Adsorption performances and electrochemical characteristics of methyl blue onto magnesium-zinc ferrites

A novel and facile rapid combustion approach was developed for the controllable preparation of small size and easy recovery magnesium-zinc ferrites for methyl blue (MB) removal in dye solution. The effects of prepared criteria of x value, calcination temperature, and the amount of ethanol on the average grain sizes and magnetic property were reviewed. The characterization results displayed that Mg0.5Zn0.5Fe2O4 nanoparticles met the expectations of the experiment at the calcination temperature of 400℃ with absolute ethanol volume of 20 mL, and they were selected to remove MB. The adsorption process belonged to chemical adsorption on the basis of the pseudo-second-order model. The electrochemical characteristics of MB onto the prepared nanoparticles were analyzed by cyclic voltammetry (CV). The influences of pH and cycle times on the removal efficiency were investigated. When the pH went beyond 3, the removal efficiency of MB onto the magnetic Mg0.5Zn0.5Fe2O4 nanoparticles maintained above 99%，the maximum adsorption capacity was 318.18 mg/g. After seven cycles, the relative removal rate of MB remained 96% of the first one.

Synthesis and Characterization of Zinc Oxide Nanoparticles Using Acacia caesia Bark Extract and Its Photocatalytic and Antimicrobial Activities

This paper presents the green synthesis and characterization of ZnO nanoparticles and their microbial and photocatalytic application. The green synthesis of ZnO nanoparticles was carried out using Zinc nitrate hexahydrate and the bark extract of Acacia caesia (L.) Willd. The nanoparticles were synthesized at an optimum temperature of 65 °C followed by calcination at 400 °C. The samples were characterized using UV-visible spectroscopy, SEM, XRD, FTIR and EDX analysis. UV-visible spectroscopy showed a characteristic peak at 338 nm and the bandgap energy was found to be 3 eV which is specific for ZnO. SEM confirmed the presence of ZnO on its nanoscale. EDX gave the elemental details of Zinc constituting to 37.77% and Oxygen comprising 20.77% of its atomic weight. XRD analysis gave the diffractogram indexed at various angles corresponding to ZnO nanoparticles. It also revealed the average crystalline size to be 32.32 nm and the shape was found to be hexagonal. The functional group present in the nanoparticles was characterized using FTIR, which gave a characteristic peak at 485 cm−1. The synthesized nanoparticles exhibited significant photocatalytic (methyl blue under UV irradiation). The presence of nanoparticles induces changes in its kinetics, whose rate constants and correlation coefficients were analyzed during the photocatalytic degradation of the model pollutant Methyl Blue. Studies on antibacterial (Escherichia coli, Staphylococcus aureus), antifungal (Aspergillus niger, Candida albicans) and anti-inflammatory (COX assay) properties were also carried out. The nanoparticles were synthesized in an eco-friendly and cost-effective method. The study opens new horizons in the field of water treatment, biosensors and nanotechnology.

Effective Removal of Methyl blue and Crystal Violet Dyes Using Improved Polysulfone / ZIF-8 Nanocomposite Ultrafiltration Membrane

Zeolitic Imidazole framework 8 (ZIF-8) was successfully prepared in an aqueous medium and then dissolved with concentrations ranging from 0.5% to 5% in polysulfone (PSF) to prepare an ultrafiltration membrane. ZIF-8 nanosized material uniformly distributed in the PSF membrane ultrafiltration membrane was prepared in a polar solvent of N,N'-dimethyl formamide (DMF) by phase inversion procedure. Significantly, ZIF-8 enhanced the membrane flux from 50.42 L/m2.h (PSF) to 83.65 L/m2.h at 100 Kpa, and the rejection of methyl blue and crystal violet dyes up to 95.1% and 89.65 %, respectively compared to the PSF membrane without ZIF-8, 41.08%, 46.32%. Wavelength dispersive X-ray fluorescence (WD-XRF), X-ray Diffraction (XRD), scanning electron microscopy (SEM), contact angle, and dead-end filtration experiment were carried out to characterize the morphology and performance of the prepared ZIF-8 and membranes. The hydrophilicity of the membrane was determined by a contact angle test between water and membrane. SEM was used to study the surface and the cross-sectional morphologies.

Concurrent Synthesis and Immobilization of Ag Nanoparticles over TiO2 via Plasma Reduction for Photocatalytic Treatment of Methyl Blue in Water

Pure TiO2 nanoparticles (TiO2NPs) were produced via the sol–gel method and then coated with silver nanoparticles (AgNPs) to reduce their optical band gap. The concurrent synthesis and immobilization of AgNPs over TiO2NPs was achieved through the interaction of an open-air argon plasma jet with a solution of silver nitrate/stabilizer/TiO2NPs. The one-pot plasma synthesis and coating of AgNPs over TiO2NPs is a more straightforward and environmentally friendly method than others. The plasma-produced Ag/TiO2 nanocomposites were characterized and tested for their photocatalytic potential by degrading different concentrations of methyl blue (MB) in water. The dye concentration, oxidant dose, catalyst dose, and reaction time were also optimized for MB degradation. XRD results revealed the formation of pure AgNPs, pure TiO2NPs, and Ag/TiO2 nanocomposites with an average grain size of 12.36 nm, 18.09 nm, and 15.66 nm, respectively. The immobilization of AgNPs over TiO2NPs was also checked by producing SEM and TEM images. The band gap of AgNPs, TiO2NPs, and Ag/TiO2 nanoparticles was measured about 2.58 eV, 3.36 eV, and 2.86 eV, respectively. The ultraviolet (UV) results of the nanocomposites were supportive of the degradation of synthetic dyes in the visible light spectrum. The AgNPs in the composite not only lowered the band gap but also obstructed the electron–hole recombinations. The Ag/TiO2 composite catalyst showed 90.9% degradation efficiency with a 5 ppm dye concentration after 120 min of light exposure.

Far Infrared Laser Detector Based on Multi-Walled Carbon Nanotubes and Blend of (Polyaniline - Polymethyl Methacrylate) Polymers with Methyl Blue Dye for Photoconductive Applications

Infrared photoconductive detectors working in the far-infrared region and room temperature were fabricated. The detectors were fabricated using three types of carbon nanotubes (CNTs); MWCNTs, COOH-MWCNTs, and short-MWCNTs. The carbon nontubes suspension is deposited by dip coating and drop–casting techniques to prepare thin films of CNTs. These films were deposited on porous silicon (PSi) substrates of n-type Si. The I-V characteristics and the figures of merit of the fabricated detectors were measured at a forward bias voltage of 3 and 5 volts as well as at dark and under illumination by IR radiation from a CO2 laser of 10.6 μm wavelengths and power of 2.2 W. The responsivity and figures of merit of the photoconductive detector are improved by coating the MWCNTs films with a thin layer of a blend (polyaniline - polymethyl methacrylate) polymer with methylene blue dye. The coated MWCNTs films showed better performances, so this type of coating can be considered as a surface treatment of the detector film, which highly increased the responsivity and specific detectivity of the fabricated IR laser detector-based MWCNTs. The photocurrent response for the coated films was increased about 25 times than that for uncoated films. The results proved the role of the polymer in the enhancement of the performance of the IR photoconductive detectors. Keywords: Carbon nanotubes, Infrared detector, Polyaniline polymer, Polymethyl methacrylate polymer, Methyl Blue dye.