A Comparative Study on Characteristics and Antibacterial Capacity of Cotton Fabrics Dyed with Reactive Dye and Diospyros Mollis Extract.

This article focuses on comparing the characteristics of cotton fabric dyed with Diospyros mollis extract (DME) solution and that of cotton fabric dyed with the reactive dye. The parameters of the cotton fabric after dyeing with both types of dyes were assessed, including color strength (K/S), structural morphology, infrared spectrum, antibacterial properties, UV resistance, color fastness to washing, rubbing, light, moisture absorption, breathability, and wastewater indices. The obtained results show that the K/S value of cotton fabric dyed with DME solution is slightly lower than that of cotton fabric dyed with the reactive dye, 18.52 and 19.36, respectively. The cotton fabric dyed with the reactive dye does not exhibit antibacterial activity against Escherichia coli and Staphylococcus aureus, whereas the antibacterial effectiveness against these bacteria for cotton fabric dyed with DME solution is 99.99 %. The UV protection capability of cotton fabric dyed with DME solution is superior to cotton fabric dyed with the reactive dye. The BOD/COD ratio of wastewater from the dyeing process with DME is higher than that of the reactive dye, with values of 0.70 and 0.32, respectively. The findings of this study indicate the superior ability of using DME solution as compared to the reactive dye, which is promising as a natural dye for fabric in medical applications.

Saccharomyces pastorianus Residual Biomass Immobilized in a Polymer Matrix as a Biosorbent for Reactive Dye Removal: Investigations in a Dynamic System.

The use of residual microbial biomass from various industries in emerging pollutant removal strategies represents a new area of research in the field. In this case, we examined how to remove reactive dyes from an aqueous solution utilizing a biosorbent made of residual biomass from immobilized Saccharomyces pastorianus (S. pastorianus) in a polymer matrix using a dynamic system. Fluidized bed column biosorption investigations were carried out on a laboratory scale. Brilliant Red HE-3B was chosen as the target molecule. The main parameters considered for this purpose were the flow rate (4.0 mL/min; 6.1 mL/min), initial pollutant concentration (51.2 mg/L; 77.84 mg/L), and biosorbent mass (16 g; 20 g). The experimental data of the fluidized bed study were evaluated by mathematical modeling. The Yoon-Nelson, Bohart-Adams, Clark, and Yan models were investigated for an appropriate correlation with the experimental data. An acceptable fit was obtained for a flow rate of 4 mL/min, an initial pollutant concentration of 51.2 mg/L, and a biosorbent amount of 20 g. The obtained results indicate that the biosorbent can be used efficiently in a dynamic system both for the removal of the studied dye and in extended operations with a continuous flow of wastewater. As a conclusion, the investigated biocomposite material can be considered a viable biosorbent for testing in the removal of reactive dyes from aqueous environments and creates the necessary conditions for the extension of studies toward the application of these types of biosorbents in the treatment of industrial effluents loaded with organic dyes.

Phytotoxicity and genotoxicity study of reactive red 141 dye on mung bean (Vigna radiata (L.) Wilczek) seedlings.

BACKGROUND: Reactive Red (RR) 141 dye is widely used in various industrial applications, but its environmental impact remains a growing concern. In this study, the phytotoxic and genotoxic effects of RR 141 dye on mung bean seedlings (Vigna radiata (L.) Wilczek) were investigated, serving as a model for potential harm to plant systems. METHODS AND RESULTS: Short-term (14 days) and long-term (60 days) experiments in paddy soil pot culture exposed mung bean seedlings to RR 141 dye. The dye delayed germination and hindered growth, significantly reducing germination percentage and seedling vigor index (SVI) at concentrations of 50 and 100 ml/L. In short-term exposure, plumule and radical lengths dose-dependently decreased, while long-term exposure affected plant length and grain weight, leaving pod-related parameters unaffected. To evaluate genotoxicity, high annealing temperature-random amplified polymorphic DNA (HAT-RAPD) analysis was employed with five RAPD primers having 58-75% GC content. It detected polymorphic band patterns, generating 116 bands (433 to 2857 bp) in plant leaves exposed to the dye. Polymorphisms indicated the appearance/disappearance of DNA bands in both concentrations, with decreased genomic template stability (GTS) values suggesting DNA damage and mutation. CONCLUSION: These findings demonstrate that RR 141 dye has a significant impact on genomic template stability (GTS) and exhibits phytotoxic and genotoxic responses in mung bean seedlings. This research underscores the potential of RR 141 dye to act as a harmful agent within plant model systems, highlighting the need for further assessment of its environmental implications.

Membrane process and adsorption on pine nut shell for removal of dye from synthetic wastewater.

Purification methods such as membrane technology and adsorption have been studied for the purification of textile effluents. This article aimed to evaluate the membrane separation process and adsorption on pine nut shell, separately and sequentially, for reactive dye blue 5G removal from a synthetic effluent. The membrane separation process was carried out in a front filtration module using polymeric membranes. The maximum dye retention was 35.9% using a regenerated cellulose membrane, with agitation and a pressure of 0.5 bar. The permeate flux was fully restored after cleaning the membrane. In the adsorption using pine nut shell, the best results were at pH 2, 50°C, and 50 ppm, with 85% dye removal. The Freundlich isotherm showed the best fit to the data, as did the pseudo-second-order kinetic model. The thermodynamic parameters indicated that the adsorption is of the physical type, with the process being endothermic and spontaneous. In the combined process, the permeate from the membrane separation process was subjected to adsorption on pine nut shell, achieving a removal rate of 98.7 for the initial concentration of 50 ppm. Therefore, this work shows the potential of pine nut shell as an adsorbent, not only to purify textile effluents but also to add value to a waste product, indicating that the combination of membrane technology and adsorption on pine nut shell could be an alternative for the treatment of textile effluents containing the reactive dye 5G blue.

Dyeing with Hydrotalcite Hybrid Nanoclays and Disperse, Basic and Direct Dyes.

Textile effluents are among the most polluting industrial effluents in the world. Textile finishing processes, especially dyeing, discharge large quantities of waste that is difficult to treat, such as dyes. By recovering this material from the water, in addition to cleaning and the possibility of reusing the water, there is the opportunity to reuse this waste as a raw material for dyeing different textile substrates. One of the lines of reuse is the use of hybrid nanoclays obtained from the adsorption of dyes, which allow dye baths to be made for textile substrates. This study analyses how, through the use of the nanoadsorbent hydrotalcite, dyes classified by their charge as anionic, cationic and non-ionic can be adsorbed and recovered for successful reuse in new dye baths. The obtained hybrids were characterised by X-ray diffraction and infrared spectroscopy. In addition, the colour was analysed by spectrophotometer in the UV-VIS range. The dyes made on cotton, polyester and acrylic fabrics are subjected to different colour degradation tests to assess their viability as final products, using reflection spectroscopy to measure the colour attribute before and after the tests, showing results consistent with those of a conventional dye.

Amine-Reactive BODIPY Dye: Spectral Properties and Application for Protein Labeling.

A boron-dipyrromethene (BODIPY) derivative reactive towards amino groups of proteins (NHS-Ph-BODIPY) was synthesized. Spectroscopic and photophysical properties of amine-reactive NHS-Ph-BODIPY and its non-reactive precursor (COOH-Ph-BODIPY) in a number of organic solvents were investigated. Both fluorescent dyes were characterized by green absorption (521-532 nm) and fluorescence (538-552 nm) and medium molar absorption coefficients (46,500-118,500 M-1·cm-1) and fluorescence quantum yields (0.32 - 0.73). Solvent polarizability and dipolarity were found to play a crucial role in solvent effects on COOH-Ph-BODIPY and NHS-Ph-BODIPY absorption and emission bands maxima. Quantum-chemical calculations were used to show why solvent polarizability and dipolarity are important as well as to understand how the nature of the substituent affects spectroscopic properties of the fluorescent dyes. NHS-Ph-BODIPY was used for fluorescent labeling of a number of proteins. Conjugation of NHS-Ph-BODIPY with bovine serum albumin (BSA) resulted in bathochromic shifts of absorption and emission bands and noticeable fluorescence quenching (about 1.5 times). It was demonstrated that the sensitivity of BSA detection with NHS-Ph-BODIPY was up to eight times higher than with Coomassie brilliant blue while the sensitivity of PII-like protein PotN (PotN) detection with NHS-Ph-BODIPY and Coomassie brilliant blue was almost the same. On the basis of the molecular docking results, the most probable binding sites of NHS-Ph-BODIPY in BSA and PotN and the corresponding binding free energies were estimated.

The Optimal Concentration of Nanoclay Hydrotalcite for Recovery of Reactive and Direct Textile Colorants.

Concerns about the health of the planet have grown dramatically, and the dyeing sector of the textile industry is one of the most polluting of all industries. Nanoclays can clean dyeing wastewater using their adsorption capacities. In this study, as a new finding, it was possible to analyze and quantify the amount of metal ions substituted by anionic dyes when adsorbed, and to determine the optimal amount of nanoclay to be used to adsorb all the dye. The tests demonstrated the specific amount of nanoclay that must be used and how to optimize the subsequent processes of separation and processing of the nanoclay. Hydrotalcite was used as the adsorbent material. Direct dyes were used in this research. X-ray diffraction (XRD) patterns allowed the shape recovery of the hydrotalcite to be checked and confirmed the adsorption of the dyes. An FTIR analysis was used to check the presence of characteristic groups of the dyes in the resulting hybrids. The thermogravimetric (TGA) tests corroborated the dye adsorption and the thermal fastness improvement. Total solar reflectance (TSR) showed increased radiation protection for UV-VIS-NIR. Through the work carried out, it has been possible to establish the maximum adsorption point of hydrotalcite.

Preparation of zeolitic imidazolate framework-67/wool fabric and its adsorption capacity for reactive dyes.

Zeolitic imidazolate framework-67 (ZIF-67) formed by Co2+ and 2-methylimidazole (MIM) is widely used for adsorption and separation of pollutants. However, there are some disadvantages for ZIF-67 powder, such as strong electrostatic interaction and difficulty in recovery from the liquid phase. The available way to solve the above problems is choosing a suitable substrate to load ZIF-67. The amino and hydroxyl of wool fabrics effectively capture and fix ZIF-67, making it easy to separate ZIF-67 by taking out the composite materials from aqueous solution. In this study, ZIF-67/Wool fabric (ZW) was successfully prepared. The results show that ZIF-67 has better adsorption performance for reactive dyes with more sulfonic groups, higher molecular weight and lower steric resistance. The equilibrium adsorption capacity of ZW for reactive red 195 was 4.15 mg g-1. The adsorption accorded with pseudo-second-order kinetic model and Langmuir isotherm. This study improved the application of ZIF-67, which provided a treatment method for dyeing wastewater and made it possible to recycle waste wool.

A systematic study of cellulose-reactive anionic dye removal using a sustainable bioadsorbent.

Cellulose-reactive anionic dyes are one of the dominant colorants used in textile finishing. Unfortunately, they also produce large quantities of wastewater that must be treated before discharge, demanding low-cost and sustainable adsorbents that can easily be implemented, especially for developing countries with thriving cotton-based textile sectors. In this study, a high specific surface area (670 m2/g) water hyacinth root powder (WHRP) bioadsorbent that is neither carbonized nor activated was prepared to remove cellulose-reactive anionic blue dye from an aqueous solution. The effect of adsorption pH (pH = 2-8), adsorbent dose (1 g/L-6 g/L), dye concentration (50 mg/L-500 mg/L), adsorbent particle size (50 µm-1000 µm), mixing speed (100 rpm -200 rpm), and adsorption temperatures (22 °C-60 °C) were systematically studied. It was found that the protonation of lignin polyphenols in WHRP at pH = 2 was responsible for the observed high (∼99%) adsorptive removal of reactive blue dye. The maximum equilibrium adsorption capacity was 128.8 mg/g when 1 g/L WHRP and 500 mg/L dye concentration were used. In addition, adsorption isotherms, kinetic models, and adsorption thermodynamics were investigated. Increasing adsorbent dose, decreasing adsorbent particle size, increasing mixing speed, and lowering temperature favored the adsorption of reactive dye to WHRP adsorbent. The batch adsorption data were best fitted with both Langmuir and Temkin models, especially at 22 °C, while the adsorption kinetic behavior was described best using pseudo-second-order kinetics. Adsorption of cellulose-reactive blue dye to WHRP was spontaneous as characterized by the negative Gibbs energy (-11 kJ/mol to -24 kJ/mol) and exothermic with negative enthalpy (-13 kJ/mol to -23 kJ/mol). The overall adsorption process was controlled by more than one mechanism since the intraparticle diffusion was not the only rate-limiting step under our experimental conditions. Taken together, the abundantly available and sustainable WHRP is an efficient adsorbent that could be scaled up for treating cellulose-reactive dye-contaminated water.

Role of nanocellulose in colored paper preparation.

Colored paper is an important industrial paper grade that has applications in various industrial sectors. The increase in coloring efficiency is a key in decreasing the use of dyes, thus can be considered as a "green" process concept; the coloring efficiency depends on the dye retention and dispersion. This work explores the use of nanocellulose, specifically, TEMPO-oxidized cellulose nanofibers (TOCNF), on the coloring efficiency of the preparation of colored paper. Two dyes (i.e. direct blue GL and reactive red 195 (RR195)) were used. Thanks to the large specific surface area and abundant active sites of TOCNF, its use largely improves the direct blue GL retention during the process. The coloring difference (∆E*ab) reached 5.334 with the addition of 13.6 wt% TOCNF and 1.8 wt% direct blue GL in the pulp furnish. The functional group in the dye is a vital factor in determining the dye retention when one chooses TOCNF to enhance the coloring efficiency in the production of colored paper. Furthermore, TOCNF significantly improved the strength properties of both direct blue GL and RR 195 dyed papers. This work demonstrates the potential of nanocellulose in the production of colored paper in improving the coloring efficiency, thus decreasing the environmental impact of the manufacturing process.

Biofilm mediated decolorization and degradation of reactive red 170 dye by the bacterial consortium isolated from the dyeing industry wastewater sediments.

Reactive dyes are extensively used in a plethora of industries, which in turn release toxic wastes into the environment. The textile dye waste remediation is crucial as it may contain several toxic elements. The utilization of bacterial consortium for bioremediation has acquired consideration, over the utilization of single strains. In this study, a microbial consortium containing three bacterial sp. (Bacillus subtilis, Brevibacillus borstelensis and Bacillus firmus) was tested for its degrading ability of the textile RR 170 dye. The bacterial consortium degraded the dye effectively at lower concentrations and the efficiency decreased as the dye concentration increased. SEM analysis revealed that, with dye treatment, the consortium appeared as tightly packed clumps with rough cell surface and were able to produce EPS and biofilms. EPS production was higher at 40 mg/l, 100 mg/l and 200 mg/l of the dye treatment conditions. Interestingly, the maximum biofilm formation was observed only at 40 µg/ml of the dye treatment, which indicates that RR 170 dye concentration affects the biofilm formation independent of EPS levels. The UV-vis spectroscopy, HPLC, FTIR and 2D-FTIR analyses confirmed the decolorization and biodegradation of RR 170 dye by the bacterial consortium. Toxicological studies performed with the dye and their degraded products in Allium cepa root cells revealed that, whereas the RR 170 dye induced genotoxic stress, the degraded dye products showed no significant genotoxic effects in root cells. Together, the investigated bacterial consortium decolorized and degraded the RR 170 dye resulting in metabolites that are non-toxic to the living cells.

Microwave-assisted rapid conjugation of horseradish peroxidase-dextran aldehyde with Schiff base reaction and decolorization of Reactive Blue 19.

Microwave irradiation has become a routine technique in homogeneous and effective heating in organic synthesis. However, its application in enzyme-containing reactions is limited since it can cause denaturation of the enzyme. In this study, we have briefly investigated the effect of microwave heating on the conjugation reaction of horseradish peroxidase (HRP) with aldehyde derivative of dextran (D-CHO). The reaction was irradiated by microwave at 50 °C for 5 min. The conjugate was confirmed via GPC, in which the conjugates of HRP and D-CHO coexist with free unbound HRP molecules. Activity studies of HRP revealed that there is a small decrease in conjugate activity relative to the free enzyme after a short bioconjugation reaction with microwave irradiation. In decolorization studies of the textile dye Reactive Blue 19 (RB19), 99% of RB19 was decolorized through the free enzyme at 35 °C while the decolorization of the dye was 96% at 25-35 °C by the conjugate, which is a critical result showing clearly that the HRP conjugated via D-CHO is not denatured and still active after microwave-assisted reaction. This phenomenon is due to the multiple point conjugation of D-CHO on the surface of HRP and locking the 3D structure which may prevent changes in the secondary or tertiary structure of the enzyme. The results reveal that microwave irradiation can be used in production of covalently modified enzymes.

Effect of calcination temperature on morphology and phase transformation of MnO2 nanoparticles: A step towards green synthesis for reactive dye adsorption.

Green synthesis of manganese oxide nanoparticles (NPs) was carried out by sol-gel method using Acacia Concinna fruit extract for removal of reactive dye. The effect of calcination temperature on its morphology was investigated. α-MnO2 and Mn3O4 NPs were synthesized at 400 °C and 900 °C respectively and were characterized by PXRD, SEM, TEM, FTIR, BET, Raman and TGA. As-synthesized MnO2 NPs were investigated for the adsorption of Reactive Blue 21 (RB-21) dye. The effect of pH, adsorbent dose, agitation speed, initial dye concentration and temperature on dye removal was explored. pHpzc was calculated from zeta potential study showing positive surface charge below pH 3.18 resulting in electrostatic force of attraction between adsorbate and adsorbent. Both linear and non-linear regression approaches were utilised for the fitting of kinetic models and adsorption isotherms. Adsorption data follows a pseudo second order kinetics and fits well with the Freundlich isotherm model. Thermodynamic parameters such as ΔHo, ΔSo and ΔGo were determined. The dye removal efficiency, in case of MnO2 NPs at pH 3.0 was obtained to be 98% whereas for Mn3O4, no such dye adsorption was observed. The mechanism of adsorption was studied theoretically confirming π-π interaction and H-bonding between the MnO2 and RB dye molecules.

Characterization of anthropogenic organic matter and its interaction with direct yellow 27 in wastewater: Experimental results and perspectives of resource recovery.

The concept of natural organic matter of anthropogenic origin is introduced and its characteristics and interaction with chemical pollutants are investigated by adopting several distinct analytic methodologies. Scanning electron microscopy indicates that the used sample of anthropogenic organic matter (AOM) has an amphiphilic nature, which allows its supramolecular organization in water. Fourier transform infrared spectroscopy, in turn, gives a clear indication about the presence of polysaccharide markers, lipidic and amidic fractions, and suggests the absence of free organic acid. AOM sample and AOM mixed with dye sample were examined by the three-dimensional excitation-emission matrix fluorescence spectra and the nuclear magnetic resonance mono-dimensional spectra. The results highlighted the interactions occurring between the AOM and the reactive dye, selected as a representative chemical pollutant. Electron Spin Resonance confirms that the used AOM is able to completely include the dye in its structure. Overall, the obtained results indicate that the fate, transport, and toxicity of pollutants in the environment can be drastically influenced by the presence of AOM.

Composites Based on Natural Polymers and Microbial Biomass for Biosorption of Brilliant Red HE-3B Reactive Dye from Aqueous Solutions.

Natural polymers have proven to be extremely interesting matrices for the immobilization of microbial biomasses, via various mechanisms, in order to bring them into a form easier to handle-the form of composites. This article aimed to study composites based on a residual microbial biomass immobilized in sodium alginate via an encapsulation technique as materials with adsorbent properties. Thus, this study focused on the residual biomass resulting from beer production (Saccharomyces pastorianus yeast, separated after the biosynthesis process by centrifugation and dried at 80 °C)-an important source of valuable compounds, used either as a raw material or for transformation into final products with added value. Thus, the biosorptive potential of this type of composite was tested-presenting in the form of spherical microcapsules 900 and 1500 µm in diameter-in a biosorption process applied to aqueous solutions containing the reactive dye Brilliant Red HE-3B (16.88-174.08 mg/L), studied in a batch system. The preparation and characterization of the obtained polymeric composites (pHPZC, SEM, EDS and FTIR spectra) and an analysis of different equilibrium isotherms (Langmuir, Freundlich and Dubinin-Radushkevich-D-R) were investigated in order to estimate the quantitative characteristic parameters of the biosorption process, its thermal effects, and its possible mechanisms of action. The modelling of the experimental data led to the conclusion that the studied biosorption process took place after reaching the Langmuir isotherm (LI), and that the main mechanism was possibly physical, being spontaneous and probably exothermic according to the values obtained for the free energy of biosorption (E = 8.45-13.608 kJ/mol, from the DR equation), as well as the negative values for the Gibbs free energy and the enthalpy of biosorption (ΔH0 = -87.795 kJ/mol). The results obtained lead to the conclusion that encapsulation of this residual microbial biomass in sodium alginate leads to an easier-to-handle form of biomass, thus being an efficient biosorbent for static or dynamic operating systems for effluents containing moderate concentrations of reactive organic dyes.

Pollutants Sorbent Made of Cotton Fabric Modified with Chitosan-Glutaraldehyde and Zinc Oxide Particles.

The paper reports on the preparation of composite materials by modifying cotton fabric with a layer of crosslinked glutaraldehyde chitosan containing zinc oxide particles. The ability of chitosan to form complexes with zinc ions has been used to control the size, structure, and distribution of the particles on the fiber surface. The three different obtained materials have been characterized by optical and scanning electron microscopy, Fourier-transform infrared spectroscopy (FTIR), and fluorescent analysis. It has been found that the interaction of the ZnO particles with the functional groups of chitosan affects its swelling ability in water and thus determines its sorption properties. The capacity of the materials to wipe water-soluble (textile reactive dye) and water-insoluble (crude oil and oil products) contaminants has been compared. The effect that the amount of zinc oxide has on the ability of the materials to remove contaminants has also been studied. The possibility for adsorption-desorption of the crude oil and reuse of the sorbent material has been investigated as well.

Design and Evaluation of a New Natural Multi-Layered Biopolymeric Adsorbent System-Based Chitosan/Cellulosic Nonwoven Material for the Biosorption of Industrial Textile Effluents.

The adsorption phenomenon using low-cost adsorbents that are abundant in nature is of great interest when the adsorbed capacity is significant. A newly designed natural polyelectrolyte multi-layered (PEM) biopolymeric system-based chitosan/modified chitosan polymer and functionalized cellulosic nonwoven material was prepared and used as an effective adsorbent for Reactive Red 198 (RR198) dye solutions. The bio-sorbent was characterized by FTIR, SEM, and thermal (TGA/DTA) analysis. The swelling behavior was also evaluated, showing the great increase of the hydrophilicity of the prepared adsorbent biopolymer. The effect of various process parameters on the performance of RR198 dye removal such as pH, contact time, temperature, and initial dye concentration was studied. The biopolymeric system has shown good efficiency of adsorption compared to other adsorbents based on chitosan polymer. The highest adsorption capacity was found to be 722.3 mgg-1 at pH = 4 (ambient temperature, time = 120 min and dye concentration = 600 mg L-1). The adsorption process fitted well to both pseudo-second-order kinetics and Freundlich/Temkin adsorption isotherm models. Regarding its low cost, easy preparation, and promising efficient adsorption results, this new concepted multi-layered bio-sorbent could be an effective solution for the treatment of industrial wastewater.

Textile dyes loaded chitosan nanoparticles: Characterization, biocompatibility and staining capacity.

Textile dyeing is a hazardous and toxic process. While traditionally it has been managed through effluent treatment, new approaches focused upon improving the dyeing process are gaining relevance. In this work, we sought to obtain, for the first time, an eco-friendly chitosan-nanoparticle based textile dyeing method. To that end, yellow everzol and navy blue itosperse loaded chitosan nanoparticles were produced and their capacity to dye textiles and cytotoxicity towards human skin cells were evaluated. The results obtained showed that it was possible to obtain nanoencapsulated dyes through ionic gelation with an average entrapment efficacy above 90 %. Nanoparticles presented a positive surface charge and sizes between 190 and 800 nm with yellow everzol NPs occurring via ionic interactions while navy blue itosperse NPs were formed through hydrogen bonds. Furthermore, the produced dye NPs presented no cytotoxicity towards HaCat cells and presented staining percentages reaching 17.60 % for a viscose/wool blend.

The biosorption of reactive red dye onto orange peel waste: a study on the isotherm and kinetic processes and sensitivity analysis using the artificial neural network approach.

The agricultural waste of orange peels (OPs) was utilized as a cheap biosorbent and then tested for its ability to treat the reactive red (RR) dye wastewater. Several experiments were done to get the equilibrium isotherm and kinetic-relevant data. In addition, several experimental factors such as solution pH, temperature, contact time, and initial RR dye concentration were studied, in light of their impact on the biosorption process. The utilized isotherm and kinetic models were evaluated by using the chi-square test and coefficient of determination parameters for their representation of real data. In addition, the obtained data of their biosorption capacities, at different conditions, were modeled by the artificial neural network (ANN) approach. The results of the isotherm study revealed that the experimental data can be best accounted by both the Langmuir and Temkin models, demonstrating that the RR molecules were sorbed to two or more different types of biosorption sites of OP. The kinetic study for determining the characteristics of the rate of diffusion demonstrated that the intraparticle diffusion process was not the sole rate-limiting step in the biosorption of the RR dye-OP couple. Furthermore, the biosorption process was chemisorption in nature, as the pseudo-second-order reaction proved to be the best representative model for the kinetic data. The outcome of modeling also assumed that using the ANN tool was useful to reproduce the data again and foretell the manner in which biosorption behaved. According to the results of the Langmuir model, it was found that the maximum OP uptake for the biosorption of the RR dye was up to 82 mg/g, observed at optimized values of the experimental parameters. Such prior results highlight that OP is an effective agent of biosorption in the elimination of RR dyes from polluted solutions, moreover, in a cost-effective manner.

Cyanuric Chloride-Based Reactive Dyes for Use in the Antimicrobial Treatments of Polymeric Materials.

This study reports a simple and practical method to introduce antimicrobial and biofilm-controlling functions into hydroxyl- or amino-containing polymers such as cellulose using compounds derived from widely used reactive dyes. Two dichloro-s-triazine-based dyes, reactive blue 4 and sodium 4-(4,6-dichloro-1,3,5-triazinylamino)-benzenesulfonate (a colorless reactive "dye"), were covalently attached to cellulose at room temperature by replacing one chloride on the dyes with the hydroxyl groups on cellulose followed by hydrolysis under alkaline conditions to transform the remaining chloride into hydroxyl groups. The chemical reactions were confirmed by FT-IR studies, energy-dispersive X-ray spectroscopy, water contact angle measurement, and zeta potential analysis. The resulting cellulose provided powerful antimicrobial activities against Staphylococcus epidermidis (S. epidermidis, ATCC 35984, Gram-positive bacteria), Escherichia coli (E. coli, ATCC 15597, Gram-negative bacteria), and Candida albicans (C. albicans, ATCC 10231, yeast) and effectively prevented the formation of bacterial or fungal biofilms. The minimum inhibition concentrations of the hydrolyzed dyes were similar to that of phenol. In the zone of inhibition studies using phenolic compounds as positive controls, the hydrolyzed dyes and their model compound cyanuric acid demonstrated antimicrobial functions, suggesting that the antimicrobial activities were associated with the phenol-like hydroxyl groups on the triazine rings. Antimicrobial mechanism investigation indicated that the phenol-like structures on the dyed cellulose caused microbial lysis and leakage of intracellular components. The antimicrobial functions were durable upon repeated washing, and the dyed cellulose showed outstanding biocompatibility toward mammalian cells.