Degradation Of Methylene Blue Dye Research Articles

IoT real-time monitoring system implemented to observe sunlight-influenced methylene blue degradation by AC/HAp.

Activated carbon (AC) and hydroxyapatite (HAp) composite were successfully prepared via mechanical mixing and exhibited a crushed snack-like morphology compared to the well-defined pore structure of pure AC. The purpose of this research was to explore the potential of AC/HAp for the degradation of methylene blue (MB) dye and hydrogen production. Despite the morphological changes, AC and AC/HAp achieved a high MB degradation rate (92.75 and 82.05) % under sunlight, at a temperature of 26.24°C and pH of 4.18, and showed optimum hydrogen production (3579mol/g.h). These performances are suspected from the decrease in crystallite size and narrowed and confirmed by image processing results with RBG enhancement showing more light transmitted by the solution. Increasing in indicates the potential for improved light interaction. IoT-enabled real-time monitoring system demonstrates its efficacy in facilitating wastewater treatment and hydrogen production, offering a promising solution for aquatic ecosystem restoration.

Photocatalytic degradation of methylene blue dye by ZnO nanoparticle thin films, using Sol–gel technique and UV laser irradiation

The focus of the current work is the study of the effect of the photo-catalytic activity of ZnO nanoparticles. The photocatalytic destruction of methylene blue dye, a common water contaminant, was used to assess the photocatalytic efficiency of the ZnO nanoparticles from its aqueous solution by using ZnO nanoparticles thin film under UV light and laser irradiation. Sol–gel methods prepared ZnO nanoparticle thin films. X-ray diffraction and a field-emitted scanning electron microscope were utilized to examine the structure of the produced ZnO nanoparticles. An extended characterization by laser-based fluorescence and UV–visible spectroscopic techniques. The effects of operational parameters such as photo-catalyst load and contact time on photocatalytic degradation of methylene blue were investigated. The recent study’s findings showed that irradiation with a UV laser increases with power density 25 µW/cm2, the photo-catalytic rate. The UV spectra show decay for the band at 664nm decreased and the concentration of M.B. in monomer form decayed to 26% of the original concentration in 24 h, while the band at 612 which is related to the dimer M.B. molecules was not affected. The laser irradiation did the same for monomer M.B. molecules in only 3 h, while the dimer decreased to 28% of its original concentration. The reaction mechanism has been discussed by molecular modelling. Quantum mechanical calculations at B3LYP/6-311g(d,p) level indicated that methylene blue changed from dimers to monomers in the existence of ZnO. The current results present a method for degrading M.B. not only in wastewater but also in the industrial waste scale.

Efficient and rapid sunlight-driven photocatalytic degradation of methylene blue dye using multiferroic BiFeO3 nanoparticles

Efficient and rapid sunlight-driven photocatalytic degradation of methylene blue dye using multiferroic BiFeO3 nanoparticles

Exploration of Pristine ZnO and Cobalt Doped ZnO for the Solar Photocatalytic Degradation of Methylene Blue Dye

The ZnO and Co-doped ZnO were prepared by eco-friendly and modest route, including thermal disintegration of zinc oxalate (ZnOx) and cobalt-zinc oxalate (CoZnOx) powders, respectively, from a mechano-chemical method. The process of conversion of metal/s oxalate dihydrate to the pristine ZnO and cobalt-doped ZnO was studied with TG-DTG and FTIR spectroscopy. ZnO and Co-doped ZnO crystallites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy dispersive X-ray (EDX), UV–visible and photoluminescence (PL) spectroscopies. Hexagonal Wurtzite crystallite structures of the aforementioned materials were illustrated from XRD data. The surface morphological investigation was done with SEM. EDX study confirms the elemental purity of materials. Chemical bonding information was obtained from FTIR spectra. Optical properties were studied from UV-visible and photoluminescence spectroscopy. Exploration of pristine ZnO and cobalt-doped ZnO for the solar photocatalytic degradation (PCD) of methylene blue dye has been done in a batch photoreactor. The various related parameters such as photocatalyst amount, initial concentration of dye and pH were also examined for maximum degradation efficiency for mentioned dye.

Novel Anodic TiO2 Synthesis Method with Embedded Graphene Quantum Dots for Improved Photocatalytic Activity

Photocatalytic degradation of pollutants have a high potential for sustainable and renewable uses. TiO2 is a widely studied photocatalyst due to its high chemical and photochemical stability and wide range of applications. However, the wide band gap and low capacity of photo-induced charge separation provide lower catalytic activity; thus, improvement of these properties must be found. The doping of TiO2 with other elements, such as carbon nanoparticles (CNP) in a quantum dot form, offers a promising pathway to improve the aforementioned properties. In addition, in situ doping methods should be investigated for practical scalability, as they offer the advantage of integrating dopants directly during material synthesis, ensuring a more uniform distribution and better interaction between the dopant and the host material, in turn leading to more consistent photocatalytic properties. Current technologies primarily involve nanoparticle combinations. This work focuses on the development of a novel in situ synthesis methodology by the introduction of three different graphene-based quantum nanodots into anodic TiO2 and the following investigation of structural, morphological, and photocatalytic properties. Results indicate that the introduction of CNP allows for the shift of a set of parameters, such as the optical band gap, increased photo-induced charge carrier density of TiO2/CNP composite, and, most importantly, the change of crystalline phase composition depending on added CNP material. Research indicates that not only a higher concentration of added CNP enhances higher photocatalytic activity as tested by the degradation of methylene blue dye, but also the type of CNP determines final crystalline phase. For the first time brookite and rutile phases were obtained in anodic titania synthesized in inorganic electrolyte by introducing hydrothermally treated exfoliated graphene.

Optical absorption studies of pulsed-laser-engineered silver nanospheres and their enhanced catalytic performance in the degradation of toxic methylene blue dye

Pulsed laser ablation in liquid is an environment-friendly and one of the fastest physical routes to synthesize surfactant-free and stable metal/metal oxide nanoparticles with high purity and no harmful residues. In this study, we report the synthesis of silver nanospheres (AgNSs) using the nanosecond pulsed laser ablation in liquid (PLAL) technique resulting in the formation of a colloidal solution. Investigation of the optical properties using UV–Vis spectroscopy revealed the effects of laser wavelength, frequency, fluence, ablation time, and re-irradiation on the light absorption of the produced silver nanospheres. Physicochemical characterizations included FE-SEM, XRD, DLS, FTIR, and XPS techniques to evaluate the size, morphology, crystal structure, size distribution, zeta potential, and surface chemistry. FE-SEM studies revealed the formation of well-dispersed spherical Ag nanospheres with an average particle size of 209 nm without any agglomeration. DLS measurements showed high stability with a recorded zeta potential value of −38.27 (+/−1.81) mV and a wider size distribution. The XRD analysis indicated a face-centered cubic crystal structure with the formation of an oxide layer over the metallic silver core. The presence of silver and oxygen was confirmed through XPS studies with binding energies at 368.1 eV and 374.1 eV and oxide formation on the surface of Ag NSs. Finally, the catalytic activity of the Ag colloid was examined for the degradation of the toxic methylene blue dye. The results revealed an excellent catalytic response with 90 % of the dye degraded in just 15 min of reaction time. The kinetics of the degradation process were studied with a rate constant of 0.054/min−1 showcasing the effectiveness of the pulsed laser-synthesized silver colloidal nanomaterial as a sustainable approach for environmental remediation.

Green synthesis of N-doped-carbon dots/ZnO for enhanced photocatalytic degradation of methylene blue dye: optimization of reaction parameters.

In this research work, nitrogen-doped carbon dots (N-CDs) adorned zinc oxide nanoparticles (N-CDs/ZnO) were successfully synthesized by a simple and cost-effective solution dispersion method and later on used as photocatalyst for decontamination of aqueous methylene blue (MB) dye on irradiation of UV light (300 W, 320-400nm) at room temperature. Both the N-CDs and ZnO were prepared through green technique utilizing non-toxic, inexpensive and eco-friendly precursors, namely Foeniculum vulgare and Psidium guajava leaf extract, respectively. All the synthesized samples exhibited crystalline nature with average diameter of particle 4.42nm, 12.38nm and 14.11nm corresponding to N-CDs, ZnO and N-CDs/ZnO, respectively. Further, band gap energy value (Eg) of 3.43, 2.76 and 2.49eV for N-CDs, ZnO and N-CDs/ZnO, respectively, were obtained by using Tauc's plot. The photocatalytic capability of the sample N-CDs/ZnO was compared with bare ZnO nanoparticles, utilizing identical experimental conditions. The results demonstrated that the composite exhibited notably higher photocatalytic degradation efficiency than bare ZnO nanoparticles up to 15.54%. Lower band gap value of N-CDs/ZnO was the major factor for exhibiting this behaviour, decreasing the recombination rate and thus enhancing the efficiency. Furthermore, N-CDs/ZnO exhibited 98.17% MB degradation under optimized conditions (0.03g, 5ppm, pH 10). The resultant N-CDs/ZnO exhibited good stability and decontamination efficiency up to five cycles with efficiency loss of only 7.89%. Along with, trapping experiments was conducted to analyze the role of active species involved for deep understanding of mechanism. The order of efficiency of active constituents was observed to be: •O2- > h+ > •OH. The study analyzed the non-toxic nature of treated water, revealing normal plant growth, suggesting its potential use in irrigation of parks and roadside areas. Overall, present research work obeys the green chemistry principles with the fabrication of highly efficient, eco-friendly, cost-effective photocatalyst N-CDs/ZnO by utilizing the green precursors for the whole research work.

Enhanced photocatalytic and antibacterial performance of CeO2-loaded carboxymethyl chitosan nanocomposites.

Carboxymethyl chitosan (CMCs) was loaded with two different concentrations of cerium dioxide (CeO2), specifically 0.3 g and 0.6 g, and compared with pure CMCs. XRD and FTIR analyses were used to evaluate the structural characteristics. The nanocomposites were examined for their photocatalytic degradation of Methylene Blue (MB) dye and antibacterial capabilities. Various parameters, including catalyst concentration, dye concentration, and pH levels, were assessed to determine the photocatalytic degradation efficiency of MB dye. The results demonstrated that the 0.6CeO2/CMCs nanocomposite outperformed the 0.3CeO2/CMCs and pure CMCs in terms of photocatalytic performance, achieving complete degradation of MB dye within 210 and 240 min after treatment with 0.3CeO2/CMCs and 0.6CeO2/CMCs nanocomposites. The agar well diffusion test was employed to assess the antibacterial activity of the nanocomposites against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa. The 0.6CeO2/CMCs nanocomposite exhibited the highest antibacterial effectiveness, with zones of inhibition measuring 29 ± 0.63 mm for E. coli, 28 ± 0.18 mm for P. aeruginosa, 25.5 ± 0.25 mm for S. aureus, and 23.6 ± 0.51 mm for E. faecalis. Additionally, the durability and reusability of the nanocomposites were confirmed after undergoing 5 cycles of MB dye degradation, with only a slight decrease in efficiency. The findings of this study highlight the potential of CeO₂/CMCs nanocomposites as powerful antibacterial and photocatalysts with important implications for environmental and biological applications.

One-step fabrication of S-scheme ZnO/g-C3N4 composites for enhanced environmental photocatalysis

This study focuses on synthesizing zinc oxide/graphitic carbon nitride (ZnO/g-C3N4) nanocomposites for efficiently degrading methylene blue (MB) dye via photocatalysis. Egg white was used as a surfactant agent in the synthesis process. The nanocatalysts were characterized using several techniques such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray analysis (EDS), Fourier-transform infrared (FTIR) spectroscopy, Brunauer-Emmett-Teller (BET) tests, UV-Vis spectroscopy, and photoluminescence (PL) spectroscopy. These ZnO/g-C3N4 nanocatalysts were then analyzed for their photocatalytic degradation of MB dye under direct sunlight. The results showed that the ZnCN2 sample achieved the highest efficiency, degrading 92% of MB within 60minutes. A pseudo-first-order kinetics was also confirmed for the photodegradation reaction. Radical scavenger studies revealed that superoxide and hydroxyl species were primarily responsible for the degradation of MB, and possible S-scheme photocatalytic mechanisms were proposed. Additionally, the ZnO/g-C3N4 composite exhibited excellent reusability and chemical stability, maintaining an unchanged degradation efficiency of MB after five cycles.

Enhanced Fenton Degradation of Methylene Blue Dye Using CuFe2O4/Fe2O3/CHCP Heterogeneous Catalyst for Superior H2O2 Activation

Enhanced Fenton Degradation of Methylene Blue Dye Using CuFe2O4/Fe2O3/CHCP Heterogeneous Catalyst for Superior H2O2 Activation

A New Tropical Wild Fern for the Green Synthesis of Gold Nanoparticles: Comprehensive Characterization and Application in Water Treatment

Utilizing natural plant extracts to synthesize of gold nanoparticles (AuNPs) has emerged as a sustainable and eco-friendly alternative to conventional methods. Nephrolepis biserrata (NB), a tropical perennial fern, is rich in bioactive phytochemicals such as alkaloids, tannins, and flavonoids, which can effectively serve as reducing and stabilizing agents in the green synthesis of AuNPs. UV-visual spectrophotometry was employed to optimize synthesis parameters, including the reactant ratio of chloroauric acid (HAuCl₄) to NB, HAuCl₄ concentration, and reaction temperature. Optimal AuNP synthesis was achieved at a 1:0.25 HAuCl₄ ratio, a concentration of 0.25 mM HAuCl₄, and a reaction temperature of 70 °C, yielding nanoparticles with an absorbance of 1.449 ± 0.039 at a λmax of 531 nm. The synthesized AuNPs were characterized using FTIR, Zeta potential, FESEM/EDX, and XRD analyses. FTIR results indicated that the hydroxyl (O–H) and carbonyl (C=O) groups in NB facilitated the reduction of Au³⁺ ions. Zeta potential measurements confirmed AuNPs’ stability at -15.1 mV. The FE-SEM images and EDX analysis verified that the AuNPs were predominantly spherical, with minimal variation in shape. The average particle size was measured to be 28.184 ± 7.87 nm. The EDX spectrum showed strong signals for atomic gold at 2.12 and 2.14 keV, indicating that gold constituted approximately 48.49% of the sample by weight, which can be attributed to the bio-reductants in the plant extracts.The peaks in the X-ray diffractogram that correspond to Bragg’s reflection values of 38°, 44°, 64°, and 77° at 2θ indicate the formation of the face-centered cubic crystalline structure of AuNPs. These nanoparticles demonstrated high catalytic efficiency in the degradation of methylene blue (MB) dye, following a pseudo-first-order reaction in the presence of NaBH₄. These findings suggest that NB-mediated AuNPs offer a promising and eco-friendly approach for catalytic applications in wastewater treatment.

Exploring the potential of CdSe nanostructured thin films for energy conversion and environmental remediation

Abstract The rapid thermal evaporation method was employed to prepare cadmium selenide (CdSe) nanostructured thin films with varying thicknesses on glass and FTO substrates. The films were characterized for their structural, optical, and electrochemical properties. Scanning electron microscope (SEM) analysis revealed inhomogeneous surfaces with particle sizes ranging from 18 to 46 nm. The photocatalytic performance of the CdSe films was evaluated by the degradation of methylene blue (MB) dye under visible light, with varying pH values, achieving a degradation efficiency of 100 % at pH 10 after 180 minutes. Photocurrent density measurements demonstrated the films' ability to sense visible light. We performed a cyclic voltammetry (CV) measurement and analyzed the CV curves of the CdSe nanostructured thin film electrodes. It clearly shows that the CV curves had a rectangular shape, which suggests that EDLC behavior was present and non-faradaic capacitance was the main type. The photoconversion efficiency measured is 1.4858 at a bias voltage of 0.66 V under illuminated conditions. Nonlinear optical properties were conducted for CdSe nanostructured thin films.

Remarkable reactions of doped and Co-doped Co3O4 thin films synthesized by spray pyrolysis technique for enhanced catalytic degradation of methylene blue dye under sun light irradiation

Remarkable reactions of doped and Co-doped Co3O4 thin films synthesized by spray pyrolysis technique for enhanced catalytic degradation of methylene blue dye under sun light irradiation

Visible Light Driven Defect Mediated Photocatalytic Activity of Spray Pyrolyzed Ga and Al Doped ZnO Thin Film Electrodes

AbstractGa and Al doped ZnO thin film electrodes are spray deposited and explored for photocatalytic deterioration of methylene blue dye. X‐ray diffraction unveils both films to have highly textured growth along the (002) plane. The surface morphology is found to have near spherical and distorted rectangular particles for Ga and Al dopants, respectively. Photoluminescence emission study reveals that both films have visible light emissions in the violet, blue, and green regions due to oxygen vacancy defects. The deposited films exhibit a reasonably higher transmittance of 89 and 77 % with mobility of 30.5 and 29.6 cm2/Vs for Ga and Al doped ZnO, respectively. Cyclic test and photo‐corrosion studies performed for selected samples were indicating significant stability. Based on these findings the electrodes are explored for the photocatalytic degradation of methylene blue dye and are found to have significant efficiency upon LED and sunlight irradiation.

Microemulsion Templating Synthesis of Hierarchical Porous Ag‐Doped SiO2‐TiO2 Composites for Efficient Degradation of Noxious Methylene Blue Dye: Effect of Calcination Environment

AbstractWe report herein a dual function mesoporous structure of titanium oxide based porous carbon with large surface‐to‐volume ratios for efficient degradation of noxious methylene blue dye (MB) from an aqueous environment. The mesoporous photocatalysts is fabricated via direct template synthesis of highly ordered silica‐titania monolith doped with Ag0/Ag2O starting from a quaternary microemulsion liquid crystalline phase. The produced monoliths are subjected in‐situ to doping by growing silver, in the cubic cavities, and on the silica/titania structure's domain. This study investigated the efficiency of novel composite materials, consisting of silver‐doped silica‐titania (SiO2/TiO2), which is synthesized using the microemulsion templating approach. The photocatalytic performance of the synthesized composite in the photodegradation of MB has been studied. The procedure of photodegradation was employed to achieve decolorization of the cationic MB dye using visible light. The catalyst effectively achieved the decolorization of the dyed solution through the processes of adsorption and photodegradation. The composite consisting of SiO2, TiO2, and Ag2O at a ratio of 1 : 1:0.5, which underwent calcination in an air environment (AgOST), exhibited a removal efficiency of 99 % compared to its calcined state under argon (AgSTC).

Evaluating the Photocatalytic Activity of Green Synthesized Iron Oxide Nanoparticles

Water pollution from dyes is a major environmental challenge, demanding advanced materials for efficient degradation. In this study, we synthesized iron oxide nanoparticles (IONPs) using an aqueous extract of Senegalia catechu leaves and evaluated their photocatalytic activity in methylene blue (MB) dye degradation under sunlight irradiation. The IONPs were characterized by UV-visible spectroscopy (UV–vis), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Spectroscopy (EDS). XRD pattern showed a highly crystalline structure with an average crystallite size of 34.7 nm, while SEM images revealed predominantly spherical particles with uneven surface texture. Photocatalytic efficiency exceeded 80% MB dye degradation after 120 min of sunlight exposure. Optimization of catalyst dose, pH, dye concentration, and other parameters is essential for maximizing degradation efficiency. The IONPs demonstrated reusability over four degradation cycles, retaining effective photocatalytic performance. This study underscores the potential of green-synthesized IONPs as eco-friendly photocatalysts for wastewater treatment and environmental remediation.

Exploring the Impact of Ni Doping in Tuning the Bandgap, Electronic, Optoelectronic and Photocatalytic Properties of ZnFe2O4

AbstractThe exploration of semiconductor nanostructures utilizing mixed metal materials is an emerging area of study across fields including field‐effect transistors, chemical sensors, photodetectors, photocatalysts, and many more. In this study, Schottky diodes based on ZnFe2O4 (ZFO) were constructed with an aim to tune their electronic and optoelectronic characteristics. Here, Ni doping facilitated the tuning of electronic properties, leading to a significant increase in the rectification ratio from 238 to 1172, along with a reduction in the potential barrier height from 0.67 V to 0.65 V. This is attributed to Ni's role as a charge carrier in ZFO, enhancing carrier concentration, confirmed by Mott‐Schottky analysis. The 5 mol % Ni‐doped ZFO also exhibited remarkable light sensitivity, with its rectification ratio surging to 1795 under illumination, four times that of the undoped version. Additionally, its photo‐sensitivity soared to 42.46 %, nearly quadrupling the undoped device's performance, and its power gain impressively climbed to 38.4 %, which is over twelvefold the undoped sample's output. Furthermore, the diode responds strongly to optical illumination, making this structure suitable for use as a photodiode or photosensor. Apart from that by employing a doping strategy, we achieved 64.61 % degradation of methylene blue dye under visible light in 120 minutes, compared to 36.85 % for the undoped sample. These indicate that hydrothermally synthesized Ni‐doped ZFO is promising for visible light‐driven multifunctional applications.

Carbon fibers decorated with TiO2 nanoparticles for photocatalytic degradation of methylene blue dye

This report demonstrates the development of carbon fibers (CFs) decorated with TiO2 nanoparticles (NPs) as an efficient photocatalyst for the photocatalytic degradation of methylene blue (MB) as a model dye. Carbon fibers were produced by carbonization of polyacrylonitrile fibers, previously produced by centrifugal spinning. Subsequently, the CFs were decorated with TiO2 NPs (CFs@TiO2) by tailored soaking protocol using aqueous TiCl4 solution with different concentrations (0.025, 0.05, 0.1, and 0.2 M). SEM analyses revealed that soaking in TiCl4 produced a smooth, conformal, continuous TiO2 nanoparticulate coating with thickness increasing from 40.4 ± 21.2 to 257.9 ± 63.9 nm with increasing TiCl4 concentration. X-ray diffraction and Raman spectroscopy confirmed the anatase nature of TiO2. Photocatalytic decomposition rates of MB were assessed under UV light illumination for all CFs@TiO2 samples, and it was revealed that the lowest amount of TiO2 NP on C yielded the highest rates. The synergistic interaction between CFs and TiO2 NPs with a uniform morphology and a well-crystalline anatase structure, present in an optimal amount of fiber bodies, is the key reason for the remarkable photocatalytic performance. This work shows that C fibers decorated with an optimal amount of TiO2 NPs have a great potential as an effective photocatalytic material.

“Sunlight-driven catalytic degradation of MB dye and multi-cycle Re-usability analysis of Cu2-xSe nanoparticles”

One of the best ways to remove organic dyes based contaminant from water resources and industrial waste water is the sunlight driven photo-catalytic degradation method. The theme of the present investigation is the photocatalytic degradation of methylene blue (MB) dye using economically produced Cu2-XSe nanoparticles (NPs) catalyst under solar radiations. The Cu2-XSe NPs crystallized in the cubic structural phase with an average crystallite size around 19 nm. The direct band gap was found to be 2.1 eV. The PL spectra and corresponding CIE diagram show the Cu2-xSe NPs emitted yellow color. The SEM micrographs show that the small grains staked over others to form large grains or patches. The FTIR and EDX spectra confirmed the formation of Cu2-XSe NPs. The obtained optimum photocatalytic degradation efficiency for Cu2-XSe NPs is 90.3 %. For first cycle analysis. The pseudo-first order and second order models were used to analyze the kinetic data of Cu2-XSe NPs for varying concentrations. The multiple-cycle degradation analysis by catalyst of MB dye in one day spam for continuous four cycles were also analysed and discussed. The sun light driven multi-cycle catalytic degradation confirms the re-usability of Cu2-xSe NPs for the treatment of industrial waste water and other contaminated water bodies for the survival of aquatic life and for saving environment.

Magnetic and visible light-induced novel green synthesized magnetic Co3O4 photocatalysts via sunflower seed meal extract for anionic and cationic dye removal by adsorption assisted photocatalytic degradation

This study was aimed at the preparation of m-Co3O4 NPs (magnetic Co3O4 nanoparticles) from sunflower seed meal (SFSM) which is the waste of sunflower seed oil factories, and their application as a photocatalyst for the adsorption assistant photocatalysis degradation of methylene blue (MB), and direct yellow-50 (DY-50) under the visible irradiations. Also, the photocatalytic performance of m-Co3O4 NPs was evaluated in synthetic wastewater. The produced m-Co3O4 NPs were ferromagnetic with a saturation magnetization value of 4.3 emu g−1 and the degradation of cationic MB and anionic DY-50 dyes by 100% and 93% in 20 min and 35 min, respectively, by adsorption-assisted photocatalytic process under visible light was achieved. The reactions were found to be pseudo-second-order equation for the adsorption-assisted photocatalytic process for both dyes. The photocatalytic activity of m-Co3O4 NPs decreased slightly even after five repeated cycles. These results show that the m-Co3O4 NPs can be used successfully in dye treatment in wastewater with their adsorption-assisted photocatalytic properties, activation by visible light, magnetic separability, and low-cost production.