Photocatalyst For Degradation Of Dye Research Articles

Fabrication of Mesoporous V2O5@g-C3N4 Nanocomposite as Photocatalyst for Dye Degradation

This study investigated the photocatalytic degradation of RB dye by V2O5@g-C3N4 nano-catalysts. The sonication method was utilized to create V2O5@g-C3N4 nano-catalysts. V2O5@g-C3N4 nano-catalysts were characterized using X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), high-resolution electron microscopy (TEM), BET-surface area analyzer, X-ray photoelectron spectroscopy (XPS), and ultraviolet spectroscopy. In the meantime, the photocatalytic activity, pH, and photocatalyst dosage are investigated in depth to account for RB dye decolorization. The rate constant for RB dye photodegradation was 0.0517 (min−1) and the decolorization rate was 93.4%. The degrading efficiency of RB dye by V2O5@g-C3N4 nanocatalysts is consistent with pseudo-first-order kinetics. The results of this study demonstrated that V2O5@g-C3N4 nanocatalysts are particularly effective at destroying dyes in water.

Construction of a 1D Cu(I)-based coordination polymer as a luminescent sensor for antibiotics and a photocatalyst for dye degradation

Antibiotics are a typical contaminants existing in water that now are polluting the aquatic environment thereby affecting the aquatic life and human health. To address this issue, we have synthesized luminescent Cu(I)-based coordination polymer with composition{[CuI(bb)]·Cl}n(1) (bb = 4,4’-bis(imidazoly)biphenyl) and characterized. In crystalline state, 1 forms a non-covalently bonded one-dimensional (1D) chain, which is stacked into a three-dimensional (3D) supramolecular architecture. The polymer, when used as luminescent sensor against antibiotics, attained a limit of detection (LOD) down to 1.21 ppm and a Ksv of 1.67 × 103 M −1for antibiotic nitrofurantoin (NFT) which shows its sensitivity towards NFT. The CP manifested a high efficiency for catalytic photodegradation of NFT 91.41% decomposition within 100 min under 100 W mercury lamp. The plausible sensing and photocatalytic mechanism have been addressed with the help of theoretical calculations.

Hierarchical ZnO/MXene (Nb2C and V2C) heterostructure with efficient electron transfer for enhanced photocatalytic activity

Recently, MXene has attracted much attention as photocatalysts for efficient pollutant degradation in the field of environmental remediation but a rapid recombination of photogenerated carriers usually leads to a decrease in the photocatalytic performance. Constructing a heterostructure is considered as an effective way to improve the catalytic performance of MXene-based photocatalysts due to the promoted interfacial electron transfer. In this work, the chimeric ZnO nanosheets with good carrier mobility were formed on the accordion-shaped MXene (Nb2C and V2C) surface to construct hierarchical ZnO/MXene heterostructure as a photocatalyst for dye degradation. The obtained ZnO/Nb2C and ZnO/V2C hierarchical structure exhibited excellent photocatalytic performance in the degradation of methylene blue (MB): the degradation rate reached 62.62% and 99.53%, respectively, after irradiation with ultraviolet light for 120 min. Also, the apparent degradation rate constants (k) were 0.00777 min−1 and 0.04317 min−1, respectively, which were 2.92 and 16.23 times higher than those of pure ZnO. This was probably attributed to the heterostructures between ZnO and MXene which could shorten the carrier transfer path, which could facilitate the transfer of photo-generated electrons from conduction band (CB) of ZnO to CB of MXene, thereby significantly improving the photocatalytic degradation efficiency. In addition, the ZnO/Nb2C and ZnO/V2C hierarchical structure showed good photocatalytic stability: the degradation rate remained at 58.6% and 97.3%, respectively, after 4 cycles while it only maintained at 22.0% for pure ZnO because the obtained ZnO/MXene hierarchical structure could provide uniform active sites on the surface and porous structure, preventing the aggregation of ZnO or MXene. Therefore, this work could provide a feasible design strategy to improve the catalytic performance of 2D photocatalysts and shed a light on the design of other photocatalysts.

Recent Review of Titania-Clay-Based Composites Emerging as Advanced Adsorbents and Photocatalysts for Degradation of Dyes over the Last Decade

Textile industry being one of the most flourishing industries keeps growing and developing every year, and the consequences are not very pleasant. Even though its contribution towards economy of a country is indisputable, there are many pros and cons associated with it that should not be brushed aside, one of them being textile dye waste which is also growing at alarming rate. Many techniques have been designed to deal with this environmental crisis including adsorption and photodegradation of dye waste by various substances, both natural and synthetic. TiO2 and clay both have gained immense popularity in this area. Over the last decade, many successful attempts have been made to design TiO2-clay-based composites to combine and make the most of their individual capabilities to degrade textile dye waste. While clay is an effective adsorbent, inexpensive, innocuous, and a great ion exchanger, TiO2 provides supplementary active sites and free radicals and speeds up the degradation rate of dyes. This review summarizes various features of TiO2-clay-based composites including their surface characteristics, their role as dye adsorbents and photocatalysts, challenges in their implementation, and modifications to overcome these challenges made over the last decade.

Synthesis, structural, FTIR and UV–vis spectroscopic, thermal and dielectric studies of magnesium ion doped nickel pyrophosphate nano-particles

Nickel pyrophosphate finds applications in energy storage device, super-capacitor, nano scale devices, catalyst for H2 generation and also used as a photo-catalyst for dye degradation. Pure and 2 %, 5 % and 10 % Mg ion doped Ni2P2O7 nano particles are synthesized through a surfactant mediated approach. In the Powder XRD pattern the broadening confirms the nano-structured nature and the monoclinic structure is found for pure α- Ni2P2O7 and Mg doped nano particles. The EDAX analysis confirms the elemental composition. The TEM study confirms the nano-size of the synthesized pure and doped samples, which are having dimensions in the range from 7.19 nm to 25.99 nm. The presence of stretching vibrations of POP and PO3 confirmed by the FT-IR study. The UV-NIR absorption spectroscopy of pure and Mg ion doped Ni2P2O7 samples over the spectral range of 210–1200 nm is carried out and the direct optical energy band gap is found to decrease as the content of Mg increases in the samples. TGA confirms the presence of water molecules in the samples and their highly stable nature. The dielectric study is conducted from 100 Hz to 10 MHz range at different temperatures from 50 °C to 100 °C. The dielectric constant and loss factor decrease with increasing frequency. The a.c. conductivity increases with increasing frequency and follows the Jonscher’s Power law. The models for a.c. conduction mechanisms are proposed based on Jonscher’s parameters.

Construction strategies to modulate the photocatalytic efficiency of Cd(ii) MOFs to photodegrade organic dyes

Two new tuned 3D Cd(ii) MOFs were synthesized and used as photocatalysts for dye degradation.

Rapid and Facile Synthesis of Z-Scheme Zno/G-C3n4 Heterostructure as Efficient Visible Light-Driven Photocatalysts for Dye Degradation and Hydrogen Evolution Reaction

Rapid and Facile Synthesis of Z-Scheme Zno/G-C3n4 Heterostructure as Efficient Visible Light-Driven Photocatalysts for Dye Degradation and Hydrogen Evolution Reaction

Photocatalytic Efficiency of Hybrid Titanium Dioxide Nanowires/Reduced Graphene Oxide (TiO2NWs/RGO) for Degradation of Methyl Orange Dye

The aim of this research is to improve the photocatalytic efficiency by implementation of titanium dioxide nanowires/reduced graphene oxide (TiO2NWs/RGO) hybrid photocatalyst for dye degradation. The hybrid photocatalyst TiO2NWs/RGO was prepared using fabrication method. The physico-chemical properties of the photocatalyst was investigated by FTIR, XRD, SEM TGA, BET and their photocatalytic efficiency was evaluated for methyl orange degradation. Almost 100% of methyl orange was degraded by TiO2NWs/RGO hybrid photocatalyst under UV light within 210 min using 1.0 g at initial concentration of methyl orange were 10 and 20 ppm. This is due to the 1D/2D heterostructures of TiO2NWs/RGO hybrid photocatalyst that leads to the larger surface area, unique morphological and crystallinity properties, as well as excellent mobility of charge carriers and thermally stable structure

Synthesis and characterisation of Cu - Doped TiO2 nanoparticles for DSSC and photocatalytic applications

In the present work, copper-doped TiO2 nanoparticles were synthesized via sol-gel technique with different molar concentration of copper precursor (0.025 M-CT-1, 0.05 M-CT-2, 0.1 M-CT-3 and 0.2 M-CT-4). The effect of copper doping on the structural, morphological, compositional, optical and electrical properties of TiO2 was systematically analyzed for its better suitability as photoanode in Dye-Sensitized Solar Cells (DSSC) and photocatalyst in dye degradation. From structural analysis, all the synthesized samples show anatase phase with a tetragonal crystal system. The broadening and shift in the peaks of the synthesized samples show the successful incorporation of Cu ions into TiO2 lattices. All the synthesized samples exhibit spherical shape morphology with slight agglomeration. EDS analysis exhibit the purity of the synthesized nanoparticles with the presence of only Ti, O, and Cu. UV-DRS analysis reveals the decrease in reflectance of the TiO2 with increasing the Cu concentration. The bandgap values of the Cu–TiO2 decreased from 2.66 to 2.40 eV with the increase of copper concentration. From PL analysis, the peak observed at 380.20, 469.56 and 535.24 nm corresponds to the band-band PL emission, free excitons, and oxygen vacancies, respectively. Further, we have fabricated DSSC using Cu-doped TiO2 as a photoanode without treatment of any scattering layer and we have obtained the maximum efficiency of 3.90% for 0.1 M Cu–TiO2 (CT-3). Similarly, the maximum degradation efficiency of 97.12% was obtained against rhodamine-B dye with the highest regression coefficient (R2 = 0.9957) and lesser half-life degradation time (t1/2 = 47.1428 min) for CT-3. This higher efficiency was not reported elsewhere using Cu-dopant concentrations. From these observations, it was concluded that 0.1 M concentration of Cu was the optimum dopant concentration with TiO2 which was suitable for DSSC and photocatalytic applications.

Black phosphorus quantum dots as photocatalyst for dye degradation with a high efficiency and rate constant

A metal-free nanocatalyst was proposed to be applied in the photocatalysis of dye degradation based on black phosphorus quantum dots (BPQDs). BPQDs were prepared by a liquid exfoliation combined with solvothermal method. BPQDs show excellent catalytic performance with higher photocatalytic efficiency and shorter degradation time than those for most of previous works. The morphological, structural, and optical properties and functional groups for BPQDs were characterized by numerous techniques. They are transmission electron microscope (TEM), X-ray diffraction (XRD), Raman, fluorescence and UV–vis absorption spectrophotometry, respectively. To investigate the photocatalytic activity of BPQDs, indigo carmine (IC) was employed as a model dye. The decolorization efficiency of IC can get to 98.22% in the sun. Furthermore, the degradation time is 23 min in the sun, which is shorter than other reports. The degradation rate constant is 0.214 min−1 which is about 10 times higher than most of previous works. More importantly, the species after degradation were confirmed by mass spectrum, which own much lower carbon content than IC. The present BPQDs as nanocatalysts may be explored to degrade more organic molecules in environmental wastewater.

Nanobiocatalysts and photocatalyst in dye degradation

Abstract In the modern era, the world today is in a mission for a new method of environmental bioremediation in faltering the damage, especially in polluted water. Recently, the global direction is regulated toward an alteration from the usual chemical-based methods to a supplementary ecofriendly green alternative. In this perspective, biocatalysts are appreciated as an economical and clean substitute which was meant to catalyze degradation of unmanageable chemicals in a rapid, green and ecologically stable manner. Among the various sources of water pollution, the textile manufacturing industries were thought to be a major dispute due to release of effluents in natural water bodies such as rivers. Other industries like paper, pulp and tannery pharmaceutical industries were also responsible in contaminating the water bodies. Photocatalysis was considered as an auspicious method for the removal of dyes from the natural bodies, specifically those with hard organic compounds; using enzymes. The present chapter briefly emphasizes on the effective methods used for degradation of dye effluents; their importance of photocatalytic and biocatalytic solution to the current environmental difficulties and future opportunities are discussed.

Plant extract mediated ZnO-NPs as photocatalyst for dye degradation: An overview

Clean water is the basic need of all, it is impossible to imagine a future without it. However, the lack of a long-term water management plan and rapid industrialization resulted in the contamination of water sources to a dangerous extent. Excessive use of toxic textile dyes and their secretion in natural water resources is one of the major concerns for today's world. Photocatalysis is one of the best phenomena to resolve the issue of harmful textile dyes in the aquatic environment, where the photo-induced electron and hole pairs generated by excitation of electrons from the valence band to the conduction band by light irradiance can be used for the degradation of dye molecules through redox reactions. ZnO is a semiconductor material that shows excellent potential in photocatalysis. As the synthesis of biocompatible ZnO nanoparticles (NPs) using plant extract as biological reducing and capping agents is one of the best ways to have all the benefits of different physicochemical properties of nanomaterials without potential environmental and human health risks resulted from nanoparticles. Therefore, the use of green synthesized ZnO-NPs prepared using various parts of the plant in the degradation of harmful textile dyes has been explored by many researchers. In this article, we will provide an overview of the procedure to synthesize the biocompatible ZnO-NPs and their use in the photocatalytic degradation of dyes.

Visible light‐assisted degradation of binary mixture of dyes using purple tea‐mediated zinc oxide nanoparticles

AbstractThis work presents completely a new, green, and non‐expensive route of synthesis of zinc oxide (ZnO) nanoparticles (NPs) using purple tea leaves. The crystalline nature of purple tea‐mediated ZnO NPs (PT‐ZnO NPs) was confirmed by XRD and SAED analyses. Further characterizations of PT‐ZnO NPs were done using UV‐vis spectroscopy, FTIR spectroscopy, SEM‐EDX, and TEM. The size of synthesized NPs was calculated to be 15.1 nm which presented spherical morphology with some sorts of agglomeration. The PT‐ZnO NPs when applied as visible light‐driven photocatalyst for degradation of dyes, Malachite green (MG) and Rhodamine B (RB) showed that degradation was found to be higher in their binary solution (MG‐RB) than in their single solution (MG/RB). MG 95% and RB 35% was degraded in their binary solution where as in their respective single dye solution MG 89% and RB 22% got degraded within the experimental time. The highly pure, PT‐ZnO NPs are considered to have comparable photocatalytic activity with respect to most of the reported works and hence might find a way for its practical application for waste water treatment in the real world. The PT‐ZnO NPs could be reused at least for five times without any significant loss in degradation efficiency.

Application of BiFeO3 and Au/BiFeO3 decorated kaolinite nanocomposites as efficient photocatalyst for degradation of dye and electrocatalyst for oxygen reduction reaction

To improve the photocatalytic performance and solve the aggregation problem of BiFeO3 nanoparticles, kaolinite-BiFeO3 photocatalyst was successfully prepared for the first time by decoration of ferromagnetic BiFeO3 nanoparticles onto kaolinite surface. Comparative characteristics of kaolinite, bare BiFeO3 and kaolinite-BiFeO3 photocatalyst were investigated in detail by XRD, TEM, SEM-EDX, XPS, FTIR, VSM, UV-DRS, PL, zeta potential and BET techniques. The photocatalytic activities of the samples were also evaluated by photodegradation of rhodamine B as a model reaction under different irradiations like UVA, visible and sunlight. The kaolinite-BiFeO3 exhibited more superior photocatalytic activity as compared with other samples, which is best fitted to pseudo-first-order kinetic. The reactive species trapping experiments indicated that photogenerated-holes play major roles in the degradation process whereas superoxide radicals possess a secondary effect. Enhanced photocatalytic activity of kaolinite-BiFeO3 is attributed to its kaolinite platform that reduces the recombination opportunities of the photogenerated holes and electrons as well as increases the surface area, decreases the particle size and aggregation of nanoparticles. In addition, we also designed a novel electrocatalytic platform based on gold nanoparticles loaded on kaolinite-BiFeO3 modified carbon paste electrode surface for the examination of electrocatalytic activity for oxygen reduction reaction in alkaline medium. Electrochemical characterizations of the Au/BiFeO3/kaolinite modified carbon paste electrode and other bare surfaces were comparatively carried out with the aid of cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. Au/BiFeO3/kaolinite modified carbon paste electrode exhibited 15-fold current enhancement together with 100 mV anodic potential shift compared with bare carbon paste electrode.

Two new coordination polymers with tetracarboxylate as photocatalysts for dye degradation

The removal of dyestuff wastewater is an important issue and project of environmental protection. Photocatalytic method is one of the most feasible strategies. Metal-organic frameworks (MOFs) have been extensively covered by in photocatalytic removal and degradation of dye molecules. Herein, we designed and prepared two isomorphic MOFs, including [Mn(L)0.5(H2O)] (1) and [Cd(L)0.5(H2O)] (2) (H4L = 1, 1′: 4′, 1′': 4′', 1′''-quterphenyl-2, 5, 2′'', 5′''-tetracarboxylic acid) to investigate and explore their photocatalytic activities. These metal centers are coordinated by four carboxylates to shape 1D assembled architecture with a paddlewheel unit, which was expanded and extended to provide a 3D supramolecular structure through the link of L. The results manifested that 1 and 2 could take as better candidate to catalyze the dye Rhodamine B (RhB) under UV irradiation. Compound 1 shows the good catalytic performance than that of compound 2. The degraded intermediates were traced using LC–MS technology and the conceivable ways of decomposition for the Rh B were supposed.

Fabrication of MIL-53(Al)/Ag/AgCl plasmonic nanocomposite: An improved metal organic framework based photocatalyst for degradation of some organic pollutants

Metal organic framework (MOF) based MIL-53(Al)/Ag/AgCl nanocomposite (NC) was synthesized as a novel plasmonic photocatalyst via a facile reflux method. The as-prepared NC was characterized by various techniques. The photocatalytic efficiency of MIL-53(Al)/Ag/AgCl was investigated by photo-degradation of six cationic and anionic dyes. The effect of different factors including weight ratio of NCs, illumination time, and initial dye concentration on the photocatalytic performance of MIL-53(Al)/Ag/AgCl were experimentally investigated. The MIL-53(Al)/Ag/AgCl(10%) exhibited the highest catalytic performance for photo-degradation of different dye contaminants. Results indicated about 80–100% of tested dyes were removed by MIL-53(Al)/Ag/AgCl under LED-light irradiation in 90 ​min. Because of heterojunction between the Ag/AgCl nanoparticles (NPs) and MIL-53(Al), the MIL-53(Al)/Ag/AgCl NC showed higher photocatalytic ability. The results confirmed that due to some considerable features of MIL-53(Al)/Ag/AgCl such as high surface area, surface plasmon resonance effect, and recyclability, the introduced NC acts as a high performance photocatalyst for degradation of dyes in aqueous solutions.

New Cd(ii) coordination polymers bearing Y-shaped tricarboxylate ligands as photocatalysts for dye degradation

Two Cd(ii) coordination polymers derived from a Y-shaped tricarboxylate ligand were synthesized and their photocatalytic properties against decomposition of methylene blue were investigated experimentally and computationally.

Eco-Friendly Photocatalysts for Degradation of Dyes

In the current era of globalization, synthetic dyes are one of the key factors of water pollution. Photocatalysis constitutes a promising technology for the treatment of wastewater, especially to those containing hard-to-remove organic compounds. Zinc oxide nanoparticles (ZnONPs) play a vital role as a photocatalyst material. This research highlights the synthesized ZnONPs with roselle flower and oil palm leaf extract. The extracts and sodium hydroxide (NaOH) act as reducing agents during the synthesis process. Synthesis without the addition of plant extract is used as blank control for the experiment. Structural and optical studies of the three variants of ZnONPs were performed. High purity of ZnONPs with element Zn and O was obtained. The size of the three variants of ZnONPs was from 10–15 nm and found in agglomerated spherical shape. Large band gap, 3.2 eV was obtained by UV-Vis and high thermal stability was proven by TGA. Oxygen vacancies that assist in the degradation phenomenon were found in ZnONPs. Five percent of ZnONPs with the presence of 10 W UV light could effectively degrade 10 ppm MO in 5 h and MB in 3 h. Besides, high antioxidant properties and low toxicity demonstrated the ability of ZnONPs to be used as photocatalysts. In conclusion, ZnONPs can be further developed for pharmaceutical and industrial use.

Synthesis and characterization of magnetically separable Zn1-xCoxFeMnO4 nanoferrites as highly efficient photocatalyst for degradation of dye under solar light irradiation

Cobalt doped magnetically separable Zn1-xCoxFeMnO4 (x = 0.0, 0.25, 0.50, 0.75, 1.0) nanoparticles of ferrite were synthesized using auto-combustion process of sol-gel utilizing glycine as a fuel. The powder XRD and Rietveld refinement studies showed that all of the samples developed a single-phase cubic spinel system. The morphological investigations demonstrate the sphere-like nanostructures, which get distorted after an increase in the concentration of cobalt. A transformation from superparamagnetic activity to ferrimagnetic character has been reported with the introduction of Co2+. As synthesized ferrite nanoparticles have demonstrated an improvement in coercivity with lower density magnetization with reduced crystallite size. A rise in the remanence ratio were observed with the Co2+ content. The optical characterization shows a blue shift in the band gap with increase of Co2+. Considering the band structure in the visible region, the photocatalytic activity of as-synthesized Zn1-xCoxFeMnO4 photocatalysts for degradation of methylene blue under natural sunlight was investigated. The Zn0.25Co0.75MnFeO4 ferrite demonstrated more than 99% degradation of MB dye within 20 min. The effect of catalyst loading, pH, and stability of photocatalyst were studied.

Synthesis and characterization of chitosan/zinc oxide nanocomposite for antibacterial activity onto cotton fabrics and dye degradation applications

The present study reports an eco-friendly synthesis of chitosan/zinc oxide (CS/ZnO) nanocomposite using S. lycopersicum leaf extract by a bio-inspired method. The synthesized CS/ZnO nanocomposite was characterized by using UV–visible spectroscopy, X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), fourier transform infrared spectroscopy (FTIR) techniques. The XRD analysis revealed wurtzite crystalline structure of CS/ZnO nanocomposite. Electron microscopy images showed agglomeration of CS/ZnO nanocomposite having spherical shaped structure with an average size of 21–47 nm. The observed bands around 400–500 cm−1 in the IR spectrum indicated the presence of metal‑oxygen bond, whereas bands at 1512 and 1745 cm−1 indicated the presence of amine groups (−NH2) which confirms the presence of CS in the CS/ZnO nanocomposite. The synthesized nanocomposite showed potential antibacterial activity against skin infection causing S. aureus and the mechanism of bactericidal activity was confirmed by using FE-SEM. The CS/ZnO nanocomposite incorporated cotton fabrics also exhibited antibacterial activity against S. aureus, B. subtilis and E. coli. Furthermore, CS/ZnO nanocomposite acted as photocatalyst for the degradation of Congo red under sunlight irradiation. In conclusion, as-synthesized CS/ZnO nanocomposite can be used as bactericidal agent in textile industries and also as photocatalyst for dye degradation.