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1.
Shokuhin Eiseigaku Zasshi ; 61(2): 58-62, 2020.
Artigo em Japonês | MEDLINE | ID: mdl-32336710

RESUMO

Violation of the Food Sanitation Act regarding detection of Patent Blue V, which is one of the non-permitted dyes for food in Japan, in imported food occurs every year. With respect to the identification of dyes of Patent Blue group, in some cases, each dye has several different names, and in other cases, different dyes have the same name. Thus, there is a risk that the detected dye is misidentified with other dyes of Patent Blue group. In this study, nine commercial available dyes of Patent Blue group, including a reagent with unclear product information, were analyzed by TLC, HPLC and LC-MS/MS. The result showed that with all three methods, the dyes could be clearly identified into one of four types of blue dyes, i.e. Patent Blue V, Azure Blue VX, Isosulfan Blue and Alphazurine A. Unification of nomenclature would reduce the risk of misidentification of dyes of Patent Blue group.


Assuntos
Corantes/análise , Aditivos Alimentares/análise , Cromatografia Líquida , Japão , Corantes de Rosanilina/análise , Espectrometria de Massas em Tandem
2.
Chemosphere ; 254: 126823, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32334264

RESUMO

Environmentally toxic organic pollutants, namely methylene blue (MB), neutral red (NR), Rhodamine B (RhB), and methyl orange (MO) dyes contain highly toxic, carcinogenic, non-biodegradable, and colored pigments which cause harm for humans and aquatic organisms even at low concentrations. To detoxify these toxic organic pollutants from the wastewater, the bimetallic solid solution-typed In-Mo(O,S)2 catalyst with various indium (In) contents were synthesized at low temperature through a simple precipitation method. The morphological, structural, chemical compositions, electrochemical and optical properties of the catalysts were thoroughly characterized. The photodegradation performance of the In-Mo(O,S)2 catalysts over the cationic, anionic and neutral dyes were studied under visible light irradiation. It has been observed that the photocatalytic activity was enhanced as In was added to the Mo(O,S)2 catalyst, and In-Mo(O,S)2-20 was found to be the best composition to completely degrade four organic dyes. The dye degradation had rate constant values of 9.5 × 10-2 min-1, 6.3 × 10-2 min-1, 4.4 × 10-2 min-1, and 15.7 × 10-1 min-1 for MB (20 ppm), NR (20 ppm), RhB (10 ppm), and MO (10 ppm) dyes, respectively. The active species for degradation of MB is different from those for RhB and MO. Single phase In-Mo(O,S)2-20 capable to degrade four kinds of dyes at a fast rate is a good photocatalyst.


Assuntos
Corantes/análise , Poluentes Químicos da Água/análise , Compostos Azo , Catálise , Corantes/química , Índio , Luz , Azul de Metileno/química , Modelos Químicos , Fotólise , Rodaminas , Sulfetos , Águas Residuárias , Poluentes Químicos da Água/química
3.
Artigo em Inglês | MEDLINE | ID: mdl-32222673

RESUMO

2-(2H-Benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV 328) is an ultraviolet light (UV) absorber which prolongs the stability of plastics and other organic compounds towards UV radiation. Therefore, it is frequently used as a preserving additive and may result in an exposure of consumers. Thus, an analytical method using dispersive liquid-liquid microextraction and subsequent gas chromatography tandem mass spectrometry analysis with advanced electron ionization was developed for a human biomonitoring of UV 328 exposure, which enabled the determination of UV 328 and six of its metabolites in human urine. Sample preparation and derivatization were optimized. Baseline separation of the analytes was assured by the application of a suitable temperature program. The validation resulted in limits of detection of 0.1 µg/L for all analytes, variation coefficients from 1 to 12% for precision in series and from 5 to 12% for interday precision. Furthermore, relative recovery rates between 80 and 120% were determined. Moreover, the procedure was successfully applied to urine samples of a volunteer exposed to UV 328. The method showed excellent sensitivity, repeatability and robustness for all parameters and may be applicable for studies to elucidate the metabolism and kinetics of the investigated UV absorber and for monitoring of individuals with specific exposure to UV 328.


Assuntos
Corantes/análise , Corantes/metabolismo , Corantes/administração & dosagem , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Limite de Detecção , Microextração em Fase Líquida , Metabolômica , Oxirredução , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem , Temperatura , Raios Ultravioleta , Coleta de Urina
4.
Artigo em Inglês | MEDLINE | ID: mdl-32163004

RESUMO

This study aimed to synthesize Bi2Fe4O9 and apply it to the degradation of tartrazine yellow dye. Bi2Fe4O9 was synthesized using the solid-state reaction and the Pechini method. The materials obtained were characterized using X-ray diffraction (XRD), visible ultraviolet spectroscopy (UV-Vis) and field emission scanning electron microscopy (FEG). The microscopic images revealed a morphological difference between the two materials in which the material obtained by the Pechini method is the most porous and have the largest surface area. The pellet obtained by the Pechini method was seen to have a lower bandgap value when compared with the sample solid state reaction. In the photocatalysis tests, the best performance was also that of the material obtained by the Pechini method, with 99.34% degradation, while the material obtained by solid state reaction showed 85.86% in 120 minutes. The solution degraded with the material obtained by the Pechini method presented 81.66% of mineralization while the solution with the material obtained by solid state reaction showed 60.97% of mineralization. The results confirmed that the material obtained by both syntheses is able to maintain its effectiveness after 10 repetitions of the photocatalytic process, proving to be promising for waste treatment in the industrial field.


Assuntos
Bismuto/química , Corantes/análise , Compostos Férricos/química , Tartrazina/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Catálise , Compostos Férricos/síntese química , Microscopia Eletrônica de Varredura , Difração de Raios X
5.
Ecotoxicol Environ Saf ; 193: 110257, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32088547

RESUMO

Chlorobenzenes (CBs) present in synthetic dyes are discharged into natural waters during the treatment of textile dyeing wastewater, which may have adverse effects on human and environment. In this study, the existence and removal of 12 CBs in different units of five treatment plants were examined. The ecological risk of CBs in textile dyeing wastewater was assessed by ambient severity (AS) and risk quotients (RQs). The results showed that trichlorobenzene, tetrachlorobenzene, pentachlorobenzene and hexachlorobenzene were ubiquitous in textile dyeing wastewater, and their distribution was similar. In one of the plants, the content of hexachlorobenzene was found to be as high as 9.277 µg/L in the raw water, which was an oil-water mixture. In other plants, there was no significant difference in the content and composition of CBs among influent and effluent suggesting that the conventional wastewater treatment plants cannot improve the existence of them. Monochlorobenzene and dichlorobenzene were not detected, which may have been related to strong volatility, biochemical properties, and weak instrument sensitivity. In the treatment process and effluent, trichlorobenzene is the main pollutant and accounted for 39.51% of all CB. CB removal was found only in the anaerobic system, while the aerobic system did not have the corresponding removal effect on CB and total organic carbon. According to ecological risk assessment, CBs in effluent has not been found the significant potential harm to human health (AS < 1), but posed moderate ecological risk to aquatic ecosystem (RQs > 0.1).


Assuntos
Clorobenzenos/análise , Corantes/análise , Indústria Têxtil , Águas Residuárias/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , China , Ecossistema , Medição de Risco
6.
Chemosphere ; 246: 125734, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31918084

RESUMO

Litchi peel biochar was prepared by hydrothermal carbonization and subsequent activation process, and its adsorption on congo red and malachite green were investigated. The structural characteristics and adsorption properties of litchi peel biochar were studied by Scanning electron microscopy, X-ray diffractometer, Brunauer-Emmett-Teller, and dye adsorption experiments, and the adsorption mechanism between litchi peel biochar and dye molecules was analyzed by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The results showed that the litchi peel biochar had a high specific surface area and pore volume of 1006 m2 g-1 and 0.588 cm3 g-1, respectively, and its adsorption capacity for congo red and malachite green was 404.4 and 2468 mg g-1, respectively. The excellent adsorption properties were due to hydrogen bonding, π-π interaction, pore filling and electrostatic interactions. In addition, the reactivated litchi peel biochar also showed good adsorption performance, and all the adsorbed dyes were completely removed by reactivation, which realized complete recycling of the litchi peel biochar without causing secondary environmental pollution. Therefore, litchi peel biochar was expected to be an effective and recyclable adsorbent for removing congo red and malachite green from aqueous solutions.


Assuntos
Carvão Vegetal/química , Corantes/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/química , Adsorção , Carbono , Corantes/análise , Vermelho Congo , Cinética , Litchi/química , Reciclagem , Corantes de Rosanilina , Espectroscopia de Infravermelho com Transformada de Fourier , Águas Residuárias/química , Poluentes Químicos da Água/análise
7.
Artigo em Inglês | MEDLINE | ID: mdl-31697217

RESUMO

The described methods are able to analyse the triphenylmethane dyes malachite green (MG), crystal violet (CV) and brilliant green (BG) as well as their leuco metabolites leuco malachite green (LMG), leuco crystal violet (LCV) and leuco brilliant green (LBG) on the basis of a simple and fast extraction. The validation of the methods in two studies without and with a heated ultrasonic treatment during the extraction of fortified trout and shrimp samples was successfully performed applying an in-house validation concept. The evaluation of the relevant validation parameters, e.g. the decision limit CCα, the detection capability CCß, the repeatability, the within-laboratory reproducibility and the recovery for both extraction versions, showed results which fulfil the requirements of Commission Decision 2002/657/EC. The investigation of incurred material of trout containing the above compounds with an additional heated ultrasonic treatment during extraction leads to higher findings of MG and BG. This effect was also confirmed by other laboratories in the framework of a proficiency test. For CV and all three leuco metabolites no increase in the detected amounts could be observed after a heated ultrasonic treatment of the incurred trout material.


Assuntos
Corantes/análise , Crustáceos/química , Análise de Alimentos/normas , Contaminação de Alimentos/análise , Alimentos Marinhos/análise , Compostos de Tritil/análise , Truta , Animais
8.
J Chromatogr A ; 1610: 460516, 2020 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-31526639

RESUMO

The new approach to the development of planar chromatogram with controlled developing solvent velocity was implemented for gradient reversed-phase chromatography of a test mixture of dyes. The developing solvent components were directly delivered onto the surface of the C18 type of silica adsorbent layer with controlled velocity by moving pipette combined with two syringe pumps. The eluent components were mixed onto the adsorbent layer, so in this way, there was no dwell volume of the developing solvent during gradient chromatogram development. The delivery of the developing solvent solution to the adsorbent layer was adjusted to its absorption rate by the adsorbent layer. Under such conditions, there was no excess of the eluent solution on the surface of the adsorbent layer, so the high performance of the chromatographic system could be obtained. In the paper, the results of the repeatability and reproducibility test of migration distances of selected separated solute zones are presented.


Assuntos
Cromatografia de Fase Reversa/métodos , Cromatografia em Camada Delgada/métodos , Corantes , Solventes/química , Corantes/análise , Corantes/isolamento & purificação
9.
Food Chem ; 310: 125963, 2020 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-31838374

RESUMO

A new MEKC-MS/MS method was developed for the determination of four Sudan dyes in chili products. The separation and MS detection conditions were optimized to achieve fast, efficient, selective, and sensitive determination of Sudan I, Sudan II, Sudan III, and Sudan IV dyes. The target compounds were extracted from chili samples with acetonitrile and cleaned by freeze-out. This two-step sample preparation led to excellent extraction efficiency and minimal matrix effect. The analytical performance of the method was very good, with r2 ≥ 0.9914 and limits of quantification lower than 22 µg kg-1. The precision was below 15.7%. The recovery for spiked samples ranged from 84.4 to 99.6%, with relative standard deviations less than 8.0%. For all evaluated samples, the matrix effects did not exceed ± 10%. The applicability of the proposed method was demonstrated with 20 chili products, two of which were found to contain Sudan I and IV residues.


Assuntos
Corantes/análise , Contaminação de Alimentos/análise , Compostos Azo/análise , Caprilatos/química , Capsicum/química , Cromatografia Capilar Eletrocinética Micelar/métodos , Fluorcarbonetos/química , Análise de Alimentos/métodos , Limite de Detecção , Micelas , Naftóis , Tensoativos/química , Espectrometria de Massas em Tandem/métodos
10.
Environ Sci Pollut Res Int ; 27(4): 3803-3818, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31838699

RESUMO

Color is a major attraction component of any fabric regardless of how admirable its constitution. Industrial production and utilization of synthetic dyestuffs for textile dyeing have consequently become a gigantic industry today. Synthetic dyestuffs have introduced a broad range of colorfastness and bright hues. Nonetheless, their toxic character has become a reason of serious concern to the environment. Usage of synthetic dyestuffs has adverse impacts on all forms of life. Existence of naphthol, vat dyestuffs, nitrates, acetic acid, soaping chemicals, enzymatic substrates, chromium-based materials, and heavy metals as well as other dyeing auxiliaries, makes the textile dyeing water effluent extremely toxic. Other hazardous chemicals include formaldehyde-based color fixing auxiliaries, chlorine-based stain removers, hydrocarbon-based softeners, and other non-biodegradable dyeing auxiliaries. The colloidal material existing alongside commercial colorants and oily froth raises the turbidity resulting in bad appearance and unpleasant odor of water. Furthermore, such turbidity will block the diffusion of sunlight required for the process of photosynthesis which in turn is interfering with marine life. This effluent may also result in clogging the pores of the soil leading to loss of soil productivity. Therefore, it has been critical for innovations, environmentally friendly remediation technologies, and alternative eco-systems to be explored for textile dyeing industry. Different eco-systems have been explored such as biocolors, natural mordants, and supercritical carbon-dioxide assisted waterless dyeing. Herein, we explore the different types of dyeing processes, water consumption, pollution, treatment, and exploration of eco-systems in textile dyeing industry.


Assuntos
Corantes/química , Resíduos Industriais , Indústria Têxtil , Corantes/análise , Meio Ambiente , Resíduos Industriais/análise , Têxteis
11.
Chemosphere ; 243: 125253, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31733540

RESUMO

Dyes & dyes intermediates are one of the important and critically polluted industrial sectors, generating a large environmental liability. Therefore characterization of microbial community structure and diversity of contaminated soils helps to optimize the bioremediation strategies and performance. This study investigated the roles of environmental variables and contamination levels in shaping microbial community structure at an abandoned aged. In total, 20 bacterial and 4 fungal phyla were identified across soils with different physiochemical properties and concentration of the contaminants. Taxonomic analysis revealed the Proteobacteria, Firmicutes, Ascomycota and Basidiomycota represented the lineages and accounted for 49.5%-51.2%, 5.1%-15.3%, 2.5%-3.8% and 1.6%-2.1% of the total population, respectively. Microbial community (site 1) achieved decolorization rate of 972 ±â€¯1.21 mg dyes kgsoil-1d-1 after 15d and 692 ±â€¯1.4 mg kg-soil-1d-1 COD removal rate after 30 day of the experiment. Microbial community mineralized intermediates, 4-amino benzenesulfonate, 6-amino naphthalene sulfonate and benzene/naphthalene sulfonate in TCA cycle and stimulate the growth of selected soil bacteria, primary nutrient as well as plant growth of contaminated soil.


Assuntos
Biodegradação Ambiental , Corantes/metabolismo , Microbiologia do Solo , Poluentes do Solo/metabolismo , Bactérias/efeitos dos fármacos , Corantes/análise , Fungos , Microbiota , Solo/química , Poluentes do Solo/análise
12.
Food Chem ; 309: 125793, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31699557

RESUMO

Saffron is a highly adulterated spice due to its limited production and high costs. Non-saffron plant material is coloured with synthetic dyes to produce counterfeit saffron. Continuous monitoring of the synthetic dyes used in counterfeit saffron is essential because some dyes are not safe for human consumption. In the present study, 104 commercial saffron samples from 16 countries were screened, and 20 samples were found to contain dyes. Thin-Layer Chromatography (TLC) analysis showed adulteration with magenta- and pink- coloured dyes (18 and 2 samples, respectively), which did not correspond to any of the dyes reported earlier. Mass spectrometry analysis identified the magenta-coloured dye as magenta III or new fuchsin and the pink-coloured dye as rhodamine B. Magenta III is regarded as possibly carcinogenic, and rhodamine B was reported to cause local sarcomas. Both of these synthetic dyes are reported as adulterants in saffron for the first time.


Assuntos
Cromatografia em Camada Delgada , Corantes/análise , Rodaminas/análise , Corantes de Rosanilina/análise , Especiarias/análise , Cromatografia Líquida de Alta Pressão , Crocus/química , Crocus/metabolismo , Contaminação de Alimentos/análise , Humanos , Espectrometria de Massas por Ionização por Electrospray
13.
Food Chem ; 309: 125745, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31678670

RESUMO

Simultaneous determination of multiclass illegal dyes possessing different chemical properties is difficult. By using LC-MS/MS via negative/positive ion switching mode, an efficient and fast multi-residual method for simultaneous determination of multiclass 52 illegal dyes with different acidic-basic properties in foodstuffs was developed and validated during one single run, including 23 fat-soluble neutral azo dyes, 8 acidic sulfonated azo dyes, 12 triphenylmethane basic dyes, three basic indole dyes, three xanthene dyes, one quinoline dye, and two anthraquinones dyes. The illegal dyes were extracted with methanol-acetonitrile and further purified with d-SPE procedure to reduce interference. Sample dilution with 100-fold was used for the elimination of matrix effects of the quantitation of LC-MS/MS analysis. Validation data showed the good recoveries in the range of 71.2-111.2%, with relative standard deviations less than 20%, suggesting the developed method is suitable for the identification and quantitation of multiclass illegal dyes at trace levels in foods.


Assuntos
Cromatografia Líquida/métodos , Corantes/análise , Contaminação de Alimentos/análise , Espectrometria de Massas em Tandem/métodos
14.
Food Chem ; 311: 125924, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31865112

RESUMO

LC-MS/MS method was developed for the efficient identification and quantification of 21 banned substances including various nitroimidazoles, nitrofurans, pharmacologically-active dyes and chloramphenicol, respectively in aquaculture products. The sample preparation was started by acid-treatment with 2-nitrobenzaldehyde (NBA) to liberate matrix-bound residues of nitrofurans. A modified QuEChERS method was optimized for the extraction and clean-up of the target analytes. The metabolites of the four conventional nitrofurans (nitrofurantoin, furazolidone, nitrofurazone and furaltadone) and of three other nitrofurans (nifursol, nifuroxazide, and nitrovin), and an underivatizable nitrofuran (nifurpirinol) were simultaneously detected. Furthermore, 21 banned substances were quantified by LC-MS/MS with ESI using one single injection. To evaluate and validate the performance of the method, the criteria of the Decision (EC) no 2002/657 were applied. Decision limit (CCα) of target analytes ranged 0.067-1.655 µg/kg in aquaculture products. The recovery ranged 77.2%-125.6%, and the relative standard deviations of inter-day analyses (RSD) were less than 25%.


Assuntos
Antibacterianos/análise , Cloranfenicol/análise , Cromatografia Líquida/métodos , Corantes/análise , Nitroimidazóis/análise , Espectrometria de Massas em Tandem/métodos , Animais , Aquicultura , Resíduos de Drogas/análise , Peixes/crescimento & desenvolvimento , Contaminação de Alimentos/análise , Furazolidona/análise
15.
Chemosphere ; 240: 124940, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31574446

RESUMO

Charged ultrafiltration (UF) membranes can repel electrically charged molecules that are smaller than the size of the membrane pores and display high rejection of solutes, high flux, and low operation pressures compared to uncharged UF, nanofiltration (NF) and reverse osmosis (RO). Here, a charged UF membrane composite (PANI/PVDF) was prepared and regulated via electrochemically reversible control in portions of amine/imine functional groups of PANI. As a result, the permeability and rejection ratios of CR2- on charged PANI/PVDF, with PVDF as a control, increased from 19.6 to a maximum of 183.3 L m-2 h-1 bar-1 and from 3.4% to 74%, which expands the trade-off confine benefited from surface potential change from -12.21 mV to -25.26 mV, furtherly, the rejection ratio of CR2- on PANI/PVDF reached up to 93% via the electrochemical regulation. Finally, a fixed-charge model was built that well describes the steric and electric repulsion effects on membrane performance and the important roles of the electrochemically controllable surface charge. Moreover, the contour map of rejection ratios containing the ratio of molecular size vs the average pore size of the membrane (r/R = 0.2-1.0) and the zeta potential (-10 to -60 mV) were taken into account, which can be used to visually understand the rejection performance of membranes. This model is also appropriate for varying molecular sizes and for molecules with different charges. Our work opens a new horizon for the design of electrochemically controllable charged membranes to remove charged compounds.


Assuntos
Corantes/análise , Técnicas Eletroquímicas/métodos , Ultrafiltração/métodos , Purificação da Água/métodos , Eletricidade , Membranas Artificiais , Propriedades de Superfície
16.
Chemosphere ; 238: 124692, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31545214

RESUMO

Diatomaceous earth or diatom (DE) are naturally available and low cost micro particles with distinct porous structure were used as an adsorbent for the removal of a hazardous dye, Eriochrome Black T (EBT). The surface modification of these DE were performed by sol-gel and hydrothermal methods to obtain a series of adsorbents such as diatom-ceria (DC), diatom-silica xerogel (DX), and diatom-silica xerogel-ceria (DXC). A cauliflower like morphology structure of ceria was observed on DE and DX. The adsorption performance of EBT was conducted by varying various parameters such as pH, adsorbent dosage, initial concentration, contact time and ionic strength. The materials DE, DC, DX and DXC showed the EBT removal efficiencies of 52, 77, 20, and 93%, respectively. The maximum adsorption capacity (qm) of DE, DC, DX and DXC was found to be 13.83, 23.64, 0.2 and 47.02 mgg-1 for the adsorption of EBT, respectively. The selectivity of EBT towards DXC was evaluated by treating a mixture of anionic dyes. The dye removal experiments was performed in presence of inorganic salts, however the presence of these salts did not affect the removal efficiency of DXC. Furthermore, the reusability of DXC was studied by recycling it up to 5 times and even at 5th cycle a removal efficiency of ∼66.8% was found. Thus, these studies demonstrate that the DXC material could be a promising candidate for the removal of EBT via adsorption for real time application in water treatment.


Assuntos
Compostos Azo/análise , Corantes/análise , Terra de Diatomáceas/metabolismo , Diatomáceas/metabolismo , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Porosidade , Reciclagem , Sílica Gel/química
17.
Environ Res ; 179(Pt B): 108837, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31678732

RESUMO

Waste from biomass was used to prepare a low-cost biochar-clay hybrid adsorbent. The hybrid adsorbent was synthesised by combining Kaolin with biomass (Vitex doniana), thereafter, modified with Deep Eutectic Solvent (DES). The materials were characterised using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), Thermal gravimetric analysis (TGA), and Brunauer-Emmett-Teller (BET), also, pHpzc of the materials were studied. The resultant adsorbents were used for both column and batch adsorption of organic pollutants; dye (Acid Blue 74; AB74) and pharmaceuticals (ciprofloxacin; CIP and acetaminophen; ACTE). Column adsorption capacity, effect of pollutant concentration and effect of flow rate were studied, also, the column was modelled using Thomas, Yoon-Nelson and Adams-Bohart model. Furthermore, batch adsorption experiments were performed, effect of change in pH, time, dose and concentration were studied. Batch adsorption data were fitted with isotherm and kinetic models. The experiment showed tremendous increase in adsorption capacity when the hybrid adsorbent (HYD) was modified with DES (HYD-DES). Acid Blue 74 on HYD-DES has the highest column sorption capacity followed by ciprofloxacin and acetaminophen. Adsorption was favoured at pH range of 2-10 for both AB74 and ACTE as there is no significant changes in the % removal performance, while adsorption was best at pH 6 and above for CIP. AB74 and CIP are best described by Langmuir isotherm, whereas ACTE adsorption was best explained by Freundlich isotherm equilibrium. The DES modified HYD has shown it can be effectively utilised as possible adsorbent for adsorbing organic dyes and pharmaceuticals.


Assuntos
Corantes/química , Poluentes Químicos da Água/química , Adsorção , Carvão Vegetal/química , Corantes/análise , Concentração de Íons de Hidrogênio , Cinética , Solventes/química , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/análise
18.
Molecules ; 24(20)2019 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-31635425

RESUMO

When the imagination conjures up an image of an Egyptian mummy, it is normally one of a human body wrapped with undyed linen bandages. However, the reality was much more colourful, as shown by the set of red mummy shrouds and textile fragments from Pharaonic Egypt considered in this work. The textiles were subjected to scientific investigation with the main aim of shedding light on the sources of red colour and on the possible reasons for the different levels of colour fading. The red colourants were investigated using various non-invasive and micro-invasive approaches. The results pointed towards the presence of three sources of red colour, which, in increasing order of lightfastness, are safflower (Carthamus tinctorius), madder (Rubia spp.), and red ochre. Micro-morphological observations and elemental analyses also enabled some hypotheses to be formulated regarding the application of these colourants to the textiles. The results not only deepen our knowledge of dyeing technologies in ancient Egypt and shed new light on the function of red shrouds and textiles as part of the funerary practices of Pharaonic Egypt, but are also essential in planning the display and future preservation of these mummies and their associated textiles.


Assuntos
Carthamus tinctorius/química , Corantes/análise , Rubia/química , Têxteis/história , Argila/química , Corantes/classificação , Antigo Egito , História Antiga , Humanos , Múmias , Têxteis/análise
19.
Anal Chim Acta ; 1090: 106-113, 2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31655635

RESUMO

Rising concern about the use of non-permitted colourants, in common food items such as dals and green vegetables sold in Indian markets, have led to a demand for low-cost point-of-use chemical analysis tools. Conventional food-analysis techniques involving tedious sample preparation protocols are not suited for in-field applications. Surface Enhanced Raman Spectroscopy (SERS) is an analytical technique that is well-suited for point-of-use chemical analysis with molecular level detection capability, which can also serve as a quality assurance tool for businesses. Effective and rapid signal collection from a large-area sample within a field-setting using disposable, low-cost SERS substrates is a key challenge in implementing such a solution. Herein, we demonstrate the use of inkjet-printed thin films comprising of robust nanostructured-silver as flexible, paper-based SERS (P-SERS) swabs for the direct detection of Metanil Yellow (MY) from toor dal (yellow split pigeon peas) samples and Malachite Green (MG) from green peas and green chillies. The macroscopic uniformity of these thin-films in combination with a portable Raman spectrometer equipped with orbital raster scanning (ORS™) technology for signal collection results in an unprecedented precision (RSD ∼ 1.6%) upon characterizing samples saturated with Rhodamine-6G (R6G), a standard Raman probe. As several food-cleansing products have appeared in the marketplace, the adulterant removal efficacy of some commercially available 'washes' as well as products such as 'ozoniser', which was determined by SERS characterization of swabs before and after use, is also reported.


Assuntos
Compostos Azo/análise , Corantes/análise , Contaminação de Alimentos/análise , Papel , Rodaminas/análise , Corantes de Rosanilina/análise , Capsicum/química , Nanoestruturas/química , Ervilhas/química , Prata/química , Análise Espectral Raman/instrumentação , Análise Espectral Raman/métodos , Verduras/química
20.
Artigo em Inglês | MEDLINE | ID: mdl-31535956

RESUMO

Non-destructive, simple and fast techniques for identifying authentic palm oil and those adulterated with Sudan dyes using portable NIR spectroscopy would be very beneficial to West Africa countries and the world at large. In this study, a portable NIR spectroscopy coupled with multivariate models were developed for detecting palm oil adulteration. A total of 520 samples of palm oil were used comprising; 40 authentic samples together with 480 adulterated samples containing Sudan dyes (I, II, III, IV of 120 samples each). Multiplicative scatter correction (MSC) preprocessing technique plus Principal component analysis (PCA) was used to extract relevant spectral information which gave visible cluster trends for authentic samples and adulterated ones. The performance of Linear discriminant analysis (LDA) and Support vector machine (SVM) were compared, and SVM showed superiority over LDA. The optimised results by cross-validation revealed that MSC-PCA + SVM gave an identification rate above 95% for both calibration and prediction sets. The overall results show that portable NIR spectroscopy together with MSC-PCA + SVM model could be used successfully to identify authentic palm oils from adulterated ones. This would be useful for quality control officers and consumers to manage and control Sudan dyes adulteration in red palm oil.


Assuntos
Compostos Azo/análise , Corantes/análise , Contaminação de Medicamentos , Contaminação de Alimentos/análise , Naftóis/análise , Óleo de Palmeira/química , Espectroscopia de Luz Próxima ao Infravermelho
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