Methylene Blue Removal Research Articles

Removal of Methylene blue dye from contaminated wastewater using lignocellulosic biomasses: A comparative study

In this study, lupine seed (Lu-SP) and pumpkin seed shells (PSSP) biomasses were used to create alternative and effective adsorbents. Methylene blue (MB) dye was removed from wastewater using the as-prepared adsorbents at variables solution pH 2.0 –11.0, contact period (0–180 min), and adsorbent mass (0.2–2.0 g/L). The solution pH had a synergistic effect on the improved removal of MB and the optimal adsorption removal for both adsorbents occurred at pH 8.0 and 120 min. The adsorption isotherm modelling results showed a good fit with the Langmuir model, with a maximum monolayer adsorption capacity of 48.98 and 77.48 mg/g for PSSP and Lu-SP, respectively. Similarly, the pseudo-first-order (PFO) model is regarded as the best-fit kinetic model for both adsorbents and suggests the predominance of physisorption via interfacial diffusion. Mechanistic investigation of the present system suggests that both intraparticle diffusion and surface sorption mechanisms control the adsorption rate. Notably, the Lu-SP with a lower surface area (54.013 m2/g) outperformed the PSSP (235.992 m2/g) in terms of adsorption capacity under varying pH. Therefore, in addition to electrostatic interaction, adsorption into the micropores via volume filling is considered one of the adsorption mechanisms. This study, therefore, revealed that the PSSP and Lu-SP may be very helpful for removing cationic MB dye from contaminated wastewater.

Investigating the synergistic effect of ZnO/GO nanocomposite films for methylene blue removal

AbstractThis study aims to reveal the growth kinetics of ZnO nanoflakes and ZnO/GO nanocomposite films obtained at different Zn precursor salt concentrations by electrochemical deposition method and to evaluate the catalytic performances of the obtained films. The films were grown on FTO substrate with Zn precursor salt concentrations of 0.1 M, 0.125 M, and 0.175 M. Characterization of the obtained films was performed by XRD, SEM, UV–vis–NIR, Raman, and XPS analyses. The strong photocatalytic capabilities of the synthesized ZnO nanoflakes and ZnO/GO nanocomposite films were demonstrated by comparative analyses with the existing literature. Accordingly, photocatalytic experiments carried out under UVA irradiation revealed the high performance of the synthesized samples in the degradation of MB dye. The reaction kinetics were investigated using the Langmuir‐Hinshelwood kinetic model, resulting in high kobs values and R2 coefficients. ZnO nanoparticles showed a kobs of 0.038 min−1 and an R2 value of 0.96, while ZnO/GO nanocomposite films showed a kobs of 0.055 min−1 and an R2 value of 0.92. The significant increase in the degradation percentage shows the significant improvement achieved by the integration of GO, despite a slightly lower R2 value for the ZnO/GO nanocomposite film compared with ZnO nanoflakes films.

Furfuryl-pyridinium-functionalization of flaxseed gum for effective methylene blue removal from aqueous solution

This study describes the modification of flaxseed gum (FSG) via furfural to obtain a furfuryl-pyridinium modified adsorbent (Flax-Py) with improved adsorption characteristics towards methylene blue (MB) versus results obtained for unmodified FSG. Materials characterization was achieved via complementary spectral methods (NMR, XPS, FT-IR, Raman, and XRD) as well as thermogravimetric analysis (TGA) and ζ-potential measurements. Synthetic modification of FSG to yield Flax-Py that led to enriched N-content (2.75 atom-% versus 0.76 atom-% for FSG), and the conversion of furfuryl to pyridinium was incomplete (ca. 50 %), where both moieties were identified. The adsorption isotherms at pH 7 showed that FSG possessed favorably high MB adsorption capacity (ca. 540 mg/g); while Flax-Py was notably lower (167 mg/g). Flax-Py facilitated 100% MB removal at low dye concentrations (1-10 mg/L) versus 50 % MB removal for the FSG bioadsorbent. Further, Flax-Py showed moderate loss of adsorption with MB (ca. 12-16% dye removal) after five regeneration cycles. Flax-Py revealed improved settling characteristics (time, density, gelation, and solubility) that facilitate enhanced phase separation of FSG fractions by circumventing the need for centrifugation. The adsorption mechanism was attributed primarily to H-bonding effects with secondary contributions due to electrostatic interactions (negative ζ-potential above pH 4.2). This study successfully modified FSG to obtain an improved adsorbent (Flax-Py) attaining nearly quantitative MB dye removal at environmentally relevant concentrations (< 15 mg/L).

Pt Nanoparticles Embedded Polypyrrole‐Carbon Black/SrSnO3 Photocatalyst with Stable and Superior Photodegradation Performance

AbstractCurrently, the primary focus for scientific authorities and regulatory departments revolves around water pollution. In this regard, photocatalysis has emerged as a highly effective, affordable, and goal‐oriented approach. Thus, recognizing the urgency of this issue, we focused our efforts towards developing a novel ternary photocatalytic structure based on mesoporous SrSnO3, combined with polypyrrole‐doped carbon black (PPC) and platinum nanoparticles (Pt NPs). Pt NPs, PPC and SrSnO3‐based nanocomposite photocatalyst was developed through a very simple chemical method followed by ultrasonication and photoreduction techniques. XRD analysis confirmed orthorhombic phase of SrSnO3, while the formation of the ternary nanocomposite among Pt NPs, PPC and SrSnO3 has been confirmed by X‐ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared (FTIR) spectroscopy. Transmission electron microscopy (TEM) revealed the presence of Pt NPs (5–15 nm), beads/dense cocoon like structures of PPC along with rod, spherical and needle shape nanostructures of SrSnO3 in newly created ternary photocatalyst. Diffuse reflectance spectroscopy (DRS) showed lowering of band gap energy in case of Pt@PPC/SrSnO3. Newly developed Pt@PPC/SrSnO3 nanocomposite worked efficiently when employed on colorless insecticide imidacloprid (IMD) and on colored methylene blue (MB) dye under UV‐light. Pt@PPC/SrSnO3 photocatalyst exhibited excellent performance with 96.03 % removal of pollutant IMD in only 20 min, almost 296 % more efficient than bare SrSnO3. Furthermore, the Pt@PPC/SrSnO3 ternary photocatalyst showed rapid removal of MB with almost total elimination of dye molecule in just 16 min.

Blended Nephelium lappaceum and Durio zibethinus wastes for activated carbon production via microwave-ZnCl2 activation: optimization for methylene blue dye removal

Herein, this work targets to employ the blended fruit wastes including rambutan (Nephelium lappaceum) peel and durian (Durio zibethinus) seed as a promising precursor to produce activated carbon (RPDSAC). The generation of RPDSAC was accomplished through a rapid and practical procedure (microwave-ZnCl2 activation). To evaluate the adsorptive capabilities of RPDSAC, its efficacy in eliminating methylene blue (MB), a simulated cationic dye, was measured. The Box–Behnken design (BBD) was utilized to optimize the crucial adsorption parameters, namely A: RPDSAC dose (0.02–01 g/100 mL), B: pH (4–10), and C: time (2–6 min). The BBD design determined that the highest level of MB removal (79.4%) was achieved with the condition dosage of RPDSAC at 0.1 g/100 mL, contact time (6 min), and pH (10). The adsorption isotherm data is consistent with the Freundlich concept, and the pseudo-second-order versions adequately describe the kinetic data. The monolayer adsorption capacity (qmax ) of RPDSAC reached 120.4 mg/g at 25 °C. Various adsorption mechanisms are involved in the adsorption of MB dye onto the surface of RPDSAC, including π–π stacking, H-bonding, pore filling, and electrostatic forces. This study exhibits the potential of the RPDSAC as an adsorbent for removal of toxic cationic dye (MB) from contaminated wastewater.

An 1,4,7,10-tetraazacyclododecane-nickel complex functionalized polymolybdate acting as artificial oxidase in removing methylene blue

The reactive oxygen species (ROS), serving as a crucial biochemical reaction medium, is intricately involved in a myriad of physiological and pathological processes. The proper use of ROS can solve many practical problems, for example killing harmful microorganisms or cells, removing pollutants in water, etc. Therefore, the design and synthesis of artificial oxidase with catalytic activity in producing ROS become a hot research spot from bio-inorganic chemistry to catalytic industry. Herein, a cyclen-nickel complex functionalized polymolybdate, [Ni(cyclen)(H2O)2]2[(AsO)6(NiMo6O24)]·3H2O (abbreviated as NiAM, cyclen = 1,4,7,10-tetrazacyclododecane), which can acting as a catalyzed oxidase to generating ROS, has been structurally characterized by means of single-crystal X-ray diffraction (SXRD), elemental analyses, IR and UV–vis spectra, powder X-ray diffraction (PXRD), and bond valence sums (Σs) calculation. The NiAM's principal element, as revealed by SXRD, indicates that it is an ionic complex that composed by two [Ni(cyclen)(H2O)2]2+and one modified Anderson-type cluster [(AsO)6(NiMo6O24)]4–. Interestingly, NiAM possesses effective ability in catalyzing the ROS generation in aqueous solution. As a result, it can remove methylene blue (MB) dyes from the stable solution system.

Valorization of lignocellulosic agave residues via pyrolysis and its use as adsorbent for methylene blue removal

Valorization of lignocellulosic agave residues via pyrolysis and its use as adsorbent for methylene blue removal

Removal of Methylene Blue from Aqueous Solutions Using Date Palm By‐Products from Algerian Sahara: Cultivar Variations Effect

AbstractThis study aims to compare the methylene blue (MB) removal capacity from aqueous solutions of seven natural Date Palm (Phoenix dactylifera L.) By‐products (DPBPS). These include: Leaflets (DPLL), Rachis of leaf (DPRL), Fruit Bunch Stalk (DPFBS), Empty Fruit Bunch (DPEFB), Leaf Base (DPLB), fibrillium (DPF) and Spathe Sheath (DPSS), obtained from three different date palm cultivars: Degla, Ghers and Takermost from Ouargla Oasis in the Algerian Sahara, and to investigate the influence of the palm date nature part and cultivar on MB adsorption. Batch adsorption experiments were conducted at different concentrations; 30, 45, 60, 75, 90, and 105 mg/L of MB with 2.5 g of DPBP of each cultivar. The DPBPS of all cultivars exhibits remarkable adsorption efficiencies for MB removal. The highest maximal experimental adsorption capacities were observed for Degla DPLB (4.192 mg/g), Ghers DPF (4.191 mg/g) and Takermost DPF (4.193 mg/g) with(99.81 %), (99.79 %), and (99.82 %) adsorption rates in their cultivar respectively. Conversely, the lowest maximal experimental adsorption capacities were found for Degla DPLL 4.048 mg/g, Ghers DPEFB (4.12 mg/g) and Takermost DPSS (4.089 mg/g) with 96.40 %, 98.09 %, and at 97.67 % adsorption rates in each cultivar respectively. The equilibrium adsorption data were analyzed using Langmuir and Freundlich models. The results indicated a good fit with the Freundlich model. The studied DPBPS represent natural, low‐cost, and locally available adsorbents that effectively remove MB from wastewater.

A green and economic approach to synthesize magnetic Lagenaria siceraria biochar (γ-Fe2O3-LSB) for methylene blue removal from aqueous solution.

In the printing and textile industries, methylene blue (a cationic azo dye) is commonly used. MB is a well-known carcinogen, and another major issue is its high content in industrial discharge. There are numerous removal methodologies that have been employed to remove it from industrial discharge; however, these current modalities have one or more limitations. In this research, a novel magnetized biochar (γ-Fe2O3-LSB) was synthesized using Lagenaria siceraria peels which were further magnetized via the co-precipitation method. The synthesized γ-Fe2O3-LSB was characterized using FTIR, X-ray diffraction, Raman, SEM-EDX, BET, and vibrating sample magnetometry (VSM) for the analysis of magnetic properties. γ-Fe2O3-LSB showed a reversible type IV isotherm, which is a primary characteristic of mesoporous materials. γ-Fe2O3-LSB had a specific surface area (SBET = 135.30 m2/g) which is greater than that of LSB (SBET = 11.54 m2/g). γ-Fe2O3-LSB exhibits a saturation magnetization value (Ms) of 3.72emu/g which shows its superparamagnetic nature. The batch adsorption process was performed to analyze the adsorptive removal of MB dye using γ-Fe2O3-LSB. The adsorption efficiency of γ-Fe2O3-LSB for MB was analyzed by varying parameters like the initial concentration of adsorbate (MB), γ-Fe2O3-LSB dose, pH effect, contact time, and temperature. Adsorption isotherm, kinetic, and thermodynamics were also studied after optimizing the protocol. The non-linear Langmuir model fitted the best to explain the adsorption isotherm mechanism and resulting adsorption capacity ( =54.55mg/g). The thermodynamics study showed the spontaneous and endothermic nature, and pseudo-second-order rate kinetics was followed during the adsorption process. Regeneration study showed that γ-Fe2O3-LSB can be used up to four cycles. In laboratory setup, the cost of γ-Fe2O3-LSB synthesis comes out to be 162.75 INR/kg which is low as compared to commercially available adsorbents. The results obtained suggest that magnetic Lagenaria siceraria biochar, which is economical and efficient, can be used as a potential biochar material for industrial applications in the treatment of wastewater.

Thermodynamic study and the development of a support vector machine model for predicting adsorption behavior of orange peel-derived beads in wastewater treatment

This study investigates the use of orange peels as a precursor for synthesizing sodium alginate-encapsulated beads for methylene blue (MB) removal. The prepared beads (BOP1 and BOP2) underwent characterization through FTIR, XRF, SEM and TGA. Subsequently, the impacts of various factors, including temperature, the initial pH, initial concentration, salt and humic acid, are studied. The adsorption isotherms show high adsorbed quantities of 764.92 and 659.78 mg/g for BOP1 and BOP2 respectively, while the obtained data are best described by the monolayer with two energies (MMTE) model, which is then used to perform a thermodynamic study of the MB adsorption mechanism. Additionally, the adsorption kinetics data are modeled using three models, with the PFO model identified as the most appropriate. The regenerated beads demonstrate the ability to be reused up to 7 cycles, The effects of NaCl and humic acid on MB adsorption reveal that NaCl inhibits adsorption due to competition with Na+, while humic acid has no effect. Finally, a support vector machine (SVM) model optimized by the Levy Flight Distribution Optimization (LFD) algorithm is developed and found to be capable of accurately predicting the adsorption behavior of the prepared beads. This model is then used in optimizing the process conditions for maximal MB removal. Overall, this study demonstrates that the prepared beads could be potential low-cost and environmentally friendly adsorbents for wastewater treatment applications.

The role of efflux pump inhibitor in enhancing antimicrobial efficiency of Ag NPs and MB as an effective photodynamic therapy agent

Efflux pumps are active transporters, which allow the cell to remove toxic substances from within the cell including antibiotics and photosensitizer complexes. Efflux pump inhibitors (EPIs), chemicals that prevent the passage of molecules through efflux pumps, play a crucial role in antimicrobial effectiveness against pathogen. In this work, we studied the effect of EPI, namely, reserpine, on photodeactivation rate of pathogens when used with Ag NPs and methylene blue (MB). Our results show that using reserpine led to a higher deactivation rate than Ag NPs and MB. The mechanism of this observation was investigated with singlet oxygen generation amount. Additionally, different sizes of Ag NPs were tested with reserpine. Molecular docking calculation shows that reserpine had higher affinity toward AcrB than MB. The improvement in bacterial deactivation rate is attributed to blockage of the AcrAB-TolC efflux pump preventing the removal of MB rather than enhanced singlet oxygen production. These results suggest that using reserpine with nanoparticles and photosynthesize is a promising approach in photodynamic therapy.

KMnO4 modified magnetic hydrochar for efficient adsorption of malachite green and methylene blue from the aquatic environment

This study exploited magnetic citrus peel hydrochar (MHC) modified by KMnO4 (MHC/Mn) for the removal of methylene blue (MB) and malachite green (MG). Effects of initial concentration, pH, dosage, temperature, and ion strength on MHC/Mn adsorption properties were investigated. The adsorption kinetics, isotherm, and mechanism were further explored. The results indicated that Fe3O4 was successfully embedded and MnO2 was coated on MHC after modification. The experiment data were well fitted to the pseudo-second-order kinetic model and Langmuir isotherm model. Thermodynamic parameters showed that the adsorption of MHC/Mn to MB is spontaneous and endothermic, and the adsorption of MG is spontaneous and exothermic. The mechanism of MB and MG interaction with MHC/Mn includes electrostatic interaction, hydrogen bond, surface complexation, and π-π interaction. The maximum adsorption capacity of MB and MG calculated were 175.63 mg/g and 1402.17 mg/g. After four adsorption–desorption cycles, the removal rate of MB and MG were 85.11 % and 69.29 %. MHC/Mn is an economical and environmentally favorable adsorbent for the removal of MB and MG in wastewater.

Engineering a staggered type-II Bi2WO6/WO3 heterojunction with improved photocatalytic activity in wastewater treatment

In recent years, the removal organic pollutants from wastewater by advanced oxidation processes, especially photocatalysis, has become a meaningful approach due to its eco-friendliness and low cost. Herein, staggered type-II Bi2WO6/WO3 heterojunction photocatalysts were prepared by a facile hydrothermal route and investigated by modern physicochemical methods (X-ray diffraction, scanning electron microscopy, low-temperature nitrogen adsorption-desorption, and diffuse reflectance spectroscopy). The optimized BWOW-5 photocatalyst exhibited a H2O2-assisted photocatalytic methylene blue removal efficiency of 94.1% (k = 0.01414 min–1) within 180 min under optimal reaction conditions, which is much higher than that of unmodified Bi2WO6 and WO3 due to efficient separation of the photogenerated charge carriers. The trapping experiments demonstrate that photogenerated hydroxyl radicals and holes plays a key role in the photodegradation reaction. Moreover, the optimized BWOW-5 heterojunction photocatalyst exhibited excellent activity in the H2O2-assisted degradation of other pollutants, namely phenol, isoniazid, levofloxacin, and dibenzothiophene with the removal rate of 63.1, 73.6, 95.0, and 72.4%, respectively. This investigation offers a design strategy for Bi2WO6-based multifunctional photocatalytic composites with improved activity for organic pollutant degradation.

By-product Eucalyptus leaves valorization in the basic dye adsorption: kinetic equilibrium and thermodynamic study

Abstract Algerian Eucalyptus Leaves (AEL), a natural biodegradable adsorbent abundantly available, was used for the removal of methylene blue (MB) dye. The AEL properties for the removal of MB were investigated under different conditions by varying the AEL amount, MB concentration, pH of the solution and the reaction temperature. Scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) techniques have been used to characterize AEL biosorbent. Experimental results showed that the adsorption of MB dye at the concentration of 50 mg L−1 reached to 91 % at pH 10 with a stirring speed of 200 rpm and after 180 min of reaction time. The experimental data were analyzed using the linear forms of different kinetic models (pseudo-first order kinetic model, pseudo-second order kinetic model, and intra-particle diffusion models). The results demonstrated that the adsorption kinetics of MB was consistent with the pseudo-second order model with R 2 value of 0.9969. The isotherm models Langmuir, Freundlich, Dubinin, Elovich, Brunaut Emmet Teller and Temkin models were also investigated to describe the adsorption equilibrium. The results show that the AEL adsorption is in accordance with Temkin isotherm. The thermodynamic study revealed that the adsorption is spontaneous and exothermic. Therefore, as a cheap green adsorbent with high MB adsorption performance, AEL is expected to become one of the best candidate materials for future industrial wastewater treatment.

Utilizing waste corn straw to photodegrade methyl orange and methylene blue: Photothermal effect of biochar enhances photodegradation efficiency

The burning of corn straw will cause serious air pollution, and the utilization of corn straw can avoid the burning of corn straw and reduce environmental pollution. The pyrolysis of corn straw into biochar (BC) is a promising approach to apply corn straw in environmentally sustainable development. Dye wastewater such as methyl orange (MO) and methylene blue (MB) is a pollution that poses a threat to human health and the environment. Herein, biochar/TiO2 (BC/TiO2) and biochar/ZnO (BC/ZnO) were prepared by pyrolysis of corn straw for the photodegradation of MO and MB in water. The MO removal rates of BC/TiO2 and BC/ZnO are up to 83.3 % and 76.2 %, respectively, and the MB removal rates of BC/TiO2 and BC/ZnO are 78.6 % and 71.4 %, respectively. The photothermal effect of BC improves the surface temperature of photocatalysts and promotes the separation and transfer of photogenerated electron-hole pairs, enhancing the photodegradation of MO and MB efficiencies. Three-dimensional (3D) FDTD simulations were performed to investigate the mechanism of photothermal effect in BC/TiO2 and BC/ZnO. This work provides a promising approach to the utilization of corn straw.

Neem biomass derived carbon quantum dots synthesized via one step ultrasonification method for ecofriendly methylene blue dye removal

This article presents a one-step ultrasonication technique for generating biomass carbon dots (BCDs) from neem bark (Azadirachta indica) powder. The BCDs were characterized using modern techniques such as UV–Vis, FTIR, Raman, XRD, HRTEM, FESEM, EDAX, and Zeta potential analyses. Unlike traditional nanocomposite bed systems, this study utilized BCDs as a liquid-phase adsorbent for the regenerative adsorption of the environmentally harmful dye, methylene blue (MB), through an in-situ precipitation reaction. This involved the formation of BCDs-MB adduct via an electrostatic mechanism. The adsorption capacity and percentage of removal were remarkable at 605 mg g–1 and 64.7% respectively, exceeding various solid-based adsorption methods in the literature. The Langmuir isotherm and pseudo-second-order kinetics model provided an excellent fit for this system. The calculated thermodynamic parameter, Gibbs free energy change (ΔG) was negative, indicating a spontaneous, exothermic, and physisorption-based mechanism. The regenerative capacity of our system was further demonstrated by successfully extracting and recovering the MB dye (64%) using ethyl alcohol as the solvent. This method provides an efficient means of recovering valuable cationic organic dye compounds from contaminated environments.

Mixed Metal Oxide W-TiO2 Nanopowder for Environmental Process: Synergy of Adsorption and Photocatalysis.

A mixed metal oxide W-TiO2 nanopowder photocatalyst was prepared by using the sol-gel method with a broad range of elemental compositions x = CW/(CW + CTi), including TiO2 and WO3. The material was structurally characterized and evaluated in adsorption and photocatalytic processes by testing its removal capacity of a representative pollutant methylene blue (MB) in aqueous solutions and under UV-A and sunlight illuminations. The nanopowders appeared to be more effective adsorbents than pure TiO2 and WO3 materials, showing a maximum at 15 mol% W, which was set as the tungsten solubility limit in anatase titania. At the same time, the photocatalytic decomposition of MB peaked at 2 mol% W. The examination of different compositions showed that the most effective MB removal took place at 15 mol% W, which was attributed to the combined action of adsorption and heterogeneous photocatalysis. Moreover, MB decomposition under sunlight was stronger than under UV-A, suggesting photocatalyst activation by visible light. The pollutant removal efficiency of the material with 15 mol% W was enhanced by a factor of ~10 compared to pure TiO2 at the beginning of the process, which shows its high potential for use in depollution processes in emergency cases of a great pollutant leak. As a result, a Wx=0.15-TiO2 catalyst could be of high interest for wastewater purification in industrial plants.

Chitosan‐based aerogel microspheres for wastewater treatment

AbstractThis study aimed to present the effect of the mediums to dissolve chitosan on the morphology of obtained chitosan microspheres and find a suitable medium for preparing porous chitosan microspheres for adsorption application. Three acidic solutions, including acetic, ascorbic, and citric acids, were used to dissolve chitosan flakes. The prepared chitosan microspheres were characterized by scanning electron microscopy (SEM), X‐ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), and Brunauer–Emmett–Teller (BET) analysis. The microspheres’ inner morphologies depended on the mediums to dissolve chitosan. The highest porosity of the chitosan microspheres was obtained using an acetic solution, while the sample showed the highest crystallinity prepared in a citric solution. Besides, the chitosan microspheres prepared in the acetic solution had the most efficient methylene blue (MB) removal from water. Its maximum MB sorption capacity was 79.37 mg g−1. The non‐linear pseudo‐second‐order kinetic model was the best kinetic fit for the interaction of MB with those chitosan microspheres. Moreover, the prepared microspheres showed good cyclic stability and easy recovery, suggesting their high feasibility in wastewater treatment.

Green Synthesis of Titanium dioxide Nanoparticles by utilizing Marchantia polymorpha and their Application in Methylene Blue Dye Removal

Green Synthesis of Titanium dioxide Nanoparticles by utilizing Marchantia polymorpha and their Application in Methylene Blue Dye Removal

Polyaniline-supported g-C3N4/ZnO/Ag2CrO4 composite for photodegradation of methylene blue under visible light irradiation

Organic dyes are a major source of environmental pollution from different industries. To remove these recalcitrant, a novel ternary g-C3N4/ZnO/Ag2CrO4 and its polyaniline-supported (PANI) composites were synthesized using an “in situ” oxidative polymerization approach. XRD, SEM, UV–Vis DRS, and PL techniques were utilized to characterize the as-prepared composites. The photocatalytic efficiency was evaluated using a model organic pollutant, methylene blue (MB), and samples of the effluent of the textile industry. The as-synthesized ternary g-C3N4/ZnO/Ag2CrO4 (ZT3= 87.87 %) composite showed better photocatalytic performance than the single (5 %) and binaries (15–25 %) counterparts for MB degradation. The influence of various experimental settings on the photodegradation of MB dye was examined and these were an initial dye amount of 10 ppm, photocatalyst load of 0.15 g/L, and pH 10. Under optimized conditions, PANI-supported g-C3N4/ZnO/Ag2CrO4 composite (PAST) demonstrated substantial degradation efficiency (97.5 %). The reusability study of the spent catalyst revealed a reduced efficiency from 97.5 to 78.5 % photodegradation of MB after four successive cycles, demonstrating the photocatalyst's stability and efficiency. According to the study on the effect of scavengers, h+ plays a significant part in the discoloration of MB. The PAST photocatalyst outperformed the MB discoloration (97.5 %) and adequate degradation for real textile effluent samples (77.7 %) collected from Hawassa textile industries. The photodegradation efficiency result of this study demonstrated that PANI-supported g-C3N4/ZnO/Ag2CrO4 might serve as an advantageous photocatalyst for the efficient removal of MB and other dyes under visible light irradiation at the optimum conditions. The total estimated cost analysis of synthesis and photocatalytic degradation using Polyaniline-supported g-C3N4/ZnO/Ag2CrO4 composite found that it was quite affordable, costing around $5 per 1,000 L of wastewater treatment.