Decolorization Of Methylene Blue Dye Research Articles

ADSORPTION OF METHYLENE BLUE FROM AQUEOUS SOLUTION USING FREE AND IMMOBILIZED ALGAE CELLS

This study was aimed to investigate the potential adsorptive behavior of mixed algae for decolorization of methylene blue dye from aqueous solution in the form of free and immobilized. Effects of initial pH value (3-9), biosorbent dosage (0.02-0.5)g/L, and initial concentration (10-50) mg/L for different contact time (0-180) min at 200 rpm shaking speed were investigated. In addition, experimental data were analyzed using adsorption (Langmuir and Freundlich) isotherms as well as kinetic models. The results demonstrated that the maximum decolorization percentage was 93% and 91% by free and immobilized algae, respectively for pH 6, 10 initial concentration, 0.3g/100mL algae dosage, and 90 min contact time. The results revealed that the Langmuir isotherm model was adequate for describing the dye removal process (R2= 0.99) for both forms. Results of pseudo-second order kinetic model revealed best fitting with the sorption data indicating that chemisorption process is the dominant mechanism controlling the dye removal. Furthermore, the characterization study performed using FT-IR and scanning electron micrograph techniques, revealed that the used algal biomass has good biosorption capabilities associated to active groups and surface structure and confirming that the immobilization was successful.

One-Step Synthesis of Porous Graphitic Carbon Nitride and the Photocatalytic Performance under Visible-Light Irradiation

Porous graphitic carbon nitride (pg-C3N4) was synthesized via a facile one-step dicyandiamide (DCDA) high-temperature calcination method using heat-labile ammonium bicarbonate (NH4HCO3) as the gaseous template, and different pg-C3N4 materials were obtained by mixing various mass ratios of NH4HCO3 into DCDA. The micro-structures and -morphologies of the porous materials were characterized by X-ray diffraction (XRD) and Scanning Electron Microscope (SEM) respectively, and the photocatalytic degradation of methylene blue (MB) dye was tested under visible-light irradiation. It is found that the thermal decomposition of NH4HCO3 promoted destruction of the layer-structured g-C3N4 and increment of the specific surface area, producing more porous structures on the material surfaces, which is considered to be vital for the improvement of photocatalytic performance. Compared with the photocatalyst calcined by pure DCDA, the pg-C3N4 photocatalysts obtained by mixing the two raw materials performed better on MB dye degradation. Moreover, photocatalytic efficiency of the catalysts improved significantly with increasing NH4HCO3 contents in the raw materials. The degradation rate photocatalyzed by pg-C3N4 materials can reach more than 90% within 1.5 h, 6.5 times higher than that of the control material. It comes up to 99% at 2 h, basically achieving the complete degradation and decolorization of MB dye.

Methacrylic Acid-Acrylamide based ZnO Hydrogel Nanocomposite Assisted Photocatalytic Decolorization of Methylene Blue Dye

In this research, preparation of methacrylic acid-acrylamide based ZnO hydrogel nanocomposite (MAA-AM)/ZnO hydrogel nanocomposite by way of co-polymerization via used acrylate acid (AA) (or acrylate salt) (AA) or methacrylic acid (MAA)) and acrylamide (AM). Nanocomposites based on acrylate are characterized via being hydrophilic and able to retain water. Nanocomposite properties were studied using different techniques (FE-SEM, TEM, and EDX). The photocatalytic degradation of methylene blue MB dye under different conditions was studied using nanocomposite like time of irradiation, mass of catalyst (MAA- AM)/ZnO hydrogel nanocomposite, initial MB dye concentration onto photocatalytic degradation and reactivation were studied. The result increases the photocatalytic degradation with the rise weight of catalyst (MAA- AM)/ZnO hydrogel nanocomposite range (0.1–0.25 g). Too, a decrease in photocatalytic degradation was observed with an increase in MB. Observed that after reuse, ((MAA- AM)/ZnO) nanocomposite hydrogel appear photocatalytic efficiency from of the use 1 to 6 cycle 87.88 to 58.87%, showing that ((MAA- AM)/ZnO hydrogel nanocomposite surface appear good stability.

Radiation synthesis and photocatalytic performance of floated graphene oxide decorated ZnO/ alginate-based beads for methylene blue degradation under visible light irradiation

Organic dye contamination, emanating from pharmaceutical, paper, and textile industries into water resources, severely threatens marine and human life even at low concentrations. Photocatalysis is one of the most important remediation techniques that decolorize water by employing the power of light. In this work, the development of floated beads of Sodium Alginate/hydroxyethyl methacrylate (Alg-g-HEMA) encompass graphene oxide (GO) decorated Zinc oxide (ZnO) utilizing ionizing radiation was designed to function as a photocatalyst when exposed to visible light. Floatability was induced using calcium carbonate. GO was sonochemically decorated with ZnO nanoparticles and the yield was characterized using XRD, FTIR, TEM, SEM, and EDX techniques. Optical characteristics of the developed nanostructure were performed using UV–Vis spectrophotometry. The photocatalytic activity of the floated (Alg-g-HEMA)-ZnO@GO beads was assessed for the photo decolorization of methylene blue dye (MB) under visible light. The upshot of operational factors such as photocatalyst dose, pH, initial dye concentration, and irradiation time on the decolorization of MB was examined. It was observed that 1 g of the developed (Alg-g-HEMA)-ZnO@GO photocatalyst was able to decolorize 1000 ml of 20 ppm of MB within 150 min at pH 9. In terms of kinetics, photo-decolorization follows Langmuir Hinshelwood pseudo-first order.

Nanobioremediation: a bacterial consortium-zinc oxide nanoparticle-based approach for the removal of methylene blue dye from wastewater.

Industrial effluents carrying dyes are considered a major environmental threat in the present era. Methylene blue (MB) dye is one of the key dyes of the thiazine group of dyes. It is broadly used in medical, textile, and various fields and is well known for its carcinogenicity and methemoglobin nature. Bacterial and other microbes-mediated bioremediation is becoming an emerging and significant section for the treatment of wastewater. Isolated bacteria were used for the bioremediation and nanobioremediation of methylene blue dye under varying conditions and parameters. A comparative study was conducted for the remediation of methylene blue dye using bacterial consortium, potential bacteria (isolated by scale-up method), and potential bacteria within zinc oxide nanoparticles. The decolorizing ability of bacteria was analyzed by UV visible spectrophotometer after stirring and static incubation in different time intervals of the isolates. Growth parameters and environmental parameters which include pH, initial dye concentration, and dose of nanoparticles were optimized with the minimal salt medium. An enzyme assay study was also done to check the effect of dye and nanoparticles on bacterial growth and the mode of action of degradation. The authors found that potential bacteria within ZnO nanoparticles showed enhanced decolorization efficiency (95.46% at pH 8) due to the properties of nanoparticles. On the other hand, the decolorization of MB dye by potential bacteria and the bacterial consortium was about 89.08 and 76.3%, respectively, for a 10-ppm dye concentration. During the enzyme assays study, the highest activity was observed for phenol oxidase, nicotinamide adenine dinucleotide (NADH), 2,6-Dichloroindophenol(DCIP), and laccase for nutrient broth having MB dye, MB dye, and ZnO NPs, while no such change was observed for manganese peroxidase enzyme activity. Nanobioremediation is a promising approach to removing such pollutants from the environment.

Surface-Related Factors Affecting the Photocatalytic Process of Semiconductor Oxides: Ceria and Titania

Nanoparticles of CeO2, with rod-, and cubic-morphology, were synthesized by hydrothermal method and compared with commercial polyhedral ceria particles. Comparison of the synthesized CeO2 with the commercial powder revealed the influence of its defectivity with the absorption edge energy. The defectivity of CeO2 has also been determined in correlation with the photocatalytic performance of CeO2 per unit particles area, under narrow band UV-light (LED) condition. Analysis of the photocatalytic performance of the synthesized and commercial CeO2, as well as the reference TiO2 powder, revealed an enhancement in the decolorization of methylene blue dye (MB) with pH. The improvement in photocatalysis was associated with the surface charge condition of CeO2 particles, which controls the adsorption of molecules during the process. Furthermore, it was observed that the highly negative surface charge of cubic-morphology CeO2 favored the decolorization of MB, despite the low BET surface area. The photoelectrochemical study of ceria electrodes revealed a low photopotential compared to that of TiO2, the impact of which leads to a worse photocatalytic performance of CeO2 compared to TiO2.

Evaluation of photocatalytic properties of zinc and cobalt mixed oxide recycled from spent Li-ion and Zn–MnO2 batteries in photo-Fenton-like process

In this study, ZnCo2O4–ZnO–Li(Mn0.75Ni0.25)2O4 mixed oxide was synthesized by green recycling of spent Li-ion and Zn–MnO2 batteries. The cathode of Li-ion batteries and the anode of Zn–MnO2 batteries were leached separately with citric acid. Then, both leachates were mixed, and oxalic acid was added, yielding an oxalate precursor material. The precursor was calcined at 450 °C for 3 h to afford a mixed oxide. Oxalate precursor and oxide structure, composition, and morphology were determined by X-ray diffraction, inductively coupled plasma optical emission spectroscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy. The photocatalytic properties of the mixed oxide were evaluated in the decolorization of methylene blue dye in aqueous solution under UVC radiation. The system composed of UVC radiation + H2O2 + catalyst reached a decolorization efficiency of 93% after 90 min of reaction.

EVALUATION OF BACTERIA RESPONSIBLE FOR DECOLOURIZATION OF METHYLENE BLUE DYE IN SOIL

The discharge of textile effluents in open streams and land poses serious environmental problems. Even after physical and chemical treatment colour removal is not 100% achieved and hence it causes environmental pollution. The present study deals with examination and isolation of potential mycorrhizal soil bacteria responsible for decolorization of Methylene blue dye which is an azo dye. The results showed Bacillus haynesii strain NRRL B-41327 and Bacillus licheniformis strain DSM 13 were responsible for decolorization of Methylene blue dye in mycorrhizal soil. These gram positive, rod shaped bacteria in consortium exhibited 52.30 % colour removal efficiency. Potential of these bacteria can be further exploited for removal of residual dyes from textile effluents for restoration of ecosystem in an eco-friendly way which will be cost effective too.

Visible light driven robust photocatalytic activity in vanadium-doped ZnO/SnS core-shell nanocomposites for decolorization of MB dye towards wastewater treatment

Vanadium metal oxide (V2O5) doped ZnO/SnS core-shell nanocomposites are fabricated by hydrothermal method at 2200C for 10 hours. All synthesized Nanocomposites were optically, structurally, morphologically and magnetically examined by different techniques such as UV-DRS, XRD, TEM, electron paramagnetic resonance (EPR), XPS and PL techniques. The photocatalytic activity (PCA) was studied for methylene blue (MB) model pollutant dye under 300 W visible light illumination. XRD peaks confirmed the mixed phase abundance with hexagonal ZnO and orthorhombic SnS. TEM micrographs inferred uneven surface with more agglomeration. XPS conclude V4+ oxidation state for vanadyl atoms along with constitutes elements. The UV-DRS inferred red shift in bandgap. EPR argued that vanadyl ions perform tetragonal compression distorted octahedral site symmetry. PL study described quantum confinement effect. The achieved MB dye degradation under visible light illumination is more than 96% in 2 hours. Enhanced PCA argued owing to plasmonic effect and tunable energy bandgap nature of heterogeneous semiconducting materials.

Investigation of biologically synthesized stable copper oxide nanoparticles using Allium sativum extract by photocatalysis of methylene blue

In this study, stable copper oxide nanoparticles (CuO-NPs) were biogenically prepared using a bulb of Allium sativum extract (as reducing and capping agents) in a surfactant-free environment. A successful synthesis of CuO-NPs and factors affecting chemical reaction at a specific time, temperature, pH, and salt concentration was monitored by the UV-VIS technique. The characterization analysis like UV-VIS and FTIR suggested CuO-NPs were monodispersed, pure, and highly stable. CuO-NPs displayed outstanding photocatalytic results (95% within 50 min) for decolorization of methylene blue dye.

Cr(VI)-Mediated Homogeneous Fenton Oxidation for Decolorization of Methylene Blue Dye: Sludge Free and Pertinent to a Wide pH Range.

Fe(II)-mediated Fenton process is commonly employed for oxidative degradation of recalcitrant pollutants in wastewater. However, the method suffers from limitations like narrow working pH range and iron sludge formation. The present work deals with the degradation of Methylene Blue (MB) dye using Fenton-like oxidation by replacing Fe(II) with Cr(VI), which eliminates the limitations of classical Fenton oxidation. The Fenton-like oxidation of MB is brought about by HO• radicals generated by the disproportionation of chromium-coordinated peroxo complexes. It was observed that the working pH range for the Cr(VI)-mediated Fenton oxidation was 3–10, and no sludge formation takes place up to four cycles as the oxidation remains in the pure solution phase. The complete mineralization of dye was confirmed by observing the decay of MB peaks by a spectrophotometer and cyclic voltammetry. The reaction parameters like pH of the solution, temperature, degradation time, concentrations of H2O2, Cr(VI), and MB were studied for optimal performance of the Cr(VI) as the catalyst. Kinetic studies revealed that the Cr(VI)-mediated Fenton reaction follows pseudo-first-order reaction kinetics and depends on the concentration of HO• radicals. The proposed Cr(VI)-mediated Fenton oxidation in the present work is best suited for the degradation of organic dyes by adding H2O2 as a precursor in chromate-contaminated wastewaters.

Synthesis and characterization of Ag-AgVO3/Cu2O heterostructure with improved visible-light photocatalytic performance.

Heterostructure Ag-AgVO3/Cu2O photocatalyst was prepared by the hydrothermal procedure. The prepared photocatalysts were characterized by different physico-chemical techniques. For Ag-AgVO3/Cu2O composites, AgVO3 shows the monoclinic phase whereas Ag and Cu2O show a cubic phase. SEM images of Ag-AgVO3/Cu2O composites illustrated that the surface of AgVO3 nanorods was covered by Ag and Cu2O nanoparticles. Ultra violet - visible diffuse reflectance spectra revealed that the calculated optical response of Ag-AgVO3/Cu2O composite was found to be 2.24 eV. Additionally, the composite catalyst demonstrated improved photo-efficiency for the decolorization of methylene blue dye compared to that of pristine AgVO3. The better performance of the composite sample can be ascribed to its high charge separation and inhibition in recombination of charges in Ag-AgVO3/Cu2O catalyst Finally, this heterostructure Ag-AgVO3/Cu2O catalyst demonstrated good stability which simply can be recycled a number of times with steadiness; thus, unwraps new possibilities for applications as innovative photocatalyst.

Phytosynthesis of Iron Oxide Nanoparticles using Juncus inflexus Shoot Extract

To elude the toxic effects of chemically synthesized nanoparticles, the phytochemically synthesized nanoparticles may provide a better alternative. For the first time, an aqueous extract of Juncus inflexus shoot with FeCl3.6H2O was used for the phytosynthesis of iron oxide nanoparticles (FeONPs). As-synthesized FeONPs were characterized by UV-Vis spectroscopy, Transmission electron microscopy (TEM), Dynamic light scattering (DLS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). FeONPs showed UV-vis absorption spectra between 300-400 nm, whereas TEM analysis confirmed the particle sizes of 40-60 nm with aggregation. XRD is confirming the polymorphic composition of Fe3O4, α-Fe2O3, and Fe0 nanoparticles. Furthermore, FTIR analysis presenting the most probable mechanism for the synthesis of FeONPs. This multiphase FeONPs was applied for the decolorization of methylene blue dye (>83%). Phytosynthesized FeONPs have the benefits of low cost, no toxicity, sustainable, and eco-friendly technology so that they may be used as adsorbent/catalyst for remediation of toxic dyes in an aqueous medium.

Facile One-Pot Decoration of SnO2 Quantum Dots on the Surface of the Iron Phosphate Nanosheets for Enhanced Catalytic Decolorization of Methylene Blue Dye in the Presence of NaBH4

Herein, a SnO2 quantum dots (SQDs) @ FePO4 nanosheets (FPNSs) was prepared by a simple procedure without additional instruments and characterized using XRD, FTIR, SEM, and TEM. SQD@FPNSs nanocomposite (FP-Sn) exhibited improved catalytic activity for the degradation of methylene blue (MB). Approximately 92% of the MB was successfully decolorized within 6 min using FP-Sn in the presence of NaBH4.

Endophytic fungi mediated synthesis of iron nanoparticles: Characterization and application in methylene blue decolorization

Endophytic microflora is a lesser approached source for nanoparticles synthesis. Myco-synthesis of iron nanoparticles was carried out using an endophytic fungi Penicillium oxalicum isolated from Tecomella undulata. Synthesized iron nanoparticles were characterized using different techniques. The UV–Visible absorption spectrum showed an absorption band at 300 ​nm, which is a characteristic of iron nanoparticles. The FTIR spectrum of iron nanoparticles showed absorption peaks ranging between 3430.70 cm−1–466.83 cm−1 range. SEM images showed 140 ​nm particles of spherical shape. AFM images indicated particle width and height being 3.9 ​nm and 100 ​nm respectively. The iron nanoparticles formed were used to study decolorization of methylene blue dye in the presence of H2O2. The dye was effectively decolourized up to 99.17% in a time interval of 6 ​h. Myco-synthesized nanoparticle mediated decolorization process confers a possibility of removal of toxic textile effluents in a sustainable way.

Decolorization of Methylene Blue Dye Using ZnO/ZSM-5 Photocatalyst Under UV-LED Irradiation

<span id="docs-internal-guid-710aacff-7fff-63c8-d621-c027e79f6f4f"><span><strong>ABSTRACT. </strong></span><span>The present research studied about decolorization of methylene blue dye using photocatalyst ZnO/ZSM-5 under UV-LED lamp. ZnO/ZSM-5 was synthesized using the impregnation method by adding two grams ZSM-5 to Zn solution 0.3 M 10 mL. Photocatalyst was characterized using X-ray diffractometer (XRD), Fourier transform infrared (FTIR), field emission scanning electron microscopy-energy dispersive X-Ray (FESEM-EDX), and surface area analyzer (SAA). Analysis using XRD show addition characteristic peaks of ZnO at 2θ 31.60°, 34.21°, 36.08°, 47.35°, 56.50°, 62.73°, 67.83°, that indicates a successful impregnation process. The photocatalysis activity test was done on methylene blue dye 100 mg L-1. ZSM-5 and ZnO activities were tested under UV-LED irradiation and dark conditions. Data showed that percent removal of dye occurred on ZnO/ZSM-5 under 15 minutes irradiation is 78.32%.</span></span>

Decolorization of Methylene Blue Dye Using ZnO/ZSM-5 Photocatalyst Under UV-LED Irradiation

<span id="docs-internal-guid-710aacff-7fff-63c8-d621-c027e79f6f4f"><span>The present research studied about decolorization of methylene blue dye using photocatalyst ZnO/ZSM-5 under UV-LED lamp. ZnO/ZSM-5 was synthesized using the impregnation method by adding two grams ZSM-5 to Zn solution 0.3 M 10 mL. Photocatalyst was characterized using X-ray diffractometer (XRD), Fourier transform infrared (FTIR), field emission scanning electron microscopy-energy dispersive X-Ray (FESEM-EDX), and surface area analyzer (SAA). Analysis using XRD show addition characteristic peaks of ZnO at 2θ 31.60°, 34.21°, 36.08°, 47.35°, 56.50°, 62.73°, 67.83°, that indicates a successful impregnation process. The photocatalysis activity test was done on methylene blue dye 100 mg L-1. ZSM-5 and ZnO activities were tested under UV-LED irradiation and dark conditions. Data showed that percent removal of dye occurred on ZnO/ZSM-5 under 15 minutes irradiation is 78.32%.</span></span>

Microbial Synthesis of Nanoparticles: Mechanisms, Characteristics, and Applications

Cadmium sulfide (CdS) and zinc sulfide (ZnS) biogenic nanoparticles (NPs) were produced by microbial synthesis using bacteria of different taxonomic groups: Gram-negative (Shewanella oneidensis MR-1) and Gram-positive (Bacillus subtilis 168) bacteria in a liquid medium under aerobic conditions in the presence of salts of the respective metals and sulfur. It was shown that the stabilization of nanoparticles in aqueous suspensions is due to the presence of certain protein molecules of the outer membrane of cells, that is, proteins of the families of various receptors, porins, and flagellin, on the nanoparticle (NP) surface. The effect of the protein coating on stability, luminescence, zeta-potential, hydrodynamics diameter and other physiochemical characteristics of nanoparticles was studied. Decolorization of methylene blue dye under the exposure to UV irradiation was used as a model to demonstrate the photocatalytic properties of NPsCdS. This opens the possibility of using biogenic nanoparticles in photocatalysis for industrial wastewater treatment.

Green synthesis of Copper oxide nanoparticles decorated with graphene oxide for anticancer activity and catalytic applications

Nanotechnology is an embryonic field that grips countless impacts on the drug delivery system. Nanoparticles as haulers increase the capability of target-specific drug delivery to many folds hence are used in the treatment of dreadful diseases such as cancer, diabetes, etc. This boom has aimed at, to synthesize Copper oxide nanoparticles (CuO-NPs) using Acalypha Indica leaf extract and then incorporated with graphene oxide (GO) to form GO-CuO nanocomposites. Secondly, to sightsee the photocatalytic activity of CuO-NPs and GO-CuO nanocomposites towards the decolorization of methylene blue-dye and to test its activity against HCT-116 Human colon cancer cell lines. Synthesized nanocomposites were characterized using FTIR, UV–vis, X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), X-ray Photoelectron Spectroscopy (XPS) and transmission electron microscopy (TEM) analysis. The photocatalytic studies revealed that synthesized nanocomposites have the efficiency to degrade methylene blue dye by 83.20% and cytotoxic activity was found to be 70% against HCT-116 Human colon cancer cell lines at 100 μg/ml. GO-CuO nanocomposites have appreciable activity towards cancer cell lines and photocatalytic activity when compared to nanoparticles as such.

Green Synthesis of BiVO4 Nanoparticles by Microwave Method using Aegle marmelos Juice as a Fuel: Photocatalytic and Antimicrobial Study

As a part of the non-hazardous way of synthesizing nanomaterials, herein we report the synthesis of BiVO4 nanoparticles by the aid of Aegle marmelos juice as a fuel. This method employed a simple, effective, and low-cost microwave irradiation technique. Further, the physical properties of synthesized nanoparticles were fully characterized by using X-ray diffraction (XRD), Fourier Transform-Infrared spectroscopy (FTIR), Besides, the surface morphology of the same nanoparticles was also confirmed by using Scanning Electron Microscopy (SEM). Furthermore, metal nanoparticles are the prominent photocatalysts for the degradation of organic pollutants, in this vision photocatalytic activities of BiVO4 was also evaluated by studying decolorization of methylene blue dye under UV irradiation. As well the results revealed that BiVO4 showed higher photocatalytic activity due to elevated generation of charge carriers by UV irradiation. Besides, BiVO4 was also examined for the application of antimicrobial studies and the synthesized samples showed prominent results against all the tested strains.