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High cost and low operational stability are the most important challenges limiting the possible use of laccase in the removal of textile dyes. To overcome these challenges, in this study, polyvinylpyrrolidone (PVP)-coated magnetic nanoparticles (MNPs) were produced and characterized. To our knowledge, this is the first study to explore the feasibility of immobilizing a Trametes trogii laccase enzyme on Fe3O4/PVP MNPs. The characterization of samples and the successful immobilization of laccase were verified by characterization methods. Besides, the biochemical properties and stability of the Fe3O4/PVP/Lac were evaluated in terms of optimum pH, optimum temperature, thermostability, thermodynamic and kinetic parameters, storage stability, operational stability, and decolorization efficiency of two different textile dyes. The optimum activities were recorded at pH 2.5 °C and 30 °C. The Fe3O4/PVP/Lac displayed remarkable thermal stability and activation energy for denaturation, enthalpy, Gibbs free energy, and entropy results confirmed the enhanced stability of Fe3O4/PVP/Lac against high temperatures. Meanwhile, the Fe3O4/PVP/Lac retained about 58% of its original activity after seven consecutive reuses, while it retained up to 25% of its original activity after 28 d of storage at room temperature. Km and Vmax for the Fe3O4/PVP/Lac were calculated to be 126 µM and 211 µmol/min, respectively. Finally, after 8 and 6 cycles of repeated use, the Fe3O4/PVP/Lac still decolorized 32.34% and 32.23% of Remazol Brilliant Blue R (RBBR) and Indigo Carmine (IC), respectively. As envisioned, this study suggests a promising way to solve the problems of high price and poor operational stability of the enzyme during biocatalytic decolorization of textile dyes in wastewaters. [ABSTRACT FROM AUTHOR]

Natural mulberry leaves and carboxylic acid-modified mulberry (Morus alba L.) leaves were used for the first time to scrutinize the effects of modification on the retention efficiency of an anionic dye (Remazol Brilliant Blue R (RBBR)) from aqueous solutions to suggest an economical and promising adsorbent for the treatment of dye-contaminated water. The characterization of the adsorbents was accomplished through common techniques including SEM, FTIR, and pHpzc determination. Several parameters studied in batch experiments pointed out that the initial pH of 2.0 and the contact time of 240 min were optimum conditions for all the developed RBBR uptake processes. An artificial neural network (ANN) model was applied to formulate a forecast model for the uptake efficiency of RBBR. The experimental data were assessed by different kinetic and isotherm models to explain the mechanism of the developed processes in more detail. Maximum monolayer adsorption capacities of natural mulberry leaves and acetic acid-, citric acid-, and oxalic acid-modified mulberry leaves were determined as 64.5, 95.2, 84.8, and 91.7 mg g−1, respectively, by the Langmuir isotherm model. These results demonstrated that the modification with carboxylic acids significantly increases the anionic dye adsorption capacity of the mulberry leaves. HIGHLIGHTS Natural mulberry leaves and carboxylic acid-modified mulberry leaves were used for the adsorptive removal of an anionic dye for the first time.; An economical and promising adsorbent was developed for industrial wastewater treatment applications.; Modification with carboxylic acids significantly increases the anionic dye adsorption capacity of the mulberry leaves.; ANN model is suitable for the prediction of RBBR adsorption efficiency.;

In this work, we report the use of spent rooibos tea leaves to fabricate activated carbon and use it to adsorptively remove the toxic Remazol Brilliant Blue R (RBBR) from the aqueous solution. The resulting activated carbon (SRTLAC) was characterized by Brunauer-Emmett-Teller N2 adsorption/desorption for surface area analysis, scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray diffraction for morphological, functional group and crystallinity analyses. A Taguchi design approach was employed to determine the optimal conditions for the RBBR adsorption onto SRTLAC. Among the process variables studied, the sorbent dosage, initial concentration, and pH predominantly affected the removal capacity. The maximum removal of 246.5 mg/g was attained at the highest initial RBBR concentration of 120 mg/L, solution pH of 2, sorbent dosage of 20 mg, and agitation time of 110 min. The analysis of variance results showed that RBBR initial concentration contributed the most significant percentage (95.33 %) towards the removal uptake, highlighting its considerable impact. The adsorption data collected at various concentrations (20 – 120 mg/L) were modelled using three non-linear regression isotherms and kinetic models. The Langmuir isotherm model provided the optimal fit for adsorption, suggesting a monolayer and homogenous sorption system with a maximum capacity of 491.38 mg/g. Meanwhile, the pseudo-2nd order kinetic models accurately elucidated the sorption mechanism. The RBBR species interacted with the SRTLAC functional groups via hydrogen bonding, dipole-dipole interactions, and ion-dipole forces. Therefore, SRTLAC presents a powerful tool for ridding the environment of RBBR dye pollution.

This work investigates the effects of the co-culture between the filamentous fungus Panus lecomtei and the yeast Sporidiobolus pararoseus in the production of laccases. The variations of time interval and inoculum volume of S. pararoseus in co-cultures with P. lecomtei stimulated laccase production, reaching its highest activity at nearly 2960.7 ± 244 U/mL with a maximum time point of 120 h and 2.0% (v/v), respectively. Further application in the pretreated sugarcane bagasse hydrolysis was performed, using P. lecomtei and S. pararoseus extract added to an enzyme mixture from the co-culture of P. lecomtei and Trichoderma reesei that positively favored the hydrolysis efficiency by 66.87%. Furthermore, the addition of P. lecomtei and S. pararoseus extract increased the degradation of industrial anthraquinone Remazol Brilliant Blue R by 78.98%. As a result, the extract derived from the co-culture of P. lecomtei and S. pararoseus rich in laccases presents potential in biotechnological applications, being suitable in the hydrolysis of lignocellulosic biomass and the degradation of unwanted dyes released in the environment. [ABSTRACT FROM AUTHOR]

Extracellular thermophilic multicopper oxidase i.e. laccase was purified, identified and characterized from Geobacillus stearothermophilus MB600. Fast protein liquid chromatography (FPLC) of lacasse showed a prominent peak at 610 nm. Sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) for laccase presented a molecular weight of 59.13 kDa. Analysis via Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) confirmed the presence of laccase similar to in Geobacillus thermoleovorans B23 and Geobacillus sp. LEMMY01. Laccase showed Km 0.532 mM for guaiacol and 0.307 mM for ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)). Its optimum activity was witnessed at 90°C, at pH 5.0. Laccase catalytic activity was completely inhibited by sodium dodecyl-sulfate (SDS), sodium azide (NaN3), and ethylenediaminetetraacetic acid (EDTA). Among the metal salts against Cu, Ca, Cd, and Li enhanced while Mg inhibited the enzyme activity. It was stable against Cl, I and solvents (Ethanol > Methanol > Dimethyl sulfoxide > Acetonitrile). Thermophilic laccase effectively degraded 93% of Remazol brilliant blue R, 92% Bisphenol A diglycidyle ether without mediator.

In the current work, a new-designed adsorbent of chitosan-salicylaldehyde Schiff base/algae/montmorillonite (CS-SA/ALG/MTN) was prepared for the effective adsorption of anionic (remazol brilliant blue R, RBBR) and cationic (brilliant green, BG) dyes from aquatic media. The Box-Behnken design (BBD) was used to inspect and statistically optimize the three major variables that affect RBBR and BG adsorption: A: CS-SA/ALG/MTN dosage (0.02–0.08 g), B: pH (4–9), and C: duration (5–55 min). The BBD model findings indicated that the ideal parameters for attaining the maximum removal of RBBR (54.3%) and BG (79.4%) were CS-SA/ALG/MTN dose (0.08 g), pH (4 for RBBR and 9 for BG), and duration (30 min). The equilibrium analysis showed that the Freundlich model matched the adsorption data of RBBR adequately, whereas the Langmuir and Freundlich models perfectly represented the adsorption of BG. The kinetic data demonstrated that the pseudo-second-order kinetic model was consistent with the adsorption behavior of RBBR and BG. The maximal adsorption capabilities of CS-SA/ALG/MTN were 148.1 mg/g for RBBR and 440.3 mg/g for BG. The adsorption mechanism of RBBR and BG by CS-SA/ALG/MTN was inferred to be associated with electrostatic attraction, n-π interaction, hydrogen bonding, and π-π stacking. The findings indicate that the new-designed adsorbent developed via this research could serve as a multi-functional adsorbent for the remediation of complicated industrial effluents. [ABSTRACT FROM AUTHOR]

Natural mulberry leaves and carboxylic acid-modified mulberry (Morus alba L.) leaves were used for the first time to scrutinize the effects of modification on the retention efficiency of an anionic dye (Remazol Brilliant Blue R (RBBR)) from aqueous solutions to suggest an economical and promising adsorbent for the treatment of dye-contaminated water. The characterization of the adsorbents was accomplished through common techniques including SEM, FTIR, and pHpzc determination. Several parameters studied in batch experiments pointed out that the initial pH of 2.0 and the contact time of 240 min were optimum conditions for all the developed RBBR uptake processes. An artificial neural network (ANN) model was applied to formulate a forecast model for the uptake efficiency of RBBR. The experimental data were assessed by different kinetic and isotherm models to explain the mechanism of the developed processes in more detail. Maximum monolayer adsorption capacities of natural mulberry leaves and acetic acid-, citric acid-, and oxalic acid-modified mulberry leaves were determined as 64.5, 95.2, 84.8, and 91.7 mg g-1, respectively, by the Langmuir isotherm model. These results demonstrated that the modification with carboxylic acids significantly increases the anionic dye adsorption capacity of the mulberry leaves. [ABSTRACT FROM AUTHOR]

Dyes are among the main environmental pollutants, due to the high amount of discharge of wastewater, lost in the dyeing process, without any further treatment. Anthraquinone dyes are stable and resistant in the aquatic system. Among the methods that have been applied to remove these dyes from wastewaters, adsorption on activated carbon has been reported as a very effective technique, and its modification with oxides and hydroxides of metals have been used to increase its surface area. In the present study, the production of activated carbon was originated by coconut shells, and a mixture of metals and metalloids, such as magnesium, silicate, lanthanum, and aluminum (AC-Mg-Si-La-Al), was used for its subsequent modification and applied to Remazol Brilliant Blue R (RBBR) removal. AC-Mg-Si-La-Al surface morphology was studied by BET, FTIR, and SEM methods. For the evaluation of AC-Mg-Si-La-Al, several parameters, such as dosage, pH, contact time, and initial RBBR concentration were studied. According to the results, in pH 5.0 ± 0.1, the dye percentage rate reached 100% by applying 0.5 g/L. Therefore, the optimal dose of 0.4 g/L and pH 5.0 ± 0.1 are selected, which leads to 99% removal of RBBR. The experimental data found to better fit to Freundlich isotherm (R2 = 0.9189) and pseudo-second-order kinetic (R2 = 0.9291) models and 4 h were the sufficient time for adsorption. According to thermodynamics, a positive value of ∆H0 (19.661 kJ/mol) suggests the endothermic nature of the process. The AC-Mg-Si-La-Al adsorbent was able to regenerate after 5 cycles of use, showing only a 17% decrease in its efficiency. Because of its effectiveness in full RBBR removal, AC-Mg-Si-La-Al could be further examined for the removal of several other dyes, even anionic or cationic. [ABSTRACT FROM AUTHOR]

The issue of industrial dyes has risen to the forefront of environmental concerns, as they are now recognized as a prevalent form of industrial waste that pollutes our surroundings. As such, it is imperative that efforts be made to address their toxicity, with a view to safeguarding the environment and public health. To this end, the application of nanotechnologies presents a promising solution to the challenge of mitigating the harmful effects of industrial dyes on our environment. Copper oxide nanoparticles (CuO NPs) have been found to possess strong photocatalytic properties and are effective in degrading toxic dyes in polluted water and industrial effluents. In this experimental work, CuO NPs were synthesized using Citrus limon leaves extract as source of bioactive molecules to obtain stable NPs. Microscopic and spectroscopic analyses confirmed the formation of CuO NPs with size range of 20–25 nm with spherical shape. In addition, the prepared NPs utilized as photocatalyst against Remazol Brilliant Blue R (RBBR) dye, which shows remarkable potency within 180 min with degradation efficiency ∼90%. Thus, CuO NPs can be used as sustainable, cost-effective and efficient alternative for the removal of toxic industrial effluents from water bodies. [ABSTRACT FROM AUTHOR]

Toxic dye removal, one of the most serious and common industrial pollutants released into natural water, is a critical issue for modern civilization. In this study, a series of UiO-66 composites was synthesized with addition of HKUST-1 using solvothermal method, which was used to remove RBBR dye. The structure, morphology and surface area of the composites were studied by several analyses. HK(5)/UiO-66 possessed a specific surface area of 557.63 m2/g and showed an adsorption capacity of 400 mg/g, higher than that of UiO-66 (261.92 mg/g) with a contact time of 50 min. Several adsorption parameters that influenced RBBR removal efficiency were investigated, such as pH, initial dye concentrations, and temperature. All the composites followed pseudo-first order kinetics and Langmuir isotherm adsorption. Moreover, the adsorption process occurred exothermically and spontaneously, indicating that the adsorption process was advantageous in terms of energy. The possible adsorption mechanism and cost analysis of the adsorbent were also studied in detail.

Extracellular thermophilic multicopper oxidase i.e. laccase was purified, identified and characterized from Geobacillus stearothermophilus MB600. Fast protein liquid chromatography (FPLC) of lacasse showed a prominent peak at 610 nm. Sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) for laccase presented a molecular weight of 59.13 kDa. Analysis via Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) confirmed the presence of laccase similar to in Geobacillus thermoleovorans B23 and Geobacillus sp. LEMMY01. Laccase showed Km 0.532 mM for guaiacol and 0.307 mM for ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)). Its optimum activity was witnessed at 90°C, at pH 5.0. Laccase catalytic activity was completely inhibited by sodium dodecyl-sulfate (SDS), sodium azide (NaN3), and ethylenediaminetetraacetic acid (EDTA). Among the metal salts against Cu, Ca, Cd, and Li enhanced while Mg inhibited the enzyme activity. It was stable against Cl, I and solvents (Ethanol > Methanol > Dimethyl sulfoxide > Acetonitrile). Thermophilic laccase effectively degraded 93% of Remazol brilliant blue R, 92% Bisphenol A diglycidyle ether without mediator. [ABSTRACT FROM AUTHOR]

This work investigates the effects of the co-culture between the filamentous fungus Panus lecomtei and the yeast Sporidiobolus pararoseus in the production of laccases. The variations of time interval and inoculum volume of S. pararoseus in co-cultures with P. lecomtei stimulated laccase production, reaching its highest activity at nearly 2960.7 ± 244 U/mL with a maximum time point of 120 h and 2.0% (v/v), respectively. Further application in the pretreated sugarcane bagasse hydrolysis was performed, using P. lecomtei and S. pararoseus extract added to an enzyme mixture from the co-culture of P. lecomtei and Trichoderma reesei that positively favored the hydrolysis efficiency by 66.87%. Furthermore, the addition of P. lecomtei and S. pararoseus extract increased the degradation of industrial anthraquinone Remazol Brilliant Blue R by 78.98%. As a result, the extract derived from the co-culture of P. lecomtei and S. pararoseus rich in laccases presents potential in biotechnological applications, being suitable in the hydrolysis of lignocellulosic biomass and the degradation of unwanted dyes released in the environment.

In this study, the adsorption abilities of Russula brevipes (RB), Agaricus augustus (AA), and Fomes fomentarius (FF) were evaluated in Basic Red 18 (BR18) and Remazol Brilliant Blue R (RBBR) biosorption from textile effluent. The adsorbents were characterized via Scanning Electron Microscopy (SEM), Energy Dispersive Spectrometer (SEM-EDS), and Fourier transform infrared spectroscopy (FT/IR). Fomes fomentarius presented a low sorption capacity contrary to the two other fungi (RB and AA). RB and AA were selected as potential adsorbents for BR18 and RBBR, respectively. The maximum BR18 removal efficiencies for 10, 25, and 50 mg/L were obtained after 60 min to be 90, 88, and 86%, respectively. The RBBR adsorption efficiencies were 96.4, 96, and 90% for dye concentrations of 10, 25, and 50 mg/L. The adsorption of BR18 onto the RB biomass followed the Freundlich isotherm, while Langmuir is the best isotherm for RBBR sorption's elucidation onto AA fungus biomass. The removal of BR18 by BR biomass was found to follow the pseudo-second order. In contrast, the adsorption of RBBR onto the AA biomass followed Lagergren's pseudo-first order. For both adsorbents, the adsorption was exothermic, feasible, and spontaneous in nature. Finally, the dyes' biosorption process was perfectly achieved onto fungi biomass via physisorption. HIGHLIGHTS Three fungi, Russula brevipes (RB), Agaricus augustus (AA), and Fomes fomentarius (FF) were used for dye adsorption.; Basic Red BR18 and Remazol Brilliant Blue RBBR dyes were tested for adsorption.; Freundlich describe perfectly the sorption process of BR18 dye onto RB fungus.; Langmuir is the best isotherm for RBBR sorption's elucidation onto AA fungus biomass.;

TiO2 and TiO2 doped Cd, Co, Mn (TiO2-M) were synthesized with a sol-gel method, and the photocatalytic activity of Remazol Brilliant Blue R and Remazol Yellow FG has been conducted. TiO2-M (Cd, Co, Mn) was synthesized with the mol Ti:M ratio of 3:1, and the materials were calcined at 300, 400, and 500 °C. The materials were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX), and UV-Vis Reflectance. The XRD result shows that at the temperature of 300 °C TiO2 and TiO2-M formed tend to be amorphous. At 400 °C the anatase phase is formed, while at 500 °C the rutile phase begins to form. And overall, the crystallinity of TiO2 is higher than metal-doped TiO2. The UV-Vis Reflectance result showed that the bandgap energy of all doping materials (TiO2-M) decreased. The larger the metal ion radius of dopant, the larger the crystal size obtained and then the higher the bandgap obtained. The results of SEM-EDX showed that the morphology of TiO2 was spherical and regular, whereas the morphology of TiO2-M had a smoother surface due to the influence of metal doping. Photocatalytic activity of TiO2-M on Remazol Brilliant Blue R and Remazol Yellow FG was greater than TiO2. The optimum pH of the solution was obtained at pH 5 and the optimum catalyst phase was obtained at the anatase phase. The percentages degradation for 30 min of Remazol Brilliant Blue R were 67.34% (TiO2), 92.12% (TiO2-Co), 85.47% (TiO2-Mn), and 83.91% (TiO2-Cd), while for Remazol Yellow FG they were 58.84% (TiO2), 74.61% (TiO2-Co), 67.93% (TiO2-Mn) and 64.19% (TiO2-Cd), respectively. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

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 > 2-HyA-CS > 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. [ABSTRACT FROM AUTHOR]

UV-based advanced oxidation processes (AOPs) (UV/H2O2 and UV/S2O82−) with a titanium(IV)-doped carbon dot, TiP-CD, as a catalyst were developed for the decomposition of Remazol Brilliant Blue R (Reactive Blue 19), an anthraquinone textile dye (at T = 25 °C and pH = 7). The Ti-CD, with marked catalytic UV properties, was successfully synthesized by the one-pot hydrothermal procedure, using L-cysteine as carbon precursor, ethylenediamine as nitrogen source, PEG (polyethylene glycol) as a capping agent, and titanium(IV) isopropoxide (precursor of TiO2 doping). Contrary to azo dyes (methyl orange, orange II sodium salt, and reactive black 5), which achieved complete degradation in a time interval less than 30 min in the developed AOP systems (UV/H2O2, UV/S2O82−, and UV/TiO2), the RBB-R showed relatively low degradation rates and low discoloration rate constants. In the presence of the catalyzer, the reaction rate significantly increased, and the pseudo-first-order rate constants for the RBB-R discoloration were UV/3.0 mM H2O2/TIP-CD-0.0330 min−1 and UV/1.02 mM S2O82−/TIP-CD-0.0345 min−1. [ABSTRACT FROM AUTHOR]

Remazol Brilliant Blue R (RBBR) is a widely used carcinogenic and toxic dye. This study focused on RBBR dye removal using chemically modified and unmodified Yarrowia lipolytica biomass. RBBR dye biosorption studies were carried out as a function of pH, initial dye concentration, biosorbent dose, contact time, and temperature. The pH of the aqueous solution strongly influenced the biosorption percent of RBBR dye. The highest dye biosorption capacity yield was obtained at pH 2–3 range. It has been found that the adsorption capacity is quite low at higher pH values. No differences were found between chemically modified and unmodified biomass in terms of RBBR dye biosorption capacity. In the first 15 min, almost 50% RBBR dye was removed from the solution and reached equilibrium within180 min at pH 2. Biosorption isotherm obeyed Langmuir isotherm model and pseudo-second-order kinetic model. [ABSTRACT FROM AUTHOR]

A laccase from Oudemansiella canarii was immobilized using the crosslinked enzyme aggregate (CLEA) methodology and applied in the degradation of the anthraquinonic dye Remazol Brilliant Blue R (RBBR). The immobilized laccase was superior to the free laccase in both thermal and storage stabilities. Both immobilized and free laccase decolourized 100 mg/L RBBR within 24 h at 30 °C and pH 5.0, but the former was still efficient in degrading the dye after at least 6 cycles. The relationship between the decolorization rate and the RBBR concentration obeyed Michaelis–Menten kinetics, with KM of 0.126 ± 0.044 mmol/L and Vmax of 1.412 ± 0.295 µmol/min for free laccase and KM of 0.159 ± 0.050 mmol/L and Vmax of 1.214 ± 0.242 µmol/min for immobilized laccase. Fourier transform infra-red spectroscopy (FTIR) and mass spectrometry allowed to conclude that the O. canarii laccase acts not only on the chromophore group of the dye, but that it also cleaves other covalent bonds, causing an effective fragmentation of the molecule. The Microtox assay detected a significant diminution in toxicity, a finding corroborated by the phytotoxicity test performed with lettuce seeds. Our results indicate that the immobilized laccase from O. canarii could be useful in biological strategies aiming at degrading unwanted dyes in the environment. [ABSTRACT FROM AUTHOR]

The properties of chitin-based adsorbents varied among studies since they are influenced by different factors, such as the types of base and acid used to extract the chitin. Therefore, this works aimed to investigate the impact of four different acid solutions on the extraction and properties of chitin from shrimp shell waste, and to evaluate the adsorption performance of the obtained chitin on removing dye from an aqueous solution. The result showed that H 2 SO 4 , HCl, and HNO 3 could remove high minerals from the shrimp shell, while the effect of CH 3 COOH was inferior. The Fourier Transform Infrared (FTIR) and X-ray diffraction (XRD) indicated that the extracted chitin was α-amorphous structure, regardless of the type of acid solution. However, the type of acid solution influenced the crystallinity index of the extracted chitin. The Scanning Electron Microscope (SEM) showed both fibrillar material and porous structures. In addition, the chitin extracted through demineralization using H 2 SO 4 was more effective in removing RBBR dye from aqueous solution, followed by HCl, HNO 3, and the last, CH 3 COOH treatment. The performances of chitin-based adsorbent could be attributed to the strength of acid solution used to remove mineral during the extraction process and the obtained pore structures. [ABSTRACT FROM AUTHOR]

Kaolin clay (KN) was employed as an inorganic filler to modify a cross-linked chitosan-glyoxal as Schiff's-based chitosan composite derivative (CTS-GLY). The resulting (CTS-GLY/KN) was found to be a promising composite synthetic biopolymer that can be potentially utilized for color removal as well as COD reduction of an industrial anionic dye (remazol brilliant blue R, RBBR). The surface porosity, crystallinity, morphology, functionality, charge, and amine content of the CTS-GLY/KN were studied using BET, XRD, SEM, FTIR, pHpzc and pH-potentiometric titration analyses, respectively. Response surface methodology-Box-Behnken design (RSM-BBD) was used to optimize the impact of the main input factors on the color removal and COD reduction of RBBR. The adsorptive performance CTS-GLY/KN towards RBBR was well-defined by both Langmuir and Freundlich isotherm models with highest adsorption capacity of 447.1 mg/g at 30 °C. This finding reveals that CTS-GLY/KN can be utilized as a promising, feasible, and environmentally friendly composite-biosorbent for color removal and COD reduction of textile dyes from aqueous medium. [ABSTRACT FROM AUTHOR]

TiO2 and TiO2 doped Cd, Co, Mn (TiO2-M) were synthesized with a sol-gel method, and the photocatalytic activity of Remazol Brilliant Blue R and Remazol Yellow FG has been conducted. TiO2-M (Cd, Co, Mn) was synthesized with the mol Ti:M ratio of 3:1, and the materials were calcined at 300, 400, and 500 °C. The materials were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX), and UV-Vis Reflectance. The XRD result shows that at the temperature of 300 °C TiO2 and TiO2-M formed tend to be amorphous. At 400 °C the anatase phase is formed, while at 500 °C the rutile phase begins to form. And overall, the crystallinity of TiO2 is higher than metal-doped TiO2. The UV-Vis Reflectance result showed that the bandgap energy of all doping materials (TiO2-M) decreased. The larger the metal ion radius of dopant, the larger the crystal size obtained and then the higher the bandgap obtained. The results of SEM-EDX showed that the morphology of TiO2 was spherical and regular, whereas the morphology of TiO2-M had a smoother surface due to the influence of metal doping. Photocatalytic activity of TiO2-M on Remazol Brilliant Blue R and Remazol Yellow FG was greater than TiO2. The optimum pH of the solution was obtained at pH 5 and the optimum catalyst phase was obtained at the anatase phase. The percentages degradation for 30 min of Remazol Brilliant Blue R were 67.34% (TiO2), 92.12% (TiO2-Co), 85.47% (TiO2-Mn), and 83.91% (TiO2-Cd), while for Remazol Yellow FG they were 58.84% (TiO2), 74.61% (TiO2-Co), 67.93% (TiO2-Mn) and 64.19% (TiO2-Cd), respectively. [ABSTRACT FROM AUTHOR]

Remazol Brilliant Blue R (RBBR), a common precursor of other dyes and a toxic organo-pollutant, is an anthraquinone dye extensively used in the textile industry. In this study, biosorption of RBBR by the bacterial strain Bacillus rigiliprofundi was investigated. The effects of various physical parameters on dye adsorption were studied. The kinetics and isotherm of adsorption were analyzed. The bacterial adsorbent was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. Phytotoxicity was evaluated before and after adsorptive removal of the dye. Up to 80% RBBR was adsorbed and removed by the bacteria in ten days. The optimum conditions for biosorption were pH 5.5, adsorbent dosage 30 mg, initial dye concentration 25 mg/L, and temperature 40°C. Adsorption followed the pseudo-first order kinetics and fitted appropriately to the Langmuir model. This is the first report on adsorptive decolorization of the highly recalcitrant RBBR by the strain Bacillus rigiliprofundi. [ABSTRACT FROM AUTHOR]

This study concerns the preparation of novel adsorbent prepared from calcium alginate bead modified with polyethyleneimine (PEI‐CaAlg). The adsorption capacity of the PEI‐CaAlg was examined by Remazol Brilliant Blue R (RBBR) and phosphate adsorption. PEI‐CaAlg showed high removal efficiencies for RBBR (90.48%) and phosphate (88.10%). The removal of both RBBR and phosphate onto the PEI‐CaAlg followed the Freundlich isotherm and the second‐order model. The adsorption was studied in terms of thermodynamic and found to be feasible and spontaneous in nature. The reusability of the modified alginate beads was also examined up to five cycles. The removal efficiency was 90.48% at the first cycle and decreased to 75.15% at the end of the fourth cycle. The adsorption of color and phosphate from real textile wastewater was also instigated. The removal efficiencies for color and phosphate ions reached 80.24% and 90.00%, respectively. Therefore, the prepared PEI‐CaAlg can be considered as a novel, eco‐friendly, and cost‐effective adsorbent for simultaneous dye and phosphate adsorption. Practitioner Points: This study aims to modify the surface of calcium alginate beads with polyethyleneimine (PEI).The adsorption of RBBR and phosphate by the modified alginate beads (PEI‐CaAlg) was investigated.PEI is an organic polymer with a linear/branch shape, which can increase the active sites on the adsorbent surface.PEI has one nitrogen atom in every three atoms provides a positive charge that can complex with the negatively charged molecules.The adsorption of RBBR and phosphate were carried out onto PEI‐CaAlg. [ABSTRACT FROM AUTHOR]

In this work, chitosan/alginate composites were developed by the gelation method with the addition of different amounts of activated carbon produced from tannery waste (ACTW). The performance of these composites was verified through the adsorption of the textile dye Remazol Brilliant Blue R (RBBR). A synergistic effect was observed by the addition of ACTW; with a specific surface area up to 45.584 m2/g, the maximum adsorption capacity was 300.96 mg/g. The synergy was due to the reduction in steric hindrance, with the adsorption capacity 1.2 times higher than expected. The material was regenerated with sodium hydroxide for 10 cycles. The composite containing 30% ACTW (AC30) was applied in the treatment of real textile effluent, with 30% reductions in the biochemical oxygen demand (BOD), 39% in the chemical oxygen demand (COD), 78% in turbidity, and 67% in color. [ABSTRACT FROM AUTHOR]

In this study, the adsorption capacity of toxic and recalcitrant organic pollutant(s) Remazol Brilliant Blue R (RBBR) onto the invader Xanthium İtalicum (XI) plant was assessed using the Response Surface Method (RSM). The adsorp-tion behavior of RBBR was determined by the spectrophotometric method, FTIR and SEM analysis were used to characterize XI, Brunauer, the Emmett and Teller (BET) analysis was accomplished to find the surface area of the ad-sorbent. The experiment procedures were planned by the Central Composite Design (CCD) whereby a model was built to examine the effects of the different parameters and the possible interaction between them. The correlation factor (R2) for the developed model was 0.985, suggesting that the model could achieve 98.5% of RBBR removal through an adsorption process. The desirability of 0.992 can be attained using the identified optimum conditions: XI = 3g, pH = 9, Time = 84min, RBBR = 50ppm. Under these conditions, the adsorption capacity reached 1.59 mg.g-1, and the removal percentage reached 95%. Freundlich isotherm had the best-fitted values with R2 of 0.999. Furthermore, the adsorption of RBBR onto XI was found to be pseudo-second-order kinetic with R2=0.999. Also, the recovery of RBBR from XI was studied through desorption experiments in presents of 0.5M NaOH. The recovery percentage after 120 min reached 47%. The maximum recovery percentage reached 73% at 24h.

UV-based advanced oxidation processes (AOPs) (UV/H2O2 and UV/S2O82−) with a titanium(IV)-doped carbon dot, TiP-CD, as a catalyst were developed for the decomposition of Remazol Brilliant Blue R (Reactive Blue 19), an anthraquinone textile dye (at T = 25 °C and pH = 7). The Ti-CD, with marked catalytic UV properties, was successfully synthesized by the one-pot hydrothermal procedure, using L-cysteine as carbon precursor, ethylenediamine as nitrogen source, PEG (polyethylene glycol) as a capping agent, and titanium(IV) isopropoxide (precursor of TiO2 doping). Contrary to azo dyes (methyl orange, orange II sodium salt, and reactive black 5), which achieved complete degradation in a time interval less than 30 min in the developed AOP systems (UV/H2O2, UV/S2O82−, and UV/TiO2), the RBB-R showed relatively low degradation rates and low discoloration rate constants. In the presence of the catalyzer, the reaction rate significantly increased, and the pseudo-first-order rate constants for the RBB-R discoloration were UV/3.0 mM H2O2/TIP-CD-0.0330 min−1 and UV/1.02 mM S2O82−/TIP-CD-0.0345 min−1.

An extensive screening of saprotrophic Basidiomycetes causing white rot (WR), brown rot (BR), or litter decomposition (LD) for the production of laccase and Mn-peroxidase (MnP) and decolorization of the synthetic dyes Orange G and Remazol Brilliant Blue R (RBBR) was performed. The study considered in total 150 strains belonging to 77 species. The aim of this work was to compare the decolorization and ligninolytic capacity among different ecophysiological and taxonomic groups of Basidiomycetes. WR strains decolorized both dyes most efficiently; high decolorization capacity was also found in some LD fungi. The enzyme production was recorded in all three ecophysiology groups, but to a different extent. All WR and LD fungi produced laccase, and the majority of them also produced MnP. The strains belonging to BR lacked decolorization capabilities. None of them produced MnP and the production of laccase was either very low or absent. The most efficient decolorization of both dyes and the highest laccase production was found among the members of the orders Polyporales and Agaricales. The strains with high MnP activity occurred across almost all fungal orders (Polyporales, Agaricales, Hymenochaetales, and Russulales). Synthetic dye decolorization by fungal strains was clearly related to their production of ligninolytic enzymes and both properties were determined by the interaction of their ecophysiology and taxonomy, with a more relevant role of ecophysiology. Our screening revealed 12 strains with high decolorization capacity (9 WR and 3 LD), which could be promising for further biotechnological utilization. [ABSTRACT FROM AUTHOR]

Adsorption potential of the struvite (recovered from the high-strength ammonium-rich synthetic wastewater) was explored for the first time for the removal of an anthraquinone dye (Remazol Brilliant Blue R, RBBR) from aqueous phases. According to the experimental findings obtained from the RBBR-struvite adsorption system, the maximum dye removal efficiency (≈ 79%) was achieved at pH of 2.0, adsorbent dose of 40 g/L, initial dye concentration of 80 mg/L, contact time of 60 min, and temperature of 60 °C. Adsorption isotherms showed that both Langmuir and Freundlich isotherm models fitted very well to the experimental data (R2 > 0.990), and adsorption kinetics were satisfactorily described by the Ho and McKay's PSO kinetic model (R2 ≈ 0.990). Based on the Langmuir isotherm model, the maximum adsorption capacity of the struvite for the RBBR dye was determined as 21.73 mg/g. The sample exhibited a mesoporous structure and had a BET surface area of 16.35 m2/g. Thermodynamic parameters (ΔG°, ΔH°, and ΔS°) confirmed that the adsorption of the RBBR dye onto the struvite was spontaneous and endothermic in nature and reflected the enhanced degree of disorderliness at the solid/liquid interface, respectively. A MIMO (multiple inputs and single output) Mamdani-type fuzzy inference system was developed for the first time in modeling of the RBBR-struvite adsorption system. The proposed fuzzy logic model showed a superior prediction performance (R2 ≈ 0.980) when compared to the conventional multiple regression methodology. Overall experimental and statistical results confirmed that struvite could be used as a promising adsorbent material for anthraquinone dye removal from aqueous solutions. [ABSTRACT FROM AUTHOR]

Synthesis of amino functionalized organosilane (AFOS) via UV-irradiation method has been conducted. In this research, the precursors for synthesizing AFOS are 3-glycydiloxypropyl trimethoxysilane (GPTMS) and ethylene diamine. Synthesis of amino functionalized organosilane was performed for 16 h monitored by Infra-red spectroscopy technique. The morphological structure of AFOS was observed by scanning electron microscopy. The adsorption process was conducted in the batch method using Remazol Brilliant Blue R (RBBR) as anionic dye model. In this study, the pH, contact time and dyes concentration were varied to determine the optimum pH, kinetic and isotherm adsorption. Based on the calculation, the kinetic rate of the RBBR adsorbed onto AFOS was determined by k2 (pseudo second-order). Moreover, the isotherm study showed that the Langmuir model fitted for the adsorption of RBBR onto AFOS with Qm by 21.3 mg g-1.

The anthraquinone dye Remazol Brilliant Blue R is largely used in the textile industry. However, its removal from wastewaters is costly and complex. Many methods have been tested to solve this ecological problem, but there is still a need for efficient methods. We propose here an alternative use of a two-chambered microbial fuel cell (MFC), fuelled with domestic wastewater in the anodic chamber, to degrade a simulated textile dye effluent made of Remazol Brilliant Blue R inoculated with an immobilised fungal strain, Pleurotus ostreatus URM 4809, as a laccase producer, in the cathodic chamber. The MFC showed continuous synthesis of laccase in the cathodic chamber, which, in turn, promoted the rapid decolourisation, of more than 86% of the textile dye effluent. The yield was further increased by the addition of glycerol. Electrochemical monitoring also indicated an increase in power density and current density. After 20 days of MFC operation, 62.1% of organic matter was removed in the anodic compartment, thus leaving the effluent with a much lower toxicity. [ABSTRACT FROM AUTHOR]

Adsorption behavior of Acid Black 210 (AB210) and Remazol Brilliant Blue R (RBBR) from aqueous solutions onto magnetite nanoparticles (MNPs) was studied. Affecting parameters such as solution pH, contact time, adsorbent amount, and initial concentration of the dyes on the adsorption process were studied. Analysis of the kinetic data indicated that the adsorption process follows pseudo-second-order kinetics. The adsorption equilibrium data were analyzed by Langmuir and Freundlich isotherm models. The adsorption capacities for AB210 and RBBR were 70.80 and 74.40 mg g−1, respectively. This study suggested MNPs as effective and reusable adsorbent to remove the dyes from aquatic solutions. [ABSTRACT FROM AUTHOR]

• Investigations of a new method for stimulation of enzymatic reactions are presented. • RMF influences on the activity of HRP. • RMF has improved HRP activity in wider range of pH. • Exposure to RMF caused an acceleration of the RBBR decolorization process. The aim of this study was to analyze the effects of a rotating magnetic field (RMF) on the activity and stability of horseradish peroxidase (HRP) and the catalyzed enzymatic process. It was found that 8 h of exposure to RMF does not influence the operational stability of HRP. At the same time, it was observed that the RMF improved HRP activity in a wider range of pH: 49% and 68% at pH 6.5 and pH 7.0, respectively. The efficiency of the catalyzed enzymatic process under exposure to RMF was analyzed by two-dimensional correlation analysis (2DCorr) on the example of the Remazol Brilliant Blue R (RBBR) decolorization process. The obtained results indicated the influence of RMF on the intensification of this process. Our studies showed an alternative method of enzymatic process intensification, which is significant in science and has practical value for applications. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Simple and Scalable solid-state synthesis of nanostructured Bi 5 O 7 NO 3 and Bi 2 O 3 photocatalysts. • Role of the presence β-Bi 2 O 3 on the visible-light driven photocatalytic activity of Bi 5 O 7 NO 3. • Sunlight photodegradation of Rhodamine B, Indigo Carmine and Remazol Brilliant Blue R dyes. • Dyes mineralization and water oxidation on β-Bi 2 O 3 /Bi 5 O 7 NO 3 heterostructured nanoflakes. Abstract A simple, solvent-free and scalable route for the synthesis of nanostructured Bi 5 O 7 NO 3 and Bi 2 O 3 polymorphs photocatalysts and their heterostructures is here presented. Morphology, porosity and crystal phases were tuned by controlling the thermal decomposition of Bi(NO 3) 3 :5H 2 O, by using different calcination temperatures and cooling processes. Bi 5 O 7 NO 3 layered nanosheets, highly porous β-Bi 2 O 3 /Bi 5 O 7 NO 3 heterostructured nanoflakes and micrometric sheets of α-Bi 2 O 3 were obtained at temperatures of 400 °C, 425–450 °C and 525 °C with a slow cooling rate, respectively. Moreover, in contrast to previous reports on Bi 5 O 7 NO 3 , the role on the visible-light driven photocatalytic activity of Bi 5 O 7 NO 3 due to the formation of a stable heterojunction with β-Bi 2 O 3 , which here was identified to be also formed by a rapid cooling after calcination at 400 °C, was deeply investigated and demonstrated. All the samples were fully characterized by X-ray Diffraction, Field-emission scanning electron microscopy, UV–vis spectroscopy, N 2 adsorption and X-ray Photoelectron Spectrometry analyses. The role of oxygen vacancies, which indicate structural defects and/or sub-stoichiometric forms of Bi 5 O 7 NO 3 or Bi 2 O 3 in the photocatalysts surface, was also analyzed and correlated to their photo-response. Simulated sunlight-driven degradation of organic dyes with different functionalities, i.e. a cationic dye (Rhodamine B) and an anionic one (Indigo Carmine), was investigated and proved to be optimized due to an efficient synergy between suitable amounts of Bi 5 O 7 NO 3 and β-Bi 2 O 3 in the heterostructured samples. An improved charge carriers separation at the heterojunction interphase and an enhanced formation of reactive oxygen species in these materials were additionally confirmed by both photocatalytic water oxidation experiments with O 2 evolution and mineralization of a refractory anionic dye, i.e. Remazol Brilliant Blue R. The latter was reached with an optimum photocatalyst/dye weight ratio of 33, which is about 2–3 times lower than previous literature results. [ABSTRACT FROM AUTHOR]

In this study, adsorbents were produced from sewage sludge via chemical and thermal activation processes. Experiments were carried out in a tubular furnace at the heating rate of 20˚C min-1 and temperature of 550 ˚C with a nitrogen flow rate of 400 mL min-1 for 1 h. Dye adsorption experiments were performed with Remazol Brilliant Blue R for its several concentrations under batch equilibrium conditions by comparing sewage sludge based adsorbents with raw material and a commercial activated carbon. Maximum adsorption capacities of carbonized sewage sludge (CSWS) and activated sewage sludge (ASWS) were found as 7.413 mg g-1 and 9.376 mg g-1 for 100 mg L-1 dye solution, whereas commercial activated carbon had a capacity of 11.561 mg g-1. Freundlich and Langmuir isotherms were used to explain the adsorption mechanism together with pseudo-first-order and pseudo-second-order kinetic models. Langmuir isotherm, which had adsorption capacities of 34.60 mg g-1 (CSWS) and 72.99 mg g-1 (ASWS), provided better fit to the equilibrium data than that of Freundlich isotherm. Pseudo second-order, model which had adsorption capacities of 7.451 mg g-1 (CSWS) and 9.319 mg g-1 (ASWS), was very favorable to explain the adsorption kinetics of the dye with high regression coefficients.

An extensive screening of saprotrophic Basidiomycetes causing white rot (WR), brown rot (BR), or litter decomposition (LD) for the production of laccase and Mn-peroxidase (MnP) and decolorization of the synthetic dyes Orange G and Remazol Brilliant Blue R (RBBR) was performed. The study considered in total 150 strains belonging to 77 species. The aim of this work was to compare the decolorization and ligninolytic capacity among different ecophysiological and taxonomic groups of Basidiomycetes. WR strains decolorized both dyes most efficiently; high decolorization capacity was also found in some LD fungi. The enzyme production was recorded in all three ecophysiology groups, but to a different extent. All WR and LD fungi produced laccase, and the majority of them also produced MnP. The strains belonging to BR lacked decolorization capabilities. None of them produced MnP and the production of laccase was either very low or absent. The most efficient decolorization of both dyes and the highest laccase production was found among the members of the orders Polyporales and Agaricales. The strains with high MnP activity occurred across almost all fungal orders (Polyporales, Agaricales, Hymenochaetales, and Russulales). Synthetic dye decolorization by fungal strains was clearly related to their production of ligninolytic enzymes and both properties were determined by the interaction of their ecophysiology and taxonomy, with a more relevant role of ecophysiology. Our screening revealed 12 strains with high decolorization capacity (9 WR and 3 LD), which could be promising for further biotechnological utilization.

ABSTRACT Lentinus crinitus is a white-rot fungus that produces laccase, an enzyme used for dye decolorization. Enzyme production depends on cultivation conditions, mainly agro-industrial by-products. We aimed to produce laccase from Lentinus crinitus with agro-industrial by-products for dye decolorization. Culture medium had coffee husk (CH) or citric pulp pellet (CP) and different nitrogen sources (urea, yeast extract, ammonium sulfate and sodium nitrate) at concentrations of 0, 0.7, 1.4, 2.8, 5.6 and 11.2 g/L. Enzymatic extract was used in the decolorization of remazol brilliant blue R. CH medium promoted greater laccase production than CP in all evaluated conditions. Urea provided the greatest laccase production for CH (37280 U/L) as well as for CP (34107 U/L). In CH medium, laccase activity was suppressed when carbon-to-nitrogen ratio changed from 4.5 to 1.56, but the other nitrogen concentrations did not affect laccase activity. For CP medium, reduction in carbon-to-nitrogen ratio from 6 to 1.76 increased laccase activity in 17%. The peak of laccase activity in CH medium occurred on the 11th day (41246 U/L) and in CP medium on the 12th day (32660 U/L). The maximum decolorization within 24 h was observed with CP enzymatic extract (74%) and with CH extract (76%).

Staphylococcus sp. K2204, a bacterial isolate, was employed in this work to decolorize Remazol Brilliant Blue R (RBBR), which belongs to the anthraquinone class of textile dye. Staphylococcus sp. K2204 biodegraded 100 mg/L RBBR at 37°C under static condition with the help of extracellular laccase and peroxidases. The products of RBBR degradation were characterized using analytical tools including mass spectral technique. The phytotoxicity tests evaluated the toxicity of RBBR and the products of biodegradation. The research outlined here is the first attempt to utilize Staphylococcus sp. K2204 for remediating the wastewater containing anthraquinone textile dye. [ABSTRACT FROM AUTHOR]

Abstract Panus strigellus is a native basidiomycete from Brazil with laccase production potential. Laccases are involved in the biodegradation of dyes and their production can be stimulated by cultivation with agro industrial by-products. This study aimed to evaluate laccase production of P. strigellus cultivated with sugarcane bagasse on dye decolorization. Culture media had different concentrations of sugarcane bagasse (SB), sources of nitrogen (urea, yeast extract, ammonium sulfate and sodium nitrate), and concentrations of copper sulfate (0, 50, 100, 200, and 300 μM). Enzymatic extract from fungal cultivation was used in the decolorization of reactive blue 220 (RB220), malachite green (MG), and remazol brilliant blue R (RBBR). Laccase production was inversely proportional to the amount of SB in cultivation medium and higher titers of enzyme were obtained when 20 g/L SB (SB20) was used. Cultivation medium with SB20 and most nitrogen sources did not have a positive effect on laccase production whereas the addition of urea or yeast-extract reduced laccase production. Most of the copper sulfate concentrations added to SB20 medium increased laccase production, and the maximum laccase production was 55,342 U/L in the SB20 medium with 200 μM copper. The crude enzymatic extract was more effective in the decolorization of azo dye (RB220), with more than 90% of decolorization in 24 h, than anthraquinone dye (RBBR), with 60% decolorization, and triphenylmethane dye (MG), with 68% decolorization, both in 72 h. Highlights • Sugarcane bagasse stimulates laccase production; • Protein and non-protein nitrogen does not increase laccase production; • Copper sulfate increase laccase production; • Panus strigellus laccase decolorizes several chemical classes of dyes. [ABSTRACT FROM AUTHOR]

Aqueous biphasic systems (ABS) are a promising method for separation and purification of several biomolecules. The use of organic compounds as phase former in ABS have been studied with the main finality to obtain systems with lower viscosity compared to conventional systems (composed of a polymer and a salt or two different salts). In this work, the effect of three different alcohols (1-propanol, 2-propanol, and tert-butanol) in ABS composed of alcohol + ammonium sulfate + water was evaluated. The phases diagrams were obtained, and the alcohol nature presented direct influence at the biphasic region. The experimental data were also correlated using an NRTL and UNIQUAC model, and the NRTL model presented a low mean deviation (RMSD < 0.33%). The partition of a textile dye, Remazol Brilliant Blue R, was evaluated and presented partition coefficients (K) higher than 26.4 and extraction efficiency up to 97.2%, indicating a potential application of these systems. [ABSTRACT FROM AUTHOR]

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Denim fabric waste was used as a carbon precursor, and chemically activated with phosphoric acid in the ratio of 1:1 ( v:m ) under a slow pyrolysis process to obtain activated carbon fibers (ACFs). The chemical and physical properties of the ACFs were investigated from the thermogravimetric analysis (TGA), N 2 porosimetry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman and Fourier transform infrared spectroscopy (FTIR), Boehm titration method, and point of zero charge ( pH PZC ). The obtained ACFs showed high yield (53%), BET surface area of 1582 m 2 g −1 , mesoporous features (average pore diameter of 3.60 nm), and surface acidic properties ( pH PZC value of 2.13 and 1.13 mmol g −1 of acidic groups). The ACFs were applied in the removal of textile dye, Remazol Brilliant Blue R (RBBR), from aqueous solution. The adsorption isotherm and kinetic studies showed that adsorption of RBBR on the ACFs were better described by the pseudo-second order kinetic model and the Freundlich equilibrium model. The maximum adsorption capacity of the ACFS for RBBR was determined to be 292 mg g −1 , which is higher than other adsorbent materials reported in the literature. The adsorption thermodynamic parameters indicated that adsorption process is spontaneous and exothermic. [ABSTRACT FROM AUTHOR]

Activated carbons are regularly used for dye wastewater treatment. They can be produced from various organic materials which have a high level of carbon content. In this study, Pinang frond based activated carbon (PFAC) was produced by using a physical activation process to study the effect of different activation times in the range of 1–7 hours. The optimum PFAC sample was found with an activation time of 3 hours, which gives the highest BET surface area and pore volume of 958.23 m2/g and 0.5469 mL/g, respectively. This sample shows well-developed pore structure with a high fixed carbon content of 79.74%. The removal of 87.6% of Remazol Brilliant Blue R (RBBR) was achieved for a sample with initial RBBR concentration of 50 mg/L, and 40.8% was achieved with 500 mg/L. The results indicated that the PFAC is very effective for RBBR adsorption from aqueous solutio

Use of aqueous extracts of leaves, stems, and roots of the pernicious aquatic weed ipomoea (Ipomoea carnea) drawn from different locations was explored in the biomimetic extracellular synthesis of silver nanoparticles (SNPs). It was found that despite the natural variability in the chemical content of ipomoea growing in different locations, certain extract–metal stoichiometries can be identified which give strikingly reproducible results in terms of the size and the shape of the SNPs. This is one of the first reports of its type in which possible role of natural variability in the chemical composition of a given botanical species on nanoparticle synthesis involving that species has been assessed. The use of the SNPs was explored in the degradation of typical organic pollutants—the dyes Alizarin Red S and Remazol Brilliant Blue R. The SNPs were found to speed up the dye degradation.

Decolorization of Remazol Brilliant Blue R (RBBR) by Trametessp. Pellets was studied in a batch reactor. Dye removal process was performed in shaken flasks which contained 100 ml of RBBR aqueous solution and fungal pellets. The process was followed for 48 h and the dye removal was analyzed at a visible spectrum of 590 nm. Response surface methodology (RSM) employing Box Behnken design at three factors i.e. initial concentration of RBBR, mass of pellet and pH was used to optimize the decolorization process) with three replicates. Response surface regression showed that the decolorization efficiency was affected by initial RBBR concentration. Mass of pellet and pH in this model were not found to be insignificant for both main and square effects. The dye decolorization varied within the range of 16.81% to 77.91%. The lowest decolorization was achieved in maximum initial concentration dye and pH. While the highest decolorization was observed when low initial dye concentration and pH were used. From the optimization, maximum dye removal efficiency of 67.9% ± 5.43 was achieved at 50 ppm RBBR solution, 4 gram of pellets at pH 5.6.