Orange G Removal Research Articles

Adsorption of orange G using activated carbon derived from common reed (Phragmites australis) in Mekong Delta, Vietnam

Activated carbon (AC) fabrication using agricultural waste biomass has been considered economical and sustainable. In this study, common reed (Phragmites australis)-derived activated carbon (CRPa-AC) was prepared via two consecutive stages, including pyrolysis and activation using K2CO3 and employed as an absorbent for orange G (OG) removal. The CRPa-AC prepared at 1073 K and the K2CO3/char weigh ratio of 1.5 had the surface area = 549.7 m2/g and exhibited the removal efficiency of OG = 91.8%. The pseudo-second order kinetic and Langmuir isotherm models accurately described the adsorption of OG on the CRPa-AC. The maximum adsorption capacity of CRPa-AC (77.5 mg·g−1) surpassed that of other biomass-based AC previously published. Thermodynamic studies suggested that the OG adsorption on the CRPa-AC surface is endothermic. The good reusability of CRPa-AC after three regeneration cycles enabled its practical use in the OG removal. This study provided a typical example of converting waste into valuable material for wastewater treatment.

Hydroxylamine promoted degradation of organic contaminants using peroxydisulfate activated by Fe-alginate

ABSTRACT To overcome the shortcomings of Fe(Ⅱ)/peroxydisulfate (PDS) system including the limited working pH range and large iron sludge production, a Fe-doped alginate (Fe-Alg) catalyst was prepared and combined with hydroxylamine (HA) to continuously activate PDS for the removal of organic pollutants in neutral condition. Due to the strong reductive capability of HA, it could significantly enhance the catalytic capability of Fe-Alg for PDS. The results of characterization suggested that Fe(Ⅲ)/Fe(Ⅱ) was evenly distributed in Alg through its complexation with carboxyl groups, and the reduction of Fe(Ⅲ) to Fe(Ⅱ) initiated by HA enabled Orange G (OG) to be continuously degraded in the Fe-Alg/HA/PDS system. The results of quenching experiments suggested that S O 4 ∙ − and HO• played a dominant role for OG removal in the Fe-Alg/HA/PDS process. The effect of influence factors (e.g. initial pH, HA concentration, Fe-Alg dose and PDS concentration) and water matrix components (i.e. S O 4 2 − , N O 3 − , Cl–, HC O 3 − and dissolved organic matters (DOM)) on the performance of Fe-Alg/HA/PDS system was systematically investigated. Other refractory organic contaminants, including diclofenac (DCF), sulfamethoxazole (SMX), oxytetracycline (OTC) and bisphenol AF (BPAF) were also efficiently eliminated in Fe-Alg/HA/PDS system, suggesting the feasibility of this system for the treatment of organic pollutants. This work provides a method to optimize Fe(Ⅱ)/PDS system and a novel process applied to degrade refractory pollutants.

Fabrication of bimetallic MOF with 2D nanosheets structure and rich active sites for enhanced removal of organic pollutants by activation of peroxymonosulfate

Due to the fast and high oxidation efficiency for organic pollutants, it is extremely challengeable to develop efficient catalysts for peroxymonosulfate (PMS) to enhance the removal efficiency of pollutants. Herein, we fabricated a bimetallic MOF (CuCo-ABDC) by a facile hydrothermal process, which displayed 2D nanosheets structure and rich active sites. The characterization results showed that CuCo-ABDC-4 with Cu:Co ratio of 1:1 synthesized via temperature gradient ((100 ℃, 24 h) + (150 ℃, 12 h)) had low-crystalline but high catalytic performance towards PMS. With orange G (OG) as the model organic pollutant, CuCo-ABDC-4 displayed the highest catalytic activity for activation of PMS, where 96.4% of OG removal efficiency was achieved within 60 min via a rate constant of 0.052 min−1. The excellent catalytic activity can be attributed to the high density and uniformly distributed unsaturated Co(II) which was considered to be the main active site, and the interaction between Co and Cu species in the bimetallic MOF. The quenching experiments indicated the production of SO4•−, ·OH, and 1O2 in CuCo-ABDC-4/PMS system and 1O2 acted as the predominant reactive species for degradation of OG. Moreover, the presence of NO2−, H2PO4−, SO42−, HCO3− and HA exhibited evident inhibition on the OG degradation rate. On the contrary, the existence of CO32− could promote the OG degradation due to the production of carbonate radical. This work introduces a novel and facile fabrication strategy to attain 2D nanosheets structure bimetallic catalysts with high catalytic performance for activation of PMS in wastewater treatment.

Removal of orange G dye by Aspergillus niger and its effect on organic acid production

Azo dyes have been found in wastewater from textile industries. These compounds continuously persist in the environment for long periods of time and may be toxic for living beings. An alternative treatment for dye removal that has proven to be effective is aerobic treatment with fungi. In this study, Aspergillus niger was investigated as a mechanism to remove orange G (OG). Removal of 200 mg/L of OG by A. niger biomass was carried out in solid and liquid medium, which showed a positive correlation between A. niger growth and dye removal. In liquid media what was proved is that the efficiency of OG removal by A. niger depends on its concentration; at 200 mg/L of OG remove by degradation and at 400 mg/L by processes as sorption and degradation. During OG removal, the generation of organic acids by A. niger was modified compared to constitutive generation, one of the modifications was the increase of gluconic acid production and the decrease of acids involved in the Krebs cycle, as well as the null detection of oxalic acid. The monitoring of organic acids by high-performance liquid chromatography (HPLC) was important because some of them have been linked to dye removal.

MOFs-derived hollow FeCo@C as peroxymonosulfate activator for degradation of organic pollutants: Insight into the catalytic sites by experimental and theoretical study

A hollow sphere (FeCo@C) is developed and serves as a highly efficient catalyst of peroxymonosulfate (PMS) for degradation of orange G (OG) with a pseudo first-order constant of 0.119 min−1 that was 5.15 and 1.43 times of Fe@C and Co@C, respectively. X-ray photoelectron spectroscopy and Density Functional Theory (DFT) calculations demonstrated that the (110) crystal plane of FeCo alloy was the most active site for activation of PMS to generate SO4− and OH. The quenching experiments and EPR test indicated that SO4−, OH, and 1O2 were generated in FeCo@C/PMS system and acted as the predominant reactive species. The synergistic effects between Fe and Co species were responsible for the high catalytic performance of FeCo@C. The carbon in FeCo@C act as a carrier to improve the stability with good reusability over five cycles at pH 7.0 and 9.0, as well as an electron mediator and activator to enhance the catalytic performance. Effects of PMS dosage, catalyst concentration, solution pH, and humic acids on OG removal were also investigated. Furthermore, the reduced toxicity of intermediate products was verified by quantitative structure–activity relationship (QSAR). This work demonstrates a feasible strategy for designing of high-performance and stable catalysts for the organic pollutant degradation based on PMS oxidation processes.

Synthesis and characterization of amino functionalized bimetallic metal-organic frameworks as peroxymonosulfate activator for water purification: Performance and mechanistic studies

The importance of new water purification technology for maintaining clean water resources and a high quality of life is self-evident. In this study, amino functionalized bimetallic metal-organic frameworks (NH2-MIL-101(FeCo)) were prepared to activate peroxymonosulfate (PMS) for removal of organic pollutants from water. The structure, morphology, and physicochemical properties of as-prepared NH2-MIL-101(FeCo) were comprehensively evaluated by X-ray diffraction, scanning electron microscopy, N2 adsorption-desorption isotherms, and X-ray photoelectric spectroscopy. Degradation tests were performed to study effects of PMS concentration, catalyst dosage, initial pH, and common substances on the orange G (OG) removal. The acidic and alkaline conditions promoted the formation of mesoporous structures in NH2-MIL-101(FeCo) and enhanced the mass transfer processes to remove OG. 100% of OG was removed through a rate constant of 0.0711 min-1 within 45 min in NH2-MIL-101(FeCo)− 2/PMS/OG system, where 1O2, SO4•−, and ·OH played pivotal contributions in the OG removal. The catalytic activity of NH2-MIL-101(FeCo) originated from unsaturated metal sites of Fe(II) and Co(II). This work demonstrates a feasible strategy towards the synthesis of functional MOFs for removal of organic contaminants.

Orange G degradation by heterogeneous peroxymonosulfate activation based on magnetic MnFe2O4/α-MnO2 hybrid

Wastewater containing an azo dye Orange G (OG) causes massive environmental pollution, thus it is critical to develop a highly effective, environmental-friendly, and reusable catalyst in peroxymonosulfate (PMS) activation for OG degradation. In this work, we successfully applied a magnetic MnFe2O4/α-MnO2 hybrid fabricated by a simple hydrothermal method for OG removal in water. The characteristics of the hybrid were investigated by X-ray diffraction, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller method, vibrating sample magnetometry, electron paramagnetic resonance, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The effects of operational parameters (i.e., catalytic system, catalytic dose, solution pH, and temperature) were investigated. The results exhibited that 96.8% of OG degradation was obtained with MnFe2O4/α-MnO2(1:9)/PMS system in 30 min regardless of solution pH changes. Furthermore, the possible reaction mechanism of the coupling system was proposed, and the degradation intermediates of OG were identified by mass spectroscopy. The radical quenching experiments and EPR tests demonstrated that SO4•̶, O2•̶, and 1O2 were the primary reactive oxygen species responsible for the OG degradation. The hybrid also displayed unusual stability with less than 30% loss in the OG removal after four sequential cycles. Overall, magnetic MnFe2O4/α-MnO2 hybrid could be used as a high potential activator of PMS to remove orange G and maybe other dyes from wastewater.

Surface activated mesoporous Ag-Fe3O4 tethered chitosan nanomatrix heterojunction photocatalyst for organic dyes degradation: Performance, recycling, and mechanism

Herein, Fabricated a magnetic core-shelled CS@Fe3O4 nanostructure with silver nanoparticle (Ag@CS-Fe3O4) was simply prepared through a one-pot hydrothermal method and utilized as ab photocatalyst for the degradation of dyes. Because the remediation of wastewater containing complex organic compounds is an important issue in environmental fields, Orange G (OG) and Rhodamine B (RhB) was selected as the main organic pollutants to clarify the photocatalytic activity of Ag@CS-Fe3O4 in this study. We confirmed the successful synthesis of nanocomposite through Fourier-transform infrared spectroscopy, X-ray diffraction, and Electron spin resonance spectroscopy analyses. The Fe3O4@ hierarchical Ag@CS shows a noticeable OG and RhB dyes removal of 98.6% and 95.4% within 120 min at the enhanced pH range. The catalytic reusability has been exceptional up to five repititive runs, and the practicability for the treatment of industrially contaminated water was confirmed by field trial. This study provides an ideal scheme for effectual optimization of hierarchical nanostructures for effective degradation of refractory pollutants in the environment.

A heterogeneous peroxymonosulfate catalyst built by Fe-based metal-organic framework for the dye degradation

The regulatory control on dyes is an important issue, as their discharge into the environment can pose significant risks to human health. MIL-101(Fe) prepared by a solvothermal method was used as a catalyst to generate sulfate (SO4•−) and hydroxyl (HO•) radicals from peroxymonosulfate (PMS) for the treatment of orange G (OG). The structural properties of MIL-101(Fe) were assessed by a number of characterization approaches (e.g., Fourier-transform infrared spectroscopy). The factors controlling the removal of OG were explored by a response surface methodology with central composite design (RSM-CCD) plus adaptive neuro-fuzzy inference system (ANFIS). The synthetized MIL-101(Fe) had uniform octahedral nanocrystals with rough surfaces and porous structures. The maximum catalytic removal efficiency of OG with MIL-101(Fe)/PMS process was 74% (the final concentration of Fe2+ as 0.19 mg/L and reaction rate of 434.2 μmol/g/h). The catalytic removal of OG could be defined by the non-linear kinetic models based on RSM. The OG removal efficiency declined noticeably with the addition of radical scavengers such as ethanol (EtOH) and tert-butanol (TBA) along with some mineral anions. Accordingly, MIL-101(Fe)/PMS is identified as an effective remediation option for the dyes based on advanced oxidation process (AOPs) based on high treatment efficiency at low dosage of low cost catalyst.

Carbon textiles electrodes modified with RGO and Pt nanoparticles used for electrochemical treatment of azo dye

• The use of a dimensionally versatile textile electrode permits efficient wastewater decolorization. • TC–RGO–Pt electrodes permit naphthalene degradation after electrolysis. • The stability of TC–RGO–Pt anodes have been proved after the electrolysis. • Very low energy consumption is needed for dye electrochemical degradation. • High mineralization of organic matter is obtained with chloride addition. • These electrodes are a valuable alternative for textile wastewater remediation. The efficiency of Orange G (OG) azo dye degradation using an electrochemical method under potentiostatic conditions has been comparatively studied in two electrolytic cells (divided and undivided cells) in the presence or absence of chloride ions with Pt-modified textile electrodes. The morphology of the carbon-based electrodes with nanoparticles of platinum electrochemically dispersed on their surface was analyzed using field emission scanning electron microscopy (FESEM) and EDX analysis. The FESEM analyses confirmed that the textile surface was coated by Pt nanoparticles. According to the experimental results obtained, when the same solutions are comparatively treated with the two cells, the undivided cell always gives a quicker decolorization than the divided cell – and the decrease in total organic carbon (TOC), chemical oxygen demand (COD), and total nitrogen (TN) confirms this result. The degree of OG removal was monitored by spectroscopic methods and high-performance liquid chromatography (HPLC). The results indicate that that full best dye removal is obtained at a loaded charge of around 0.17 Ah L −1 which is associated with an electrical energy per order (EEO) of 0.189 kW h m −3 order −1 . Based on the results obtained, the electrochemical process with TC-RGO-Pt electrodes could be useful as a pretreatment technique or treatment for decolorizing wastewaters containing dyes.

Removal of Orange G Dye from Aqueous Solution by Adsorption: A Short Review

Adsorption is a widely used technique for wastewater remediation. The process is effective and economical for the removal of various pollutants from wastewater, including dyes. Moreover, Besides commercial activated carbon, different low-cost materials such as agricultural and industrial wastes are now used as adsorbents. The present review focused on the removal of a teratogenic and carcinogenic dye, orange G (OG) via adsorption using several adsorbents, together with the experimental conditions and their adsorption capacities. Based on the information compiled, various adsorbents have shown promising potential for OG removal.

Polyaniline coated hematite sand supported on graphene oxide (HS@PANI‐GO) as a new magnetic material for advanced catalytic oxidation based on sulfate radicals: optimization using response surface methodology

AbstractBACKGROUNDWe report here on the synthesis of a new magnetic and natural material: polyaniline coated hematite sand supported on graphene oxide (HS@PANI‐GO) which was used as an heterogeneous catalyst to activate persulfate (PS) for aqueous solution Orange G (OG) degradation.RESULTSThe characterization results have revealed that the hematite sand is rich in iron oxide, and the inorganic particles were well coated with polyaniline and successfully dispersed in graphene oxide. Further, catalytic oxidation experiments demonstrated that HS@PANI‐GO material exhibited high activity in the PS activation for the OG degradation. It was found that complete OG removal from aqueous solution was achieved in 90 min at natural pH. In addition, the influence of various reaction conditions such as temperature, concentration of PS, catalyst dose, pH and decomposition time over the HS@PAN‐GO/PS system were investigated and optimized. The catalyst HS@PAN‐GO could be recycled easily by a magnet with good reusability. Finally, the effects of various parameters such as PS concentration, catalyst dose, initial OG concentration, and contact time, were investigated using the response surface methodology (RSM). It transpires that the experimental elimination of OG is 98.14%, as obtained under optimal conditions, was very close to the predicted value (96.58%) determined by RSM.CONCLUSIONThis study provides a promising way for the activation of green oxidant ‘PS’, by using a new magnetic composite suited for environmental remediation and oxidation catalysis. © 2019 Society of Chemical Industry

Highly efficient degradation of azo dye Orange G using laterite soil as catalyst under irradiation of non-thermal plasma

In this study, laterite soil containing various mineral oxides (e.g., Al2O3, Fe2O3 and TiO2), used as an alternative catalyst, was combined with gliding arc plasma treatment for Orange G (OG) degradation in aqueous solution. The results showed that the incorporation of laterite soil (as catalyst) in (OG solution exposed to plasma led to a significant degradation enhancement from 17% for plasma treatment alone to almost 100%. Compared with P25 TiO2, Fe2O3, and TiO2/Fe2O3 photocatalysts, the decolorization rate of OG can be increased from 56, 68 and 75% respectively to 100% after 60 min laterite-mediated plasma treatment. In the calcinated laterite, Fe2O3 was considered not only as TiO2 sensitizer due to its narrow band-gap but also as the heterogeneous Fenton catalyst. These synergistically enhanced the generation of the reactive species, i.e., OH, in the gliding arc plasma system and thus process efficiency for OG removal. Under optimized operating conditions, approximately 83% mineralization of OG solution was achieved within 60 min of treatment with the combined process. From the kinetics point of view, OG oxidation fitted with Langmuir–Hinshelwood model with the second-order rate constant (kr) and adsorption constant (Ks) of 5.74 mg min−1 and 0.12 L mg−1, respectively, suggesting that the reaction occurs at the catalyst surface. The catalyst was highly stable even after 5 consecutive cycles.

Activation of persulfate by manganese oxide-modified sludge-derived biochar to degrade Orange G in aqueous solution

ABSTRACTManganese oxide-loaded sludge-derived biochar (Mn-SDBC) was synthesized and used to activate persulfate (PS) for Orange G (OG) degradation. X-ray fluorescence and Fourier transform infrared spectroscopy analysis indicated that the manganese oxides were successfully loaded on the SDBC. The result of batch experiments suggests that OG can be efficiently degraded by PS activated by Mn-SDBC. Metal loading rate, biochar dosage and PS concentration play a crucial role in experiments, whereas pH has a minor effect on OG removal. The free radical quenching experiment was investigated to determine the predominant radical species, and the activation mechanism was also illustrated. The as-synthesized Mn-SDBC can efficiently activate PS and removal OG under a continuous flow condition in a fixed-bed column. Our study suggests that Mn-SDBC would be a promising catalyst for the remediation of dye-contaminated wastewater.

Fe3O4-CeO2 loaded on modified activated carbon as efficient heterogeneous catalyst

A novel Fe3O4-CeO2/activated carbon (AC) composite was synthesized by an immersion-precipitation process. The Fe3O4-CeO2/AC composite was characterized by BET surface area measurement, Fourier Transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopic (XPS), and vibrating sample magnetometer (VSM). Its catalytic activity was evaluated by azo organic dye Orange G (OG) oxidation in heterogeneous Fenton system. Due to excellent performance of AC in adsorption and conductivity, the catalyst exhibited enhanced catalytic activity compared with AC-Fe3O4, CeO2-AC, Fe3O4-CeO2 and AC. Some parameters, such as initial concentration of OG, pH, catalyst loading, H2O2 dosage, were studied. At pH 2.5, H2O2 18 mM, OG 50 mg L−1, Fe3O4-CeO2/AC 0.4 g L−1 and 35 °C, the OG removal rate and the total organic carbon (TOC) removal reached 98.8% and 56.3% within 60 min. The stability and reusability of the Fe3O4-CeO2/AC were also tested. Besides a possible OG degradation pathway was proposed and eight intermediates were determined.

Efficient degradation of Orange G with persulfate activated by recyclable FeMoO4

In this study, FeMoO4 was applied to activate persulfate (PS, S2O82−) for azo dye Orange G (OG) degradation. The catalyst was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and nitrogen adsorption-desorption isotherms. FeMoO4 showed excellent efficiency in activating PS for OG removal. More than 95% could be removed after 40 min under reaction conditions of 4 mM PS, 0.3 g L−1 FeMoO4 and 0.2 mM OG. The effect of different parameters (PS doses, FeMoO4 doses and pH) were evaluated. The results showed that acid condition provided higher efficiency and overdosing FeMoO4 and PS presented a scavenging effect. Major intermediates were identified and possible degradation pathway was proposed. Recycle tests presented that FeMoO4 had excellent recyclable stability in activating PS for OG removal. Sulfate radicals and hydroxyl radicals all occurred in the oxidation reactions and the former came first. The oxidation reaction was involved in the translation of Fe2+/Fe3+ occurred on the surface layer. This study revealed that the FeMoO4/PS system is a very promising method for degrading organic contaminants in the environment.

Accelerated degradation of orange G over a wide pH range in the presence of FeVO4

In this study, FeVO4 was prepared and used as Fenton-like catalyst to degrade orange G (OG) dye. The removal of OG in an aqueous solution containing 0.5 g·L–1 FeVO4 and 15 mmol·L–1 hydrogen peroxide at pH 7.0 reached 93.2%. Similar rates were achieved at pH 5.7 (k = 0.0471 min–1), pH 7.0 (k = 0.0438 min–1), and pH 7.7 (k = 0.0434 min–1). The FeVO4 catalyst successfully overcomes the problem faced in the heterogeneous Fenton process, i.e., the narrow working pH range. The data for the removal of OG in FeVO4 systems containing H2O2 conform to the Langmuir–Hinshelwood model (R2 = 0.9988), indicating that adsorption and surface reaction are the two basic mechanisms for OG removal in the FeVO4–H2O2 system. Furthermore, the irradiation of FeVO4 by visible light significantly increases the degradation rate of OG, which is attributed to the enhanced rates of the iron cycles and vanadium cycles.

Degradation of Orange G by Fenton-like reaction with Fe-impregnated biochar catalyst

This study was conducted to evaluate the catalytic activity of Fe-impregnated sugarcane biochar (FSB) for removing azo dye Orange G (OG) from solution under various Fenton-like oxidation conditions. The optimum molar Fe concentration for impregnation to achieve maximum catalytic activity of FSB in Fenton-like reaction with acceptable effluent Fe release was 0.25 M (163.4 Fe mg/g in FSB). High removal efficiency of 99.7% was achieved within 2 h of reaction at optimum conditions of 0.075 g/L H2O2, 0.5 g/L FSB for 0.1 g/L OG at initial pH 5.5 under 25 °C. For every 10 °C increase, the time for maximum OG degradation efficiency decreased by 0.5 h. The OG removal by FSB exhibited a slow induction reaction followed by fast OG decomposition. FSB can be used successively for at least 4 runs with >89.3% OG removal. The FSB was more economical, efficient, and recyclable than other conventional Fenton oxidation catalysts.

Removal of Orange G and Rhodamine B dyes from aqueous system using hydrothermally synthesized zinc oxide loaded activated carbon (ZnO-AC)

This study reports the synthesis of zinc oxide loaded activated carbon (ZnO-AC) using hydrothermal method and its use to remove organic dyes [Orange G (OG) and Rhodamine B (Rh-B)] from the aqueous system under varying process conditions. ZnO-AC nanoparticles were characterized using XRD, SEM, EDX, DLS, and FTIR. The Langmuir adsorption model was best fitted to the experimental data for both the dyes. Langmuir adsorption capacity (qmax) for OG and Rh-B was 153.8 and 128.2mg/g, respectively. The rate of adsorption was investigated by various models namely pseudo-first-order, pseudo-second-order and intraparticle diffusion model. Rate mechanism was described by pseudo-second-order model for both the dyes. Thermodynamic studies suggested that removal of Rh-B onto ZnO-AC was endothermic up to a temperature of 40°C while OG removal decreased with increase in temperature. Negative values ofΔG0for adsorption of dyes suggested spontaneous adsorption processes.

Enhanced degradation of Orange G by permanganate with the employment of iron anode.

Iron anode was employed to enhance the degradation of Orange G (OG) by permanganate (EC/KMnO4). Continuously generated Fe2+ from iron anode facilitated the formation of fresh MnO2, which plays a role in catalyzing permanganate oxidation. The EC/KMnO4 system also showed a better performance to remove OG than Fe2+/KMnO4, indicating the importance of in situ formed fresh MnO2. Besides, the effects of applied current, KMnO4 dosage, solution pH, and natural organics were evaluated and results demonstrated that high current and oxidant dosage are favorable for OG removal. And the application of iron anode has a promoting effect on the KMnO4 oxidation over a wide pH range (5.0-9.0), while the Fe2+/KMnO4 process does not. For natural organics, its presence could inhibit OG removal due to its competitive role. And the promoting effect of OG removal by the EC/KMnO4 process in natural water was confirmed. At last, the EC/KMnO4 process showed a satisfying performance on the decolorization and mineralization of OG. This study provides a potential technology to enhance permanganate oxidation and broadens the knowledge of azo dye removal.