Presence Of Synthetic Dyes Research Articles

Evaluation of Adsorbent Biomaterials Based on Coconut Mesocarp for Treatment of Wastewater Contaminated with Tartrazine Dye

The presence of synthetic dyes in industrial wastewater poses significant environmental and health concerns due to their persistent nature and potential toxicity. Tartrazine is a synthetic yellow dye known for its stability and resistance to conventional treatment methods. As a result, its discharge into natural water bodies can lead to adverse ecological impacts and can jeopardize public health. The objective of this work was to functionalize coconut shells (CSs), coconut cellulose (CC), and modified coconut cellulose (MCC) bioadsorbents with cetyl trimethyl ammonium chloride (CTAC) for their use in the elimination by adsorption of the dye tartrazine in aqueous solutions. CC was synthesized through a double extraction with sodium hydroxide, and a chemical treatment was performed with CTAC at 100 mmol L−1. The final dye concentration was determined through UV-Vis at 500 nm. An FTIR analysis showed multiple active sites, represented in groups such as hydroxyl, COO-, NHx-, and hydrocarbon compounds. Increasing the initial concentration had a positive effect on the efficiency of the process, reaching 99% removal with an adsorption capacity of 11.89 mg/g at equilibrium using MCC. The test showed that equilibrium was reached after 30 min. Initially, the removal of the dyes was rapid, about 97% of the contaminant being removed in the first 5 min. The Langmuir and Freundlich models were satisfactorily fitted to the adsorption isotherm, showing physical and chemical adsorption. It can be concluded that MCC is a promising bioadsorbent for the removal of tartrazine dye in aqueous solutions.

Biochar-ZnO Composites from Petung Bamboo Stems to Increase Adsorption and Photocatalytic Degradation of Methylene Blue in Wastewater

The rapid development of industrial sector worldwide has contributed greatly to environmental pollution. In many countries, surface and groundwater are polluted by industrial wastewater effluent, such as synthetic dyes. Dyes are difficult to decompose naturally and cause disruption to aquatic ecosystems. To eliminate risks associated with the presence of synthetic dyes, photocatalytic-adsorption is still considered the most environmentally friendly and effective for dye removal. In this work, a novel biochar-ZnO composite was synthesized from petung bamboo stems having a high cellulose content, and used to eliminate methylene blue dye in the water. Biochar-ZnO composite was prepared from bamboo stems via a two-step pyrolysis process in a furnace with nitrogen flow at 400°C and 700°C for one hour. The addition of ZnO into biochar enhanced methylene blue removal up to 94.6% at an initial concentration of 10 mg.dm-3, pH 3, and contact time of 180 minutes, under UV light. It can be concluded that biochar-ZnO composite is highly feasible for dye removal from wastewater.

Approach to assessing the quality and identifying the naturality of pomegranate juices

The unique chemical composition and exceptional organoleptic properties cause not only the growing demand for pomegranate juice, but also its cost, and, consequently, vulnerability to falsifi cation, especially of high quality. Therefore, the identifi cation of the authenticity of pomegranate juice has remained an important area of scientifi c research. In this case, the most reliable algorithm should be considered the one that combines the study of several indicators: anthocyanins and polyphenolic substances, the concentration of sugars, organic acids, etc. The purpose of the work is a comprehensive study of the chemical composition of pomegranate juices purchased from trade organizations in order to identify juice authenticity. The experiment determined the organoleptic and physicochemical parameters of pomegranate juice samples, including chromatic characteristics. It has been established that, in terms of dry matter content, only sample No. 1 meets the requirements of TR CU 023/2011; it has been shown that in samples No. 2 and 3, there are no natural anthocyanin dyes, while the presence of synthetic dyes in these samples has been established. Pomegranate juice sample No. 1 has been proven to contain all of the organic acids normally found in authentic samples of this product. Meanwhile, samples No. 2 and 3 do not contain tartaric and quinic acids, and sample No. 2 does not contain malic acid either. The conducted studies are aimed at forming a unifi ed methodological approach to assessing the quality and identifying the authenticity of pomegranate juice, which will be developed and tested in further studies.

Biological and molecular approaches of the degradation or decolorization potential of the hypersaline Lake Tuz Bacillus megaterium H2 isolate

The presence of synthetic dyes in water bodies and soil is one of the major issues affecting the global ecology, possibly impacting societal well-being adversely due to the colorants’ recalcitrance and toxicity. Herein, the study spectrophotometrically monitored the ability of the Bacillus megaterium H2 azoreductase (AzrBmH2) to degrade four synthetic dyes, reactive blue 4, remazol brilliant red, thymol blue, and methyl red, followed by in-silico assessment using GROMACS. We found that the bacterium degraded as much as 60% of all four synthetic dyes at various tested concentrations. The genome analysis revealed five different azoreductase genes, which were then modeled into the AzrBmH21, AzrBmH22/3, and AzrBmH24/5 templates. The AzrBmH2-substrate complexes showed binding energies with all the dyes of between −10.6 to −6.9 kcal/mol and formed 4–6 hydrogen bonds with the predicted catalytic binding residues (His10, Glu 14, Ser 58, Met 99, Val 107, His 183, Asn184 and Gln 191). In contrast, the lowest binding energies were observed for the AzrBmH21-substrates (−10.6 to −7.9). Molecular dynamic simulations revealed that the AzrBmH21-substrate complexes were more stable (RMSD 0.2–0.25 nm, RMSF 0.05 − 0.3 nm) and implied strong bonding with the dyes. The Molecular Mechanics Poisson-Boltzmann Surface Area results also mirrored this outcome, showing the lowest azoreductase-dye binding energy in the order of AzrBmH21-RB4 (−78.18 ± 8.92 kcal/mol), AzrBmH21-RBR (−67.51 ± 7.74 kcal/mol), AzrBmH21-TB (−46.62 ± 5.23 kcal/mol) and AzrBmH21-MR (−40.78 ± 7.87 kcal/mol). In short, the study demonstrated the ability of the B. megaterium H2 to efficiently decolorize the above-said synthetic dyes, conveying the bacterium’s promising use for large-scale dye remediation. Communicated by Ramaswamy H. Sarma

The Kinetic Analysis and Adsorption Isotherm of Chicken Egg Shells and Membranes Against Synthetic Dyes

Textile industry waste at this time is enough to worry the community and the environment. The presence of synthetic dyes in water is hazardous, even in small concentrations. These synthetic dyes are derivatives of aromatic compounds such as benzene, toluene, and naphthalene, which are more resistant and stable than natural dyes. The adsorption method is used because it is easier to do, has no side effects, and does not require complicated and expensive equipment. In this study, the shells and membranes of discarded chicken eggs became useful as an absorbent of indigo carmine dye with an adsorption capacity of 6.399 mg/g. The adsorption reaction kinetics were analyzed from the optimal contact time data, and the reaction isotherm was analyzed from the adsorption optimal concentration data. The kinetic model that fits the research is the second pseudo-order with R2 = 0.9998. The adsorption mechanism demonstrates that the adsorption capacity is proportional to the adsorbent's active sites. The adsorption isotherm model, with R2 = 0.9748, is more closely related to the Freundlich isotherm model, indicating that adsorption occurs in several layers. From an economic point of view, chicken egg shells and membranes can be recommended as dye absorbers that are eco-friendly, efficient, and simple to obtain while lowering organic solid waste.

Adsorption of an anionic dye from aqueous solution on a treated clay

The presence of synthetic dyes in water causes serious environmental issues due to the poor water quality, toxicity to the environment and human carcinogenic effects. Adsorption has progressively become an economical and feasible method for dye wastewater decontamination. Clay minerals are an interesting alternative for removing colorants from colored aqueous solutions because they are inexpensive, easy to extract and handle, and non-toxic. In this work, a bentonite treated with H2SO4 is used to adsorb an azoderivative dye such as methyl orange (MO). The physicochemical properties of the solids were evaluated through X-ray powder diffraction (XRD), Brunauer Emmett Teller surface area analysis (BET), Scanning electron microscopy coupled with Energy dispersive spectroscopy (SEM-EDS), and Fourier transform infrared spectroscopy (FTIR). The initial dye concentration, adsorbent mass, contact time, temperature and pH influence the adsorption capacity. Acid modification of the clay increased its capacity to adsorb MO. For a concentration of 200 mg/L MO, an adsorption capacity of 125 mg/g was achieved. The adsorption process follows the pseudo second-order kinetic model. The thermodynamic study indicates that the adsorption is spontaneous and exothermic. The adsorption isotherm is best fitted to the Freundlich mathematical model. The results obtained show that, after receiving an acid treatment, clay can be effectively used to remove MO in aqueous solution.

Fabrication of magnetic cerium-organic framework-activated carbon composite for charged dye removal from aqueous solutions

The presence of synthetic dyes in water leads to health and ecological concerns due to their toxic and carcinogenic effects. For the remediation of coloured wastewater, we have fabricated a Ce-MOF@Fe3O4@activated carbon composite. The composite showed a ∼97–98% removal of indigo carmine and methylene blue at pH 7, whereas it was ∼83–85% for activated carbon. The adsorption and kinetic data followed the Temkin and Elovich models, respectively. Which suggested the involvement of physicochemical forces in the adsorption process. The thermodynamic study confirmed the adsorption process to be endothermic, where the adsorption performance improved with the increasing temperature. The increased intensity of the band at 824 cm−1 (CH) and 1004 cm−1 (aromatic CC) in the Raman spectra confirmed the adsorption of dyes onto the adsorbent. Dye adsorption was further confirmed by the N 1s peak at 400 eV for CNC in the dye-adsorbed composite. The shift in the binding energy of Fe 2p and Ce 3d peaks by 0.3–0.4 eV concluded the involvement of electrostatic and cation-π interactions in the adsorption process. A ∼90–98% dye removal capacity of the adsorbent even in the fourth cycle made it a highly stable and reusable adsorbent for remediation of coloured wastewater.

Acid Red 66 Dye Removal from Aqueous Solution by Fe/C-based Composites: Adsorption, Kinetics and Thermodynamic Studies.

The presence of synthetic dyes in water causes serious environmental issues owing to the low water quality, toxicity to environment and human carcinogenic effects. Adsorption has emerged as simple and environmental benign processes for wastewater treatment. This work reports the use of porous Fe-based composites as adsorbents for Acid Red 66 dye removal in an aqueous solution. The porous FeC and Fe/FeC solids were prepared by hydrothermal methods using iron sulfates and sucrose as precursors. The physicochemical properties of the solids were evaluated through X-ray diffraction (XRD), Scanning electron microscopy coupled with Energy dispersive spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared s (FTIR), Raman and Mössbauer spectroscopies, nitrogen adsorption–desorption isotherms, Electron Paramagnetic Resonance (EPR) and magnetic saturation techniques. Results indicated that the Fe species holds magnetic properties and formed well dispersed Fe3O4 nanoparticles on a carbon layer in FeC nanocomposite. Adding iron to the previous solid resulted in the formation of γ-Fe2O3 coating on the FeC type structure as in Fe/FeC composite. The highest dye adsorption capacity was 15.5 mg·g−1 for FeC nanocomposite at 25 °C with the isotherms fitting well with the Langmuir model. The removal efficiency of 98.4% was obtained with a pristine Fe sample under similar experimental conditions.

Sustainable and cleaner microwave-assisted dyeing process for obtaining eco-friendly and fluorescent acrylic knitted fabrics

Synthetic garments pose significant environmental and human risks, which are further increased by the presence of synthetic dyes. As synthetic fibers cannot be eliminated, steps need to be taken in order to improve their sustainability. The paper presents a sustainable and cleaner microwave (MW)-assisted process of dyeing acrylic knitted fabrics with natural dyes based on curcumin extracted from turmeric powder (TP). The process is a novelty because it leads to fluorescent acrylic fabrics. The curcumin was extracted from TP, with or without 0.1 mL solvent. Based on the absorption curves in the ultraviolet–visible domain, the analysis indicates that 100 g of TP contains 3.6 g of pure curcumin. The factors influencing the MW-assisted extraction are presented and discussed. The eco-friendly dyeing was performed in the presence of MW, using only freshly extracted dyes, no additives. The research investigates the effects of the concentration of natural dyes (5–20%), presence of solvents, dyeing time (2–15 min), temperature gradient and nature of the textile support on color intensity (K/S) and CIELab measurements. Spectroscopy analyses highlight the effects of the MW treatment on the Melana and Dralon L samples and on two pretreated samples subjected to grafting and saponification. The presence of MW modifies the internal structure of the fibers, while the chemical pretreatments generate chemical modifications/functionalizations. The advantages of the cleaner MW-assisted process refer to the ease of application, eco-friendly process, shorter duration, low consumption of chemicals, leading to uniform dyeing and high fluorescence, to a level that was never before obtained with natural dyes. The use of natural dyes improves the sustainability of the process in terms of recycling.

Degradation of Adsorbed Azo Dye by Solid-State Fermentation: Improvement of Culture Conditions, a Kinetic Study, and Rotating Drum Bioreactor Performance

The presence of synthetic dyes in effluents leads to an environmental imbalance characterized by a decrease in photosynthetic activity and, therefore, a reduction of available oxygen, which affects all living aquatic species. To reduce this problem, a combination adsorption and biodegradation treatment strategy is proposed. In this work, Red 40 dye was adsorbed onto a low-cost waste product, followed by degradation by Trametes versicolor under solid state fermentation conditions. The principal aim of this research was to establish the best fermentation conditions using a kinetic evaluation of both degradation and laccase enzyme activity. The process was scaled-up using a rotating drum bioreactor. The best process conditions were a carbon:nitrogen ratio of 30:1, a moisture percentage of 75%, and an inductor concentration of 0.5 mM; the maximum dye degradation was 96.04%. Under these optimized conditions, the highest enzymatic activity was 8.49 U/gdm after 14 days of culture at the flask scale. Using a rotating drum bioreactor, 630 mg of azo dye was degraded after 30 days of culture. Red 40 dye degradation was confirmed using infrared spectroscopy Fourier transform infrared spectrometer and HPLC-MS techniques. The results show that the degradation percentage has a direct relation with laccase activity, and the obtained efficiency in the rotating drum bioreactor confirms the potential of this methodology for implementation at the industrial level.

Calotropis procera an effective adsorbent for removal of Congo red dye: isotherm and kinetics modelling

From environmental point of view, the removal of effluents from aquatic systems caused by presence of synthetic dyes is extremely important. Oven dried leaf powder solid waste of low-cost bioadsorbent Calotropis procera, has been tested for the removal of azo dye, Congo red (CR) from aqueous solution. Adsorption of CR onto this natural adsorbent has been characterized with X-ray fluorescence, X-ray diffraction, scanning electron microscopy and Fourier transformer infrared. The effects of different parameter such as; contact time, initial dye concentration, adsorbent amount, pH, temperature, electrolyte, surfactant concentration and desorption have been studied. The adsorption has been represented with Langmuir, Freundlich, Tempkin and Dubinin–Radushkevich isotherm models. The maximum adsorption capacity of CR onto bioadsorbent has been found to be 25.77 mg g− 1. The adsorption process has been followed the Weber–Morris Intra-particle diffusion model with the involvement of pseudo second order and Elovich models. The calculated values of thermodynamic parameters such as ΔH and ΔS for uptake of CR have been found to be 35.26 kJ mol− 1 and 120.11 J mol− 1K− 1 respectively. Negative values of ΔG indicate the spontaneous nature of the adsorption process. The results indicate that C. procera has high potential application towards removal of CR dye due to its high adsorption capacity.

Bioremediation of Acid blue 25 dye by anthracene degrading Pseudomonas pseudoalcaligenes ASU-016

Presence of synthetic dyes in water bodies, even at very low concentrations can be highly toxic to living organisms, reducing the growth of different microorganisms and preventing the photosynthesis in aqueous flora. Pseudomonas pseudoalcaligenes and biofilm supported on activated carbon were used for adsorption of acid blue 25 (AB 25). The effect of initial dye concentration (0-300 mg/L), contact time (0- 240 min), and pH values (3.0- 8.0) were studied. The optimum pH value for biosorption of AB 25 was pH 3.0 for the two biosorbents, while contact time was180 min for P. pseudoalcaligenes cells and 210 min for the biofilm. The biosorption isotherm study revealed that both Langmuir and Freundlich models were suitable for biosorption process. The maximum adsorption capacities for AB 25 by P. pseudoalcaligenes and biofilm were 98 and 113.4 (mg/g), respectively. On the other hand, the pseudo-second order was a good model for description the biosorption kinetics. Fourier Transform Infrared FT-IR spectrum analysis showed that the presence of amines plays an important role in biosorption process. According to experimental data, the presence of P. pseudoalcaligenes could be enhanced the capacity of activated carbon to adsorb the dye from aqueous solutions.

Kinetic and Isotherm Studies of Congo Red Adsorption from Aqueous Solution by Biowaste Material

Toxicity caused by the presence of synthetic dyes in aquatic system is extremely important from the environmental point of view because most of these dyes are toxic, carcinogenic and mutagenic. In the present work the ability to remove 'Congo red' from aqueous solution has been studied by using waste material Pigeon dropping, as an adsorbent. Effects of various parameters on adsorption process such as; contact time, adsorbent dose, initial dye concentrations, pH and temperature was studied. The isotherm data was described by the Langmuir and Freundlich adsorption isotherms. The kinetic data were used for modelling from the second-order kinetic models and intra-particle diffusion model. The thermodynamic studies showed that the process is exothermic and physiosorption. The present investigation confirms that Pigeon dropping can be successfully employed as a good adsorbent for the removal of dye from effluent.

Acid-Base Properties of the Adsorption of Synthetic Dyes from Solutions

The presence of synthetic dyes is often underestimated in environmental protection. However, it has been demonstrated the impact of colored compounds in ecology and human health. Green tea (GT) and peppermint (PM) tea bag wastes were used as potential adsorbents of dyes from aqueous solutions to evaluate the effect of pH on the adsorption. Basic yellow 57, basic blue 99 and crystal violet were chosen as model dyes due to their widespread use in the industry. Dye solutions at different pH values were placed in contact with the adsorbents in batch experiments at room temperature. Results indicate that crystal violet is totally removed from the solution by the adsorbents (100% removal), followed basic blue 99 and basic yellow. PM reports the highest dye removal. Our data was compared to recently published reports, indicating their potential applicability to real wastewaters, as it is optimum at neutral pH values. These results demonstrate that these materials are excellent and cost-effective candidates for the removal of dye pollutants from contaminated solutions.

Methylene Blue Degradation by Sphingomonas paucimobilis under Aerobic Conditions

The presence of synthetic dyes in industrial wastewaters may create serious environmental problems due to their mutagenicity and toxicity to aquatic life and humans. In this study, the decolourization and degradation of methylene blue (MB) by a Sphingomonas paucimobilis strain isolated from industrial wastewater was investigated under aerobic conditions. Decolourization extent of MB in medium was over 85 % when the bacterium was grown on a high concentration of the dye (1,000 mg/L) after a retention time of 5 days, while reduction in COD was 92.99 % suggesting mineralization of dyes as a result of microbial activities. The bacterium retained decolourizing activity over a wide range of pH (2–10), with peak activity obtained at pH 9. Analysis of samples extracted from decolourized culture flasks at pH 9 using UV–visible and Fourier transform infrared (FTIR) spectroscopy confirmed that the mechanism of colour removal was due to biodegradation rather than adsorption of dye on cells. Scanning and transmission electron microscopy revealed the secretion of exopolysaccharides (EPS) by S. paucimobilis cells on exposure to MB—a probable physiological defence mechanism to ensure controlled diffusion of dye molecules into cellular structures. Biokinetic coefficients, namely, growth yield, Y; specific biomass decay, Kd; maximum specific substrate rate, k; saturation constant for substrate, Ks; and maximum specific biomass growth rate, μmax, were determined by the Monod type kinetic equation. Results indicate that S. paucimobilis holds a promise as a good candidate for the biological treatment of industrial effluent containing high concentrations of synthetic dyes.

The combination and optimization study on RB29 dye removal from water by peroxy acid and single-wall carbon nanotubes

The presence of synthetic dyes in aquatic environments poses potential health and ecological risks. Several techniques are available for dyes’ removal. In this study the degradation of an anthraquinone dye, Reactive blue 29 (RB29), using an advanced oxidation process followed by single-wall carbon nanotubes (SWCNTs) was investigated. Advanced oxidation process was optimized over a period of 60 min by varying the ratio of acetic acid to hydrogen peroxide, the compounds which form peroxy acid. Reduction of 20.2–56.4% of RB29 was observed when the ratio of hydrogen peroxide/acetic acid/dye changed from 344/344/1 to 344/344/0.08 at different times (60, 120 and 180 min). Hydrogen peroxide served as controls in all advanced oxidation process and demonstrated minimal degradation over the time course study. The optimum ratio of acetic acid/hydrogen peroxide/dye was found to be 344/344/0.16 over 60 min. The resultant then introduced for further removal by SWCNTs as adsorbent. The adsorption of RB29 onto SWCNTs was...

Removal of methylene blue dye from aqueous solutions by adsorption using yellow passion fruit peel as adsorbent

The removal of color from aquatic systems caused by presence of synthetic dyes is extremely important from the environmental viewpoint because most of these dyes are toxic, mutagenic and carcinogenic. In this present study, the yellow passion fruit ( Passiflora edulis Sims. f. flavicarpa Degener) peel a powdered solid waste, was tested as an alternative low-cost adsorbent for the removal of a basic dye, methylene blue (MB), from aqueous solutions. Adsorption of MB onto this natural adsorbent was studied by batch adsorption isotherms at room temperature. The effects of shaking time and pH on adsorption capacity were studied. An alkaline pH was favorable for the adsorption of MB. The contact time required to obtain the maximum adsorption was 56 h at 25 °C. Yellow passion fruit peel may be used as an alternative adsorbent to remove MB from aqueous solutions.

Photocatalytic Degradation of four Textile Azo Dyes in Aqueous TiO2 Suspensions: Practical Outcomes and Revisited Pathways

AbstractThe non-biodegradability of textile wastewaters is mainly due to the presence of synthetic dyes. We have studied the photocatalytic degradation of four commercial (i.e. containing additives) azo dyes (viz. Yellow Cibacron FN-2R, Red Cibacron FN-R, Navy Erionyl R 180%, Everdirect Black VSF) in aqueous suspensions of TiO