Remazol Brilliant Blue R Research Articles

One-Step Room-Temperature Synthesis of Bimetallic Nanoscale Zero-Valent FeCo by Hydrazine Reduction: Effect of Metal Salts and Application in Contaminated Water Treatment.

The effect of initial salt composition on the formation of zero-valent bimetallic FeCo was investigated in this work. Pure crystalline zero-valent FeCo nanoparticles (NPs) were obtained using either chloride or nitrate salts of both metals. Smaller NPs can be obtained using nitrate salts. Comparing the features of the FeCo prepared at room temperature and the solvothermal method revealed that both materials are almost identical. However, the room-temperature method is simpler, quicker, and saves energy. Energy-dispersive X-ray (EDX) analysis of the FeCo NPs prepared using nitrate salts at room temperature demonstrated the absence of oxygen and the presence and uniform distribution of Fe and Co within the structure with the atomic ratio very close to the initially planned one. The particles were sphere-like with a mean particle size of 7 nm, saturation magnetization of 173.32 emu/g, and surface area of 30 m2/g. The removal of Cu2+ and reactive blue 5 (RB5) by FeCo in a single-component system was conformed to the pseudo-first-order and pseudo-second-order models, respectively. The isotherm study confirmed the ability of FeCo for the simultaneous removal of Cu2+ and RB5 with more selectivity toward Cu2+. The RB5 has a synergistic effect on Cu2+ removal, while Cu2+ has an antagonistic effect on RB5 removal.

Wheat straw-based microbial electrochemical reactor for azo dye decolorization and simultaneous bioenergy generation

Microbial fuel cells have emerged as a technique that can effectively treat wastewater with simultaneous electricity generation. The present study explored the performance of microbial fuel cell for decolorizing and degradation of azo dyes including, remazol brilliant blue (RBB), mordant blue 9 (MB9), acid red1 (AR1), and orange G (OG), while, simultaneously generating electricity. Wheat straw and its hydrolysate was used as a potential substrate in MFC. The hydrolysate was prepared through the degradation of wheat straw by P. floridensis, P. brevispora and P. chrysosporium, while the yeast Pichia fermentans was used as biocatalyst. Dye decolorization was carried out in a fungus-yeast mediated single-chambered MFC batch mode, U-shaped reactor, and bottle reactor in continuous mode. The maximum power density recorded in U shaped continuous reactor was 34.99 mW m−2 on 21st day of the experiment. The best response of dye decolorization was observed in the case of MB9 (96%) with P. floridensis in the continuous electrochemical reactor followed by RBB (90–95%), OG (76%), and AR1 (38%). The toxicity of the treated wastewater was assessed using phytotoxicity analysis.

Kinetic, equilibrium, adsorption mechanisms of RBBR and MG dyes on chitosan-coated montmorillonite with an ecofriendly approach

In this study, by modifying the montmorillonite mineral with chitosan, chitosan/montmorillonite composites were synthesized, and research was performed as to its usage as an adsorbent in removing Remazol Brillant Blue R and Malachite Green dyestuffs from aqueous solutions. SEM, FT-IR, XRD, and BET analysis techniques were utilized to determine the characteristics of the synthesized composite. The effects of different batch parameters such as initial pH value (2−9), contact time (5–120 min), initial dyestuff concentration (50–300 mg/ L), adsorbent dose (0.05–0.5 g/100 mL), and process temperature (293–313 K) on the adsorption process were examined. The optimum pH was 2 for RBBR, whereas it was 8 for MG. Also, the optimum removal time was 120 min for RBBR; it was 210 min for MG. As per the Langmuir isotherm model, the maximum adsorption capacity (qmax) was found as 332.58 mg/ g for RBBR, and it (qmax) was 400 mg/ g for MG. This capacity was interpreted as an indicator of usability in removing the RRBR and MG dyes specified in the study from wastewater. The results revealed that the equilibrium isotherm follows the Langmuir equation, and the kinetic model shows consistency with the pseudo-second-order equation. The thermodynamics of adsorption was studied, too. The experimental results demonstrated that CCS/MTs are suitable adsorbents for RBBR and MG removal from aqueous solutions because of their high adsorption capacity.

Co-metabolic biodegradation of structurally discrepant dyestuffs by Klebsiella sp. KL-1: A molecular mechanism with regards to the differential responsiveness.

In this study, an attempt was made to decipher the underlying differential response mechanism of Klebsiella sp. KL-1 induced by exposure to disparate categories of dyestuffs in xylose (Xyl) co-metabolic system. Here, representative reactive black 5 (RB5), remazol brilliant blue R (RBBR) and malachite green (MG) belonging to the azo, anthraquinone and triphenylmethane categories were employed as three model dyestuffs. Klebsiella sp. KL-1 enabled nearly 98%, 80% or 97% removal of contaminants in assays Xyl+RB5, Xyl+RBBR or Xyl+MG after 48h, which was respectively 16%, 11% or 22% higher than those in the assays devoid of xylose. LC-QTOF-MS revealed an increased formation of smaller molecular weight intermediates in assay Xyl+RB5, whereas more metabolic pathways were deduced in assay Xyl+RBBR. Metaproteomics analysis displayed remarkable proteome alteration with regards to the structural difference effect of dyestuffs by Klebsiella sp. KL-1. Significant (p-value<0.05) activation of pivotal candidate NADH-quinone oxidoreductase occurred after 48h of disparate dyestuff exposure but with varying abundance. Dominant FMN-dependent NADH-azoreductase, Cytochrome d terminal oxidase or Thiol peroxidase were likewise deemed to be responsible for the catalytic cleavage of RB5, RBBR or MG, respectively. Further, the differential response mechanism towards the structurally discrepant dyestuffs was put forward. Elevated reducing force associated with the corresponding functional proteins/enzymes was transferred to the exterior of the cell to differentially decompose the target contaminants. Overall, this study was dedicated to provide in-depth insights into the molecular response mechanism of co-metabolic degradation of refractory and structurally discrepant dyestuffs by an indigenous isolated Klebsiella strain.

Synthesis of novel chitosan Schiff base and its ZnO nanocomposite for removal of synthetic dye, antimicrobial, and cytotoxicity activity

In this work, a novel chitosan Schiff base 4-(2-Hydroxyaniline)pent-3-en-2-one chitosan (2-HyA-CS) and its ZnO nanocomposite (2-HyA-CS/ZnO) were sensitized and characterized by appropriate methods; FTIR, XRD, Elemental analysis, SEM, TEM and TGA. The result of characterization methods confirms the preparation of 2-HyA-CS and 2-HyA-CS/ZnO. The SEM images reveal that chitosan, 2-HyA-CS, and 2-HyA-CS/ZnO have a varied roughness and porous surfaces. The reason for this difference was attributed to the formation of Schiff base 2-HyA-CS and the presence of ZnO nanoparticles in 2-HyA-CS/ZnO. The patterns of XRD and FTIR confirm the formation of 2-HyA-CS and 2-HyA-CS/ZnO. The degree of substitution (DS) of modified chitosan 2-HyA-CS was calculated using Elemental analysis and FTIR.ATR, it was found to be 74%. The adsorption efficiency of the produced adsorbents was compared with pure chitosan to remove of Remazol Brilliant Blue R (RBBR) from an aqueous medium and antimicrobial activity. The removal percentage of RBBR by chitosan, 2-HyA-CS, and 2-HyA-CS/ZnO are 47.12%, 91.9%, and 96.56%, respectively with the following order: 2-HyA-CS/ZnO &gt; 2-HyA-CS &gt; chitosan. Their antimicrobial activities were studied against two Gram negative bacteria ( E. coli and P. aeruginosa), two Gram positive bacteria ( S. aureus and B. cereus) and ( C. albicans) as a yeast strain, the inhibitory zone measurements revealed that the activity of 2-HyA-CS/ZnO is excellent and higher than 2-HyA-CS and pure chitosan. The cytotoxicity of the prepared compound 2-HyA-CS and 2-HyA-CS/ZnO along with pure chitosan was estimated against two human cancer cells MCF-7 cells and HepG-2 cells, the result indicates that 2-HyA-CS/ZnO having higher Inhibitory activity against both MCF-7 and HepG-2 cells with 53.5 ± 2.86 and 27.4 ± 1.23 µg/mL respectively and 2-HyA-CS possessing moderate Inhibitory activity against both MCF-7 and HepG-2 cancer cells with IC50 = 216.5 ± 7.48 and 135.6 ± 6.49 µg/ml respectively.

Surface Modification of a Thin-Film Composite (TFC) Nanofiltration Membrane with 3-Aminopropyltriethoxysilane (APTES) for Efficient Dye–Salt Separation

Nanofiltration (NF) technology is attractive in desalting and concentrating dyeing wastewater in the textile industry. A highly efficient NF membrane is critical in reducing the cost of the process. Here, a facile and reliable approach to prepare an NF membrane for the selective separation of dye/salt is proposed by surface grafting of 3-aminopropyltriethoxysilane (APTES) on a fresh polyamide (PA) layer after interfacial polymerization (IP). A thin layer of APTES with a thickness of ∼64 nm was found successfully covalently bonded onto the PA surface via esterification and amidation reactions. The thin-film composite (TFC)-1.0 membrane grafted with 10% APTES achieved a high water permeance of 44.8 L m–2 h–1 bar–1, which was 4.7 times higher than that of the control TFC membrane. Interestingly, the rejection of monovalent salt (NaCl, 11.5%) and divalent salt (Na2SO4, 17.2%) decreased significantly, while the rejection for different dyes (Congo red, reactive blue-19, Coomassie blue G-250, and methyl blue) remained over 99.0%. These noticeable changes in separation performances could be attributed to the large pore size of the active layer, resulting from the interference of APTES on the post-cross-linking of a PA network. The poly(ethylene glycol) (PEG) filtration experiments confirmed that the mean pore size of the membrane was enlarged significantly from 0.51 to 1.17 nm after surface modification. Finally, the modified membrane showed good long-term stability and excellent separation efficiencies in fractionation of a high salinity Congo red/NaCl (0.2/50 g L–1) mixture. Overall, this work provides a practical strategy to prepare a permeable and selective NF membrane for dye and salt separation by surface grafting of the nascent PA layer.

LACCASE PRODUCTION BY NEWLY ISOLATED GANODERMA LUCIDUM WITH SOLID STATE FERMENTATION CONDITIONS AND ITS USING FOR DYE DECOLORIZATION

Laccase production capacity of newly isolated fungus Ganoderma lucidum was studied during solid state fermentation on solid substrates. Because wheat bran was detected as the most effective solid substrate, effect of various culture parameters and some inducers on laccase production in wheat bran media was investigated. Wheat bran with moisture content of 75%, pH 5.0 and 30 °C was the most effective medium and 10 mM copper addition supported the highest amount of laccase. In glass tray fermenter 2973±220 U/L laccase activity was obtained. Crude laccase gave the highest activity at 70 °C. It was stable at 60°C for 6 hours and retained 37% activity at 70 °C for 2 hours. It decolorized 61% of Remazol Brilliant Blue R within 20 min. Results showed that this strain could produce high amount of laccase and suitable inducer such as copper could induce its laccase production. The crude laccase obtained could be used for textile dye decolorization applications.

Hybrid magnetic CoFe2O4@γ-Fe2O3@CTAB nanocomposites as efficient and reusable adsorbents for Remazol Brilliant Blue R dye

ABSTRACT The main goal of the present survey was to elaborate, characterize and evaluate the efficiency of ferrite-based nanoparticles modified with cetyltrimethylammonium bromide (CTAB) as potential magnetic nanoadsorbents to remove Remazol Brilliant Blue R (RBBR) from water. It is proposed an innovative nanomaterial architecture based on highly magnetic and chemically stable core@shell nanoparticles covered by an adsorptive surface layer of CTAB (CoFe2O4@γ-Fe2O3@CTAB). Samples of two different mean sizes (7.5 and 14.6 nm) were synthesized using a hydrothermal coprecipitation followed by surface treatment and functionalization. Batch tests were performed to evaluate the influence of contact time, temperature, pH, shaking rate, presence of interferents and mean size on the performance of the proposed nanomaterials. The kinetics of the adsorption process followed the pseudo-second-order model with an equilibrium time of 20 min. The adsorption capacity was estimated by the Langmuir isotherm model and was found to be 56.3 mg/g (smaller size) and 45.6 mg/g (larger size) at pH = 3 and a shaking rate of 400 rpm. The process was spontaneous, exothermic, and showed increased randomness. Sulphate ions negatively impacted the removal of RBBR. The best performance of the nanoadsorbent based on smaller mean sizes can be correlated to its larger surface area. Regeneration and readsorption tests showed that the nanoadsorbents retain more than 80% of their original removal capacity, therefore they can be effectively recycled and reused.

Enhanced photocatalytic degradation of reactive blue 19 using zeolitic imidazolate framework-8 composited with Fe3O4/MnO2 heterojunction

The present study offers a novel recyclable Fe3O4/MnO2/ZIF-8 heterojunction photocatalyst for the degradation of reactive blue 19 (RB19) under visible light irradiation. The catalyst was facilely synthesized by depositing Fe3O4/MnO2 nanocomposite onto the surface of ZIF-8 and characterized by field-emission scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, nitrogen adsorption–desorption isotherms and UV–vis spectroscopy. Morphology and structure characterization of the prepared photocatalyst indicated that polyhedral ZIF-8 (ca. 500 nm) was coated by MnO2/Fe3O4 nanorods. The synergy effect of Fe3O4/MnO2/ZIF-8 composite exhibited an excellent photocatalytic activity toward RB19 degradation of 99.5 % after 60 min of irradiation due to high surface area and heterojunction formation. According to scavenger tests, the photodegradation of RB19 dye over Fe3O4/MnO2/ZIF-8 was mainly contributed by OH and O2− reactive radicals. The kinetic study showed that the catalytic degradation of RB19 on Fe3O4/MnO2/ZIF-8 was better described by the first-order kinetic model. The new catalyst was easily recovered using an external magnetic field because of its magnetic properties. Besides, Fe3O4/MnO2/ZIF-8 showed high recyclability and stability, maintaining a high removal efficiency of 91.3 % even after ten repeated cycles. The overall results indicated that the fabricated composite can be used as an efficient photocatalyst for treating organic dyes in wastewater.

Corn Cob as a Green Support for Laccase Immobilization-Application on Decolorization of Remazol Brilliant Blue R.

The high demand for food and energy imposed by the increased life expectancy of the population has driven agricultural activity, which is reflected in the larger quantities of agro-industrial waste generated, and requires new forms of use. Brazil has the greatest biodiversity in the world, where corn is one of the main agricultural genres, and where over 40% of the waste generated is from cobs without an efficient destination. With the aim of the valorization of these residues, we proposed to study the immobilization of laccase from Aspergillus spp. (LAsp) in residual corn cob and its application in the degradation of Remazol Brilliant Blue R (RBBR) dye. The highest yields in immobilized protein (75%) and residual activity (40%) were obtained at pH 7.0 and an enzyme concentration of 0.1 g.mL−1, whose expressed enzyme activity was 1854 U.kg−1. At a temperature of 60 °C, more than 90% of the initial activity present in the immobilized biocatalyst was maintained. The immobilized enzyme showed higher efficiency in the degradation (64%) of RBBR dye in 48 h, with improvement in the process in 72 h (75%). The new biocatalyst showed operational efficiency during three cycles, and a higher degradation rate than the free enzyme, making it a competitive biocatalyst and amenable to industrial applications.

The evaluation of reactive textile dyes regarding their potential to cause organ-specific cyto- and geno-toxicity

The textile industry extensively uses synthetic chemicals such as dyes. Several studies report the deleterious effects (e.g., cell death and DNA damage) of dispersive dyes on humans. Humans can be exposed to toxic dyes by ingesting contaminated waters or dermal contact with colored garments. Thus, toxicity evaluations of textile dyes using organ-specific cell lines are relevant to estimating their hazard. Cyto- and geno-toxicity of the dyes Reactive Green 19 (RG19), Reactive Blue 2 (RB2), Reactive Blue 19 (RB19), Reactive Red 120 (RR120) and Reactive Orange 16 (RO16) were evaluated by the In Vitro MicroFlow® kit with immortalized human keratinocyte cell line (HaCaT) and immortalized human hepatic cell line (HepaRG). Concentrationdependent cytotoxicity was observed for HaCaT cells exposed to three of the five tested dyes (RB2, RB19, RO16), while in HepaRG cells, cytotoxic effects were only verified after exposure to RB19 and RO16 at the highest tested concentration (1000 µg/mL). Genotoxicity was not detected in any tested textile dyes under both test conditions (HaCaT and HepaRG). In conclusion, our data provide evidence that, although the tested reactive dyes are not genotoxic, which is in agreement with published literature, they can cause cytotoxicity in both target tissue, and the effect can be more severe in epidermal cells (HaCaT) than in liver cells (HepaRG). This differential cytotoxicity data emphasizes the need to assess the toxicity of textile dyes to the target organ specificity.

Compendium data and preliminary results based on alum sludge and gravel continuous fixed-packed-bed column substrate as sustainable practice for constructed wetland development in northern Egypt

The present investigation represents the valuable reclaims of the aluminum-based waterworks sludge that is so called “alum sludge” to close the loop concerning the sludge waste production and the sustainable ecosystem. In this study the adsorption behaviors of aluminium based sludge, namely alum sludge (AS) and gravel as cost-efficient adsorbents regarding dye elimination from aqueous synthetic stream were analyzed in fixed bed column. The influence of variable boundaries such as column pack depth and influent concentration on the effluent concentrations via breakthrough curves were examined. It is estimated that the removal uptake and sorption capabilities elevated as the initial influent loading of the dye dismissed for the fixed bed height of the both adsorbents, namely, gravel and AS. Thereafter, a preliminarily results were checked to investigate the feasibility of the adsorption column in Reactive Blue 4 (RB4) adsorption. The maximum adsorption capacities were observed around 4 mg L-1 for sample with pH 7.5 that is signified as the natural pH of the synthetic stream. However, increasing the initial dye loading increasing the adsorption capacity which reached to 5.5 mg L-1 for the dye loading 27.8 mg L-$$$1 of Reactive Blue 4 (RB4). Thus, the first results will be a valued scheme in the development of adsorption systems to build up a constructed wetland facility.

Isolation of Bacillus sp. with high laccase activity for green biodecolorization of synthetic textile dyes.

New Bacillus sp. strains with spore-laccase activity were isolated from rotten wood and soil samples and were identified as Bacillus sp. FM-78 and Bacillus paramycoides FM-86 by 16S rDNA gene sequence analysis. Both laccases were stable at broad pH range and high temperature. The laccase of strain FM-78 showed preferable activity and stability, with no loss of activity after 7 days incubation at pH 9.0, and 20.36% of its initial activity obtained after 10 h at 80 °C. 1 mmol/L EDTA, NaN3 and SDS resulted in about 46-59% inactivation and strongly inhibition (87.88%) was caused by 1 mmol/L L-cysteine. However, the spore laccase could tolerate towards 0.5 mol/L NaCl as well as 10% of organic solvents. Reactive black 5, reactive blue 19 and crystal violet were decolorized by the spore laccase in the absence of mediator. The decolorization process was efficiently promoted with the presence of acetosyringone, and the color removal ratio was more than 80% in 1 h with the pH values of 6.6 or 9.0. Finally, the above unusual properties of Bacillus sp. spore laccase indicated it as a potential candidate in the dye decolorization in an ecofriendly and cost-effective way.

In-situ sol-gel generation of SiO2 nanoparticles inside polyamide membrane for enhanced nanofiltration

Interfacial polymerization (IP) has been deemed as the principal strategy to fabricate thin film composite (TFC) nanofiltration (NF) membranes. However, the separation performances of TFC membrane are prone to be impaired with the issue of trade-off relationship between selectivity and permeability. Herein, a combined IP and in-situ sol-gel method was proposed to synthesis novel thin film nanocomposite (TFN) NF membrane. The nano-enhanced polyamide (PA) functional layer was created by the IP reaction, while the in-situ generated silicon dioxide (SiO2) nanoparticles were formed through the hydrolysis and condensation process. The optimal separation performance was obtained by tailoring the formation process of SiO2 nanoparticles via varying the NaOH concentration. The results revealed that the in-situ generated SiO2 nanoparticles were uniformly distributed within the PA layer, which greatly enhanced the hydrophilicity due to the abundant Si-OH groups. The membrane decorated by 1 ml TEOS under 0.3 wt% NaOH condition possessed a pure water permeability up to 70.69 L m−2 h−1 bar−1 and high rejection rates against dyes (99.99 % for Congo red, 99.55 % for Coomassie blue G-250, 99.39 % for Reactive blue 19), while maintaining low salt rejections (4.92 % for NaCl, 7.14 % for Na2SO4). Meanwhile, the membrane presented an excellent long-term operational stability.

Toxicity Mitigation of Textile Dye Reactive Blue 4 by Hairy Roots of Helianthus annuus and Testing Its Effect in In Vivo Model Systems.

An anthraquinone textile dye, Reactive Blue 4 (RB4), poses environmental health hazards. In this study, remediation of RB4 (30-110 ppm) was carried out by hairy roots (HRs). UV-visible spectroscopy and FTIR analysis showed that the dye undergoes decolourization followed by degradation. In addition, toxicity and safety analyses of the bioremediated dye were performed on Allium cepa and zebrafish embryos, which revealed lesser toxicity of the bioremediated dye as compared to untreated dye. For Allium cepa, the highest concentration, i.e., 110 ppm of the treated dye, showed less chromosomal aberrations with a mitotic index of 8.5 ± 0.5, closer to control. Two-fold decrease in mortality of zebrafish embryos was observed at the highest treated dye concentration indicating toxicity mitigation. A higher level of lipid peroxidation (LPO) was recorded in the zebrafish embryo when exposed to untreated dye, suggesting a possible role of oxidative stress-inducing mortality of embryos. Further, the level of LPO was significantly normalized along with the other antioxidant enzymes in embryos after dye bioremediation. At lower concentrations, mitigated samples displayed similar antioxidant activity comparable to control underlining the fact that the dye at lesser concentration can be more easily degraded than the dye at higher concentration.

Inconsistency of BDD reactivity assessed by ferri/ferro-cyanide redox system and electrocatalytic degradation capability

Ferri/ferro-cyanide ([Fe(CN)6]3−/4−) redox couple has been extensively used as a benchmark to assess electrocatalytic degradation capability of boron-doped diamond (BDD) electrodes. However, the [Fe(CN)6]3−/4− is far more sensitive to the surface terminal groups of BDD surface than the other factors (e.g. surface morphology and electrode configuration) that are closely related to electrocatalytic degradation properties. Thus, inconsistency exists while correlating the degradation properties of BDD with electrochemical properties determined from ferri/ferro-cyanide redox couple. Herein, an exemplar pollutant, reactive blue 19 (RB-19), was electrochemically degraded using various terminated BDD electrodes, including hydrogen-terminated (H-BDD), oxygen-terminated (O-BDD) and porous oxygen-terminated BDDs (OE-BDD), obtained via cathodic and anodic polarization as well as oxygen plasma etching, respectively. Surprisingly, OE-BDD with the lower heterogeneous electron transfer rate constant for [Fe(CN)6]3−/4− showed a better electrocatalytic degradation capability toward RB-19, indicating the inconsistency for qualitatively evaluating degradation properties according to the kinetic parameters extracted from [Fe(CN)6]3−/4− redox system.

Removal of Remazol Brilliant Blue R (RBBR) by Absorbsion on Zeolit Cuo Catalyst

The pollution caused by dyestuffs has been a serious environmental problem for years. Within the overall category of dyestuffs, Remazol Brilliant Blue R (RBBR) is an anthraquinone dye used in textile industries. This paper concerns the study of the different experimental parameters which affect the decolorization efficiency of the RBBR mixture. Thermal degradation is done by carried out with 4 mL of 10 ppm RBBR solution into the reaction flask. Added a number of H2O2 and CuO zeolite catalyst. The reactor was heated in oil bath glycerin and stirred for 90 minutes. The optimum catalyst weight was obtained at 100 mg, which was able to decrease the reaction time 50 minutes compared to the reaction without catalyst. The percentage of dye removal on this catalyst loading was 96.26%. The micro pores of CuO zeolite is about 20 nm, which shows formation of nanoCuO particles in zeolite structure. This structural feature may be important since it increases the total surface area. The diffusion into such pores can explain the absorption capacity.

Removal of Remazol Brilliant Blue R (RBBR) by Absorbsion on Zeolit Cuo Catalyst

Removal of Remazol Brilliant Blue R (RBBR) by Absorbsion on Zeolit Cuo Catalyst

Design and Fabrication of Membranes Based on PAN Copolymer Obtained from Solutions in N-methylmorpholine-N-oxide.

An original method is proposed for preparing highly concentrated solutions of PAN copolymer in N-methylmorpholine-N-oxide (NMMO) and forming membranes for nanofiltration from these solutions. The high activity of the solvent with respect to the polymer provides short preparation time of spinning solutions in comparison with PAN solutions obtained in other solvents. The use of the rheological approach made it possible to find the optimal concentration for obtaining membranes. The formation of PAN membranes from the obtained solutions is proposed by the rolling method. The morphology of the formed membranes depends on the method of removing the precipitant from the sample. The features of the formed morphology of PAN membranes were studied by scanning electron microscopy. It was revealed that the use of water as a rigid precipitant leads to the formation of a homogeneous and symmetric morphology in the membrane. The average pore sizes in the membrane have been obtained by porosimetry. The study of the separating properties of PAN membranes revealed noteworthy values of the permeability and rejection for the anionic dyes Orange II and Remazol Brilliant Blue (74 and 97%, respectively). The mechanical properties of PAN membranes from solutions in NMMO are not inferior to analogs formed from commercially used direct solvents.

Reusable Halophilic Bacteria Attached Cellulose Acetate Nanofiber Webs for Removal of Cr (VI) and Reactive Dye

Hexavalent Chromium (Cr (VI)) and Reactive Blue (RB) removal efficiencies of halotolerant Citricoccus sp. were examined for different parameters such as initial pH, contact time, temperature static/shaking, NaCl concentration, and different pollutant concentrations. In this research, Citricoccus sp. attached cellulose acetate (CA) nanofiber webs (NfW) were produced by electrospinning method to improve the removal yield even further. The Cr (VI) removal yield was calculated as 11.39 ± 0.002% for the pristine CA-NfW, whereas it was 39.19 ± 0.43% for bacteria attached CA-NfW. Therefore, the Cr (VI) removal capacities of bacteria attached CA-NfW were significantly higher than that of pristine CA-NfW. In addition, reusability tests revealed that bacteria attached CA-NfW can be used at least three successive times in decolorization and Cr (VI) removal steps. The decolorization rate of the RB and Cr (VI) removal yield was found to be 31.5 ± 0.2% and 5.63 ± 0.30%, respectively. These results are promising and therefore suggest that bacteria attached CA-NfW could be applicable for the removal of wastewater containing Cr (VI) and reactive dye due to their versatility and reusability.