping of rock art paintings using microfading spectrometry

Rock art documentation is a complex task that should be carried out in a complete, rigorous and exhaustive way, in order to take particular actions that allow stakeholders to preserve the archaeological sites under constant deterioration. The pigments used in prehistoric paintings present high light sensitivity and rigorous scientific color degradation mapping is not usually undertaken in overall archaeological sites. Microfading spectrometry is a suitable technique for determining the light-stability of pigments found in rock art paintings in a non-destructive way. Spectral data can be transformed into colorimetric information following the recommendations published by the Commission Internationale de l’Eclairage (CIE). The fading degree can be evaluated through the color changes produced, computing both color and chromatic differences. Microfading Tester (MFT) measurements on spot samples are time-consuming and difficult to materialize on-site. This paper presents the results of statistical Gaussian process interpolation to map the potential MFT spectral variations overtime on a scene full of prehistoric rock art paintings. In addition, a descriptive analysis of color variations that may suffer the rock art motifs over time has been carried out. The advanced statistical methodology implemented can highlight potential changes on some rock support areas, and stable conditions on the painted red motifs over time, which can help to establish future conservation actions in the archaeological site.

Graphitic carbon nitride nanosheets (g-C3N4 NS) as dual responsive template for fluorescent sensing as well as degradation of food colorants

In this work, fluorescent g-C3N4 NS with laminar morphology and ultrathin thickness were fabricated. The as synthesized NS were well characterized by UV–Visible and Fluorescence spectroscopy, FT-IR, XRD and HR-TEM. The bright blue fluorescent suspension of g-C3N4 NS was utilized for efficient detection of food colorant; tartrazine (Tz) and sunset yellow (SY). Both food colorant were able to quench fluorescence of NS efficiently were able to detect them selectively over other interfering analytes. The chemosensor showed linear range response for low concentration of Tz and SY with limit of detection for Tz and SY as 0.0325 μM (32.5 nM) and 0.221 μM (221 nM), respectively. They served as non-toxic and low cost photocatalyst. The catalytic degradation process was confirmed by mass and UV–Visible spectra analysis. The g-C3N4 NS served dual role of detection as well as photocatalytic degradation of food colorant.

Effect of thermal and ultrasonic pretreatment on enzyme inactivation, color, phenolics and flavonoids contents of infrared freeze-dried rose flower

The effects of ultrasound and thermal pretreatment prior to freeze drying combined with infrared on enzyme activity, color changes and antioxidant activities of dried rose flowers were studied. The activities of polyphenol oxidase (PPO) and peroxidase (POD) in rose after ultrasonic pretreatment were significantly decreased than thermal treatments. Ultrasonic pretreatment could improve the color of dried rose flowers. In addition, low-frequency ultrasound pretreatment could significantly improve the content of anthocyanins content and reduce the degradation rate. The antioxidant activity of low-frequency ultrasound pretreatment rose was also higher than that of dried rose flowers by thermal and high-frequency ultrasound pretreatment. However, thermal pretreatment as high temperatures affected the total phenolic content and product quality in different way such as loss of color and nutrients degradation.