Degradation Of Cationic Dyes Research Articles

Enhanced piezocatalytic degradation of cationic dyes using graphene oxide and magnetic beads Nanomaterials: Synthesis, Characterization, and mechanistic insights

Sequestration of organic pollutants by the method of degradation is one of the safest ways to completely remove them from water bodies, without generating harmful by-products. Piezocatalytic degradation for this approach has been gaining much research attention, in recent times, due to its high efficiency. The present work reports synthesis of four types of Graphene Oxide-Chitin-Magnetic Iron Oxide Beads Nanomaterials, each with a different ratio of Graphene oxide (GO) and Chitin (CH). Among these, GO-CH-MIOBs NM-4 showed a superior Piezocatalytic degradation capacity towards methylene blue (MB), crystal violet (CV) and Rhodamine 6G (R6G) dyes. Various parameters influencing the piezocatalytic performance of the material such as kinetic factors, initial dye concentration, strength of ultrasonic vibration etc., have been analyzed thoroughly. Degradation rate constant (K) values of 63.4, 59.34 and 48.36 /min were obtained for MB, CV and R6G Dyes respectively. Moreover, cycling tests for all three dyes reflected significant stability of these materials as evident from the high degradation efficiencies of 99.80, 99.24 and 99.12 % within 60 min being retained for MB, CV and Rh6G dyes even after the 5th cycle. These nanomaterials can be a good addition in the list of high efficiency piezocatalyts for water purification with no secondary wastes being produced. Comparison of the XPS spectra before and after sonication gave insight into the mechanism of piezocatalytic degradation which highlighted hydroxyl and superoxide radicals as the main attacking species which are responsible for the degradation process.

SnO2-TiO2 materials for photocatalytic degradation of cationic dye under UV and visible light and a chitosan composite film investigation

The possibility of SnO2 incorporation and immobilization as films forming composites opens new perspectives for TiO2 to profit visible light and to facilitate the photocatalytic process, respectively. In this study, 0 %, 1 % and 10 % wt. of SnO2 was incorporated into TiO2 (SnO2-TiO2) by coprecipitation in a sol-gel method by ammonia addition, followed for calcination at 500 °C. The photocatalysts were characterized by N2 adsorption-desorption, FTIR spectroscopy, XRD Rietveld refinement, TG-DTG, SEM-EDS, DRS and elemental analysis. The performance of all solids was evaluated in the photocatalytic degradation of the cationic dye methylene blue in aqueous phase, under visible and UV irradiation, at 25 °C for 2 h. The results showed that the incorporation of Sn into TiO2 improved the textural properties and decreased the bandgap. All solids presented only TiO2 typical diffractograms, with anatase as the main phase, but catalyst with 10 % SnO2 presented also brookite phase, inferring that Sn atoms were incorporated into TiO2 structure, corroborated by MEV results. All tin-based photocatalysts show high activity under UV and visible light, with the 10 % SnO2 material reaching 83 % and 88 % degradation after 2 h under UV and visible radiation, respectively. This material was tested as an immobilized film, achieving 14 % of decolorization, and the reuse was also evaluated. Our investigation demonstrates that SnO2-TiO2 catalysts could be used to decompose a dye under UV and Visible light as powder in a batch reactor and immobilized as a composite film with chitosan, that opens new perspectives to facilitate the application using solar light.

Metal-Free Polydiacetylene-Functionalized Polymer for Photocatalytic Anionic and Cationic Dye Degradation and CO2 Capture

Metal-Free Polydiacetylene-Functionalized Polymer for Photocatalytic Anionic and Cationic Dye Degradation and CO₂ Capture

The Using of Plain PAC and PAC Impregnated with MgO and Fe2O3 as Catalysts for the Degradation of Cationic Dyes: Homogenous and Heterogeneous Ozonation

This study presented the removal of methylene blue in the batch system based on catalytic ozonation (heterogeneous and homogenous). The effect of variables such as initial MB (methylene blue)concentration, initial pH of solution (3-11), contact time (5-40 min), and catalyst dosage on homogeneous and heterogeneous ozonation systems was examined. The findings of the research showed that dye removal was better in alkaline conditions. The amount of dye removed in acidic conditions was slightly better than in neutral conditions (approximately 10% to 15%). In addition, the removal efficiency of dye was decreased by increasing of concentration. Besides, as the amount of catalyst (dosage) increased, the removal efficiency of MB had been increased by 40%. Due to the use of catalyst, the significant difference was between the use of two processes of single ozonation processes (SOP) and catalytic ozonation processes (COPs). The results indicated thatMB degradation in COPs was several times faster (approximately 4.7 times). It was due to the numerous advantages of these processes in the removal of environmental pollutants, they can be widely used in the removal of various pollutants if their cost can be reduced.

Role of transition metals in coinage metal nanoclusters for the remediation of toxic dyes in aqueous systems.

A difficult issue in chemistry and materials science is to create metal compounds with well-defined components. Metal nanoclusters, particularly those of coinage groups (Cu, Ag, and Au), have received considerable research interest in recent years owing to the availability of atomic-level precision via joint experimental and theoretical methods, thus revealing the mechanisms in diverse nano-catalysts and functional materials. The textile sector significantly contributes to wastewater containing pollutants such as dyes and chemical substances. Textile and fabric manufacturing account for about 7 × 105 tons of wastewater annually. Approximately one thousand tons of dyes used in textile processing and finishing has been recorded as being discharged into natural streams and water bodies. Owing to the widespread environmental concerns, research has been conducted to develop absorbents that are capable of removing contaminants and heavy metals from water bodies using low-cost technology. Considering this idea, we reviewed coinage metal nanoclusters for azo and cationic dye degradation. Fluorometric and colorimetric techniques are used for dye degradation using coinage metal nanoclusters. Few reports are available on dye degradation using silver nanoclusters; and some of them are discussed in detailed herein to demonstrate the synergistic effect of gold and silver in dye degradation. Mostly, the Rhodamine B dye is degraded using coinage metals. Silver nanoclusters take less time for degradation than gold and copper nanoclusters. Mostly, H2O2 is used for degradation in gold nanoclusters. Still, all coinage metal nanoclusters have been used for the degradation due to suitable HOMO-LUMO gap, and the adsorption of a dye onto the surface of the catalyst results in the exchange of electrons and holes, which leads to the oxidation and reduction of the adsorbed dye molecule. Compared to other coinage metal nanoclusters, Ag/g-C3N4 nanoclusters displayed an excellent degradation rate constant with the dye Rhodamine B (0.0332 min-1). The behavior of doping transition metals in coinage metal nanoclusters is also reviewed herein. In addition, we discuss the mechanistic grounds for degradation, the fate of metal nanoclusters, anti-bacterial activity of nanoclusters, toxicity of dyes, and sensing of dyes.

A near-infrared-II light-response BODIPY-based conjugated microporous polymer for enhanced photocatalytic degradation of cationic dyes and H2O2 production.

A BODIPY-containing conjugated microporous polymer (CMP, LBFD-1) was modified with calixarene to develop a hydrophilic CMP (LBFD-2) with broader absorption extending to the near-infrared-II region. LBFD-2 exhibited an H2O2 production rate of 2.14 mmol g-1 h-1 in the air without any sacrificial agents. The removal efficiency (η) of LBFD-2 towards methylene blue and rhodamine B reached >99.5% within 20 and 40 min in light. LBFD-2 can withstand diverse environmental changes, showing excellent reusability and potential for practical applications in real-water systems.

Bacterial cellulose based TiO2-CdS nanocomposite gel with enhanced photocatalytic activity for adsorptive degradation of cationic dye

Dye released by industrial is one of the main known pollutants in wastewater, which is harmfully affected to the human health. Adsorptive method by absorbents and photocatalytic degradation technique are advanced technologies to remove dyes from wastewater. However, the single technique mentioned above has imperfections limiting its application. Herein, in order to integrate the two techniques and take both advantages, bacterial cellulose (BC) based titanium dioxide (TiO2)‑cadmium sulfide (CdS) nanocomposite gel was prepared by microwave-assisted solvothermal synthesis. The BC@TiO2-CdS nanocomposite gel was characterized by SEM, EDS, XRD, XPS, Raman spectral and TG, its photocatalytic mechanism was proved by PL. The results showed the TiO2-CdS nanophotocatalyst exhibited binary hierarchical structure and followed the Z-scheme type photocatalytic system. The Z-scheme heterojunction is advantageous for photo-generated charge separation and migration. The photocatalytic performance of BC@TiO2-CdS nanocomposite gel was evaluated by MB degradation under visible light irradiation. Due to synergistic effect of BC matrix and TiO2-CdS, the as-prepared BC@TiO2-CdS nanocomposite gel possesses enhanced photocatalytic activity with 94.47 % removal of methylene blue (MB) after 180 min visible light irradiation. Therefore, this work provides a facile route to fabricate bio-mass based efficient nanophotocatalytic material for pretreating the water pollution.

Mesoporous composite aerogel derived from cellulosic waste for efficient adsorption and eco-friendly degradation of cationic dye

Mesoporous composite aerogel derived from cellulosic waste for efficient adsorption and eco-friendly degradation of cationic dye

Degradation of binary mixtures of dyes by step-scheme quaternary photocatalyst in continuous flow-loop ultrasound assisted micro-photoreactor

The development and design of micro-scale photocatalytic systems to achieve the degradation of organic pollutants such as dyes to improve environmental conditions is very desirable. In the current study, a microfluidic-based ultrasound-assisted photocatalytic microreactor was used for degradation of a mixture of cationic dyes including RhB and MB in binary mode by quaternary CeO2/Co3O4/Ag/Ag3PO4 step-scheme (S- scheme) photocatalyst under visible LED light. Various characterizations were performed to determine the morphology and structure of the photocatalyst. The ultrasound-assisted photocatalytic micro-photoreactor shows a much higher degradation performance than the simple micro-photoreactor for the degradation of cationic dyes. Besides, the batch process shows higher photocatalytic activity compared to the micro-photoreactor under ultrasound-assisted process. In addition, the reaction constant of CeO2/Co3O4/Ag/Ag3PO4 composite in ultrasound assisted micro-photoreactor are about 0.0087 1/s and 0.0081 1/s (RhB and MB) which are almost 2.3 and 1.7 times higher than micro-photoreactor due to free radicals, ultrasonic waves and Dean vortices. The observation of findings illustrated the photocatalytic degradation of dyes by the as-prepared composite in various processes were in the order of batch mode > ultrasound assisted micro-photoreactor > micro-photoreactor. The strategy of micro-photoreactor with ultrasonic waves using photocatalytic composite to improve dye degradation performance can lead to the development of advanced micro-photoreactor based on photocatalytic composites with high performance for wastewater treatment applications.

Poly(acrylic acid–butyl acrylate)-Based Physical Hydrogel for Adsorption and Microwave-Assisted Fenton Degradation of Cationic Dye

Poly(acrylic acid–butyl acrylate)-Based Physical Hydrogel for Adsorption and Microwave-Assisted Fenton Degradation of Cationic Dye

Role of the thermal regime in the defect formation of zinc oxide nanostructures prepared by the thermal decomposition process

Abstract The intrinsic defect of ZnO depicts a crucial role in the charge transfer owing to the suppression of the exciton recombination, exhibiting superior semiconducting performance. In this study, the intrinsic defect of ZnO nanostructures prepared by direct thermal activation of 300–900 °C was investigated. X-ray diffraction (XRD) was employed to analyze phase, crystallite size, Zn–O bond length, and dislocation density. The relation of Williamson–Hall (W–H) was used to calculate crystallite size and micro-strain. The atomic coordination was approximated through the Rietveld method. Morphology and crystal growth investigation was carried on by scanning electron microscope (SEM) and tunneling electron microscope (TEM), exhibiting rod-like nanostructures transform to oval shape particle with high residual strain when increasing calcination temperature, exhibiting the crystal growth direction of (101). Specific surface and pore analysis reveals a significant value corresponding to SEM analysis. Fourier transform infrared spectroscopy (FT-IR) detected Zn–O stretching vibration bands, presenting a notable increase in the intensity when heat at 600 °C. Relating to the thermal regime, energy bandgap (Eg) was found to be 3.41–3.50 eV as increasing heat treatment temperatures. Photoluminescence (PL) was applied to determine intrinsic defects through emissive spectra. The surface charge was determined through the zeta potential measurement. The photo-induced dye degradation was measured to understand the effect of the defect in semiconductors. The X-ray photoelectron spectroscopy (XPS) confirms the wurtzite structure appearance, including the intrinsic defects. The observed intrinsic defects are discussed, associating with the structural constants, emissive spectra, cationic dye degradation, and binding energy.

Efficient degradation of cationic dyes by ZnO and ZnO–Fe(III) quantum dots under natural sunlight and UV light

Zinc oxide (ZnO) quantum dots (QDs) are very attractive to many applications due to their optical and electronic properties and low toxicity. Among the applications, ZnO has been applied to photocatalysis for degradation or organic pollutants. However, what is still not clear is the function of organic dyes that absorb in the visible region, when they are together with semiconductors known for their best photocatalytic performance in the UV region. Herein, the degradation efficiency of two cationic dyes under natural sunlight irradiation and UV light in the presence of ZnO and ZnO:Fe(III) QDs with the dopant at 0.02, 0.04, and 0.07 mol% was investigated. The QDs were prepared via sol-gel method in ethanol and the photocatalytic assays were carried out in the same environment. Fe(III)-doped ZnO QDs with 0.04 mol% gave the highest apparent rate constants with degradation percentage equal to 84.3% and 66.9%, for methylene blue (MB) and astrazon blue FGGL 300% (AB), respectively, after 7 min under sunlight irradiation. Experiments were carried out with scavengers for hydroxyl (⋅OH) and anion superoxide (O2−⋅) radicals, tert-butanol and 1,4-benzoquinone (1,4-BQ), respectively. MB degradation course did not change in the ethanolic medium, known as ⋅OH scavenger, as well as with an extra amount of tert-butanol. However, the photocatalytic efficiency strongly decreased under the presence of 1,4-BQ. Thus, it is assumed that the MB degradation route in ethanol occurs mainly through the radical species O2−⋅. The study proved to be very sustainable and eco-friendly, being carried out in an ethanolic environment and with natural sunlight. This strategy ensured maximum surface efficiency and photocatalytic activity.

Optical and photocatalytic properties of TiO2–Bi2O3–CuO supported on natural zeolite for removing Safranin-O dye from water and wastewater

A series of n–p heterojunction catalysts (TiO2–Bi2O3–CuO) were synthesized by the ceramic method. X-ray diffraction, scanning electron microscopy coupled with energy dispersive X-ray, Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy, and photoluminescence were used for the characterization of the synthesized materials. The optical optimization demonstrated that the solid solution TiO2–0.2Bi2O3–0.25CuO exhibited the best optical property. This catalyst supported on natural zeolite under ultrasonic waves improved notably the adsorption-photodegradation capacity of the resultant material. The impact of the n–p junction supported on zeolite on the photodegradation of a polluting solution showed excellent results for the degradation of cationic dye with removal efficiency reaching 94.1% and 80.23% under sunlight for Safranin-O dye in distilled water and in wastewater from a local textile dyeing plant.

Green-fabrication of CuO nanoparticles using various plant extracts and their multifaceted applications in photocatalytic cationic dye degradation and antimicrobial activities

Green-fabrication of CuO nanoparticles using various plant extracts and their multifaceted applications in photocatalytic cationic dye degradation and antimicrobial activities

Exploring the multipotentiality of plant extracts for the green synthesis of iron nanoparticles: A study of adsorption capacity and dye degradation efficiency

The goal of the project was to create environmentally friendly and economically viable materials for thoroughly purifying contaminated water. An affordable, phytogenic, and multifunctional plant-based nanomaterial was prepared in this context. The work demonstrates an effective green synthesis method for producing iron nanoparticles (FeNPs) using six different plant extracts as a reducing agent. The characterization of green synthesized catalysts was concluded via Spectroscopy (tauc plot), XRD, FE-SEM, and FT-IR. The produced nanomaterial, which had an X-ray diffractogram (XRD) peak at 43.33⁰ and a size range of 1.82–63.63 nm, functioned as a highly effective nano-photocatalyst for the degradation of cationic dye. Due to the presence of a lower overall secondary metabolites quota, Ocimum sanctum plant extract reduced iron precursor produced the highest yield of dried NPs, followed by Azadirachta indica, Prosopis cineraria, Syzygium cumini, Citrus limon, and Salvadora oleoides. Further, the synthesized catalyst was tested for its effectiveness against gentian violet dye degradation. Ocimum sanctum plant extract reduced iron precursor produced the highest yield of dried NPs, followed by Azadirachta indica, Prosopis cineraria, Syzygium cumini, Citrus limon, and Salvadora oleoides, in that order. The dye removal efficiency of nanoparticles was 51% (Azadirachta indica), 83% (Ocimum sanctum), 59% (Syzygium cumini), 40% (Salvadora oleoides), 59% (Prosopis cineraria), and 63% (Citrus limon) after 12 h of visible light irradiation. The key factor in the process of deterioration is •O2−. As a result, the nanoparticles can be used in antibacterial and photocatalytic processes. The reduced band gap was responsible for the increased photocatalytic quantity. The maximum adsorption capacity at the time of equilibrium was obtained in order as Ocimum sanctum > Citrus limon > Prosopis cineraria > Syzygium cumini > Azadirachta indica > Salvadora oleoides. The simplicity of production, low cost, magnetic property, and high adsorption capacity will increase the efficacy of the water treatment method. This article reports on the creation of unique iron nanoparticles and their use in the purification of water.

Ti–N–C Bonded Close‐Coupled TiO2/g‐C3N4 for Rapid Degradation of Cationic Dyes from a Multi‐Dye System by Persulfate Activation

AbstractA novel Z‐Scheme photocatalyst (TCN) was prepared with TiO2 and graphitic carbon nitride (GCN) and utilized to study the degradation efficiency of a binary dye mixture consisting of 5 ppm Rhodamine B (RhB) and 5 ppm Crystal Violet (CV) solutions by persulfate activation. Derivative spectrometric analysis was adopted to find the degradation efficiencies of the individual dyes in the mixture. The results indicate that in the presence of persulfate ions 0.6 TCN gives 100 % degradation in 60 min and 30 min for Rh B and CV, respectively. Hydroxyl radicals, superoxide radicals, and sulfate radicals were found to be the active species involved in photocatalytic degradation. From the results of radical scavenging experiments and band potentials of the semiconductors, a plausible mechanism of photocatalytic degradation of the model pollutants is proposed.

La-doped WO3@gCN Nanocomposite for Efficient degradation of cationic dyes

In present investigation, gCN supported carbon coated Lanthanum doped tungsten oxide (C@LWO/gCN) composite were synthesized via hydrothermal approach. The photodegradation of different cationic dyes like malachite green (MG), crystal violet (CV) and methylene blue (MB) has been carried out under prepared C@LWO/gCN composite. Furthermore, the comparative photodegradation was also performed using pristine LWO and C@LWO nanowires. The synthesized samples were characterized via physiochemical techniques such as XRD, FESEM, EDX, FTIR, BET and UV/Vis spectroscopy. The results proved incorporation of La ions into WO3 lattice and reduced band gap of doped sample which significantly boost up the capability of the material towards photodegradation. The maximum degradation was found out at pH = 6, 5 mg catalyst dose, 5 ppm dye concentration and 35 °C temperature. The achieved results proved that the trapping agents compete with prepared composite specie for the h+, e−, HO● and O2●- radicals. The obtained experimental records of photodegradation of cationic dyes using C@LWO/gCN composite has correlation with pseudo first order kinetics, Langmuir-Hinshelwood model and t1/2. The simplest facile synthetic approach, remarkable photodegradation performance against colored and colorless effluents suggest that C@LWO/gCN composite exhibit great potential for large-scale wastewater treatment.

Green synthesis of orthorhombic Mn2O3nanoparticles; influence of the oxygen vacancies on antimicrobial activity and cationic dye degradation

An environmentally friendly bottom-up method for oxidizing and reducing heterocyclic chemicals from biological sources and producing metal oxides is proposed.

Novel PVA/chitosan composite membrane modified using bio-fabricated α-MnO2 nanoparticles for photocatalytic degradation of cationic dyes.

By integrating the benefits of poly vinyl alcohol (PVA) and chitosan (CS) with α-MnO2 nanoparticles (MNPs), a novel type of nano-polymer composite (PVA/CS-MNP) membrane was synthesized through a simple and facile casting method. In this proposed work, the membrane prepared was used for removal of organic textile dyes from their aqueous solutions. The as-synthesized PVA/CS-MNP membrane was examined using different analytical techniques such as Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscopy (FESEM), and mechanical properties of material was also studied. Two cationic dyes, methylene blue (MB) and eosin yellow (EY), were chosen as template dyes to be removed from industrial waste water. These dyes were degraded by carrying out a reaction in which the synthesized membrane was used as a photocatalyst. The study of kinetics revealed that the reaction process followed pseudo-first-order kinetics. The efficiency of catalyst and the rate of reaction were also examined by varying parameters such as pH, initial concentration of dyes, and composition of membrane. The maximum efficiency of catalyst was observed at pH 12 as more than 95% of dyes degraded within 1h of time span. The catalyst was found to be reusable as its efficiency did not deteriorate even after using it for several times. Such functional membrane having higher stability, low production cost, excellent efficiency to degrade dyes, and good recyclability are promising material for distinctly effective deletion of organic dyes from waste water.

Applications ofPeristrophe paniculataDerived Plasmonic Nanoparticles for DNA Binding and Photocatalytic Degradation of Cationic Dyes

AbstractResearch on plasmonics and their applications in diverse fields has increased significantly over the last decade. The present work primarily aimed to bio‐fabricate silver and gold plasmonic nanoparticles and to study their potential as photocatalysts and as DNA binders. To achieve this, Ag and Au NPs were derived employingPeristrophe paniculataand their optical, morphological and structural properties were investigated by standard analytical techniques. The formation rate constant k was 2.58×10−2 min−1and 3.56×10−2 min−1for Ag and Au NPs correspondingly. FT‐IR analysis showed that the water‐soluble alkaloid, 5‐amino‐3,4‐dihydro‐2H‐pyrrole‐2‐carbonitrile was responsible for the stabilization of nanoparticles. Transmission electron microscopic studies disclosed the formation of uniform spherical AgNPs and irregularly shaped AuNPs and the diameter was 9.32 nm and 27.85 nm respectively which was again corroborated by XRD studies (16.64 nm and 36.08 nm). The interaction of ct‐DNA with Ag and Au NPs was investigated using absorption spectroscopy in the UV‐Vis range and the binding constant values were 2.2×105 M−1and 8.1×106 M−1respectively. The degradation of methylene blue and malachite green by AgNPs was almost 100 % and 65 % respectively in 3 h under sunlight and neutral pH (pseudo first order rate constants were 7.9×10−3 min−1and 1.9×10−3 min−1). Moreover, the derived AgNPs exhibited mitigate activity against targeted pathogens. Thus, this green technique could be implicit for the eco‐friendly synthesis of Ag and Au NPs, and the prepared nanoparticles may be explored as photocatalysts for the degradation of cationic dyes without any added oxidants.