A novel cellulose nanocrystals biosorbent (CNCs) that has been synthesized, characterized, and used to remove indigo carmine blue (ICB) dye from wastewater. The characteristics of the cellulose ...nanocrystals biosorbent were assessed using various methods, including N2 adsorption-desorption isotherm, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM), SEM, and Fourier-transform infrared spectroscopy (FTIR). To examine the influence of various reaction parameters, for instance temperature, initial dye concentration, pH, and contact time, on the adsorption of the ICB, a comprehensive study was carried out. Under the ideal conditions, the highest adsorption capacity reached 746.24 mg/g, achieved after 100 min at pH 4. The Langmuir model was employed to describe the adsorption isotherm, and the pseudo-second-order model was applied to describe the kinetics of the adsorption process. The adsorption of ICB is more accurately represented by the Langmuir model rather than the Freundlich model, indicating the formation of a selective monolayer on the CNCs surface. Both film and intraparticle diffusion contribute to the adsorption of the dye. The adsorption process is characterized as chemisorption, with an adsorption energy of 17 kJ/mol. The values of enthalpy change (∆H°) and entropy change (∆S°), which are 86.55 kJ/mol and 303.69 J/mol/K, respectively, suggest that the removal process of ICB is endothermic. The interaction mechanism between ICB dye and CNCs biosorbent likely involves various forces, such as π-π interactions, hydrogen bonding, electrostatic interactions, and pore filling. Furthermore, even after undergoing five consecutive cycles of reuse, the results consistently showed that the CNCs biosorbent maintained its effectiveness. These findings indicate that porous CNCs hold significant promise as an innovative biosorbent for the treatment of wastewater containing ICB.
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•The laccase activity in aqueous solutions of surfactant-based ionic liquids was determined.•The use of micellar systems to improve the degradation of textile dyes was ...addressed.•Surfactant-based ionic liquids improve the efficiency of laccase to degrade indigo carmine.•The largest removal of color by laccase micellar system showed 93% of decolorization.
The intensive use of water containing dyes by the textile industry, and consequently the contamination of soils and water, represents serious environmental concerns. Amongst the several processes applied in the treatment of textile effluents, biological-based processes, if designed to be cost-effective and ecofriendly, are promising alternatives to decolorize textile effluents. In this work we investigate and propose the novel use of ionic liquids (ILs) with surfactant characteristics to improve the degradation of the largely used and highly hydrophobic textile dye indigo carmine (IC) by laccase. An initial screening on the activity of laccase in aqueous solutions of twelve surfactant-based ILs from three different families, namely tetraalkylammonium- and imidazolium-based cationic surfactants and cholinium-based anionic surfactants, at different concentrations, was carried out. Significant improvements in the activity of laccase were observed with decyltrimethylammonium bromide, N10111Br, and 1-decyl-3-methylimidazolium chloride, C10mimCl, at 75 mM (above the critical micellar concentration of each IL). These ILs were then investigated in aqueous solutions to simultaneously encapsulate laccase and IC for the in situ enzymatic biodegradation of the dye. The use of ILs remarkably increases the degradation rate of the dye and decolorization efficiency; a degradation efficiency of IC of 82% is attained in 0.5 h using aqueous solutions of N10111Br, whereas without IL only 6% of IC is degraded. Furthermore, 93% of the dye decolorization was achieved with N10111Br. The overall gathered results show that it is possible to significantly improve the degradation of hydrophobic dyes by enzymes using appropriate surfactant-based ILs, while foreseeing the use of the treated water by the same textile industries in new dyeing steps and thus contributing to a substantial decrease of the economic input and environmental footprint of these industries.
The photochemical properties of indigo, a widely used industrial dye, has attracted both experimentalists and theoreticians from the beginning. Especially the high photostability of indigo has been ...the subject of intensive research. Recently, it was proposed that after photoexcitation an intramolecular proton transfer followed by a nonradiative relaxation to the ground state promote photostability. In indigo the hydrogen bond and the proton transfer occur between the opposing hemiindigo parts. Here, we provide experimental and theoretical evidence that a hydrogen transfer within one hemiindigo or hemithioindigo part is sufficient to attain photostability. This concept can serve as an interesting strategy towards new photostable dyes for the visible part of the spectrum.
Beyond the blue: The vastly different photochemical properties of 4,4′‐dihydroxythioindigo and its dimethoxy derivative demonstrate that excited‐state proton transfer within the rigid ring system of only one hemithioindigo moiety improves photostability. This promoting mechanism is the same as that in indigo and in many UV stabilizers. This concept may serve as an interesting strategy towards new photostable dyes for the visible part of the spectrum.
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•Nanostructure of MgO were synthesized by a simple method, using new templates.•Different templates affect on the size and species of particles.•MgO nanostructuere were utilized for ...decolorization of Indigo carmine.
Magnesium oxide powders have been prepared by simple method using different templates as Hexamine (T1), alkylate-hexamine salt (T2) and alkylate–dihexamine salt (T3). The annealed products were systematically investigated by using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and UV–Visible absorption. It was found that the formation of nanoparticle could involved the role of performed “nucleus” and used template to control the growth rate of nucleuses. The results were shown that different templates affect on the size and species of particles. In this study, the crystallite size of the MgO products were in a range from 4 to 7nm. The optical band gap of MgO nanoparticles was in the range 4.27–4.77eV. The morphology of MgO was nanospheres or nanokongelemere-like. In this investigation photocatalytic degradation of Indigo carmine (IC) in water was studied. The effects of some parameters such as pH, amount of catalyst, initial concentration of dye were examined.
This Minireview focuses on the hemithioindigo photoswitch and its use for the reversible control of three‐dimensional peptide structure and related biological functions. Both the general design ...aspects and biophysical properties of various hemithioindigo‐based chromopeptides are summarized. Hemithioindigo undergoes reversible Z→E photoisomerization after absorption of visible light. The unique ultrafast switching mechanism of hemithioindigo combines picosecond isomerization kinetics with strong double‐bond torsion after light absorption, making it the ideal tool for instantaneous modulation of biological structure. Various inhibitors and model peptides based on hemithioindigo are described that can directly regulate biological signaling or allow the fastest events in peptide folding to be studied. Finally, a diverse range of chromopeptides with photoswitchable β‐hairpin structures based on azobenzenes, stilbenes, and hemithioindigo are compared to emphasize the unique properties of hemithioindigo.
Observing rapid changes: Hemithioindigos (HTIs) are promising photoswitchable tools for various applications. The design, applications, biophysical studies, and ultrafast spectroscopy of HTI amino acid building blocks and peptides with picosecond isomerization dynamics are reviewed. Photoresponsive chromopeptides allow structural transitions in the secondary structure of peptides to be monitored in time regimes down to nanoseconds (see figure).
Tyrian purple, mainly composed of 6,6'-dibromoindigo (6BrIG), is an ancient dye extracted from sea snails and was recently demonstrated as a biocompatible semiconductor material. However, its ...synthesis remains limited due to uncharacterized biosynthetic pathways and the difficulty of regiospecific bromination. Here, we introduce an effective 6BrIG production strategy in Escherichia coli using tryptophan 6-halogenase SttH, tryptophanase TnaA and flavin-containing monooxygenase MaFMO. Since tryptophan halogenases are expressed in highly insoluble forms in E. coli, a flavin reductase (Fre) that regenerates FADH
for the halogenase reaction was used as an N-terminal soluble tag of SttH. A consecutive two-cell reaction system was designed to overproduce regiospecifically brominated precursors of 6BrIG by spatiotemporal separation of bromination and bromotryptophan degradation. These approaches led to 315.0 mg l
6BrIG production from tryptophan and successful synthesis of regiospecifically dihalogenated indigos. Furthermore, it was demonstrated that 6BrIG overproducing cells can be directly used as a bacterial dye.
Indigo is a bis-indolic alkaloid that has antioxidant and anti-inflammatory effects reported in literature and is a promissory compound for treating chronic inflammatory diseases. This fact prompted ...to investigate the effects of this alkaloid in the experimental model of Duchenne muscular dystrophy. The main aim of this study was to evaluate the potential role of the indigo on oxidative stress and related signaling pathways in primary skeletal muscle cell cultures and in the diaphragm muscle from mdx mice. The MTT and Neutral Red assays showed no indigo dose-dependent toxicities in mdx muscle cells at concentrations analyzed (3.12, 6.25, 12.50, and 25.00 µg/mL). Antioxidant effect of indigo, in mdx muscle cells and diaphragm muscle, was demonstrated by reduction in 4-HNE content, H₂O₂ levels, DHE reaction, and lipofuscin granules. A significant decrease in the inflammatory process was identified by a reduction on TNF and NF-?B levels, on inflammatory area, and on macrophage infiltration in the dystrophic sample, after indigo treatment. Upregulation of PGC-1a and SIRT1 in dystrophic muscle cells treated with indigo was also observed. These results suggest the potential of indigo as a therapeutic agent for muscular dystrophy, through their action anti-inflammatory, antioxidant, and modulator of SIRT1/PGC-1α pathway.
A new adsorbent was prepared from municipal wastes (a mixture of Corn Stover, Paper Waste, and Yard Waste) by cationization with 3 ̶ Chloro ̶ 2 ̶ Hydroxypropyl Trimethylammonium Chloride. The FTIR ...spectrum confirmed the quaternary ammonium group's presence on the adsorbent surface (1450 cm−1). The maximum adsorption capacity (148 mg/g) was higher than the earlier reported values. Liu isotherm described well the adsorption process, with a high R2adj value (0.997). The pseudo-first-order equation fits well for kinetic data, and thermodynamic experiments demonstrated the endothermic nature of the adsorption. The deep neural network (DNN) is applied to simulate the adsorption process, which outperformed the classical machine learning and shallow neural network models. The DNN model predicted accurately the adsorption process with the lowest deviation from the actual values with Mean Absolute Error (MAE = 3.2), Root Mean Squared Error (RMSE = 4.89), and the highest performance accuracy of R2 (0.96) as compared to various classical ML algorithms such as Linear Regressions (MAE = 12.53, RMSE = 18.01, R2 = 0.42), Random Forest (MAE = 5.81, RMSE = 10.05, R2 = 0.82), and Extra Trees (MAE = 4.35, RMSE = 8.22, R2 = 0.88). The utilized DNN model can be used for predicting the removal efficiency of dyes for various combinations of input parameters without going through laboratory experiments.
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•Matrix of municipal waste was converted into an absorbent by surface cationization.•The adsorbent had higher adsorption capacity for anionic dye Indigo Carmine.•Liu isotherm described well the adsorption process.•Classical machine learning models didn’t predict accurately.•Deep Neural Network was able to model the adsorption process with 96% accuracy.
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•Methacryloxyethyltrimethyl ammonium chloride functionalized KF was successfully prepared.•Single and competitive adsorption n of MO and IC were studied.•IC uptake is almost not ...change but MO uptake sharply decreased in binary system.•the SF of IC/MO could reach 129.53.•The selective adsorption mechanism between MO and IC was attributed to the displacement impact.
Since industrial effluents contain several dye species, investigation on the competitive adsorption and selective adsorption mechanism is quite necessary. In this paper, single and competitive adsorption of Indigo Carmine (IC) and Methyl Orange (MO) dyes using methacryloxyethyltrimethyl ammonium chloride functionalized kapok fiber (DKF) were investigated. The maximum adsorption capacity of individual adsorption was 1011.3 mg/g and 1079.9 mg/g for MO and IC, respectively. However, IC has significant inhibitory effect on MO uptake but IC adsorption almost not change in binary system, which is in contrast to the reported results that competitive adsorption capacity was greatly reduced for each dye in binary system. The separation factor of IC/MO could reach 129.53 when the concentration of IC and MO equal 0.2 mol/L, indicating good selectivity toward IC. The selective adsorption mechanism between MO and IC was attributed to the displacement impact. Therefore, this work provided a potential adsorbent for selectively removing dye from industrial effluents and give a new sight to the competitive adsorption mechanism among dyes.
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