Affinity Of Dye Research Articles

Green Nanocomposite for the Adsorption of Toxic Dyes Removal from Colored Waters

The discharge of dyes from textile industries led to a broad range of toxicological and environmental effects, posing severe health issues for humans and animals worldwide. These dyes are highly stable and, if not adequately treated, remain in the environment for extended periods. Adsorption, the most efficient and cost-effective method, offers unique advantages for using natural adsorbents, such as marble waste composites, for dye removal. The easy availability of marble waste, its low cost, its eco-friendly nature, its ease of operation, its simplicity of design, its flexibility, and its great affinity for dyes make it a suitable option for dye removal. Golden marble waste nanocomposites are prepared for dye removal. The results from the studies suggested that treated golden marble composite materials exhibit better adsorption efficiency (224.8, 299.5, and 369.2 mg/g) for adsorptive removal of dyes than untreated golden marble composite materials (114.4 mg/g). This research also used isothermic and kinetic models to evaluate the effects of numerous parameters, for example, the initial dye concentration, pH, time, temperature, and adsorbent dose. The highest removal of 369.9 mg/g was achieved during the present study for blue dye at an optimized pH of 7 and a temperature of 30 °C. It was observed that golden marble waste composites gave better R2 (0.99) values for second-order kinetics in the kinetic model. Results obtained from comparing Langmuir, Freundlich, Temkin, Dubinin, and Herkin Jura isotherms showed that the R2 values of the Langmuir isotherm for Foron red (0.97), the Temkin isotherm for Foron blue (0.98), and the Freundlich isotherm for Foron black dye (0.97) fit on adsorption for both treated and untreated composites. Characterization techniques, such as scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), are also discussed for the structural determination of golden marble waste composites.

Monte Carlo technique to study the adsorption affinity of azo dyes by applying new statistical criteria of the predictive potential

ABSTRACT Azo dyes are broadly used in different industries through their chemical stability and ease of synthesis. However, these dyes are usually identified as critical environmental pollutants. Hence, a mathematical model for the adsorption affinity of azo dyes can be applied for solving tasks of medicine and ecology. Quantitative structure-property relationships for the adsorption affinity of azo dyes to a substrate (DAF, kJ/mol) were established using the Monte Carlo method by generating optimal SMILES-based descriptors. The index of ideality of correlation (IIC) and the correlation intensity index (CII) improved the model’s predictive potential, especially when they were used simultaneously. The statistical quality of the best model on the validation set was characterized by n = 18, r 2 = 0.9468, and RMSE = 1.26 kJ/mol.

Natural dyeing of cellulose fibers using syzygium cumini fruit extracts and a bio-mordant: A step toward sustainable dyeing

Increasing environmental awareness has led to a growing interest in natural dyes in the textile dyeing industry as the consumers become more aware of the toxicity of synthetic dyes that are harmful to the environment and health. Although natural dyes are environmentally friendly compared to synthetic dyes, in general their performance is less than that synthetic dyes. Typically, metallic mordants are used to enhance the affinity of natural dyes to textile materials, perhaps this process breaks the journey of the green story. In this work, we perform the potential alternative for the metal mordant and used soy protein as bio-mordant for dyeing cotton fabric with a natural dye extracted from Syzygium cumini fruits. Sonochemical mordanting and dyeing were examined compared with the conventional water bath. In the experiments, characteristics such as ultrasonic power, temperature, pH, dyeing duration, and dye concentration were examined during the dyeing process. FT-IR, color measurements, washing, crocking, and light fastness tests were used to monitor the effects of the bio-mordant in both conventional and ultrasonic baths. Overall, the sonochemical-assisted dyeing was shown considerably increase the dye absorption and K/S values as compared to the conventional bath. Experiments in this work yield valuable insights into the development of green routes toward the utilization of natural dyes and bio-mordants on natural cellulose-based materials. Using the soy protein mordanted and Syzygium cumini colored fabrics as a comparison, it was found that the sonic dyeing method costs 9.56 €/kg while conventional dyeing methods cost 9.91 €/kg, as the sonicated dyeing method required less cost (i.e., € 0.35) than the conventional bath techniques, nevertheless, sonicated produce darker color than the conventional method. Meanwhile, the cost for dyeing with metal mordant is increased as it severely required a wastewater treatment plant (WWTP). More than that, metal mordant is not a sustainable choice.

Efficient delivery of abciximab using mesoporous silica nanoparticles: In-vitro assessment for targeted and improved antithrombotic activity

Abciximab (ABX) is a chimeric monoclonal antibody reported for antithrombotic activity but their delivery remains challenging due to its poor stability in a biological system. The purpose of this research was to deliver ABX on the target efficiently using mesoporous silica nanoparticles (MSN). ABX coated mesoporous silica nanoparticles (MSN-ABX) were formulated and analyzed for particle size, shape, zeta-potential, surface morphology and surface chemistry. XPS analysis confirmed the presence of ABX on the surface of amino functionalized mesoporous silica nanoparticles (MSN-NH2). The degree of ABX attachment was 67.53 ± 5.81 % which was demonstrated by the Bradford assay. Furthermore, the targeting efficiency of the targeted nanoparticles has been evaluated by capturing the fluorescent images in-vitro which showed the significant accumulation of the ABX coated nanoparticles towards activated platelets. The significant (P < 0.05) increase in affinity of DiD dye loaded nanoparticles towards the activated platelets was confirmed by using an in-vitro imaging through photon imager optima. The hemolysis study of the nanoparticle formulations revealed that they were non-hemolytic for healthy human blood. The in-vitro antithrombotic effects of MSN-ABX were observed by blood clot assay which revealed its superior antithrombotic activity over clinical injection of ABX and could be a promising carrier for improved ABX targeted delivery.

Mechanisms of Selected Anionic Dye Removal by Clinoptilolite

The extensive use of color dyes in modern society has resulted in serious concerns of water contamination. Many organic dyes bear charges; thus, materials of opposite charges have been tested for sorptive removal. However, the results from several studies also showed that anionic dyes methyl orange (MO) and alizarin red S (ARS) could be removed from water using minerals of negative charges, but the mechanisms were not addressed. In this study, negatively charged clinoptilolite was tested for its removal of anionic dyes MO and ARS from water under different physico-chemical conditions and to investigate the mechanism of Mo and ARS removal. The sorption capacities were 166 and 92 mmol/kg for MO and ARS, respectively, confirming the uptake of anionic dyes on negatively charged framework silicates. The influence of solution pH and ionic strength on MO removal was minimal, indicating the strong affinity of anionic dyes for clinoptilolite in comparison to other inorganic species. It was speculated that the N in the dimethyl group may bear a partial positive charge, which may have a net electrostatic attraction to the negatively charged mineral surfaces for MO sorption. For ARS, sorption may involve hydrogen bonding formation between the dye and the clinoptilolite. Moreover, under the experimental conditions, the MO molecules form dimers in solution via dimeric π-π interactions. Thus, the sorption of the dimers or aggregation of the MO monomers and dimers on clinoptilolite surface was attributed to additional MO removal, as suggested by molecular dynamic simulations. The speculation was supported by FTIR analyses and molecular dynamic simulations. As such, negatively charged Earth materials may be used as sorbents for the removal of certain anionic dyes via sorption, a new perspective for the innovative use of Earth materials.

Teaching Color‐Deficient Medical and Dental Students in Histology: Developing Best Practices and Strategies for Student Success

Introduction &amp; Objective– Histology as a discipline requires the use of a variety of staining methods to highlight and visualize normal components of cells and tissues. For students with a color deficiency, they may be unable to perceive, or distinguish between, certain colours that are commonly used in histological preparations. Considering many cells are named based on their affinity for certain histological dyes (ex: eosinophils), this can make learning histology difficult for students who cannot identify cells or tissues based on their colour appearance. From an instructor perspective, teaching students with a color deficiency can be challenging without having an established plan, or strategies, to ensure that these students can fully participate and succeed in their coursework. The objective of this study is to outline several successful strategies and recommendations for histology instructors when teaching students with a color deficiency. These strategies are based on recent experiences in teaching students with a color deficiency in medical and dental histology courses.Materials and Methods– In the fall of 2021 at the University of Buffalo, several students in the Jacobs School of Medicine and the School of Dental Medicine required accommodations in their histology courses due to a recognized color deficiency. Both histology courses used a flipped‐classroom approach with pre‐recorded lectures. To accommodate these students, a greyscale strategy was used, in which, all color images were paired with an identical greyscale image in all computer‐based histology laboratories and examinations. Students had the option of viewing the pre‐recorded histology lectures in greyscale by adjusting their computer monitor settings. All color‐deficient students successfully completed their courses using the greyscale strategy.Results –The following are instructor recommendations for teaching students with color deficiency based on course experiences in the fall of 2021: 1) The instructor should address color deficiency in the histology course syllabus and course introduction to establish that a plan is available for students; 2) Although images were provided in both color and greyscale, instructors should provide further training for students to successfully interpret the cellular morphology in greyscale. For example, recognition of peripheral blood leukocytes in greyscale required analysis of both nuclear morphology (shape, texture) and the properties (size, shape, density) of their specific granules; 3) Instructors should teach the entire class using the paired color/greyscale images to create an inclusive learning environment. The greyscale images provided a different perspective of the cell and tissue morphology that was beneficial for all students; 4) The greyscale images used in all coursework should be scrutinized by the instructor as they may require adjustments in brightness and contrast.Conclusion –By incorporating greyscale images into histology coursework, all students can fully participate irrespective of the severity of color deficiency of individual students in the class. These recommendations may provide a useful framework in assisting histology teaching faculty in designing coursework for color‐deficient students.

Salts and water‐free dyeing of cellulose nanofibers using novel green deep eutectic solvents: Isotherm, kinetics, and thermodynamic studies

AbstractRecently, dyeing of cellulose nanofibers (CNF) has gained substantial interest due to its multifunctional properties, but discharge of hazardous effluent containing salts are biggest challenges for sustainability for textile processing sectors. Herein, we report deep eutectic solvents (DES) as a novel green dyeing medium to dye CNF with anionic reactive dyes (without salts) for the first time and dyeing parameters were optimized. Dyed CNF in DES showed 37% higher color yield compared to CNF dyed in conventional dyeing medium (with auxiliaries). The diffusion and standard affinity of both reactive dyes towards CNF in DES medium were greater than conventional (CN) medium. CNF dyed in DES revealed smooth morphology and the presence of reactive dyes confirmed by FTIR, it also offers enhanced wettability, and good color fastness properties. Therefore, DES can potentially be utilized as an effective dyeing medium.

Effect of the enantiomeric structure of hydrophobic polymers on the encapsulation properties of a second near infrared (NIR-II) fluorescent dye for in vivo deep imaging.

Over-thousand-nanometer (OTN) near-infrared (NIR) fluorophores are useful for biological deep imaging because of the reduced absorption and scattering of OTN-NIR light in biological tissues. IR-1061, an OTN-NIR fluorescent dye, has a hydrophobic and cationic backbone in its molecular structure, and a non-polar counter ion, BF4−. Because of its hydrophobicity, IR-1061 needs to be encapsulated in a hydrophobic microenvironment, such as a hydrophobic core of polymer micelles, shielded with a hydrophilic shell for bioimaging applications. Previous studies have shown that the affinity of dyes with hydrophobic core polymers is dependent on the polarity of the core polymer, and that this characteristic is important for designing dye-encapsulated micelles to be used in bioimaging. In this study, the dye–polymer affinity was investigated using hydrophobic polymer films with different chiral structures of poly(lactic acid). IR-1061 showed higher affinity for l- and d-lactic acid copolymers (i.e., poly(dl-lactic acid) (PDLLA)) than to poly(l-lactic acid) (PLLA), as IR-1061 shows less dimerization in PDLLA than in PLLA. In contrast, the stability of IR-1061 in PDLLA was less than that in PLLA due to the influence of hydroxyl groups. Choosing hydrophobic core polymers for their robustness and dye affinity is an effective strategy to prepare OTN-NIR fluorescent probes for in vivo deep imaging.

Coating layered double hydroxides with carbon dots for highly efficient removal of multiple dyes

Layered double hydroxides (LDHs) and layered double oxides (LDOs) are desirable adsorption materials for printing and wastewater treatment owing to their outstanding anion exchange abilities, abundant active sites, and eco-friendly nature. In this study, a versatile LDO hybrid coated with carbon dots (CDs@MgAl-LDO) was constructed by modifying sodium dodecylbenzene sulfonate on the surface of MgAl-LDH as a carbon precursor, followed by ligand carbonization and hydrotalcite dehydration at 450 °C under N2 flow. CDs@MgAl-LDO displayed a hexagonal lamellar architecture with a plate lateral size of approximately 500 nm. It had a higher BET specific surface area (28.61 m2/g) than MgAl-LDO (11.48 m2/g). X-ray diffraction analysis revealed that CDs@MgAl-LDO maintained the “memory effect” of LDOs and could retrieve the original structure when dispersed in water. Moreover, the modified carbon dots change the intrinsically hydrophilic nature of LDOs and help to improve the affinity for organic contaminants, including both cationic and anionic dyes. The adsorption of dyes on CDs@MgAl-LDO followed a pseudo-second-order kinetic model with correlation coefficients (R2) ranging from 0.9901 to 0.9911 and exhibited Freundlich-type heterogeneous adsorption. It showed superior adsorption performance for three dyes, with the maximum adsorption capacity of 3628.9–5174.1 mg/g, thereby outperforming previously reported LDH-based adsorbents. This work developed a facile approach for preparing new carbon dots-LDH hybrids for the highly efficient removal of multiple dyes.

Preparation of cationic cotton through reaction with different polyelectrolytes.

Cationization of cotton fabrics was performed by exhaustion procedure utilizing four different reagents provided with quaternary ammonium groups: poly diallyldimethylammonium chloride (PDDACl), poly acrylamide-co-diallyldimethylammonium chloride (PAcD), poly[bis(2-chloroethyl) ether-alt-1,3-bis[3-(dimethylamino)propyl]urea] quaternized (P42) and 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTAC). Pretreated samples were dyed using Reactive Red 195 dye. The cationic fabrics were analyzed by colorimetric and fastness properties, zeta potential, SEM, FTIR and an estimate of the bactericidal effect. Cationic cotton treated with PDDACl and CHPTAC showed a higher affinity for the reactive dye, with color strength (K/S) values varying from 41 to 48, against 32 for conventional dyeing. P42 presented competitive results with K/S of 27–28. The cationic dyeing considerably reduced the amount of effluent, especially for the CHPTAC samples, which requires a single washing bath for complete removal of unfixed dye. The PDDACl and P42 samples presented bactericidal activity.Graphic abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s10570-021-04260-4.

A New Function for Amyloid-Like Interactions: Cross-Beta Aggregates of Adhesins form Cell-to-Cell Bonds.

Amyloid structures assemble through a repeating type of bonding called “cross-β”, in which identical sequences in many protein molecules form β-sheets that interdigitate through side chain interactions. We review the structural characteristics of such bonds. Single cell force microscopy (SCFM) shows that yeast expressing Als5 adhesin from Candida albicans demonstrate the empirical characteristics of cross-β interactions. These properties include affinity for amyloid-binding dyes, birefringence, critical concentration dependence, repeating structure, and inhibition by anti-amyloid agents. We present a model for how cross-β bonds form in trans between two adhering cells. These characteristics also apply to other fungal adhesins, so the mechanism appears to be an example of a new type of cell–cell adhesion.

Polypyrrole-functionalized magnetic Bi2MoO6 nanocomposites as a fast, efficient and reusable adsorbent for removal of ketoprofen and indomethacin from aqueous solution

Pharmaceutical and personal care products (PPCPs) as emerging organic pollutants have received widespread attention. A novel composite adsorbent was successfully prepared through the modification of polypyrrole (PPy) onto the surface of magnetic Bi2MoO6 (MnFe2O4/Bi2MoO6/PPy) and acted as excellent adsorbent to remove organic compounds from aqueous solution. The adsorbent was characterized by SEM, TEM, FT-IR, XRD, BET, VSM, XPS and PES. The resulting composites combined the advantages of all three parts and possessed porous structure and magnetic properties, which showed excellent adsorption performance for ketoprofen (KET) and indomethacin (IDM), as evidenced by 87.03% and 86.24% of removal in just 120 min at initial concentration of 10 mg/L, respectively. The adsorption processes of MnFe2O4/Bi2MoO6/PPy for PPCPs were well fitted with the pseudo-second order kinetic model and described better by Langmuir isotherm model. The possible adsorption mechanisms of KET and IDM by MnFe2O4/Bi2MoO6/PPy were provided. Additionally, the effect of other coexisting substances was also explored using Cu2+ as a model. Moreover, the adsorption performances were further studied to remove several dyes, in which showed superior affinity for anionic dyes. In practical application, it had almost equal removal capacity for KET both in the Yellow River water and sewage treatment plant inlet water.

Molecular dynamic simulations and quantum chemical calculations of adsorption process using amino-functionalized silica

Present study focused on the adsorption behavior of two cationic dyes (Neutral Red (NR) and Rhodamine B (RB)) on mesoporous silica (MPS) and amino-functionalized MPS with N1-(3-Trimethoxysilylpropyl) diethylenetriamine linker (TAF/MPS). In order to provide more details about adsorption mechanism of dyes on the adsorbents surface, the molecular dynamics (MD) simulations were employed. A very promising simulation approach for adsorption of NR and RB dyes by functionalized and bare MPS adsorbents were obtained by MD results. The obtained results of quantum chemical calculations confirmed the highest adsorption energy for TAF/MPS-water-RB configurations, while the MPS-water-NR had the lowest adsorption energy. According to the results, functionalization of MPS with amino groups led to improvement in adsorption affinity of both dyes. The Sigma profiles demonstrated higher RB adsorption on both adsorbent while lower HOMO–LUMO energy gap was observed for RB dye compared to NR dye. Based on the energies of the HOMO and LUMO, other quantum chemical descriptors were calculated for different dyes, water and adsorbent configurations. These descriptors include: hardness (η), softness (σ), chemical potential (μ), nucleophilicity (ɛ) and electrophilicity index (ω). It was observed that the chemical reactivity, softness, and polarizability of RB dye were more than that of NR dye. The results of this study provide deeper atomic/molecular understanding into the adsorption mechanism of dye molecules on adsorbent surface which could help to get new insights about interactions of molecules. Moreover, MD simulation can be a very useful approach in term of cost-efficient and time saving for predicting the adsorption behavior of structures.

High structural stability of colored carbon fiber cloths modified by FeOOH

Coloring carbon fiber has always been a challenge due to its inherent high crystallinity and insufficient affinity for chemical dyes. Herein, multicolored carbon fiber cloths were simply fabricated using an eco-friendly one-step hydrothermal method. The bright colors of the carbon fiber cloth were easily controlled by adjusting the hydrothermal temperature to change the size of FeOOH particle grown on the surface of carbon fiber. Impressively, the cloths have excellent structural stability and can withstand laundering under acidic and basic conditions, light irradiation, plasma etching and mechanical rubbing. In addition, considering such impressive characteristics as well as reflection spectra in the visible and near-infrared regions, the above colored carbon fibers were used as the new candidate of photothermal deicing, demonstrating a superior temperature increasement up to ~16 °C with respect to the control sample.

Preparation of Magnetic Composite Polyaniline/Fe3O4−Hydrotalcite and Performance in Removal of Methyl Orange

Magnetic composite fabricated from polyaniline and Fe3O4-hydrotalcite (Pan/MHT) was successfully applicated for removal of methyl orange (MO) from wastewater. The structure and properties of Pan/MHT were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, vibrating sample magnetometer, and Brunauer-Emmett-Teller adsorption isotherm. Adsorption kinetic results indicated that the adsorption process followed pseudosecond-order kinetic model ([Formula: see text]), MO adsorption onto Pan/MHT was well described by Freundlich isotherm ([Formula: see text]), and the MO adsorption capacity of 2 Pan/MHT obtained the highest with [Formula: see text]. Batch adsorption experiments were carried out using magnetic composite with the effects of initial MO concentration, solution pH, and adsorbent dosage. The results revealed that the magnetic Pan/MHT exhibited efficient adsorption of MO in the aqueous solution as a result of the affinity for organic dyes, microporous structure, and suitable surface area for adsorption (15,460 m2/g). The superparamagnetic behavior of Pan/MHT (with[Formula: see text], [Formula: see text], and[Formula: see text]) helps that it could be separated from the solution and performs as an economical and alternative adsorbent to removal and degrade azo dye from wastewater. Pan/MHT was also investigated to reuse after desorption of MO in 0.1 M HCl, and the results show that 2 Pan/MHT can be reused for 4 cycles with [Formula: see text]

Studija o snazi monofunkcionalnih reaktivnih boja - uticaj jonske jačine rastvora na obojenost pamučne tkanine

Reactive dyes are the most popular dyes for dyeing cellulose fibers. The low affinity of dyes on cotton determines the presence of large amounts of electrolytes and additional substances in the dyeing bath. In recent years, methods for increased use of dyes with minimal consumption of chemicals and natural resources have been popular. The number of ions formed by the dissociation of electrolytes determines the ionic strength of the solution and has a promotional effect on exhaustion and fixation of reactive dyes. In this work, the influence of neutral salts (NaCl and Na2SO4) and alkali salt (Na2CO3) on the color intensity of cotton fabric by reactive dyes has been investigated. A bath with a higher ionic strength of neutral salt has a greater exhaustion of reactive dyes. The addition of an alkaline electrolyte to activate the chemical dye/fiber reaction has an additional promotional effect on the exhaustion of reactive dyes.

Efficient removal of three dyes using porous covalent triazine frameworks: adsorption mechanism and role of pore distribution.

Dyes are widely used in production and life. In this study, porous covalent triazine frameworks (CTFs) were synthesized and the adsorption behavior for three dyes was investigated by batch adsorption experiments. CTFs were characterized by various spectroscopic techniques for structure, porosity and surface properties. Several possible adsorption mechanisms were proposed including pore-filling, electrostatic attraction and hydrogen bonding interaction with the triazine structure of CTFs. The mechanisms were further verified by the pore size distribution and pH dependence. Additionally, CTFDCBP displayed stronger adsorption affinity and faster adsorption kinetics for dyes, because of the wide pore size distribution. This study provides a new insight into the mesoporous CTFs, which exhibit great potential as an effective adsorbent for dye removal.

The volume of changes in the nerve cells of the intervertebral nodes in the active state

The Nissl method showed that every nerve cell consists of two substances: the main one, which does not stain with this treatment, and the other, interspersed with the first, having a selective affinity for the main aniline dyes. The type, method of distribution in the nerve cell of this chromophilic substance is different depending on the nature of the group to which this nerve cell belongs. Most often, this substance is in the form of grains, differing in an extreme variety of size and shape. This new word in the study of the structure of the nerve cell gave, together with the darkness, a new basis for the study of the issue of changes in the nervous cells in the active state. Thanks to this, a number of studies by authors appeared, such as Hodge, Vas, Mann, Lambert, Lugaro, Levi, Valensa, Magini, whose purpose was to answer the question whether the nerve cells change during activity, and if they change, then what are these changes, which is, consequently, the histological picture of the process of excitation of the nerve cell. To regret, the data, which appeared to answer this question, disagree with each other. In fact, the size of the calm nerve cells, decreasing with irritation, according to Hodge, increases according to Vas and according to Lambert's opinion, they remain without changes. Chromophiles according to Vas and Lambert, moving into an irritated cell to the periphery, according to the opinion of the other authors, do not change their position. The amount of nuclear chromatin increasing along Vas decreases according to Mann. Also contradictory data and volume of changes in the size of the nucleus and nucleolus. Only one thing is that all researchers agree, this is that neither the size nor the number of chromophiles change during the appearance of irritation of the nerve cell. True, Mann says that during rest, various coloring substances accumulate in the cell, which are then consumed during activity, but this indication does not seem to refer to chromophiles, but to the chromatin of the nucleus.

Cleaner colorant extraction and environmentally wool dyeing using oak as eco-friendly mordant.

Textile and dyeing are one of the most significant industries in many states. The employing of natural dyes in dyeing procedure is very important due to the environmental security of the area. To obtain a green, clean, and environmentally friendly dyeing of yarns, two natural dyes of madder and weld, which are native to Iran, were employed for dyeing yarns for carpet preparation. Due to the low affinity of natural dyes and maintaining the biocompatibility of the dyeing process, the oak was used as a new tannin rich mordant. The ultrasound-microwave-assisted method in water solution was used for extraction, and yield to the process was obtained about 27, 32, and 36% for madder, weld, and oak, respectively. The extractions were analyzed by UV-Visible and SEM techniques, and the ash, humidity, and density properties of these were investigated. The pre-mordanting method was employed for this study, and ferrous sulphate was used for compare of natural mordant performance. The washed, mordanted, and dyed yarns were investigated by analytical techniques, and the accuracy of these processes was confirmed. The fastness properties as well as the colorimetric characteristics of dyed yarns were assessed using related standards, and the dyed yarns have acceptable performance and could compete with metal mordant, colorimetrically.

Enhancement of the adsorption properties of two natural bentonites by ion exchange: equilibrium, kinetics and thermodynamic study

ABSTRACTIn this investigation, Maghnia (Ma) and Mostaganem (Ms) bentonite clays, mined from west Algeria, with no prior affinity for anionic dyes, were modified by simple ion exchange with aqueous Fe3+ solutions, followed by calcination at 500°C. The resulting materials, Fe-Ma and Fe-Ms, respectively, were employed as adsorbents for methyl orange. The starting materials and the two adsorbents were characterized by X-ray diffraction, N2 adsorption–desorption isotherms, Brunauer–Emmett–Teller specific surface area and X-ray fluorescence and by determining the point of zero charge. The effects of various variables, such as initial dye concentration, contact time, adsorbent dose, initial pH and adsorption temperature, were studied. The kinetics were well described by the pseudo-second-order model and the mechanism was determined from the intraparticle diffusion model, while corresponding isotherms fitted better to the Freundlich model. Thermodynamic parameters showed that the adsorption process was endothermic, spontaneous and physical in nature, accompanied by an increase of entropy.