4BS Dye Research Articles

Ag-Doped TiO2: Synthesis, Characterization and Photodegradation of 4BS Dye

Ag doped TiO2 nanoparticles with different metallic content (0.0, 0.1, 0.15 and 0.2 wt.%) were prepared by using EDTA-Glycol method. For the sake of comparison blank TiO2 sample is also prepared using same method. All the samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). X-ray diffraction technique revealed that Ag-doped TiO2 has anatase structure and as the concentration of Ag increases the particle size will get decreases. The morphologies of TiO2 samples are influenced by doping Ag as shown by SEM images. The present work is mainly focused on the enhancement of photocatalytic reactivity of as synthesized samples by the photodegradation of 4BS under visible light irradiation using a LED lamp of (15 W) as a light source. A 96.3% of photodegradation of 4BS dye was achieved by utilizing 1 g/L of Ag-doped TiO2 at pH 6 for 100 min.

Retention and separation of 4BS dye from wastewater by the N-TiO2 ceramic membrane

The aim of this work was to study the retention and separation of 4BS dye from aqueous solution using N-doped TiO2 (N-TiO2) ceramic membrane. An N-TiO2 sol was synthesized by the sol–gel technique and applied to a ceramic membrane to synthesize a composite membrane. XRD analysis confirmed that the N-TiO2 had an anatase structure. SEM images revealed that the TiO2 particles with a diameter of 7–9 nm had been loaded on a ceramic support to form the nanoporous composites. 4BS dye containing aqueous solution was treated by the composite membranes. The operating conditions studied were the dye concentration, solution pH, the pressure and velocity of cross flow. With the coupling of photocatalysis and membrane separation, the retention rate of 99% for dye and the higher permeation flux (over 96%) were obtained. The composite membranes were found to be stable and to perform reproducibly.

Adsorption of direct fast scarlet 4BS dye from aqueous solution onto natural superfine down particle

In this study, the agricultural solid waste, natural down fibers were produced into superfine down particle (NSDP), which was used as a low-cost adsorbent for the removal of direct fast scarlet 4BS (DFS-4BS) from aqueous solution. Scanning electron microscopy (SEM), N2 adsorption/desorption, and Fourier Transform infrared spectroscopy (FTIR) were used to characterize the adsorbent material, respectively. The effects of pH, adsorbent dose, initial dye concentration, temperature, and contact time on the adsorption capacity of DFS-4BS by NSDP were studied. The experimental adsorption data were well fitted by Langmuir adsorption isotherm and the maximum adsorption capacity of DFS-4BS by NSDP was found to be 120.34 mg/g at 45 °C, which was higher than other reported adsorbent. Overall, NSDP could be used as an effective and low-cost adsorbent to remove DFS-4BS from industrial wastewater.

Synthesis, characterization and visible light photocatalytic properties of Bi2WO6/rectorite composites

Visible light-induced Bi2WO6/rectorite (BR) composites were prepared by a sol–gel method. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–vis diffuse reflectance spectrum, Fourier transform infrared (FTIR) spectrum, X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmet–Teller (BET). The UV absorption edges of the BR-450 catalyst showed a marked red shift as compared to that of the pure Bi2WO6. The photocatalytic activities of the as-prepared samples were evaluated by the photocatalytic degradation of 4BS dye in aqueous solution under visible light irradiation (>420nm). The results showed that the BR-450 catalyst exhibited a strong adsorption capability and a higher photocatalytic degradation activity than the pure Bi2WO6 for 4BS dye, which could be attributed to the synergetic effects of the adsorbability of rectorite and the photocatalytic property of Bi2WO6 in it.

Efficient removal of organic contaminants by a visible light driven photocatalyst Sr 6Bi 2O 9

Sr 6Bi 2O 9 powders were synthesized by a sol–gel method using Bi(NO 3) 3·5H 2O and Sr(NO 3) 2 as the starting materials and were characterized by X-ray diffraction (XRD), UV–vis diffuse reflectance spectrum (UV–vis DRS), Fourier transform infrared (FT-IR) spectrum and Raman spectrum. The as-prepared Sr 6Bi 2O 9 powders showed an efficient photocatalytic activity in the decomposition of 4BS dye (a widely used azo dye) and 4-nitrophenol (4-NP, a priority pollutant) under visible light irradiation ( λ > 400 nm). TA-PL analysis reveals that HO was not the dominant photooxidant. The radical scavengers experiments indicated that the main active species was O 2 − in the photocatalytic degradation of dye under visible irradiation. A possible photodegradation mechanism of organic pollutants by the visible light driven Sr 6Bi 2O 9 was discussed.

Synthesis of nanometer-size Bi 3TaO 7 and its visible-light photocatalytic activity for the degradation of a 4BS dye

Most of tantalate photocatalysts are mainly synthesized by solid-state (SS) reaction methods and only show photocatalytic activity under UV light irradiation. Ta 2O 5 as a raw material shows an extremely high chemical stability, limiting its application to a few systems. A novel nanometer Bi 3TaO 7 photocatalyst was synthesized by a facile and low-cost sol–gel method using Ta 2O 5 and Bi(NO 3) 3·5H 2O as the Ta and Bi sources, respectively. The as-obtained samples were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), UV–vis diffuse reflection spectroscopy (DRS) and Fourier transform infrared spectroscopy (FT-IR). The band gap energy of the as-obtained nanometer Bi 3TaO 7 photocatalyst was determined to be about 2.75–2.86 eV. The Bi 3TaO 7 nanopowders show a strong adsorbability and a high visible-light photocatalytic activity for the degradation of 4BS, which can be ascribed to the surface physicochemical properties and structure of the Bi 3TaO 7 nanometer catalyst. The degradation of 4BS is attributed to the photocatalysis but not to the adsorption of 4BS on the as-prepared catalyst.

Photocatalytic Degradation of 4BS Dye by N,S-Codoped TiO2 Pillared Montmorillonite Photocatalysts under Visible-Light Irradiation

The photocatalytic activities of nitrogen and sulfur codoped TiO2 pillared montmorillonite (N,S-TiO2-PILM) for the degradation of 4BS dye under visible-light irradiation (λ >400nm) were studied. The catalysts were synthesized by impregnating doped titania sol into the interlayer of montmorillonite (MMT) and characterized by the UV−vis diffuse reflectance spectra, transmission electron microscopy, and the FT-IR absorption spectra. The ordered structure of MMT was destroyed to some extent and the size of TiO2 particles is about 2−6 nm. The absorption edge of the doped samples shows a red-shift as compared to that of pure TiO2. The photocatalyic activity of N,S-TiO2-PILM with a mole ratio of Ti:S of 1:4 and obtained at 350 °C for 2 h is higher than that of the other samples and Degussa P25 under visible light irradiation. The chromophore in the molecular structure of 4BS was destroyed completely by the photocatalytic reaction and the naphthalene rings and benzene rings were also decomposed partly.

Kinetic Study on Photocatalytic Degradation of 4BS Azo Dye Over TiO2 in Slurry

Adsorption and photocatalytic degradation of 4BS dye over fine particulate TiO2 are studied in an opened batch slurry reactor. The influences of mixing of solid–liquid and external diffusion on degradation rate are eliminated by increasing stirred rate. The adsorption experimental results indicate that pH and temperature of solution affect adsorption considerably, a Langmuir equilibrium adsorption isotherm can be used to described them. Meanwhile, catalyst dosage, reaction time, pH of solution, stirring speed, initial concentration, direct irradiation area, and illumination intensity of UV light can affect the reaction rate. Favorable pH for 4BS dye degradation is about 3.5, suitable dosage of catalyst is about 1.0 g • L−1. After numeric analysis to experimental data, a kinetics model is established; the rate constants are different for catalyst dosage in 0.5 g • L−1 or 1.0–6.0 g − L−1.