Photocatalytic Degradation Of Acid Red Research Articles

Photocatalytic degradation of Acid Red 18 by synthesized AgCoFe2O4@Ch/AC: Recyclable, environmentally friendly, chemically stable, and cost-effective magnetic nano hybrid catalyst

Chitosan (Ch) is a linear biodegradable natural carbohydrate polymer and the most appealing biopolymer, such as low-cost biodegradability, biocompatibility, hydrophilicity, and non-toxicity. In this case, Ch was utilized to synthesize AgCoFe2O4@Ch/Activated Carbon (AC) by the modified microwave-assisted co-precipitation method. The physical and chemical structure of magnetic nanocomposites was analyzed and characterized by Field Emission Scanning Electron Microscope (FESEM), Transmission electron microscopy (TEM), X-ray diffraction (XRD), Energy Dispersive Spectroscopy (EDS), Diffuse Reflection Spectroscopy (DRS), Value stream mapping (VSM), Fourier transform spectroscopy (FTIR) and BET. The effects of various parameters on the removal of dye (Acid Red18), including catalyst dose, dye concentration, pH, and time were studied. Results showed that the highest removal efficiencies were 96.68 % and 84 % for the synthetic sample and actual wastewater, respectively, in optimal conditions (pH: 3, the initial dye concentration: 10 mgL−1, the catalyst dose: 0.14 gL−1, time: 50 min). Mineralization, according to the COD analysis, was 89.56 %. Photocatalytic degradation kinetics of Acid Red 18 followed pseudo-first order and Langmuir-Hinshelwood with constants of kc = 0.12 mg L−1 min−1 and KL-H = 0.115 Lmg−1. Synthesized photocatalytic AgCoFe2O4@Ch/AC showed high stability and after five recycling cycles was able to remove the pollutant with an efficiency of 85.6 %. So, the synthesized heterogenous magnetic nanocatalyst AgCoFe2O4@Ch/AC was easily recycled from aqueous solutions and it can be used in the removal of dyes from industries with high efficiency.

Photocatalytic Azo Dye Degradation Using Graphite Carbon Nitride Photocatalyst and UV-A Irradiation

The photocatalytic degradation of Acid Red 26 was examined utilizing a graphitic carbon nitride (g-C3N4) catalyst and a UV-A light in this study. We investigated how successfully the photocatalytic approach removed Acid Red 26 from synthetic and actual municipal wastewater. Both aqueous matrices allowed for extremely high clearance rates. Wastewater degraded at a slower rate than the other matrices, this might be ascribed to the wastewater’s complicated chemical composition. Using a liquid chromatography-mass spectrometry (LC-MS), the IPs in both synthetic and actual municipal effluent were determined. The photocatalytic degradation mechanisms of Acid Red 26 are hypothesised to comprise oxidation, dealkylation, and methoxy group cleavage based on the observed intermediate products (IPs). Using proven scavengers, we were also able to investigate the role of reactive species in the degradation process and illustrate the significance of h+ and O2• in the reaction. Chlorococcum sp. and Dunaliella tertiolecta microalgae were also utilised to assess the development of ecotoxicity. We observed low toxicity throughout the process when clean water was used as the matrix, with no production of hazardous IPs. In the case of actual municipal wastewater, there was an early rise in toxicity, which scientists believe was caused by the matrix’s chemical make-up. To lower the toxicity, a heterogeneous photocatalysis was used, and at the end of the treatment, nearly full detoxification was obtained.

CdTe quantum dots incorporated in CoNiAl layered double hydroxide interlayer spaces as a highly efficient visible light driven photocatalyst for degradation of an azo dye and Bisphenol A

The photocatalytic application of CdTe quantum dots (QDs) is restricted by the charge carriers recombination and tendency to aggregate in suspended systems. Novel functionalized CdTe (F-CdTe) QDs and CoNiAl layered double hydroxide (LDH) nanocomposite have been prepared to utilize the unique advantages of CdTe QDs. The nanocomposite is prepared via in situ synthesis of LDH in the presence of as-prepared F-CdTe QDs where the QDs partially intercalated in the interlayer spaces of LDHs. As a result of the effective electronic coupling between F-CdTe QDs and CoNiAl LDH, the light-harvesting ability has been enhanced and the absorption edge expands toward the higher visible light wavelengths. Moreover, the charge carriers recombination in nanocomposite has been considerably suppressed compared to the pristine CoNiAl LDH and F-CdTe QDs. Also, the nanocomposite shows remarkable enhancing in photocatalytic degradation of Acid Red 14 (AR14) and Bisphenol A (BPA) as the sample pollutants. The photogenerated holes and hydroxyl radicals have a determining role in the degradation of AR14. The plausible mechanism is proposed based on the experimental results and theoretical calculations. The prepared nanocomposite represents superior photocatalytic activity after 5 consecutive runs. So, the CdTe QDs can be effectively utilized in photocatalytic applications through the proposed promising approach.

Sol-gel synthesis of suspensible titanium dioxide-hollow glass microsphere composites for photocatalytic degradation of Acid Red 1

Titanium dioxide was supported on hollow glass microspheres (HGM) via a sol-gel route to prepare xTiO2-HGM composites. The growth and aggregation of the anatase TiO2 crystals were restrained after supporting them. A thin layer of TiO2 was coated on the external surface of the hollow glass microspheres when the TiO2 content was not high. The absorption edges of the xTiO2-HGM composites moved to a shorter wavelength region with decreasing TiO2 content. The band gap energy of the TiO2 (3.21 eV) did not apparently change after loading on the hollow glass microspheres. The mesopores in the xTiO2-HGM composites were much larger than the pores in the TiO2 powders, and the pore size distribution in the xTiO2-HGM composites was broadened. The density of the xTiO2-HGM composites could be adjusted by altering the weight content of the TiO2. When the TiO2 content was more than 50% in the composites, the photocatalytic activity of the composites was very close to the activity of the TiO2 powders. The first order reaction rate constants were 0.00938, 0.0103 and 0.0121 min−1 for Acid Red 1 degradation on the 30TiO2-HGM, 50TiO2-HGM and TiO2 powders.

Optimization, kinetics and thermodynamics of photocatalytic degradation of Acid Red 1 by Sm-doped CdS under visible light

Sm-doped CdS nanoparticles were synthesized through an ultrasound-assisted co-precipitation method and their photocatalytic efficiency was investigated by applying them to photodegradation of Acid Red 1 (AR1) under visible light. The effect of the operational factors on the photocatalytic process was systematically evaluated using response surface methodology. Under the optimal conditions ([AR1]0 = 15 mg L−1, [2% Sm-CdS]0 = 1 g L−1, pH = 4 and t = 94 min), >83% of the AR1 molecules were degraded. The kinetics of the process was well described by the Langmuir-Hinshelwood's pseudo-first-order model (kapp = 0.0163 min−1). Furthermore, thermodynamics of the process was demonstrated by the activated complex theory of Eyring, which declared that the photocatalytic process is endothermic and nonspontaneous in the temperature range of 25–45 °C. In addition, the main products and intermediates of AR1degradation were determined by the GC–MS technique.

Efficient photocatalytic degradation of Acid Red 57 using synthesized ZnO nanowires

Zinc oxide photocatalyst was synthesized through a low‐temperature co‐precipitation process using zinc sulfate as precursor for the degradation of Acid Red 57 (AR57) under UV irradiation. The activities of the prepared photocatalyst at different calcination temperatures (400, 500, and 600 °C) were investigated. The synthesized zinc oxides were characterized by different techniques such as X‐ray diffraction, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, N2 adsorption–desorption, and pH titration for the determination of the zero‐point charge (pHZPC). The efficiency of photocatalytic degradation of ZnO prepared at the calcination temperatures of 400, 500, and 600 °C was 90.03, 77.67, and 72.71%, respectively, after 190 min. The kinetics and scavengers of the reactive species during the degradation were also investigated. It was found that the degradation of AR57 fitted first‐order kinetics and the OH• radicals were the main species. During irradiation, the formation of OH• free radicals was ascertained by photoluminescence studies using terephthalic acid as the probe molecule.

Tailored Pt/TiO₂ Photocatalyst with Controllable Phase Prepared via a Modified Sol-Gel Process for Dye Degradation.

Pt/TiO2 photocatalysts with controllable phase were successfully prepared by controlling the hydrolysis pH values during the sol-gel process followed by Pt photodeposition. The effect of different phases of TiO2 coated with Pt on the catalytic properties and the photocatalytic activities were also investigated. The characterization results of the synthesis of TiO2 under neutral/alkaline and acidic conditions during the hydrolysis step revealed the facile formation of the anatase phase and the brookite/rutile phase, respectively. Pt/TiO2 photocatalysts prepared at hydrolysis pH values of 2, 7, and 10 had different TiO2 phase compositions, but the main crystalline sizes of the photocatalysts were all close to 6 nm. The Pt/TiO2 particles prepared at various hydrolysis pH values were all spheroidal. The PL results indicated that the anatase/rutile junction of a Pt/TiO2 sample had a lower recombination rate than did the anatase phase of Pt/TiO2 owing to the longer recombination pathway. However, the anatase phase of Pt/TiO2 exhibited better degradation ability than the anatase/rutile junction of Pt/TiO2, and the degradation rate decreased with a decrease in the anatase composition of TiO2, indicating that anatase composition in the Pt/TiO2 system played an important role of enhancing the photocatalytic degradation of Acid Red 1 dye.

Single-crystal Bi2Ga4O9 nanoplates with exposed {110} facets for photocatalytic degradation of Acid Red 1

Single-crystal Bi2Ga4O9 nanoplates with exposed {110} facets have been synthesized without any organic facet-controlling agents. The nanostructures and the formation process mechanism of the obtained Bi2Ga4O9 nanoplates are investigated using XRD, TEM and SEM. UV–vis DRS and VB-XPS analyses demonstrate that the CB position of Bi2Ga4O9 nanoplates is shifted up by 0.21eV compared with that of Bi2Ga4O9 particles. PL spectra and photoelectrochemical texts show that the separation efficiency of photogenerated electron-hole pairs of Bi2Ga4O9 nanoplates is higher than that of Bi2Ga4O9 particles. The enhanced photocatalytic activity of Bi2Ga4O9 nanoplates is mainly ascribed to the exposed {110} facets. PL technique and radical trapping experiments demonstrate that h+, OH and O2− are responsible for the degradation of Acid Red 1 (AR1) over Bi2Ga4O9 nanoplates.

Synthesis and characterization of barium-doped TiO2 nanocrystals for photocatalytic degradation of Acid Red 18 under solar irradiation

Addition to the aesthetic negative environmental impacts, dyes have serious negative biological and chemical effects on the environment. The aim of this study was to investigate the removal of acid red 18 from aqueous solution using novel barium oxide added to titanium oxide nanocrystals. Moreover, these doping conditions resulted in reducing the bandgap energy significantly, which in turn makes them active under sunlight illumination. The barium doped TiO2 nanocrystals were synthesized under mild hydrothermal conditions and were characterized by XRD, FTIR, SEM, and EDS to investigate the structure and textural features of the nanocrystals. The photodegradation experiments were conducted through the influence of batch degradation parameters such as pH, illumination time, nanocrystals dosage, and initial dye concentration. The results revealed that the removal efficiency of Acid Red 18 was 98.6 under acidic conditions. Moreover, the removal efficiency increased by reducing the initial dye concentration, increasing illumination time, and nanocrystals dosage. The characterization results confirmed the high crystallinity, lack of agglomeration and excellent dispersion of the barium doped TiO2 nanocrystals in the media. Therefore, the barium doped TiO2 nanocrystals could be used for photodegradation of organic pollutants from the aqueous media. © 2017 Desalination Publications. All rights reserved.

Preparation and solar-light photocatalytic activity of TiO2 composites: TiO2/kaolin, TiO2/diatomite, and TiO2/zeolite

Three TiO2 loaded composites, TiO2/kaolin, TiO2/diatomite, and TiO2/zeolite, were prepared in order to improve the solar-light photocatalytic activity of TiO2. The results showed that the photocatalytic activity could obviously be enhanced by loading appropriate amount of inorganic mineral materials. Meanwhile, TiO2 content, heat-treatment temperature and heat-treatment time on the photocatalytic activity were reviewed. Otherwise, the effect of solar light irradiation time and dye concentration on the photocatalytic degradation of Acid Red B was investigated. Furthermore, the degradation mechanism and adsorption process were also discussed.

Carboxymethyl‐β‐cyclodextrin enhanced TiO2 removal of Acid Red R and lead ions in suspended solutions

AbstractBackgroundIt is necessary to find an effective method for the removal of dyes and heavy metals from aqueous solutions. In this work, the effects of carboxymethyl‐β‐cyclodextrin (CMCD) on the photocatalytic degradation of Acid Red R (ARR) and photocatalytic reduction of Pb2+ were investigated in TiO2 suspensions, and the synergistic effects on the simultaneous conversion of ARR and Pb2+ in the presence of CMCD were also evaluated.ResultsThe results showed that CMCD can enhance the photocatalytic degradation of ARR and photocatalytic reduction of Pb2+ in a single system with ARR or Pb2+, respectively. When CMCD was added to the mixed reaction system of ARR and Pb2+, the synergistic effects on the simultaneous conversion of ARR and Pb2+ in aqueous solutions were further enhanced. The photocatalytic removal rates of ARR and Pb2+ in the mixed system were markedly enhanced compared with those in the single systems, and the reaction rate constants of ARR and Pb2+ in the presence of CMCD were higher than those in the absence of CMCD.ConclusionsCMCD can simultaneously enhance the photocatalytic removal of ARR and Pb2+ in mixed systems. CMCD‐enhanced photocatalytic technology may be a good alternative for the treatment of wastewaters containing dyes and heavy metal ions. © 2013 Society of Chemical Industry

Preparation of Er3+:YAlO3/Fe-doped ZnO composite and investigation on solar light photocatalytic degradation of organic dyes

The Er3+:YAlO3/Fe-doped ZnO composite, a new photocatalyst which could effectively utilize visible light, was prepared. In succession, the Er3+:YAlO3/Fe-doped ZnO was characterized by XRD and SEM, respectively. Acid Red B dyes, was degraded under solar light irradiation to evaluate the photocatalytic activity of the Er3+:YAlO3/Fe-doped ZnO. In addition, the effects of Er3+:YAlO3 content, heat-treatment temperature and time on the photocatalytic activity of Er3+:YAlO3/Fe-doped ZnO were reviewed. Otherwise, the effect of initial dye concentration, Er3+:YAlO3/Fe-doped ZnO amount and solar light irradiation time on the photocatalytic degradation of Acid Red B were also investigated. It was found that the photocatalytic activity of Er3+:YAlO3/Fe-doped ZnO is much higher than that of Fe-doped ZnO and pure ZnO for the similar system. Perhaps, the use of the Er3+:YAlO3/Fe-doped ZnO may provide a new way to take advantage of ZnO in sewage treatment aspects using solar energy.

Photocatalytic degradation of Acid Red 1 dye using ZnO catalyst in the presence and absence of silver

The investigation of the degradation of Acid Red 1 (AR1) dye was carried out in an aqueous suspension photoreactor. Different parameters that affect the degradation of AR1 dye such as the presence and absence of a photocatalyst, light source, air, catalyst loading, initial substrate concentration were studied. The activity of Ag-doped ZnO prepared by photoreduction of Ag+ ion on ZnO catalyst for AR1 dye degradation was investigated. The effects of different amount of Ag+ deposited on ZnO particles and catalysts loading on the photocatalytic degradation rate of AR1 dye were evaluated. The surface morphologies of both Ag-doped ZnO and ZnO catalysts were studied by scanning electron microscopy (SEM), while X-ray diffraction (XRD) was used to study the crystallography of the catalysts. The experimental results revealed that the presence of photocatalyst, light, and air are signifi cant for the photodegradation process. The optimum catalyst loading was 2 g catalyst per liter solution. The presence of Ag+ in th...

Photocatalytic Degradation of Acid Red G by Bismuth Titanate in Three-phase Fluidized Bed Photoreactor

AbstractThe objectives of this study were to prepare a high-performance bismuth titanate photocatalyst and to develop a novel photocatalytic reactor with three-phase internal circulating fluidized bed photoreactor (TPICFBP). Bismuth titanate photocatalyst was hydrothermally prepared under optimum operating parameters such as hydrothermal temperature, reaction time and molar ratio of Bi to Ti. The photocatalytic activity of bismuth titanate using TPICFBP was evaluated for the photocatalytic degradation of Acid Red G (ARG). The photodegradation of ARG over Bi

Investigation on solar photocatalytic activity of TiO 2 loaded composite: TiO 2/Skeleton, TiO 2/Dens and TiO 2/HAP

The TiO 2/Skeleton, TiO 2/Dens and TiO 2/HAP composites were prepared by sol–gel method. X-ray diffraction (XRD) and scanning electron microscope (SEM) were carried out to characterize them. Their photocatalytic activities were evaluated by degradation of Acid Red B under solar light irradiation. The results showed that the photocatalytic activity of the TiO 2 catalyst can be greatly enhanced by using appropriate amount of loaded biomaterials or biomimetic material. Otherwise, the influencing factors, such as TiO 2 loaded content, heat-treated temperature and heat-treated time on the photocatalytic activity of TiO 2/Skeleton, TiO 2/Dens and TiO 2/HAP were reviewed. Meanwhile, the effect of solar light irradiation time and dye initial concentration on the photocatalytic degradation of Acid Red B dye in aqueous solution were also investigated in detail.

Photocatalytic degradation of organic dyes with Er 3+:YAlO 3/ZnO composite under solar light

The Er 3+:YAlO 3/ZnO composite, a new photocatalyst that could effectively utilize visible light, was prepared by ultrasonic dispersion and liquids boiling method in this work. In succession, the Er 3+:YAlO 3/ZnO composite, Er 3+:YAlO 3 particle and pure ZnO powder were characterized by X-ray diffraction (XRD). The Acid Red B dye as a model compound was degraded under solar light irradiation to evaluate the photocatalytic activity of the Er 3+:YAlO 3/ZnO composite. In addition, the effects of Er 3+:YAlO 3 content, heat-treated temperature and heat-treated time on photocatalytic activity of Er 3+:YAlO 3/ZnO composite were reviewed through the degradation of Acid Red B dye under solar light. Otherwise, the effects of initial concentration, Er 3+:YAlO 3/ZnO amount, solution acidity and solar light irradiation time on the photocatalytic degradation of Acid Red B dye were investigated in detail. It was found that the photocatalytic activity of Er 3+:YAlO 3/ZnO composite is much higher than that of pure ZnO powder for the similar system. Perhaps, the use of this Er 3+:YAlO 3/ZnO composite may provide a new way to take advantage of ZnO in sewage treatment aspects using solar energy.

Photocatalytic degradation of Acid Red 4 using a titanium dioxide membrane supported on a porous ceramic tube

A photocatalytic membrane supported on a porous ceramic tube was described, in which permeation of solutes through the membrane and tube and photocatalytic reaction occur simultaneously. In this photocatalytic membrane reactor, TiO 2 catalyst was coated on the surface of a porous ceramic tube and all experiments were conducted in one pass dead-end system. The objectives of this study are to demonstrate the predominance of dead-end operation and to determine the reaction kinetics model of the photocatalytic reaction. Acid Red 4 (AR 4) dye was used as a model pollutant. A detailed study of physical parameters including flow configurations (dead-end and cross-flow), flow rate, initial dye concentration, light intensity and catalyst loading has been performed to obtain the reaction kinetics. The simultaneous effect of light intensity and catalyst loading was also determined experimentally. Experiments were also conducted to compare the photocatalytic degradation of AR 4 in the dead-end and cross-flow system. The major findings of this study are: (1) the decomposition ratios for dead-end system were three and five times higher than cross-flow system at flow rates of 6.67 × 10 −8 and 4.00 × 10 −7 m 3/s, respectively. (2) The decomposition ratio increased with increasing catalyst loading and light intensity, but remained constant at higher catalyst loading. (3) The decomposition ratio was found to be decreased with increasing flow rate.

Bulk phase degradation of Acid Red 14 by nanophotocatalysis using immobilized titanium(IV) oxide nanoparticles

Immobilized titanium(IV) oxide nanoparticles were used for the photocatalytic degradation of Acid Red 14 (AR 14). A simple and effective method was used for immobilization of titanium(IV) oxide nanoparticles. Photocatalytic degradation processes were performed using pilot scale (7 L) colored dye solutions. UV–vis and ion chromatography (IC) analyses were employed to obtain the details of the photocatalytic degradation of AR 14. It has been found that adsorption has a negligible effect on the aqueous dye concentration and the photocatalytic process occurred at solution bulk. The effects of operational parameters such as H 2O 2, dye concentration, anions (NO 3 −, Cl −, SO 4 2−, HCO 3 − and CO 3 2−) and pH were investigated. Reaction rate was drastically inhibited by carbonate. Produced aromatic intermediates were not studied. Formate, acetate and oxalate anions were detected as dominant aliphatic intermediates where, they were further oxidized slowly to CO 2. Nitrate and sulfate anions were detected as the photocatalytic mineralization of AR 14. Kinetics analysis indicates that the photocatalytic decolorization rates can usually be approximated first-order model for AR 14. Results show that the employment of optimal operational parameters may lead to complete decolorization and mineralization of dye solutions.