French Fries-Like Bismuth Oxide: Physicochemical Properties, Electrical Conductivity and Photocatalytic Activity

Bismuth oxide synthesis using hydrothermal method has been conducted. This study aims to examine the effect of the hydrothermal reaction time on product characteristics and photocatalytic activity in degrading methyl orange dye. Bismuth oxide synthesis was initiated by dissolving bismuth nitrate pentahydrate (Bi(NO3)3.5H2O) and Na2SO4 in a distilled water and added NaOH gradually. The solution formed was transferred into a Teflon-lined autoclave and heated at 120 °C with time variations of 8–16 h. The formation of bismuth oxide was indicated by the vibrations of the Bi−O−Bi and Bi−O groups and the crystal structure consisting of a-Bi2O3, β-Bi2O3, and g-Bi2O3. In addition, the highest photocatalytic activity can be examined through several factors, such as: content of Bi−O−Bi and Bi−OH groups, crystal structure, band gap values, morphology, and surface area, acquired as a result of the effect of hydrothermal reaction time. 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).

Antibacterial Films of Alginate-CoNi-Coated Cellulose Paper Stabilized Co NPs for Dyes and Nitrophenol Degradation

The development of a solid substrate for the support and stabilization of zero-valent metal nanoparticles (NPs) is the heart of the catalyst system. In the current embodiment, we have prepared solid support comprise of alginate-coated cellulose filter paper (Alg/FP) for the synthesis and stabilization of Co nanoparticles (NPs) named as Alg/FP@Co NPs. Furthermore, Alginate polymer was blended with 1 and 2 weight percent of CoNi NPs to make Alg-CoNi1/FP and Alg-CoNi2/FP, respectively. All these stabilizing matrixes were used as dip-catalyst for the degradation of azo dyes and reduction of 4-nitrophenol (4NP). The effect of initial dye concentration, amount of NaBH4, and catalyst dosage was assessed for the degradation of Congo red (CR) dye by using Alg-CoNi2/FP@Co NPs. Results indicated that the highest kapp value (3.63 × 10−1 min−1) was exhibited by Alg-CoNi2/FP@Co NPs and lowest by Alg/FP@Co NPs against the discoloration of CR dye. Furthermore, it was concluded that Alg-CoNi2/FP@Co NPs exhibited strong catalyst activity against CR, and methyl orange dye (MO) degradation as well as 4NP reduction. Antibacterial activity of the prepared composites was also investigated and the highest l activity was shown by Alg-CoNi2/FP@Co NPs, which inhibit 2.5 cm zone of bacteria compared to other catalysts.

Modified Composite Based on Magnetite and Polyvinyl Alcohol: Synthesis, Characterization, and Degradation Studies of the Methyl Orange Dye from Synthetic Wastewater

The goal of the present paper was to synthesize, characterize, and evaluate the performance of the modified composite based on magnetite (Fe3O4) and polyvinyl alcohol (PVA). The obtained composite was used to degrade Methyl Orange dye from synthetic wastewater by a laboratory photocatalytic reactor. Various parameters of the photodegradation process were tested: composite dosage, amount of hydrogen peroxide (H2O2), and pH. The composite was characterized by Fourier Transform Infrared (FTIR) Spectroscopy, X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). The degradation experiments indicated that the complete dye decolorization depended on the amount of H2O2. In addition, the H2O2 could accelerate Methyl Orange degradation to more highly oxidized intermediates in the presence of UV light (99.35%). The results suggested that the obtained modified composite could be used to treat wastewater containing various types of dyes.

Characterization of algae residue biochar and its application in methyl orange wastewater treatment

In this work, Spirulina residue was used as the raw material to prepare different biochars by changing the pyrolysis time. Moreover, the obtained products were characterized by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction energy spectrum. This experiment used the batch adsorption method to study the adsorption effect of pH, dosage, and pyrolysis time on methyl orange. The adsorption of methyl orange onto Spirulina residue biochar fitted with the Langmuir isotherm model and pseudo-second-order kinetics. The results showed that the surface functional groups of Spirulina residue biochar obtained by dry pyrolysis were abundant, and it can effectively adsorb methyl orange dye in an aqueous solution. The sample prepared at 500 °C for 5 h had the best adsorption effect on methyl orange. The change of pyrolysis time will affect the physicochemical properties of biochar from Spirulina residue, thereby affecting its adsorption effect on methyl orange dye. The analysis showed that the chemical adsorption of Spirulina residue biochar on methyl orange might be the primary way of dye removal. The results can provide a reference for preparing biochar from algae residue and biochar application in the removal of dye wastewater.