Naphthol Green B Research Articles

Facile Color Tuning, Characterization, and Application of Acid Green 25 and Acid Yellow 25 Co-intercalated Layered Double Hydroxides

Acid Green 25 (AG25) has been cointercalated with Acid Yellow 25 (AY25) into the interlayer of ZnAl layered double hydroxides (LDH) via a coprecipitation method to tune the color of hybrid pigments based on LDHs. The prepared hybrids were analyzed by X-ray diffraction, scaning electron microscopy, Fourier transform infrared microscopy, inductively coupled plasma–emission spectroscopy, thermogravimetry–differential thermal analysis, UV–vis, and CIE 1976 L*a*b* color scales, which show that AG25 and AY25 have been cointercalated into LDH and the color of the prepared LDH can be easily tuned from greenish blue to bluish green and green by adjusting the molar ratio of AY25/AG25. There exists host–guest and guest–guest interactions in the hybrids, and the intercalation into LDH significantly improves the thermal stability of the AY25. The hybrids were used as colorant to prepare green coatings and films, showing their potential application in the fields of paints and plastics.

Synthesis and evaluation of a molecularly imprinted polymer for selective adsorption and quantification of Acid Green 16 textile dye in water samples

An alternative for determining environmental pollutants, like textile dyes, is the use of molecularly imprinted polymers (MIPs) as solid phase extraction (SPE) or as sensor recognition systems. MIPs are tailor-made artificial receptor sites in a polymer, which present good affinity and selectivity. This work shows the synthesis of MIPs for the Acid Green 16 (AG16) textile dye and the results of rebinding, selectivity and application of this MIP in water samples. MIP synthesis was performed using AG16 dye (template), 1-vinylimidazole (functional monomer), ethylene-glycol-dimethacrylate (cross-link), 2,2′-azobis(2-methylpropionitrile) (initiator) and methanol (solvent) by bulk synthesis. The imprinted polymer presented excellent rebinding of 83%, an imprinted factor of 6.91 and great selectivity in comparison with other textile dyes. Additionally, the MIP showed high efficiency in the extraction of this dye in water samples, presenting a recovery rate close to 100% and a better performance when compared to commercial SPE cartridges. Due to this excellent performance for AG16, the application of this MIP to determine dyes in different matrices of environmental importance is promising.

Electrodegradation of the Acid Green 28 dye using Ti/β-PbO2 and Ti-Pt/β-PbO2 anodes

The statistical Response Surface Methodology (RSM) is applied to investigate the effect of different parameters (current density, j, NaCl concentration, [NaCl], pH, and temperature, θ) and their interactions on the electrochemical degradation of the Acid Green (AG) 28 dye using a Ti/β-PbO2 or Ti-Pt/β-PbO2 anode in a filter-press reactor. LC/MS is employed to identify intermediate compounds. For both anodes, the best experimental conditions are j = 50 mA cm−2, [NaCl] = 1.5 g L−1, pH = 5, and θ = 25 °C. After 3 h of electrolysis, a dye solution treated under these conditions presents the following parameters: electric charge per unit volume of the electrolyzed solution required for 90% decolorization (Q90) of 0.34–0.37 A h L−1, %COD removal of ∼100%, specific energy consumption of 18–20 kW h m−3, and %TOC removal of 32–33%. No loss of the β-PbO2 film is observed during all the experiments. The β-PbO2 films present excellent stability for solutions with pH ≥ 5 ([Pb2+] < 0.5 mg L−1). Chloroform is the only volatile organic halo compound present in the treated solution under those optimized conditions. Hydroxylated anthraquinone derivatives, aromatic chloramines, and naphthoquinones are formed during the electrolyses. The Ti/β-PbO2 and Ti-Pt/β-PbO2 anodes show significantly better performance than a commercial DSA anode for the electrochemical degradation of the AG 28 dye. The Ti/β-PbO2 anode, prepared as described in this work, is an excellent option for the treatment of textile effluents because of its low cost of fabrication and good performance.

Decoration of biogenic AgNPs on template free ZnO nanorods for sunlight driven photocatalytic detoxification of dyes and inhibition of bacteria

A facile, template free innovative and inexpensive route based on the biogenic method has been demonstrated for the synthesis of AgNPs decorated on ZnO nanorods. The as-synthesized Ag–ZnO nanorods have been characterized by a host of different techniques such as X-ray diffraction, diffuse reflectance spectroscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, energy dispersive spectroscopy and photoluminescence. The sunlight-induced photocatalytic feature of Ag–ZnO nanorods was verified towords the degradation of Methyl Orange and Acid Green-25. The cytotoxicological test indicate that toxicity of photocatalytically degraded products were significantly reduced as compared to original dyes. Also antimicrobial studies against Pseudomonas aurogenosa (NCIM 5032) and Bacillus Subtilis (NCIM 2635), were evaluated. The Ag–ZnO nanorods have exhibited an excellent sunlight-induced photocatalytic degradation of dyes compared to pristine ZnO. The experimental results suggest that sunlight induced photocatalytic activity is favoured due to extension of the optical response from UV to visible and suppression of recombination of photogenerated electrons and holes.

Interactions of two food colourants with BSA: Analysis by Debye-Hückel theory

We have focused on exploring pH- and ionic strength-modulated binding of acid red 1 (AR1) and acid green 50 (AG50) with bovine serum albumin (BSA) by fluorescence, UV–vis absorption and FTIR spectra. The results implied that the quenching mechanism of BSA-AR1/AG50 system was a static quenching, electrostatic force dominated the formation of BSA-AR1/AG50 complex, and the binding affinity of AR1 was greater than that of AG50 on the subdomain IIA of BSA. Moreover, their true thermodynamic binding constant (Keq), true free energy change (ΔG0I→0), and effective charge (ZP) in the anion receptor pocket of BSA were calculated using Debye-Hückel limiting law. The local charge bound by AR1/AG50 rather than the overall or surface charge of BSA played a key role in determining their interaction strength. Besides, the thermal and structural stabilization of BSA was discussed by analyzing the changes of Tm and Hurea without/with the addition of AR1/AG50, respectively.

Resonance Rayleigh Scattering Spectra of an Ion-Association Complex of Naphthol Green B-Chitosan System and Its Application in the Highly Sensitive Determination of Chitosan.

This work describes a highly-sensitive and accurate approach for the determination of chitosan (CTS) using Naphthol Green B (NGB) as a probe in the Resonance Rayleigh scattering (RRS) method. The interaction between CTS and NGB leads to notable enhancement of RRS, and the enhancement is proportional to the concentration of CTS over a certain range. Under optimum conditions, the calibration curve of ΔI against CTS concentration was ΔI = 1860.5c + 86.125 (c, µg/mL), R2 = 0.9999, and the linear range and detection limit (DL) were 0.01–5.5 µg/mL and 8.87 ng/mL. Moreover, the effect of the molecular weight of CTS on the accurate quantification of CTS was studied. The experimental data were analyzed through linear regression analysis using SPSS20.0, and the molecular weight was found to have no statistical significance. This method has been applied to assay two CTS samples and obtained good recovery and reproducibility.

Simultaneous removal of acid green 25 and mercury ions from aqueous solutions using glutamine modified chitosan magnetic composite microspheres

In this current work, the magnetic composite microsphere containing glutamine modified chitosan and silica coated Fe3O4 nanoparticles (CS-Gln-MCM) has been successfully prepared and extensively characterized, which is a kind of biodegradable materials. CS-Gln-MCM shows enhanced removal efficiency for both acid green 25 (AG25), an amphoteric dye, and mercury ions (Hg2+) from water in the respective while measured pH range compared with chitosan magnetic composite microsphere (CS-MCM) without modification. It is due to the fact that the grafted amino acid provides a variety of additional adsorption active sites and diverse adsorption mechanisms are involved. In AG25 and Hg2+ aqueous mixture, the modified adsorbents bear preferential adsorption for AG25 over Hg2+ in strong acidic solutions ascribed to multiple interactions between AG25 and CS-Gln-MCM, such as hydrogen bonding and electrostatic interactions. While, in weak acidic conditions, an efficient simultaneous removal is observed for different adsorption effects involved in aforementioned two pollutants. Besides, CS-Gln-MCM illuminates not only short equilibrium time for adsorption of each pollutant less than 20.0 min but also rapid magnetic separation from water and efficient regeneration after saturated adsorption. Therefore, CS-Gln-MCM bears great application potentials in water treatment.

Biosynthesis of FeS nanoparticles from contaminant degradation in one single system

Biogenetic nanomaterials have attracted growing interests in recent years attributed to their “green” synthesis nature, but expensive precursors are typically needed. On the other hand, release of hazardous intermediates during contaminant biodegradation/conversion is usually encountered in wastewater treatment processes. This study reports an effective coupling of both processes in one simple system to overcome the individual limitations. By using Shewanella oneidensis MR-1 as the inoculum, the Fe2+ ions released from naphthol green B (NGB) bioreduction and H2S from thiosulfate reduction were utilized in-situ to generate ferrous sulfide (FeS) nanoparticles, with an average size of ∼30nm. In addition, we discovered for the first time that FeS nanoparticles could be synthesized both extracellarly and intracellularly by this strain, and identified the essential role of the Mtr respiratory pathway in the biosynthesis process. This study deepens our understanding of the bioconversion behaviors of metal-complex dyes, and may provide implications for development of sustainable nanomaterial fabrication processes.

REMOVAL OF ANIONIC DYES (DIRECT BLUE 106 AND ACID GREEN 25) FROM AQUEOUS SOLUTIONS USING OXIDIZED MULTI-WALLED CARBON NANOTUBES

Background and purpose: The presence of dyes in wastewaters may cause serious problems for the environment because of their high toxicity to a quatic organisms and unfavorable aesthetical impact. In the present study, multi-walled carbon n anotubes (MWCNTs) were used for removal of anionic dyes Direct Blue 106 (DB106) and Acid Green 25 (AG25), from water samples. Materials and Methods: MWCNTs were oxidized and characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). In batch tests, the effects of various parameters such as pH solution (2.0-7.0), oxidized MWCNT dose (0.01-0.04 g), contact time (7-60 minutes), initial dye concentration (30-350 m g/l), and temperature (25-55° C) were investigated . Results: The optimum pH for removing of investigated anionic dyes from water solutions was found to be 2.0. The adsorption of the dyes reached equilibrium at 15 minutes. Langmuir, Freundlich and Temkin models were used to study the adsorption isotherms and the equilibrium adsorption was best described by Langmuir isotherm model. Kinetic adsorption data were analyzed using pseudo-first-order kinetic model and pseudo-second-order model. The regression results showed that the adsorption kinetics was mor e accurately represented by pseudo-secondorder model. Conclusion: The results suggest that oxidized MWCNT could be employed as an effective material for the removal of anionic dyes from aqueo us solutions and the maximum adsorption capacity was found to be 500 and 333 mg/g for DB106 and AG25, respectively. [Sobhanardakani S, *Zandipak R. Removal of Anionic Dyes (Direct Blue 106 and Acid Green 25) from Aqueous Solutions Using Oxidized Multi-Walled Carbon Nanotubes . Iran J Health Sci 2015; 3(3): 48-57] http://jhs.mazums.ac.ir

Template free large scale synthesis of multi-shaped ZnO nanostructures for optical, photocatalytical and antibacterial properties

In this article, ZnO nanostructures with diverse morphologies have been synthesized via a simple, rapid and cost effective solid state thermal decomposition method. The as-synthesized ZnO nanostructures were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy, scanning electron microscope (SEM), high-resolution transmission electron microscope (HR-TEM), UV–Vis. diffuse reflectance spectra (UV–Vis-DRS) and photoluminescence (PL). The XRD patterns and HR-TEM image indicated a hexagonal wurtzite structure of ZnO. The SEM images of ZnO samples show the different morphologies such as nanowire, nanorods, spherical and irregular microsphere at different calcination temperatures. Room temperature PL spectra of the samples exhibited characteristics blue and green emission bands in accordance with calcination temperature. Moreover, photocatalytic as well as antimicrobial activities were evaluated using ZnO synthesized at different calcination temperatures. The effects of calcination temperature, catalyst loading and pH on the photodegradation efficiency were systematically studied. A highest (99 %) photocatalytic activity of ZnO nanorods towards the Acid Green 25 (AG-25) was achieved within 35 min at optimal conditions under UV light. As-synthesized ZnO nanorods are found to be more efficient than TiO2 (P25) towards the degradation of AG-25. It was found that the antimicrobial activity of ZnO nanorods (13 mm) obtained at 300 °C showed significantly higher inhibition efficiencies than the other samples. The mineralization of AG-25 was confirmed from a reduction of 85 % the chemical oxygen demand within 35 min. In addition, ZnO nanorods could be easily reusable up to four runs without changing its photocatalytic activity.

Modeling and optimization of the flocculation processes for removal of cationic and anionic dyes from water by an amphoteric grafting chitosan-based flocculant using response surface methodology

In this study, an amphoteric grafting chitosan-based flocculant (carboxymethyl chitosan-graft-poly(2-methacryloyloxyethyl) trimethyl ammonium chloride, denoted as CMC-g-PDMC) was applied to removal of the anionic and cationic dyes, acid Green 25 (AG25) and Basic Bright Yellow (7GL), from water. Flocculation conditions have been optimized by response surface methodology (RSM) on the basis of central composite design (CCD) using flocculant dosage, initial solution pH and temperature as input variables. The second-order and cubic regression models, which have been both tested by the analysis of variance (ANOVA), were constructed to link the output response (the dye removal factor) with the aforementioned input variables, respectively. The second-order regression model well described the process of AG25 removal, whereas the cubic one is more suitable for that of 7GL. The effects of those variables on the flocculation performance of CMC-g-PDMC for removal of the two dyes containing opposite charges from aqueous solutions have been studied, and the flocculation mechanisms including the interactive effects between various influencing factors have been discussed in detail also.

Modeling and kinetics study of acid anthraquinone oxidation using ozone: energy consumption analysis

An anthraquinone dye as a persistent organic material was eliminated by an environmentally safe method. In this work, decolorization of acid green 25 (AG25) was carried out using ozonation in a semibatch bubble column. Results showed that the process efficiency was affected by three operational parameters of influent ozone mass flow, initial AG25 concentration, and reaction time. Moreover, inhibitory effects of ethanol, 2-propanol, and carbonate as scavengers on the process efficiency were also evaluated. Kinetics study indicated that AG25 removal was a pseudo first-order reaction with respect to various concentrations of AG25, ozone, and radical scavenger. An artificial neural network (ANN) was developed to predict the process performance. The obtained weights from ANN were used for sensitivity analysis of the process. This analysis indicated that relative importance of influent ozone mass flow, initial AG25 concentration, and reaction time was 22, 14, and 64 %, respectively. Cost-effectiveness analysis of the process was implemented by calculating electrical energy consumption at various concentrations of AG25. Based on the results, the range of electrical energy consumption was found between 1.2 and 2.3 kWh/m3/order.

Carbon Nanotube-Based Electrochemical Sensor for the Determination of Anthraquinone Hair Dyes in Wastewaters

The present work describes the development of a voltammetric sensor for the selective determination of Acid Green 25 (AG25) hair dye, widely used in commercial temporary hair dyes. The method is based on a glassy carbon electrode modified with multiwalled carbon nanotubes activated in the presence of sulfuric acid, where the anthraquinone group present as a chromophore in the dye molecule is reduced at −0.44 V vs. Ag/AgCl in a reversible process involving two electrons in Britton-Robinson (B-R) buffer solution at pH 4.0. Analytical curves were obtained using square wave voltammetry in the range from 1.0 × 10−7 to 7.0 × 10−6 mol·L−1, achieving a detection limit of 2.7 × 10−9 mol·L−1. The voltammograms recorded for the Acid Black 1 (AB1) dye showed that the azo groups of the dye were reduced on the carbon nanotube-modified electrode (CNTME), presenting a pair of redox peaks at −0.27 V and −0.24 V in the reverse scan. Under these experimental conditions, both dyes could be detected in the water sample, since the AG25 dye is reduced at −0.47 V. The presence of other hair dyes bearing other chromophore groups, such as Acid Black 1, Acid Red 33 and basic blue 99, did not interfere with the method, which showed an average recovery of 96.7 ± 3.5% (n = 5) for AG25 dye determination in the presence of all of these dyes. The method was successfully applied to tap water and wastewater samples collected from a water treatment plant.

Efficient flocculation of an anionic dye from aqueous solutions using a cellulose-based flocculant

In this current work, a series of cellulose-based flocculants, carboxymethyl cellulose-graft-poly[(2-methacryloyloxyethyl) trimethyl ammonium chloride] (CMC-g-PDMC) with different grafting ratios were successfully synthesized. CMC-g-PDMC bears high flocculation performance in removal of an anionic dye, Acid Green 25 (AG25), at various pH conditions, which is due to improvement of both positive charge and molecular weight after modification. Moreover, the dye removal efficiency is mostly improved with the increase of grafting ratio. Among the four tested salt additives, CMC-g-PDMC exhibits good salt resistance except for sodium chloride in the measured salt concentration range. Furthermore, the image analysis in combination with fractal theory has been employed to investigate the flocs properties including floc size and fractal structure for studying the flocculation mechanism in detail. It is confirmed that charge neutralization and bridging flocculation effects both play important roles in removal of AG25 from water.

Thermodynamic properties of dye removal from colored textile wastewater by poly(propylene imine) dendrimer

In this paper, the thermodynamic properties of textile dye removal from aqueous solutions using poly(propylene imine) (PPI) dendrimer were studied. Direct Red 80 (DR80) and Acid Green 25 (AG25) were used as model dyes. The surface coverage of dendrimer was obtained to investigate the adsorbent characteristics. The effect of temperature on dye removal has been studied at different dye concentrations. The adsorption isotherms (Langmuir and Freundlich) and kinetics (pseudo-first-order and pseudo-second-order) were studied in various temperatures. Thermodynamic parameters such as free energy of adsorption (∆G), enthalpy (∆H), and entropy (∆S) changes were calculated to predict the nature of the adsorption. It was found that the isotherm data of DR80 and AG25 followed Langmuir model at different temperatures. Adsorption kinetics of dyes was found to conform to pseudo-second-order with a good correlation coefficient. The estimated values for ∆G showed that the adsorption process was spontaneous. Based on the data of the present study, it can be concluded that PPI dendrimer, as an eco-friendly material, is a suitable adsorbent for the elimination of dyes from colored textile wastewater at different temperatures.

Fe-modified local clay as effective and reusable heterogeneous photo-Fenton catalyst for the decolorization of Acid Green 25

Locally sourced Bandar Baru clay (BBC) from Kedah in Malaysia was modified with NaCO3 and applied as catalyst support. Six different Fe supported BBC (Fe-BBC) catalysts were prepared with different calcination temperature (300–500°C) and time (4–6h) and their activities were tested on the decolorization of Acid Green 25 (AG25) pollutant dye. The best Fe-BBC was that calcined at 300°C for 4h, and it was characterized. The BET result showed increase in surface area and pore volume which was supported by the SEM result. The presence of the incorporated Fe in the catalyst was verified with EDX, XRD and FTIR techniques. The best experimental condition decolorized 99% of 50ppm (AG25) in 20min with 1.25g/L Fe-BBC300/4 and 6.7mM of hydrogen peroxide at pH 3. Its reusability after three cycles showed 97.5% decolorization of 50ppm of AG25. The versatility of Fe-BBC300/4 was also verified on the decolorization of Reactive Blue 4 and Direct Blue 71.

Catalytic activity of copper modified bentonite supported ferrioxalate on the aqueous degradation and kinetics of mineralization of Direct Blue 71, Acid Green 25 and Reactive Blue 4 in photo-Fenton process

In order to enhance depuration of pollutants in photo-Fenton process, copper modified bentonite supported ferrioxalate catalyst (CuMBFOx) was synthesized. The catalyst was characterized with TGA, XRF, XRD, FTIR, BET and SEM techniques. Its catalytic activity was evaluated on the degradation of Direct Blue 71 (DB71), Acid Green 25 (AG25) and Reactive Blue 4 (RB4) dye pollutants in batch photo-Fenton process without pH adjustment. The results showed complete depuration below the detection point of UV–vis spectrophotometer as monitored on their respective UV–vis degradation spectra. The extent of mineralization ability of the CuMBFOx was monitored with chemical oxygen demand (COD) analysis and was used to study the kinetics of mineralization of the dyes using a developed phenomenological mathematical model. The result showed that the efficiency reduced in the order DB71>AG25>RB4 owning to their chemical components and structural complexities. CuMBFOx demonstrated excellent qualities toward depuration of DB71, AG25 and RB4.

Sensitive Determination of Proteins with Naphthol Green B by Resonance Light Scattering Technique

A new quantitative determination method for trace proteins using naphthol green B (NGB) by resonance light scattering (RLS) spectroscopy has been developed. The method is based on the interaction of protein and NGB at pH 3.00, which causes a substantial enhancement of the resonance scattering signal of NGB in the wavelength range 300–550 nm with the maximum RLS at 392.0 nm. Under optimum conditions, the linear range is 0.010–28.2 μg/ml for bovine serum albumin (BSA) and 0.010–31.3 μg/ml for human serum albumin (HSA). The detection limits (S/N=3) are 8.2 ng/ml for BSA and 7.9 ng/ml for HSA, respectively. There is little or no interference from amino acids, most of the metal ions, or other coexisting substances. The easy-to-use method, with high sensitivity and good reproducibility, was satisfactorily applied to the determination of total protein in human serum samples. The determination results for human serum samples are identical to those provided by clinical physicians.

Iron-clay as a reusable heterogeneous Fenton-like catalyst for decolorization of Acid Green 25

Decolorization of Acid Green 25 (AG25) was achieved by using Fe-Ipoh clay (Fe-IC) as catalyst on Fenton-like process. The catalyst was prepared by impregnation method and was characterized.The effect of various parameters such as catalyst calcination temperature and duration of time, pH, initial concentration of hydrogen peroxide (H2O2) and AG25, catalyst dosage, and reaction temperature was studied. The best performance of AG25 decolorization was found to be 95% after 2 h of reaction by using 1.25 g/L catalyst dosage of Fe-IC calcined at 500°C for 6 h and 6.7mM of H2O2 at pH 3. Besides, the developed catalyst also indicated an advantage of low iron leaching and ability for reuse up to three runs, with slightly reduced decolorization of AG25 from 95 to 93% at the same reaction time.

Mineralization of Acid Green 50 by Fe2O3–Al2O3 as a highly active hetero-Fenton catalyst

The oxidation of Acid Green 50 (AG50) textile dye using Fe2O3–Al2O3, prepared from the calcination of FeIII–Al(OH)4-gel, as a highly active catalyst in the heterogeneous Fenton oxidation process was studied. It was found that the ferric ions loaded on the surface of neutral Al(OH)4− gel and then calcined at different temperatures is an efficient catalyst in the heterogeneous Fenton reaction for the mineralization of aqueous AG50. According to the X-ray analysis, the iron catalyst is a mix of Fe2O3 and Al2O3. The thermal treatment gives long-term stability to the catalyst because it minimizes iron leaching from the catalyst. The catalyst was used in four successive recycling heterogeneous Fenton oxidations generating a colorless solution with the removal of over 95% of total organic carbon (TOC) in 90 min. This shows that the Fe2O3–Al2O3 catalyst is highly efficient for the degradation of AG50 after being used in several cycles during the dye treatment. It was also found that the degradation of AG50 increased by increasing the hydrogen peroxide concentration.