Degradation Of Methyl Orange Dye Research Articles

Photocatalytic Degradation of Methyl Orange and Methylene Blue Dyes by Engineering the Surface Nano-Textures of TiO2 Thin Films Deposited at Different Temperatures via MOCVD.

TiO2 thin films were deposited on quartz substrates by metal-organic chemical vapor deposition (MOCVD) at temperatures of 250, 350, and 450 °C. X-ray diffraction (XRD) data revealed the production of a pure anatase phase, a decrease in crystallite size, and a textural change as deposition temperature increased. Atomic force microscopy (AFM) was used to study the morphological properties and confirm XRD results. UV-Vis.-NIR spectroscopy was used to investigate the optical properties of the samples. The effect of deposition temperature on wettability was investigated using contact angle measurements. Sunlight photocatalytic properties increased with the increase in deposition temperature for methyl orange and methylene blue. Films were post-annealed at 500 °C for 2 h. The effect of annealing on all the above-mentioned properties was explored. The kinetic analysis demonstrated superb agreement with the kinetic pseudo-first-order model. The rate of photocatalytic degradation of MB was ~8, 13, and 12 times that of MO using 250, 350, and 450 °C deposited films, respectively. Photodegradation was found to depend on the specific surface area, type of pollutant, and annealing temperature.

In Situ Hydrothermal Synthesis of Ni1-xMnxWO4 Nanoheterostructure for Enhanced Photodegradation of Methyl Orange.

The monoclinic nanocrystalline Ni1-xMnxWO4 heterostructure has been successfully synthesized by the hydrothermal technique for achieving better sensitive and photocatalytic performances. Different characterization techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible (UV-Vis), and photoluminescence (PL) spectroscopy have been employed to investigate their structural, microstructural, and optical properties. Mn-ion incorporation in the NiWO4 lattice reduces the particle size of the sample compared with the pure undoped NiWO4 sample, which has been confirmed from the transmission electron microscope image. The Tauc plot of the Ni1-xMnxWO4 sample exhibits a significant decrease in bandgap energy compared with the pure undoped NiWO4 sample due to the quantum confinement effect. Finally, the material was explored as a photocatalyst for the degradation of methyl orange (MO) dye from wastewater under visible light irradiation. Various reaction parameters such as pH, catalyst dose, reaction time, and kinetics of the photodegradation were studied using the batch method. The results showed that the Ni1-xMnxWO4 is highly efficient (94.51%) compared with undoped NiWO4 (65.45%). The rate of photodegradation by Ni1-xMnxWO4 (0.067) was found to be 1.06 times higher than the undoped NiWO4 (0.062).

Facile Synthesis and Fabrication of NIPAM-Based Cryogels for Environmental Remediation.

Herein, polymeric cryogels containing poly(N-isopropylacrylamide) were synthesized by cryo-polymerization at subzero temperature. The synthesized cryogels were loaded with silver and palladium nanoparticles by the chemical reduction method at room temperature using the reducing agent NaBH4. Moreover, for comparison with cryogels, pure poly(N-isopropylacrylamide) hydrogel and its silver hybrid were also prepared by the conventional method at room temperature. The chemical structure and functional group analysis of the pure cryogels was confirmed by Fourier transform infrared spectroscopy. The synthesis of hybrid cryogels was confirmed by the X-ray diffraction technique and energy dispersive X-ray. The pore size and surface morphology of the pure cryogels, their respective hybrid cryogels and of conventional hydrogels were studied by using the scanning electron microscopy technique. The hybrid cryogels were successfully used as a catalyst for the degradation of methyl orange dye. The degradation performance of the hybrid cryogels was much better than its counterpart hybrid hydrogel for methyl orange dye. The effect of temperature and amount of catalyst on catalytic performance was studied by UV-visible spectroscopy. The reduction follows pseudo-first-order reaction kinetics. In addition, the antibacterial activities of these cryogels were evaluated against Gram-positive bacteria (Staphylococcus aureus, ATCC: 2593) and Gram-negative bacteria (Escherichia coli, ATCC: 25922). Both hybrid cryogels have shown much better antibacterial activity for these two strains of bacteria compared to pure cryogels. The results indicate that these cryogels are potential candidates for water purification systems as well as biomedical applications.

Effect of sulfur precursors on hydrothermal growth of MoS2 nanostructures and its visible-light-driven photocatalytic activities

The molybdenum disulfide (MoS2) nanostructures such as nanosheets, nanoflowers, nanoparticles, and nanoflakes are promising candidate materials for environmental pollution control. In this work, the effect of sulfur precursors i.e. thioacetamide, thiourea, and elemental sulfur on the morphology of hydrothermally grown MoS2 material was studied followed by their visible-light-driven photocatalytic activities toward methyl orange (MO) dye degradation at ambient conditions. Interestingly under scanning electron microscope (SEM) images, the morphologies of synthesized materials were seen to consist of systematic nanosheets, aggregates, and agglomerates. Raman spectroscopy and XRD studies suggested that the grown materials were composed of primarily 1T-2H mixed phase of MoS2 along with a minor oxide phase of molybdenum. Moreover, photocatalytic MO dye degradation activities exhibited by thioacetamide-grown MoS2 nanostructures were found to be better than those of elemental sulfur and thiourea counterparts. The kinetic rates of degradation towards MO dye by materials synthesized with thioacetamide, elemental sulfur, and thiourea were found to be 0.00804 min−1, 0.00614 min−1, and 0.00531 min−1, respectively. The relatively better photocatalytic activities exhibited by thioacetamide-grown MoS2 material were attributed to its predominant nanosheet morphology and the presence of a greater amount of MoS2 contents. This work will be helpful for a better understanding of morphological control hydrothermal synthesis of MoS2-based materials and their subsequent organic dye degradation activities.

Degradation of the dye methyl orange using cow and goat milk iron nanoparticles

ABSTRACT Environmental pollution is a global issue, and the contamination of water by dyes is a matter of concern. This work reports an environmentally friendly method for degrading methyl orange dye using iron nanoparticles (INPs) synthesized from pasteurized cow and goat milk and ferric chloride (FeCl3). INPs were synthesized using FeCl3 and milk mixed in a 1:2 (v/v) ratio and subsequently heated at 70 0C. The formation of INPs was monitored by visualizing the color changes. The synthesized NPs were characterized by FTIR, SEM, EDS, TEM, XRD, and XPS. The XRD results showed that INPs were formed and had an amorphous structure. TEM data showed smaller semi-spherical particles with sizes of 8-27 nm, and they were present in an aggregated state. Dye degradation studies were conducted using INP with UV light exposure and H2O2 addition. Both the processes were monitored using UV/Vis scans at different time intervals. The results showed that the degradation of methyl orange was faster in the presence of H2O2 (over 85% efficiency in 60 min) than in the presence of UV light. The current study shows that the INPs formed using milk have the potential to be used as catalysts in azo dye degradation reactions.

Nanostructured Zn0.1Co2.9O4 material: Synthesis, characterization and its applications for energy storage and electrocatalytic dye degradation

This article presents the synthesis and characterization of a cobalt oxide nanomaterial with potential applications in dye degradation and energy storage. The nanomaterial, Zn-doped cobalt oxide (Zn0.1Co2.9O4), was synthesized using a coprecipitation method followed by calcination at 300 °C for 5 h. Various techniques including XRD, TEM, and BET were employed to analyze the phase formation, particle size, morphology, and surface area of the calcined sample. The XRD analysis confirmed the phase purity of the material, revealing a nanocrystalline structure with an average crystallite size of 10 nm. TEM imaging revealed spherical-shaped particles with a mean particle size of 11 nm. The material exhibited mesoporous characteristics, with a surface area of 60 m2/g and a pore size of 33 nm according to BET analysis. Cyclic voltammetry (CV) measurements conducted at different scan rates demonstrated the redox behavior of the material, as evidenced by the presence of oxidation and reduction peaks. Galvanostatic charge–discharge (GCD) experiments revealed a specific capacitance (Cs) of 117 F/g at a current density of 0.1 A/g, which decreased to 78 F/g at 1 A/g. The electrocatalytic dye degradation of methyl orange dye (5 ppm) was carried out using a stainless steel electrode coated with the Zn0.1Co2.9O4 nanomaterial. An applied potential of 15 V and a current of 0.03 A resulted in a 98% degradation of the dye after 30 min. The experiment was repeated for five successive cycles, yielding consistent levels of dye degradation.

Surface-decorated porphyrinic zirconium-based metal-organic frameworks (MOFs) using post-synthetic self-assembly for photodegradation of methyl orange dye.

We report herein the surface decoration of a water-soluble free-base porphyrin, namely, 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin-tetra(p-toluenesulfonate) (H2TMPyP), over three different zirconium-based metal-organic frameworks of different linker structure and functionality; namely UiO66, UiO66-NH2, and MIP-202, via self-assembly. The synthesized MOFs along with the resulting complexes have been characterized via spectroscopic and analytical techniques (XRD, FT-IR, TEM, N2 adsorption/desorption, and laser scanning confocal microscopy). The self-assembly of H2TMPyP with the examined three MOFs was observed by using the steady-state absorption and fluorescence, as well as the fluorescence lifetime studies. It was evident that the highest complex interaction was recorded between porphyrin and UiO-66-NH2 compared with the lowest interactions between porphyrin and MIP-202. This is in good agreement with the high surface area and pore volume of UiO-66 (1100 m2 g-1 and 0.68 cm3 g-1) and compared to that of MIP-202 (94 m2 g-1 and 0.26 cm3 g-1). The photocatalytic activities of the three porphyrin entities immobilized zirconium-based MOFs were compared toward methyl orange dye degradation from aqueous solution under visible light irradiation (λex = 430 nm). The photocatalytic studies render the fabrication of the self-assembled H2TMPyP@UiO-66-NH2 composite as a promising material for dye degradation from polluted wastewater.

Synthesis of NiFe2O4/SiO2/NiO Magnetic and Application for the Photocatalytic Degradation of Methyl Orange Dye under UV Irradiation

NiFe2O4/SiO2/NiO magnetic was successfully synthesized using NiFe2O4, SiO2, and NiO as the core, interlayer, and shell, respectively. NiFe2O4/SiO2/NiO under UV light irradiation was used for photocatalytic degradation of methyl orange dye with different pH, catalyst dose, and initial dye concentration. This composite was characterized by X-ray Diffraction (XRD), Fourier Transform Infra-Red (FTIR), Scanning Electron Microscopy-Electron Dispersive X-ray Spectroscopy (SEM-EDs), Vibrating Sample Magnetometer (VSM), UV-Vis Diffuse Reflectance Spectroscopy (UV-Vis DRS), and Point of Zero Charge (pHpzc). The results showed that the composite is a superparamagnetic material with a saturation magnetization value of 44.13 emu/g. It also has a band gap of 2.67 eV with a pHpzc of 6.33. The optimum conditions for photocatalytic degradation were at pH of 4; 0.50 g/L catalyst dose, and 10 mg/L initial concentration. NiFe2O4/SiO2/NiO degradation efficiency to methyl orange dye was 95.76%. The photocatalytic degradation in different concentrations follows the pseudo-first-order, where the greater the concentration, the smaller the constant rate (k). After five cycles of repeated usage, NiFe2O4/SiO2/NiO has good catalytic performance as well as efficient and favourable of a recyclable photocatalyst. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Efficient photodegradation of methyl orange dye using electrogenerated copper-zinc oxide hybrid

A photoactive Cu-doped ZnO (Cu/ZnO) hybrid was synthesized via a simple electro-generation procedure. The resultant catalyst was then subjected to UV–vis DRS and BET analysis for band gap and porosity properties studies. The photocatalytic efficiency of the Cu/ZnO hybrid was then evaluated via discoloration reaction of dye pollutant, methyl orange (MO) under visible light irradiation. To study the effect of Cu loadings on the hybrid catalyst performance, a series of catalysts with different Cu wt.% were synthesized and tested for MO degradation. As result, ZnO doped with 5 wt% Cu was found as the most active catalyst with 100 % MO removal followed by 3 wt% Cu/ZnO (94 %), 7 wt% Cu/ZnO (71 %) and 10 wt% Cu/ZnO (40 %). Whereas, in the presence of pure ZnO, only 23 % MO was managed to be degraded, remarking its low catalytic reactivity compared to Cu/ZnO hybrids, especially 5 wt% Cu/ZnO. This might be due to the increase in surface area and lower band gap of 5 wt% Cu/ZnO (3.11 eV) compared to ZnO (3.20 eV) as analyzed by BET and UV–vis DRS respectively. Meanwhile, the optimum reaction conditions were found to be pH 3, 10 mg/L initial dye concentration, and 0.38 g/L of 5 wt% Cu/ZnO. Conclusively, the electrogenerated Cu/ZnO catalyst was highly capable of degrading methyl orange dye pollutants and therefore has a high potential for future wastewater treatment application.

Photocatalytic Activity of Defective TiO2-x for Water Treatment/Methyl Orange Dye Degradation

This study is designed to highlight photocatalytic activity of TiO2 nanoparticles in methyl orange (MO) dye degradation. Titanium dioxide TiO2 nanopowder was synthesized by conventional sol-gel method and calcined in air atmosphere at different temperatures 350C, 550C and 850C. The prepared TiO2 nanoparticles then were subjected to a solid state reaction with calcium hydride (CaH2) at the same temperatures but calcined in argon atmosphere. X-Ray Diffraction (XRD) measurements used for phase and crystalline size identification showed that the obtained samples have the same TiO2 anatase phase, but the crystalline size decreased after reduction treatment. The electronic properties obtained via UV spectroscopy showed the decrease in calculated energy gap from 3.3 eV for prepared TiO2-550 to 2.65 eV for reduced TiO2-CaH2-550, which extend the absorption spectra toward visible light region. Energy dispersive spectroscopy (EDS) and scanning electron microscope (SEM) measurements revealed that the particle size decreased after reduction treatment similar to the XRD crystalline size. EDS results indicated that the deficient in oxygen content relates to formation oxygen vacancies responsible for nonstoichiometric TiO2-x oxides formation. The synthesized reduced TiO2 showed an excellent photo-catalytic activity in methyl orange dye degradation under optimum condition: pH 4.5, 40 mg catalyst loading and 10 ppm initial dye concentration.

Precursor-directed approach to fabricate TiO2-gCN composite: An efficient photocatalyst to harness solar spectrum

ABSTRACT In this study the porous composites, in-situ TiO2-g-C3N4 (in-situ TiO2-g-CN), was fabricated by in-situ generation of TiO2 from titanium tetra-oximate during thermal polymerisation of urea into gC3N4. For comparison, TiO2-g-C3N4 composite (TiO2-g-CN) and g-C3N4 (gCN) were also prepared by decomposition of urea in the presence and absence of TiO2 nanoparticles (NPs), respectively. The synthesised composites were characterised by FT-IR, SEM-EDX, TGA, and XRD analyses. The analyses of the samples revealed that the particle size of the composites decreases with the addition of TiO2 precursor, titanium tetra-oximate, during g-C3N4 Synthesis. A comparative study has been conducted on the photocatalytic degradation of methylene blue (MB) and methyl orange (MO) dyes in the presence of in-situ TiO2-g-CN, TiO2-g-CN, and gCN under the solar spectrum. In the presence of in-situ TiO2-g-CN, 99.7% degradation of MB and 68.4% degradation of MO was observed within 100 min, and it is superior as compared to TiO2-g-CN and gCN.

Synthesis, characterization, and photocatalytic degradation of anionic dyes using a novel ZnO/activated carbon composite

Zinc oxide/activated carbon from Thapsia transtagana stems (ZnO/ACTTS) composite demonstrated good photocatalytic properties for removing methyl orange (MO) dye from aqueous solution. This study utilized the chemical activation method using phosphoric acid to prepare activated carbon, which was then used to synthesize the ZnO/ACTTS composites by the hydrothermal technique at different percentages of the amount of ZnO (15, 30, 50 and 75 %). XRD, FTIR, and SEM-EDX were used to characterize the produced composite materials. The photocatalytic degradation of the catalysts was investigated for the degradation of MO dye from aqueous solution. The effects of zinc oxide content, pH of solution, and catalyst dosage were studied. Experimental results indicate that the ZnO/ACTTS (75 %) composite with exhibited good activity under acid pH conditions with an optimal catalyst dosage of 0.5 g/L. Photodegradation kinetics followed a pseudo-second order kinetics. ZnO/ACTTS composite will be a catalyst to degrade a wide range of dyes from the textile industry in the aquatic medium.

Novel green synthesis of N-doped carbon dots from fruits of Opuntia ficus Indica as an effective catalyst for the photocatalytic degradation of methyl orange dye and antibacterial studies

• We have prepared Undoped and N-doped C-dots from Opuntia ficus Indica plant extract. • The synthesized Undoped and N-doped C-dots exhibit, the green fluorescence. • We found higher photocatalytic activity in N-doped C-dots than Undoped C-dots. • N-doped C-dots have utilized as photocatalytic for the degradation of Methyl orange dye. • Further we have study them anti-bacterial activity using gram negative and gram positive bacterias. A carbon dot is an attractive material for the photocatalytic degradation of organic pollutant. Moreover it’s extensively used as a material to control the growth of micro organisms. Herein we are reporting the synthesis of Undoped and N-doped carbon dots (N-CDs) derived from Opuntia Ficus Indica (O.F.Indica) fruits. Further we have well characterized by UV-Vis, FT-IR, XPS spectral, HR-TEM, Raman and XRD techniques. The synthesized Undoped and N-CDs are stable for 3 months. Finally we have found the N-CDs shows the higher photocatalytic activity then Undoped C-dots, due to presence of N-atom. We also have discussed the possible degradation mechanism of Methyl Orange (MO). Finally the N-CDs was utilized their antibacterial activities. We used Streptococcus Pyogenes, Staphylococcus Aureus , Klebsiella Pneumoniae, and Shigella Flexneri. Among them we found Streptococcus Pyogenes a bacterium was largely controlled the growth by our N-CDs.

Photodegradation of methyl orange based on manganese-substituted bismuth ferrite nanoparticles

Herein, a microwave-assisted approach for the synthesis of manganese (II) (Mn2+)-doped bismuth ferrite (BMFO) nanoparticles is presented. Various techniques were used to examine the structure, morphology and electrical characteristics of the as-synthesized BMFO nanoparticles. X-ray diffraction and Raman analysis revealed a rhombohedral distorted perovskite structure with space group R3c. The crystallite size of BMFO was found to be 18.77 nm. Scanning electron microscopy studies of the BMFO nanoparticles showed the highly agglomerated nature of the particles. The ultraviolet diffuse reflectance spectrum of BMFO revealed a bandgap of 1.56 eV, which was smaller than the bandgap of pure bismuth ferrite (2.41 eV). The methyl orange (MO) dye degradation behavior of the synthesized BMFO was examined for a dye sample solution in the presence of solar radiation. After 120 min, irradiation resulted in 81.08% photodegradation of the MO dye. Kinetic studies demonstrated a pseudo-first-order rate mechanism for the photodegradation of the MO dye. The corresponding coefficient of determination R 2 and t 1/2 were 0.92864 and 63.0 min, respectively. Finally, a methodology for the degradation of MO dye using BMFO is proposed.

Efficient photocatalytic degradation of methyl orange dye using facilely synthesized α-Fe2O3 nanoparticles

In this paper, α-Fe2O3 nanoparticles were fabricated via the combustion process using glucose and sucrose as organic fuels for the first time. The fabricated products were characterized using XRD, FT-IR, HR-TEM, and UV–vis spectrophotometer. The average crystallite size of the α-Fe2O3 samples, which were synthesized using glucose and sucrose fuels, is 27.25 and 6.13 nm, respectively. The HR-TEM images confirmed the presence of spherical and irregular shapes with an average diameter of 31.92 and 8.83 nm for the α-Fe2O3 samples, which were synthesized using glucose and sucrose fuels, respectively. The optical energy gap of the α-Fe2O3 samples, which were synthesized using glucose and sucrose fuels, is 2.00 and 2.48 eV, respectively. Additionally, the synthesized α-Fe2O3 samples were employed as a photocatalyst for the degradation of methyl orange dye under UV irradiations in the absence and presence of hydrogen peroxide. The optimum pH, irradiation time, and dose of α-Fe2O3 that achieved the highest degradation efficiency in the presence of hydrogen peroxide (82.17 % in the case of using an α-Fe2O3 sample which was synthesized using glucose or 95.31 % in the case of using an α-Fe2O3 sample which was synthesized using sucrose) are 3, 100 min, and 0.05 g, respectively.

Photocatalytic efficiency of green synthesized ZnO nanoparticles for the degradation of methyl orange dye: A review

The primary global source of water pollution is industrial and textile dyes. These industries produce Highly stable organic dyes that are released untreated into nearby ponds, lakes and rivers. As ZnO nanoparticles (NPs) are inexpensive, non-toxic, chemically and thermally stable, and have a higher UV absorption capacity, they are an effective nano-catalyst for removing hazardous contaminants such as organic and inorganic dyes from wastewater. The green synthesis of synthesised ZnO NPs, their shape and size, and their photocatalytic effectiveness against the dye methyl orange are all described in this paper. The emphasis is on environmentally friendly synthesis of ZnO NPs using plant extracts because the synthesis process impacts the characteristics and applications of ZnO NPs. Additionally, based on recently published literature, the shape and size factors that affect the photocatalytic activity in the degradation of MO dye are highlighted.

Behavior of Silica Nanoparticles Synthesized from Rice Husk Ash by the Sol-Gel Method as a Photocatalytic and Antibacterial Agent.

Silica nanoparticles (SiO2 NPs) are one of the most well-studied inorganic nanoparticles for many applications. They offer the advantages of tunable size, biocompatibility, porous structure, and larger surface area. Thus, in this study, a high yield of SiO2 NPs was produced via the chemical treatment of rice husk ash by the sol-gel method. Characteristics of the prepared SiO2 NPs were validated using different characterization techniques. Accordingly, the phase, chemical composition, morphological, and spectroscopic properties of the prepared sample were studied. The average particle size of the SiO2 NPs was found to be approximately 60-80 nm and the surface area was 78.52 m²/g. The prepared SiO2 NPs were examined as photocatalysts for the degradation of methyl orange (MO) dye under UV irradiation. It was found that the intensity of the characteristic absorption band of MO decreased gradually with exposure time increasing, which means the successful photodegradation of MO by SiO2 NPs. Moreover, the antibacterial activity of obtained SiO2 NPs was investigated by counting the coliform bacteria in the surface water using the most probable number (MPN) index method. The results revealed that the MPN of coliform bacteria untreated and treated by SiO2 NPs was estimated to be 170 CFU/100 mL and 10 CFU/100 mL, respectively, resulting in bacterial growth inhibition of 94.12%.

Waste toner-derived porous iron oxide pigments with enhanced catalytic degradation property

‘Wealth from Waste’ is an emerging concept, since it leads an effective waste treatment and waste recyclability. On the other hand, cost effective production iron oxide (IO) nanomaterials is still needed to develop, owing to their wide applications. Herein, we proposed a simple direct calcination method to prepare porous IO (Fe3O4 and Fe2O3) nanomaterials from waste toner powder. Characterization techniques reveal that a structural change happened from Fe3O4 to γ-Fe2O3 and γ-Fe2O3 to α-Fe2O3 at the calcination temperature of 500 °C and 700 °C respectively. Consequently, optical (band gap) and magnetic parameters of IO samples were significantly varied. The pigment characteristics of the IO samples were evaluated using Commission Internationale de l’Eclairage (CIE) analysis. IO900 sample has shown good brown-red coloration (L* = 43.11, a* = 13.26 and b* = 5.69) and it also exhibited good stability in acidic and basic conditions. Practical applicability of IO pigments were also tested by mixing with plaster of paris (PP) powder. Further, porous IO samples were also used as catalysts in the reductive degradation of methyl orange (MO) dye in presence of excess sodium borohydride (NaBH4). IO, prepared at 900 °C exhibited ∼99.9% reduction efficiency within 40 min. Recycling experiments indicated that IO900 possess good stability up to seven cycles. The present porous IO samples will become potential in pigment and environmental remediation.

Ultrasonic assisted synthesis of ZnO nanoflakes and photocatalytic activity evaluation for the degradation of methyl orange

In the present investigation, ZnO nanoflakes was prepared via sonochemical synthesis route. Effect of ultrasonic treatment time was studied based on structural, morphological and optical properties. X-ray diffraction (XRD) reveals the formation of wurtzite hexagonal crystalline structure of ZnO nanoflakes. Ultrasonic treatments affected the crystallite size and the density of dislocation, which is due to increased nucleation and growth rates of nanoflakes. The samples synthesized at 40–50 min ultrasonic treatment showed a strong absorption band at 605 and 650 (cm −1 ) versus other treatments, which is an indication of 2D nanostructure (nanoflakes). FE-SEM analysis further confirms the formation of 2D nanostructures of the ZnO. The composition and purity was confirmed by the energy dispersive X-ray (EDX) analysis, which displays the occurrence of Zn and O elements in the sample. Photocatalytic activity (PCA) of ZnO nanoflakes was studied for methyl orange (MO) dye degradation under UV light exposure and up to 93.13 % dye degradation is achieved within 90 min. Effect of various parameters (dye concentration, mass of photocatalytic material) and kinetic study was also performed. Results revealed that the ultrasonic treatment affected the optical and photocatalytic properties of the of ZnO nanoflakes, which could be employed for the remediation of dyes in textile effluents.

Use of the CuFe2O4/biochar composite to remove methylene blue, methyl orange and tartrazine dyes from wastewater using photo-Fenton process.

In this study, CuFe2O4 ferrite was supported on biochar produced from malt biomass residues as a photocatalyst for degradation of methylene blue (MB), methyl orange (MO), and tartrazine (TZ) dyes. XRD, FT-IR, and FE-SEM were used to characterize the crystallinity and morphology of the samples. The characterization showed that the ferrite was uniformly supported on the surface of the biochar, confirming the formation of the composite. Degradation tests showed that CuFe2O4 degraded approximately 50, 47, and 62% of MB, MO, and TZ dyes, respectively, after 60min of reaction. On the other hand, the CuFe2O4/biochar composite showed a significant increase in dye degradation, ~ 100%, for all three dyes. This increase in degradation efficiency may be due to less agglomeration of supported particles and due to decreased recombination of electron/hole pairs. Thus, results showed that the photocatalyst composite produced in this study is an effective alternative for removing dyes from wastewater.