Catalytic Degradation Of Organic Dyes Research Articles

A new technique for the synthesis of lanthanum substituted nickel cobaltite nanocomposites for the photo catalytic degradation of organic dyes in wastewater

Developing cost-effective and more efficient nanocatalysts for the treatment of organic pollutants from process industry is always challenging for the researchers working in the field of chemistry, chemical, energy and environment engineering. In this work, a cost-effective and more efficient nanocatalysts, i.e., Nickel Cobaltite nanocomposites and its Lanthanum (La) doped derivatives with controlled surface morphology has been synthesized at 393.15 K through single step sol–gel method. The surface morphology, chemical composition, and crystal structure of the synthesized nanocomposites were analysed by scanning electron microscopy (SEM), Fourier transformed infrared spectroscopy (FTIR), and X-rays diffraction (XRD), respectively. The rough surface and well-crystallized metallic nanocomposites confirm the successful synthesis of nanocatalysts. The molar ratio of Lanthanum to Cobalt (Lax:Coy) showed a significant influence on the surface morphology and catalytic activity (Kapp = 0.15–0.47 min−1) of the products. Synthesized nanocomposites showed high catalytic activity for the reduction of methylene blue under solar irradiation. Photocatalytic results for the reduction of methylene blue show that the catalytic activity of synthesized nanocatalysts increases with the increase in the doping concentration of Lanthanum.

Catalytic degradation of organic dyes using green synthesized Fe3O4-cellulose-copper nanocomposites

In this work, the magnetically reusable Fe3O4-cellulose-copper nanocomposite was synthesized through a green synthesis method using Ceratonia siliqua aqueous extract as a reducing and stabilizing agent. The magnetically retrievable catalyst was characterized by a vibrating sample magnetometer (VSM), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA) techniques. The catalytic activity of the green synthesized catalyst was evaluated in the reduction of organic pollutants such as 4-nitrophenol, 2,4-dinitrophenylhydrazine, methyl orange and potassium ferricyanide in the presence of sodium borohydride as reducing agent at room temperature. This catalyst could also be utilized for reduction of organic dyes and the selective oxidation of benzyl alcohol to benzaldehyde providing excellent yields in short reaction time.

Microplasma-assisted synthesis of CuO nanostructures for catalytic degradation of organic dyes under solar irradiation

In this research work, CuO nanostructures were synthesized using atmospheric pressure microplasma (AMP) electrochemical process. The synthesized CuO nanostructures were characterized by various techniques such as X-ray diffractometer (XRD), scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectrometer, and UV-Vis spectrometer. XRD pattern showed that CuO has a monoclinic structure. Morphological analysis revealed that the shapes of nanostructures were sheet like. FTIR spectra confirmed the presence of the Cu–O stretching bond. Optical properties were studied by UV-Vis spectrometer. The bandgap was found to be 2.54 eV. The synthesized nanostructures were also employed for photodegradation of organic dyes such as methyl orange and rhodamine B under solar irradiation. It was observed that the percentage removal for both the dyes increased with increasing contact time and a significant removal was attained after a time of 80 min. The obtained results were confirmed by isotherm and kinetic studies. The dye adsorption data were fitted well to Temkin isotherm, while the adsorption process was well described by pseudo-first-order and intraparticle diffusion kinetics. These results would be extremely helpful for environmental applications regarding the removal of dyes from aqueous solutions as wastewater remediation.

Interfacial self-assembly of carbon nitride-based nanocomposites with zinc terpyridyl coordination polymers for photocurrent generation and the photocatalytic degradation of organic dyes

Graphite-like carbon nitride (g-C3N4)-based nanocomposites with zinc terpyridyl (ZnTPy) coordination polymers (CPs) were developed for photo-induced current generation and the catalytic degradation of organic dyes. The oxidized g-C3N4 nanoparticles (O-g-C3N4) were reacted with silane and terpyridyl benzyl bromide (TPyBenBr) to form O-g-C3N4TPy nanohybrids, which then acted as a support for the construction of O-g-C3N4-based nanocomposites, using Zn(CF3SO3)2 as a connector, and bidentate ligand of 1,4-di([2,2′:6′,2′'- terpyridin]-4′-yl)benzene (BTPy) as a linker, respectively. The luminescent emission features revealed that the recombination of charged carriers was inhibited in the O-g-C3N4@(ZnBTPy)n nanocomposites. As a consequence, the photocurrent density for the electrode, modified by the developed nanocomposites, was about 5.6 times higher than that modified by the original O-g-C3N4 particles; furthermore, their catalytic degradation efficiency for methyl orange (MO) and Congo red (CR) was about 20–25 times higher than that for the original O-g-C3N4 nanoparticles. The improved performance was attributed to the fact that, in addition to their enhanced absorption ability, the ZnBTPy CP films could effectively improve the electron transfer efficiency and generation of O2− radicals on the surfaces of the nanocomposites.

The Effect of Metal Ions as Dopants on OMS-2 in the Catalytic Degradation

Here we first designed, synthesized and compared Ni, Ag and Ce doped manganese oxide octahedral molecular sieves, (Ni-OMS-2, Ag-OMS-2 and Ce-OMS-2) for the catalytic degradation of organic dyes, such as reactive red 2, acid orange 7, methylene blue, and rhodamine B, in the presence of potassium peroxymonosulfate in aqueous solutions. These results show that the catalytic efficiency increases in the order of Ce-OMS-2 < OMS-2 < Ag-OMS-2 < Ni-OMS-2 for organic dyes degradation, which is in accordance with the concentration of oxygen vacancy defects on the surface of materials. Then pH condition and various amounts of Ni-OMS-2, organic dye and potassium peroxymonosulfate concentration have also been investigated for the reactive red 2 degradation. In addition, TEM and XRD have confirmed the heterogeneous catalyst Ni-OMS-2 has been successfully recycled at least 5 times with a very slight reduction efficiency by the simple filtration. We have designed, synthesized and compared Ni, Ag and Ce doped OMS-2, (Ni-OMS-2, Ag-OMS-2 and Ce-OMS-2) for the degradation of organic dyes. And they show the catalytic efficiency increases in the order of Ce-OMS-2 < OMS-2 < Ag-OMS-2 < Ni-OMS-2 for the degradation.

Highly efficient flow-through catalytic reduction of methylene blue using silver nanoparticles functionalized cotton

Organic dye pollution has become a serious problem threating environment and human health. Noble metal nanoparticles based catalytic degradation of organic dyes has attracted intensive attentions due to their outstanding catalytic activities. Compared with the catalytic systems using free noble metal nanoparticles, the flow-through systems based on the immobilized noble metal nanoparticles are more suitable for both high efficiency reaction and recycling of nanoparticles. In this study, the fibrous natural material cotton is selected as the support of silver nanoparticles (Ag NPs) and used for flow-through catalytic reduction of methylene blue (MB). Ag NPs were one-step immobilized onto cotton by immersing the cotton into a mixture solution of silver nitrate, poly (ethylene glycol) methyl ether thiol and dopamine. The reaction rate constant K of Ag NPs functionalized cotton towards MB reached high up to 0.478 min−1. The flow-through system with Ag NPs functionalized cotton was operated to achieve a super high permeation flux of 2000 L m−2 h−1 and also a very high MB reduction of more than 99%, which is far better than the reported results (below 500 L m−2 h−1). Moreover, the Ag NPs on cotton were very stable and released very slowly. After 24 h flowing-through test, only 0.9% of silver lose from the cotton. Our work provides a facile and applicable way to prepare the low-cost catalysts with high performances for continuous and efficient dye-containing waste water treatment.

A novel one-step strategy for preparation of Fe3O4-loaded Ti3C2 MXenes with high efficiency for removal organic dyes

Transition-metal carbides, nitrides or carbonitrides (named as MXenes) are a novel type of two-dimensional (2D) materials with the features of traditional 2D materials but more variable chemical compositions. MXenes and related materials have raised more and more research attention and been extensively explored for different applications. In this work, we developed a novel method to synthesize magnetic MXene composites (Ti3C2-MNPs) for the first time through a one-pot route, which relied on the incorporation of Fe3O4 nanoparticles into Ti3C2 nanosheets via thermal treatment. The potential utilization of these Ti3C2-MNPs for catalytic degradation of organic dyes through advanced oxidation processes (AOPs) were also evaluated in details. We demonstrated that Fe3O4 nanoparticles with size about 5 nm could be anchored onto Ti3C2 with well dispersed state. The catalytic degradation results demonstrated that Ti3C2-MNPs possess extremely high degradation efficiency towards different organic dyes under optimal conditions. The electron spin resonance (ESR) spectra identified that both hydroperoxyl radicals (•OH) and superoxide radicals (•O2-) radicals were involved in the degradation process. This work reported a novel one-step method for fabrication MXenes based multifunctional composites, which show extremely high efficiency for AOPs. This method could also be extended for fabrication of many other multifunctional composites for various applications.

Effective Catalytic Degradation of Organic Dyes by Nickel Supported on Hydroxyapatite-Encapsulated Cobalt Ferrite (Ni/HAP/CoFe2O4) Magnetic Novel Nanocomposite

The present study reports the synthesis, characterisation and efficiency in the degradation of organic dye of nickel/hydroxyapatite/cobalt ferrite (Ni/HAP/CoFe2O4) novel nanocomposite. The composite was applied as both nanoadsorbent and heterogeneous catalyst for the degradation of organic dyes methylene blue and methyl orange. The composite was not very effective in the degradation of the dyes by adsorption method. However, in the presence of H2O2, significant catalytic degradation of both the dyes was observed. The catalyst showed a degradation of about 90% (methyl orange) and 99.1% (methylene blue) in 90 min in the presence of hydrogen peroxide. Reactive oxygen species (ROS), such as hydroxyl and perhydroxyl radicals (HO• and HOO•), were formed and Fenton and Fenton-like mechanisms were involved in the decolourisation process. Kinetic studies showed that the degradation process followed first-order. The nanocomposite Ni/HAP/CoFe2O4 showed high catalytic activity, stability and superparamagnetic property.

Organic–inorganic bimetallic hybrid particles with controllable morphology for the catalytic degradation of organic dyes

Amphiphilic bimetallic hybrid Janus nanoparticles with controllable morphology and ability to perform highly efficient catalytic degradation of organic dyes.

A simple strategy to design 3-layered Au-TiO2 dual nanoparticles immobilized cellulose membranes with enhanced photocatalytic activity

Cellulose-based photocatalysts of supported nanoparticles feature high photocatalytic activity but their facile construction and photocatalytic mechanism exploration are highly challenging. Herein, a simple structural design principle and synergistic properties of 3-layered porous cellulose-based membranes are used for catalytic degradation of Rhodamine B in an aqua system. The 3-layered Au-TiO2 cellulose membranes were fabricated through the tape method and the suction filtration process. The composite membranes with strong redox ability, high charge-separation efficiency, and wide absorption range could stimulate the solar-driven plasma evaporation of Au nanoparticles and the photocatalytic function of TiO2 nanoparticles simultaneously. As characterized by Scanning Electron Microscopy, well-defined Au nanoparticles with an average size of 18.24 ± 3.17 nm were uniformly distributed on the TiO2-CM surface. Compared with TiO2-CM, TiO2-Au-CM showed better catalytic degradation of organic dye. This work demonstrated that a simple strategy design of Au-TiO2-CM could efficiently enhance the photocatalytic activity for the degradation of dyes in water.

Enhanced adsorption and catalytic degradation of organic dyes by nanometer iron oxide anchored to single-wall carbon nanotubes

Abstract Arc discharge method with Fe catalyst was used to prepare single-wall carbon nanotubes (SWCNTs) and there are an amount of iron nanoparticles formed tightly on SWCNTs. Nanometer iron oxide anchored to SWCNT composite (AO-Fe-SWCNTs) was obtained in situ by oxidizing the above as-grown SWCNTs (As-Fe-SWCNTs) in air at 375 °C. AO-Fe-SWCNTs exhibited an excellent performance of adsorption, Fenton and photo-Fenton degradation of methyl blue (MB) and methyl orange (MO) in aqueous solutions. Adsorption of MB and MO by AO-Fe-SWCNTs could reach equilibrium within 10 min and its maximum adsorption capacity for MB and MO was up to 256.69 mg g−1 and 93.58 mg g−1, respectively. MB could almost be decomposed within 10 min depending on their concentration using AO-Fe-SWCNTs as catalyst under the assistance of H2O2. UV–Vis light irradiation further speeded up the above Fenton reaction and the degradation of MB and MO in solutions. It was revealed that the small sizes of iron oxides (several nanometers) and their good dispersion on SWCNTs are the main reason responsible for the good property of AO-Fe-SWCNTs. Furthermore, iron oxides-SWCNTs heterojunctions probably improve electron-hole separation during irradiation and promote the generation of hydroxyl radicals. The present study indicates that AO-Fe-SWCNTs with firm web structure are a promising material for adsorption and degradation of organic dyes.

Porous nanofibrous superhydrophobic membrane with embedded Au nanoparticles for the integration of oil/water separation and catalytic degradation

Effective separation of oil/water emulsion and removal of organic dyes are of critical importance for environmental protection. In this study, superhydrophobic polyacrylonitrile (PAN) nanofibrous membrane embedded Au nanoparticles (NPs) in cavity has been prepared through a facile electrospinning and subsequent surface-modification strategy. The as-prepared Au@ZIF-8@PAN-TD membrane exhibited a water contact angle (WCA: ∼155.5°), an oil contact angle in air (OCA: ∼0°) and a WCA under-oil (∼158°). The composite membrane has demonstrated its ability to achieve efficient water/oil separation and in situ catalytic degradation of organic dye (e.g. 4-nitrophenol). The superhydrophobic Au@ZIF-8@PAN-TD membrane with a hierarchical porous structure would open an avenue for the purification of polluted oily water system.

Facile synthesis of reusable magnetic Fe/Fe3C/C composites from renewable resources for super-fast removal of organic dyes: Characterization, mechanism and kinetics

Hierarchically structured Fe/Fe3C-carbon composites materials with highly dispersed Fe/Fe3C magnetic nanoparticles have been successfully fabricated via a facile pyrolysis from renewable resources. The high surface area material (1779.3 m2 g−1) has major mesopore distribution centered at 2–4 nm, exhibiting super-fast adsorption and efficient catalytic degradation of organic dyes within 5 min, i.e., methylene blue (Qe,exp = 531 mg g−1), methy red (Qe,exp = 500 mg g−1), malachite green (Qe,exp = 500 mg g−1) and methy orange (Qe,exp = 500 mg g−1). Detailed characterization and mechanism shows that the super-fast removal ability is ascribed to the stronger electrostatic interaction between Fe/Fe3C/C composites and dye, and the breaking of chromophore group though the redox reaction. Particularly, the adsorption isotherm of methylene blue in aqueous solution follows a Langmuir isotherm model at an adsorption capacity of up to 641.0 mg g−1 at 298 K. In view of the abundance and low-cost of walnut shell and iron salt, together with the facile synthesis methodology, the materials reported here are sustainable and promising for practical applications in removing dyes.

Photocatalytic and catalytic degradation of organic dye by uncapped and capped ZnS quantum dots

ZnS quantum dots were prepared with different concentrations of 2-mercaptoethanol as a capping agent by simple and fast co-precipitation method. The synthesized nanopowders were characterized using various analytical chemistry as well as image visualizing techniques to elucidate the changes in structure and shape of quantum dots. The lowest average estimated crystallite size of ZnS quantum dot was 4.2 nm that showed relevancy to 2-Mercaptoethanol amount. X-ray diffraction (XRD) confirmed purity of nanosized ZnS with cubic and rhombohedral crystalline structures. Upon capping increased absorption around 300 nm was recorded by UV–vis spectroscopy that suggests ZnS interaction with 2-mercaptoethanol. The surface morphology of capped ZnS showed nanorod shape with agglomeration of particles confirmed by field emission electron microscopy (FESEM). The presence of functional groups and strong chemical bonding at the interface of quantum dots was confirmed by fourier transform infrared spectroscopy (FTIR). However, thermal analysis revealed no decomposition till 200 °C evidenced by DSC-TGA that suggests its high temperature stability. Moreover, uncapped ZnS quantum dot showed extensive methylene blue (MB) dye degradation with maximum absorption peak (λmax) at 664 nm that suggests visible light activity. The synthesized ZnS quantum dots has strong potential to be used as effective dye degradation agents in textile, tanneries and leather industries.

Synthesis of eco-friendly copper nanoparticles for augmentation of catalytic degradation of organic dyes

This study presents a simple, single-step process for preparing copper nanoparticles (CuNPs) using l-ascorbic acid as a reducing and capping agent along with the investigation of its photocatalytic dye degradation activity. Standard characterization techniques such as, ultraviolet visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and dynamic light scattering were employed to confirm the formation, crystallinity and morphology of the copper nanoparticles. CuNPs exhibited exceptional catalytic activity in the reductive degradation of three different dyes namely, methylene blue (91.53%), methyl red (73.89%) and Congo red (84.89%), respectively under optimal conditions. Thus, the efficient photocatalytic property along with economic feasibility and trivial toxicity assert the copper nanoparticles an alluring option for wastewater treatment.

Adsorption and photo-Fenton catalytic degradation of organic dyes over crystalline LaFeO3-doped porous silica

LaFeO3 (LFO)-doped mesoporous silica (HPS) (HPS-xLFO with theoretical LFO/silica molar ratio x = 0.075, 0.15, 0.3) was successfully prepared via impregnation of metal ions into the porous silica HPS-0LFO support and subsequent calcination. The characterization studies suggest that increasing the doping of LFO, which exhibited a particle size of ∼10–15 nm, in the silica support led to a reduction in surface area and bandgap of the resulting catalyst. The use of HPS-0.15LFO yielded a superior removal rate (98.9%) of Rhodamine B (RhB), thanks to the effective dark adsorption and visible light-induced photo-Fenton degradation, both of which were greater than those of pure LFO crystals. This enhancement could be explained by the unique properties of the mesoporous silica support. In particular, the wide-opening mesopores created a large surface area to dope LFO as active sites and minimize diffusion of RhB into pores during the photo-Fenton reaction. The photo-Fenton catalytic degradation of RhB could reach 98.6% within 90 min exposure to visible light irradiation under optimized conditions: RhB concentration = 10 mg L−1, catalyst dosage = 1 g L−1, pH = 6 and H2O2 = 15 mM. Moreover, the recycle and reuse test proved the good stability and repetitive use of HPS-0.15LFO for high performance RhB removal.

In-situ construction of novel silver nanoparticle decorated polymeric spheres as highly active and stable catalysts for reduction of methylene blue dye

A facile strategy has been developed for the preparation of novel silver/poly(styrene-N-isopropylacrylamide-methacrylic acid) (Ag/PSNM) nanocomposite spheres with high catalytic activity and good storage stability. Silver (Ag) nanoparticles are successfully deposited on poly(styrene-N-isopropylacrylamide-methacrylic acid) (PSNM) spheres surfaces via in situ reduction and simultaneously protected by polyvinylpyrrolidone (PVP). The prepared Ag/PSNM nanocomposite spheres show good temperature/pH responsive property and improved thermal property. Moreover, they also exhibit high catalytic activity and good recyclability for the catalytic reduction of methylene blue (MB) to leuco methylene blue (LMB). The result of clock reaction indicate that the redox reaction generates a colorless (LMB) solution which easily reverts back to blue (MB) in air. The catalytic activity increase with the increasing of temperature and the reaction rate constant (k) follows the typical Arrhenius-type dependence on temperature. In addition, the prepared Ag/PSNM nanocomposite spheres show good storage stability and the catalytic activity remains almost unchanged after storage for 90days at room temperature. Therefore, the prepared Ag/PSNM nanocomposite spheres can have a highly potential use in the catalytic degradation of organic dyes in wastewater treatment applications.

Green synthesis of the Ag/ZnO nanocomposite using Valeriana officinalis L. root extract: application as a reusable catalyst for the reduction of organic dyes in a very short time

A facile and green synthesis of the Ag/ZnO nanocomposite by extract of Valeriana officinalis L. root in the absence of any stabiliser or surfactant has been reported in this work. The green synthesised Ag/ZnO nanocomposite was characterised by Field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), elemental mapping, Fourier-Transform infrared (FT-IR), X-ray diffraction analysis (XRD) and UV-Vis spectroscopy. According to SEM and TEM images, the Ag and ZnO particles are spherical with diameters of less than 20 and 40–50 nm, respectively. The Ag NPs/ZnO nanocomposite proved to be an effective catalyst in the reduction of various dyes including methyl orange (MO), Congo red (CR) and methylene blue (MB) in the presence of NaBH4 in aqueous media at ambient temperature. A maximum degradation (100%) of dyes was performed using Ag/ZnO nanocomposite. The extraordinary performance of the prepared Ag/ZnO nanocomposite is attributed to the synergetic effect induced by both ZnO and Ag NPs in the catalytic degradation of organic dyes. The catalyst could be reused and recovered several times with no significant loss of catalytic activity.

Hydrothermal synthesis of Cu-Fe3O4 nanocomposites towards catalytic degradation of organic dyes

Degradation of hazardous organic dyes utilizing multifunctional catalytic materials is supposed to be an efficient and promising method. Here, homogeneous Cu-Fe3O4 nanocomposites are synthesized through a facile and versatile one-pot hydrothermal method. The prepared Cu-Fe3O4 possesses spherical structure with rough surface and average diameter of 230 nm. High catalytic activity and structure stability make Cu-Fe3O4 nanocomposites effectively degrade rhodamine B, methylene blue, methyl orange, and congo red. The existence of magnetic Fe3O4 leads the nanocomposites to separate from the solution through external magnet and reuse for cycle degradation. And during the cyclic utilization, Cu-Fe3O4 nanocomposites keep high catalytic activity and, thus, could be used as an efficient degradation catalyst for the application of organic dyes.

Catalytic degradation of organic dye using reduced graphene oxide–polyoxometalate nanocomposite

Silicotungstic acid (SiW) decorated reduced graphene oxide (rGO) nanocomposite (rGO-SiW) has been prepared and evaluated as a heterogeneous nanocatalyst for the degradation reactions of methylene blue (MB) and rhodamine B (RhB). The structural and morphological properties of rGO-SiW nanocomposite were investigated by various techniques such as Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction (XRD), Atomic force microscopy (AFM) and Scanning electron microscope (SEM), which revealed the homogeneous and noncovalent anchoring of SiW nanoparticles on rGO sheets. The catalytic activity of rGO-SiW nanocomposite on the degradations of MB and RhB has been monitored using UV–visible absorption spectrometry in the presence of NaBH4 as the reducing agent at room temperature in water. The reduction reactions followed pseudo-first order kinetics and degradation were achieved in 34 min for MB and 81 min for RhB using rGO-SiW as catalysts.