Kinetics Modeling on the Biosorption of Remazol Black B Dye by Aspergillus flavus

Azo dyes, such as Remazol Black B, are different from conventional dyes in that they establish covalent bonds with textile fibers like cotton. They are widely utilized in the textile industry because of their favorable properties of bright color, water resistance, simple application procedures, and low energy consumption. Their discharge into receiving streams has major environmental consequences, such as reducing photosynthesis in aquatic life due to lower light penetration. The biosorption isotherm data of Remazol Black B dye biosorption by Aspergillus flavus were investigated using two models—pseudo-1st order and pseudo-2nd order—and fitted using non-linear regression. The pseudo-1st order model was found to be the best by statistical analysis using root-mean-square error (RMSE), adjusted coefficient of determination (adjR2), bias factor (BF), accuracy factor (AF), corrected AICc (Akaike Information Criterion), Bayesian Information Criterion (BIC), and Hannan–Quinn information criterion (HQC). At 250 mg/L, kinetic analysis using the pseudo-1st order model yielded an equilibrium sorption capacity qe of 4.61 mg/g (95 % confidence interval from 4.54 to 4.68) and a pseudo-1st-order rate constant, k1 of 0.15 (95% C.I. from 0.128 to 0.164).

Remazol Black Decontamination Study Using a Novel One-Pot Synthesized S and Co Co-Doped TiO2 Photocatalyst

This study investigated the decolorization of Remazol Black (RBB) using a TiO2 photocatalyst modified by S and Co co-doped TiO2 (S-Co-TiO2) from a single precursor. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and UV–Vis specular reflectance spectroscopy were used to characterize the photocatalysts. The results revealed that the band-gap energy of the doped and co-doped TiO2 decreased, with the S-Co-TiO2 8% showing the greatest one, and was found to be 2.78 eV while undoped TiO2 was 3.20 eV. The presence of S and Co was also identified through SEM-EDX. An activity study on RBB removal revealed that the S-Co-TiO2 photocatalyst showed the best result compared to undoped TiO2, S-TiO2, and Co-TiO2. The S-Co-TiO2 8% photocatalyst reduced RBB concentration (20 mg L−1) up to 96% after 90 min of visible light irradiation, whereas S-TiO2, Co-TiO2, and undoped TiO2 reduced it to 89%, 56%, and 39%, respectively. A pH optimization study showed that the optimum pH of RBB decolorization by S-Co-TiO2 was 3.0, the optimum mass was 0.6 g L−1, and reuse studies show that S-Co-TiO2 8% has the potential to be used repeatedly to remove colored pollutants. The results obtained indicate that the modification of S, Co co-doped titania synthesized using a single precursor has been successfully carried out and showed excellent characteristics and activity compared to undoped or doped TiO2.

Degradation of Remazol Black dye from Aqueous Solution by Heterogeneous NH3(MoO3)3/H2O2 System

Aims: The pollution of the environment by organic dyes in water is a matter of great concern. Wastewater containing dyes is difficult to treat by conventional wastewater treatment methods such as coagulation, ozonation, biological treatment, etc. This is why the implementation of an effective method by not generating pollutants secondary is necessary. The objective of this work is to study the degradation of remazol black, an azo dye, by the coupling of hydrogen peroxide - molybdenum oxide nanoparticle. The nanoparticles were synthesized by the aqueous sol-gel method using a reflux assembly. Study Design: Random design. Methodology: The nanoparticles were synthesized by the aqueous sol-gel method using a reflux assembly and then characterized by X-ray diffraction and using software origin to determine the particles size by Scherrer's formula. The influence of hydrogen peroxide, molybdenum oxide and hydrogen peroxide / molybdenum oxide coupling, and the degradation kinetics of remazol black were studied. We also studied the influence of the pH of the solution, the mass of molybdenum nanoparticles and the concentration of remazol black on the dye degradation process. Results: The results showed that the synthesized oxide is ammonium molybdenum trioxide NH3(MoO3)3) with a hexagonal structure and size 22.79 nm. The study of the catalytic effect revealed a degradation rate of 17%, 0.83% and 42% respectively for H2O2, NH3(MoO3)3 and the coupling NH3(MoO3)3/H2O2. The study also showed that the degradation of remazol black by the couple NH3(MoO3)3 /H2O2 is better at pH = 4 and for a mass of nanoparticles of 400 mg. This degradation kinetics are pseudo 1st order. In addition, the degradation rate decreases when the concentration of remazol black increases. The efficiency of the coupling (NH3(MoO3)3 / H2O2 showed at ambient temperature, that it was possible to remove about 60% of the initial color of remazol black from the water in a batch reaction. Conclusion: The reflux method makes it possible to synthesize molybdenum nanoparticles. The molybdenum oxide hetero-Fenton process is effective in removing remazol black dye from water.

Graphite/NiO/Ni Electrode for Electro-oxidation of the Remazol Black 5 Dye

Graphite/NiO/Ni electrode had been fabricated for the electro-oxidation of remazol black 5 dye. The electrode was synthesized by electrodeposition method. Electro-oxidation of 100 ppm remazol black 5 dye was carried out at various concentrations of NaCl, 0.025; 0.05; 0.1; 0.25; and 0.5 M, variations in electro-oxidation time were 15, 30, 45, and 60 minutes, and pH variations were 4, 6, and 8. Cyclic voltammetry test revealed that graphite/NiO/Ni electrode had higher electrocatalytic capability compared to graphite electrode. The X-ray diffraction (XRD) patterns showed the decreasing value of 2θ from 44.6° for Ni to 43.5° for NiO. Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX) showed that NiO/Ni deposited on the graphite surface in the form of solid grains and cracks, FTIR showed that δ(Ni−O) bond appeared at 582–511 cm−1. The decolorization efficiency of remazol black 5 for graphite/NiO/Ni electrode was 100% for 45 minutes of the electro-oxidation process, while the decolorization efficiency of remazol black 5 for graphite electrode was 99.74% for 60 minutes of the electro-oxidation process. 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).

Enhanced photocatalytic degradation of Remazol Black under visible light illumination through S doped TiO2 (S-TiO2) nanoparticles: Operational factors and kinetic study

<p>The degradation of Remazol Black (RBB) by S-TiO2 photocatalyst was investigated. X-ray diffraction, fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and UV-vis specular reflectance spectroscopy has been used to characterize S-TiO2. The results suggested that the optical absorption edge of TiO2 was red-shifted by the addition of S dopants and the bandgap energy was 3.02 eV. The sulfur species were found to be evenly dispersed on the TiO2 crystal lattice as cationic sulfur (S6+) which corresponds to the cationic substitution on TiO2. The particle size decreased to 4-14 nm after S doping, which indicates that the addition of S dopants has contributed to an improvement in the photocatalyst surface area. The degradation of RBB was achieved 94% after 120 min visible light irradiation, a remarkable increase compared to bare TiO2 which was only able to degrade 48% of RBB at the same time. Optimization of the pH showed that the optimum pH for RBB degradation was 3.0, and the photocatalyst dose was 0.8 g L-1. Kinetic study showed that S-TiO2 photocatalytic degradation of RBB followed the pseudo-second-order kinetics model. Reducing the bandgap has been found to increase the activity of photodegradation in the visible light region.</p>

Optimization of Remazol Black B Removal Using Biochar Produced from Caulerpa scalpelliformis Using Response Surface Methodology

Optimization of process conditions for the removal of Remazol Black B was investigated using response surface methodology (Box–Behnken design). The biodecolorization of dye was studied using biochar produced from waste biomass of Caulerpa scalpelliformis (marine seaweeds). The reactions were optimized by varying sorbent dosage, solution pH, temperature, and initial dye concentration. The results indicated that dye removal efficiency of 80.30% was attained at an operating condition of 4 g/L (sorbent dosage), 2.0 (solution pH), 35°C (temperature), and 0.25 mmol/L (initial dye concentration). The regression coefficient of the developed model was calculated to be 97% which shows good fit of the model.