Dye-containing Wastewater Research Articles

Physicochemical and structural characterization of novel praseodymium and neodymium-incorporated TiO2 for photocatalytic application

Abstract Novel photocatalytic metal–organic framework (MOF) materials are an exciting research topic. However, the lack of investigating rare-earth doped semiconductor as well as understanding their physicochemical and structural characterization will prevent commercial or industrial applications. To overcome this obstacle, this study investigates the physicochemical and structural characterization of novel applied Titania-based materials synthesized via MOF strategy for photodegradation of methyl orange (MO). The studied materials are TiO2, Pr-doped TiO2 (Pr@TiO2), and Nd-TiO2 (Nd@TiO2) and applied as promising photocatalysts. The synthesized photocatalysts were prepared via metal–organic framework strategy and characterized by Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS). SEM analysis revealed that only Nd resulted in smaller, more uniform particle sizes. XRD patterns confirmed the retention of the anatase phase in the case of Nd-modification, indicating successful lattice distortions. XPS results showed the chemical existence of Pr and Nd, increased oxygen vacancies, and surface hydroxyl groups, essential for enhanced photocatalytic activity. Photodegradation studies demonstrated that both Pr-TiO2 and Nd-TiO2 exhibited better performance compared to TiO2 without Pr or Nd, following pseudo-first-order kinetics. These findings highlight the potential of Pr and Nd modification in the TiO2 photocatalysts for efficient environmental remediation, particularly in the treatment of dye-containing wastewater.

Bioremoval of industrial dyes using different microorganisms

Textile dyeing effluents are a major source of water pollution because of their pigmentation and the creation of harmful or potentially cancer-causing intermediate compounds, such as aromatic amines originating from azo dyes. The extensive industrial expansion and uncontrolled rapid growth of current textile manufacturing facilities have led to the discharge of large volumes of untreated textile dye effluents, which contain a variety of hazardous contaminants like dyes, metal ions, heavy metals, organic substances, and other toxic materials. Bioremediation is a promising alternative to conventional treatment methods for textile dyeing effluents. It is a cost-effective and environmentally friendly approach that uses biological organisms to degrade and remove pollutants from the environment. This review evaluates the performance and typical attributes of bioremediation and stands out as a practical and effective option for addressing the treatment of textile dyes. It also highlights the current challenges and anticipated advancements in the field of bioremediation techniques for the removal of dye-containing wastewater in the future.

Treatment of dye-containing wastewater using discarded animal blood-derived hemoglobin crystals

Treatment of dye-containing wastewater using discarded animal blood-derived hemoglobin crystals

A Hybrid Photo-Catalytic Approach Utilizing Oleic Acid-Capped ZnO Nanoparticles for the Treatment of Wastewater Containing Reactive Dyes

In pursuit of overcoming Fenton oxidation limitations in wastewater treatment, an introduction of a heterogeneous photocatalyst was developed. In this regard, the current work introduces ZnO nanocrystals that were successfully prepared via a thermal decomposition technique and then capped with oleic acid (OA). The synthesized ZnO-OA and the pristine ZnO were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FE-SEM). Then, the study introduces the application of such materials in advanced oxidation processes, i.e., a Fenton reaction to treat dye-containing wastewater. Synthetic wastewater that was prepared using Reactive Blue 4 (RB4) was used as a simulated textile wastewater effluent. Fenton’s oxidation was applied, and the system parameters were assessed using the modified Fenton’s system. The synthesized samples of ZnO were characterized by a recognized wurtzite hexagonal structure. The surface modification of ZnO with oleic acid (OA) resulted in an increase in crystallite size, lattice parameters, and cell volume. These modifications were linked to the efficient capping of ZnO nanoparticles by OA, which further improved the dispersion of the nanoparticles, as demonstrated through SEM imaging. The optimum conditions of ZnO- and ZnO-OA-synthesized modified Fenton composites showed 400 mg/L and 40 mg/L for H2O2 and the catalyst, respectively, at pH 3.0, and within 90 min under UV irradiation the maximal dye oxidation reached 93%. The catalytic performance at its optimal circumstances was in accordance with a pseudo-second-order kinetics model for both ZnO-OA- and the pristine ZnO-based Fenton’s systems. The thermodynamic parameters, including the enthalpy (ΔH′), the entropy (ΔS′), and Gibbs free energy (ΔG′) of activations, were also checked, and their values settled that both ZnO and ZnO-OA Fenton systems are non-spontaneous in nature. Furthermore, the reaction signified for processing at a low energy barrier condition (10.38 and 31.38 kJ/mol for ZnO-OA- and the pristine ZnO-based Fenton reactions, respectively).

Sustainable Removal of Phenol Dye-Containing Wastewater by Composite Incorporating ZnFe2O4/Nanocellulose Photocatalysts

The escalating issue of phenol-containing wastewater necessitates the development of efficient and sustainable treatment methods. In this context, we present a novel composite photocatalyst comprising ZnFe2O4 (ZFO) nanoparticles supported on nanocellulose (NC), aimed at addressing this environmental challenge. The synthesis involved a facile hydrothermal method followed by the impregnation of ZFO nanoparticles onto the NC matrix. The morphology and structure of ZFO, NC, and ZFO/NC were investigated by TEM, SEM-EDX, UV–vis, FT-IR, XRD, and XPS analyses. ZFO, as a weakly magnetic semiconductor catalytic material, was utilized in photocatalytic experiments under magnetic field conditions. By controlling the electron spin states through the magnetic field, electron–hole recombination was suppressed, resulting in improved photocatalytic performance. The results demonstrated that 43% and 76% degradation was achieved after 120 min of irradiation due to ZFO and 0.5ZFO/NC treatment. Furthermore, the composite 0.5ZFO/NC demonstrated the highest photocatalytic efficiency, showing promising recyclability by maintaining its activity after three cycles of use. This study underscores the potential of the ZFO/NC composite for sustainable wastewater treatment, offering a promising avenue for environmental remediation.

Development of antifouling nanofiltration membranes for separation of dye/salt mixture through incorporation of novel polyelectrolyte-decorated silica

Various physical and chemical methods can improve hydrophilicity and prevent fouling in polyethersulfone (PES)-based nanofiltration membranes. Here, two additives containing hydrophilic polymer brushes were used to modify the hydrophilicity of PES membranes. First, the surface of mesoporous silica (MS) was modified with poly(2,3-epoxypropyl methacrylate) (P(EPMA)) and poly[2-(acryloyloxy)ethyl]trimethylammonium chloride (P(AEtMAC)) brushes using the surface-initiated atom transfer radical polymerization (SI-ATRP) method to prepare MS-g-P(EPMA-SO3) and MS-g-P(AEtMAC) as additive. Various weight percentages of the additives from 0.05 to 0.2 wt% were used to fabricate PES-based membranes and by adding the polymer brushes, the hydrophilicity of PES-based membranes increased. The membrane containing 0.075 wt% of MS-g-P(AEtMAC) additive exhibited a higher water flux of 18.6 (L/m2.h) at 5 bars. The separation of Coomassie Brilliant Blue G-250 (CBB) and Congo Red (CR) dyes (100 mg/L) was investigated; all membranes rejected more than 99 % of both dyes. However, the PES/MS-g-P(EPMA-SO3) membrane, M2, showed a rejection rate of 11.5, 6.1, and 5.1 % for Na2SO4, MgCl2, and NaCl, respectively. PES/MS-g-P(AEtMAC) membrane, M6, rejected Na2SO4, MgCl2, and NaCl at 6.2, 11.9, and 6.8 %, respectively. Finally, the constructed membranes demonstrated remarkable selectivity for dye/salt mixtures, indicating great potential for treating dye-containing wastewater.

Synthesis of MOF@COF composites and study on dye adsorption properties

MOF@COF hybrid materials not only have high stability and adjustable function, but also have the characteristics of MOFs and COFs materials, which make them have important application value in the field of adsorption. This article employs 1,3,5-benzene tricarbonyl chloride and p-Phenylenediamine as covalent organic framework monomers. Through the in-situ growth of covalent organic frameworks (COF) on the surface of NH2-MIL-88(Fe) material, a novel, stable, and porous COF-on-MOF hybrid material (NH2-MIL-88(Fe)/COF) was synthesized. The structure, morphology, and performance of the hybrid material were thoroughly examined using characterization techniques, including Fourier-transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA). Subsequently, We explored the MOF@COF hybrid material as an effective adsorbent for removing organic dyes, namely methylene blue (MB), methyl orange (MO), and crystal violet (CV). The influence of various adsorption parameters, such as adsorption time, initial dye concentration, and different pH values, on dye adsorption performance was systematically investigated. Experimental results revealed that at pH = 7, NH2-MIL-88(Fe)/COF demonstrates maximum adsorption capacities of 114 mg·g−1, 106 mg·g−1, and 102 mg·g−1 for methylene blue, methyl orange, and crystal violet, respectively. The adsorption process follows pseudo-second-order kinetics and Langmuir isotherm models. Lastly, NH2-MIL-88(Fe)/COF maintains high removal efficiency for the three dyes even after five repeated uses, establishing it as a stable and efficient adsorbent. The research findings suggest that MOF@COF hybrid materials hold promising applications in the treatment of dye-containing wastewater.

Performance of Dye-Containing Wastewater Treatment Using MnxOy-Catalyzed Persulfate Oxidation

Dye wastewater is characterized by high salinity, intense coloration, difficulty in degradation, and complex organic compositions, posing significant environmental risks. Manganese oxide (MnxOy)-based materials have been widely used for the removal of recalcitrant organic pollutants in water environments. In this study, various MnxOy polymorphs were prepared, and their catalytic activities for persulfate (PS) activation were evaluated using Orange II (AO7) as a model molecule. After 50 min treatment, the degradation efficiency of AO7 ranked as α-MnO2/PS > γ-MnO2/PS > β-MnO2/PS > Mn2O3/PS, with α-MnO2/PS achieving the highest efficiency of 98.6%. XPS, XRD, and electrochemical analyses indicated that α-MnO2 exhibited an exceptional crystal structure and performance. The α-MnO2/PS system exhibited a strong pH adaptability across a wide pH range of 3.0–9.0. The presence of coexisting anions at 0.1 mM, including Cl−, NO3−, CO32−, and SO42−, slightly reduced the degradation rate of AO7. The reactive oxygen species, mainly SO4•− and 1O2, predominantly destroyed the naphthalene ring structure of AO7. Furthermore, α-MnO2 exhibited an excellent stability, allowing for multiple reuse cycles without interference from common anions in water, highlighting its strong potential for practical applications. These results provided insights into the environmental fates of AO7 in the α-MnO2/PS system.

Novel versatile 5-aminoisophthalic acid modified chitosan nanofiber pads for adsorption toward Congo red, methyl orange, crystal violet, and methylene blue

To structure novel nanofiber pads for organic dye removal from dye-polluted water, we previously prepared CSP nanofiber pads by chitosan (CS) and polyethylene oxide (PEO) via electrospinning, followed by preparation of CSRP nanofiber pads through partial PEO removal from CSP, and the subsequent fabrication of CS-A nanofiber pads via grafting 5-aminoisophthalic acid (5-AIPA) to CSRP. FTIR, XRD, and elemental analyses confirmed the successful synthesis of CS-A nanofiber pads (crosslinking and crystalline degrees of 36.64 % and 4.57 %). CS-A nanofiber pads had porous nanofiber structures (diameter and pore size of 153.46 and 3.82 nm), high specific surface area (102.06 m2/g), great thermal stability (total mass loss of 50.2 %), excellent hydrophilicity (water contact angle of 12.0°), superior swelling performance (2331 %), good pH stability (pH of 3.0–11.0), and 6.8 of pHpzc, evidenced by SEM, Brunauer-Emmett-Teller (BET), thermogravimetric (TG), differential thermogravimetric (DTG), wettability, swelling, and solid addition tests. Optimum adsorption parameters (e.g., pH, dosage, and initial concentration) were selected by batches of tests on adsorption toward four organic dyes. CS-A’s surfaces were heterogeneous, and the adsorption belonged to spontaneous endothermic chemical adsorption, confirmed by kinetic and isothermal models and thermodynamic results. CS-A nanofiber pads were of great reusability and easy to be separated. Adsorption mechanisms involved electrostatic attractions, hydrogen bondings, π-stacking interactions, and pore fillings. Dynamic adsorption toward Congo red showed the Thomas model well fitted the breakthrough curves (R2 > 0.9971), showing the maximum adsorption capacity of 949.15 mg/g. Totally, CS-A nanofiber pads were effective adsorbents suitable for organic dye-containing wastewater purification.

Optimum and Green Fabrication of MIL-100(Fe) for Crystal Violet Dye Removal from Aqueous Solution

MIL-100(Fe) was prepared and subsequently used to remove crystal violet dye from aqueous solutions simulating dye-containing wastewater in the environment. In the future, it is aimed that MIL-100(Fe) can be used in managing dye-containing wastewater in the environment and reducing the negative impacts it can cause. Here, MIL-100(Fe) fabrication needs to be optimized to obtain optimum process conditions, which are environmentally friendly and can produce MIL-100(Fe) with the best characteristics. This study focused on optimizing the fabrication of MIL-100(Fe), which is a type of MOF with good chemical stability, thermal stability, and flexible structure. In this study, the room-temperature fabrication of MIL-100(Fe) was established using a ligand-to-metal molar ratio of 0.95 and an acetic acid concentration of 5.1 vol% for 6.2 h. The optimum MIL-100(Fe) was tested for crystal violet removal and provided an optimum removal capacity of 182.66 ± 3.81 mg/g. Statistical approaches are used to investigate the independent parameters and their interactions contributing to MIL-100(Fe) formation.

Kinetic Adsorption Studies of Cationic Dyes onto Molecular Sieve and Activated Carbons

Background: Dye-containing wastewater causes irreparable damage to the ecological water system. Although adsorbents are widely used for treating wastewater containing dyes, the comparative investigation on these materials is still insufficient for their wide applications in the industries. Objective: With the aim of comparing efficient and fast adsorbent materials for cationic dyes, we analyzed and evaluated the adsorbents of the MCM-41 molecular sieve and activated carbons. Methods: The adsorption performance was studied on the common colored organics, such as cationic dyes of rhodamine B (RhB) and methylene blue (MB) dyes. The present work examined the impact of experimental variables, including initial dye concentration, adsorption time, and pH, on the adsorption process and performance, as well as the adsorption kinetics of the diverse adsorbents towards two cationic dyes. Results: MCM-41 molecular sieves showed relatively high adsorption capacity for RhB and AC-2, which made their adsorption capacity for MB much higher than that of MCM- 41 molecular sieves. A comprehensive analysis was conducted using pseudo-first-order and pseudo-second-order to decipher the mechanism of dye adsorption. The heterogeneous adsorption mechanism could explain the dye adsorption behavior of MCM-41 molecular sieve and activated carbons. Conclusion: The results demonstrated the influence of the pore structure and surface properties of the adsorbents on the adsorption capacity of dye molecules in an aqueous solution. For the initial concentration of cationic dye solutions of 20 mg/L, the MCM-41 molecular sieve had a MB adsorption capacity of 130.8 mg/g under alkaline conditions at pH=10, while the activated carbon adsorbents showed a stable MB adsorption capacity of 266.6 mg/g under different pH conditions, proving their applicability in treating wastewater containing dyes under different acid/base environments.

Mixed matrix membranes by post-modified UiO-66-NH2 for efficient treatment of dyeing wastewater

The preparation of modified membranes utilizing the UiO-66 framework for wastewater filtration is regarded as one of the most promising approaches to wastewater treatment, owing to its high efficiency and cost-effectiveness. In this study, a post-modified MOF, UiO-66-RSA, was synthesized via the condensation reaction of UiO-66-NH2 and 2,4-dihydroxybenzaldehyde. PVDF mixed matrix membranes (MMMs) were fabricated for the first time by mixing UiO-66-RSA into PVDF using the non-solvent induced phase separation (NIPS) method. Compared to pure PVDF membranes, the newly developed membrane, M4, demonstrated enhanced compatibility and superior mechanical strength. In dyeing wastewater treatment applications, M4 showed excellent separation efficiency for dye and heavy metal mixed wastewater, achieving rejection rates exceeding 90 %. Additionally, it maintained a high flux recovery rate (FRR > 90 %) and rejection rate (Rejection > 90 %) after six filtration cycles of dye-containing wastewater, indicating strong recyclability. These findings suggest that MMMs embedded with UiO-66-RSA hold significant promise for dyeing wastewater treatment.

Preparation of hollow MgO nanosorbents via the templating method and study of their adsorption mechanism

The treatment of dye-containing wastewater has been a concern in recent years. Herein, we used laboratory-waste-skimmed cotton as a biotemplate and successfully synthesized MgO hollow tubular nanosorbents via a mild microwave solvent-thermal method. In adsorption experiments, the response surface methodology and Box–Behnken design were used to optimize and determine the optimal Mg(OAc)2 concentration (0.4 mol/L), skimmed cotton template mass (0.4 g), and calcination temperature for Congo red adsorption (600 °C). The adsorption process was comprehensively analyzed from thermodynamic and kinetic perspectives. Results showed that the adsorption process of MgO-urea template (MgO-UT) hollow nanosorbent conforms to the Dubinin–Radushkevich equation of the ion-exchange adsorption process and follows the pseudo-second-order kinetic model. The maximum amount of Congo red adsorbed by MgO-UT hollow nanosorbent is 3511.35 mg/g, demonstrating its excellent adsorption effect. Therefore, MgO hollow tubular nanosorbents prepared using biological templates can be used as novel organic dye adsorbents.

Efficient water purification: CuO-enhanced biochar from banana peels for removing Congo red dye.

Treating dye-containing wastewater poses numerous challenges due to its high chemical complexity and its persistent nature. Thus, the present study aims to synthesize biochar derived from banana peel (BC) and its nanocomposites with copper oxide nanoparticles (CuOx/BC1-x) for the purpose of adsorptive removing Congo red (CR) dye from water. Several analytical methods were utilized to describe the physicochemical features of the CuOx/BC1-x nanocomposites. It was found that the crystallinity of the nanocomposites gradually improved, while the specific surface area and the surface electronegativity were reduced with increasing x value. The effects of x values (0-0.5), interaction time (10-120 min), adsorbent dose (0.01-0.05 g), initial CR concentration (20-200 mg/L), and the solution temperature (20-60 °C) were evaluated on CR removal. The obtained results revealed that the CuO0.5/BC0.5 nanocomposite showed the highest adsorption efficiency with a maximum adsorption capacity of 233.6 mgg-1. Analysis of the equilibrium experimental data revealed that the Langmuir and the pseudo-2nd-order models were the most proper to describe the current adsorption process. Moreover, the thermodynamics studies demonstrated that the adsorption process was spontaneous, endothermic, and random.

Central composite experimental design for Indigo Carmine dye removal from solutions by applying electro-coagulation and electro-oxidation processes

Textile and food industries produce toxic or harmfull dye-containing wastewaters that should be treated for safely discharge. The electro-coagulation (EC) and the electro-oxidation (EO) methods for removal of dyes from wastewaters are being investigated nowadays by researchers. In this study, the Indigo Carmine, a textile and food coloring agent, removal was investigated by applying the electro-coagulation and the electro-oxidation methods. For this purpose, aluminum electrodes for EC and graphite plates for EO were used. The central composite experimental design was applied as the optimization method for the EC and the EO processes. The optimization parameters were selected as time (10-30 minutes), current density (0.4-2 Ampere/500 mL) and concentration (50-250 mg/L), natural pH (5.78-6.90) and room temperature (20-25 °C). The EO process was determined to be effective than the EC process. Statistically important parameters were concentration and time-current density interaction for the EC, but all the parameters were statistically unimportant for the EO. Dye removal percentages by the EC were calculated between 82.75% and 98.38%, and dye removal percentages by the EO were calculated between 46.88% and 100% for the determined experimental matrix. Electrical consumptions were almost equal for the EO and the EO prosesses. A column ion exchange process (Selion SBA 2000 resin) was applied to the dye residue after the EO treatment. From the oxidation reduction measurements, the treated solutions were determined as dischargeable.

Efficient degradation of methylene blue at near neutral pH based on heterogeneous Fenton-like system catalyzed by Fe2O3/MnO2

The contamination of aquatic environments by organic dye contaminants in industrial wastewater has attracted widespread global attention. The heterogeneous Fenton-like process presents an attractive method for degrading dye pollutants, especially when such reactions are conducted under neutral pH. In this study, Fe2O3/MnO2 composite was employed as a novel heterogeneous catalyst for activating hydrogen peroxide (H2O2) to oxidize and subsequently degrade methylene blue (MB) under neutral pH. Multiple characterization results have confirmed the presence of MnO2 and Fe2O3 as the primary phases of the synthesized compound catalyst. Degradation experiments have demonstrated that the degradation efficiency of MB approaches 100% under the conditions of H2O2 concentration of 0.30% and Fe2O3/MnO2 amount of 0.888 g/L. Furthermore, the Fe2O3/MnO2 catalyst exhibits consistent and outstanding catalytic activity within a broad pH range from 5 to 9 benefiting from the strong interface interaction in Fe2O3/MnO2. The investigation into the kinetics of the Fenton-like reaction indicates that the catalytic degradation of MB by Fe2O3/MnO2 in conjunction with H2O2 follows pseudo-first-order kinetics. Moreover, supplementary scavenging experiments have demonstrated the crucial role played by hydroxyl radicals (·OH) in the catalytic oxidation mechanism of MB. This study offers a promising catalyst for the treatment of dye-containing wastewater under neutral pH condition.

Enhanced photocatalytic performance of ternary g-C3N4/UiO-66/Ag3VO4 composite for methylene blue degradation under visible light irradiation

Anovel Ag3VO4/UiO-66/g-C3N4-based photocatalystwassynthesized using the solvothermal approach and characterized using XRD, SEM, FTIR, PL, and UV–Vis DRS. The photodegradation capacityof each componentwas tested using aqueous solutions of methylene blue (MB) and real sample solutions. It was found that the ternary composites (g-C3N4/UiO-66/Ag3VO4, 1 wt%, 5 wt%, 10 wt%, and 15 wt% g-C3N4) demonstrated higher degradation efficiency than the single and binary constituentsowing to beneficial interactions in the composite, which favor successful interfacial charge transfer and improve photogeneratede--h+pair separations. The influence of various experimental factors such as pH, initial dye amount, photocatalyst dose, and scavengers on MB degradation was examined. At optimal conditions of pH 6, catalyst load of 60 mg, and initialdye content of 10 ppm, the percent photodegradation of MB under irradiation with visible light (indoorsystem) was 99.35 %, while in the outdoor system,it was 99.5 % in 240 min. The selected photocatalyst was also applied for the degradation of real sewage sample solution, which was found to be 80.2 % under indoor and 89 % under outdoor experimental undertakings. After five cycles, the potential of the photocatalystremained substantial, indicating remarkable reusability. The scavenging experiment suggested that the principal active species were found to be superoxide (O2•) and hydroxide radicals (•OH). Thus, the composite g-C3N4/UiO-66/Ag3VO4 could be a promising option for industrial effluent removalapplications, particularly in the purification of organic dye-containing wastewater.

Effective hydrogen production and coupling degradation of organics (4-nitrophenol, methylene blue, and Rhodamine B) in wastewater by electrospun PAN@Fe0 composite nanofibers

The pursuit of clean energy generation and environmental preservation is of utmost importance for societal progress. However, couple clean energy production and pollution control is still a difficulty. In this study, a novel electrospun composite mat, with nano zero valent iron (Fe0, nZVI) encapsulated into polyacrylonitrile (PAN) nanofibers was acted as a catalyst. The activation energy (Ea) for the hydrolysis of NaBH4 to produce hydrogen is 22 kJ·mol−1, hydrogen atom utilization efficiency (HGE) of NaBH4 is 60.80%. Three kinds of organic dyes 4-nitrophenol (4-NP), methylene blue (MB), and Rhodamine B (RhB) were served as the model pollutant, to construct NaBH4-organic system for energy production and pollution reduction. The NaBH4-organic system demonstrates a collaborative capability to simultaneously remove organic pollutants and generate hydrogen, with a coupling equilibrium point between the two processes. The hydrogen generation rate (HGR) and HGE increased with the concentration of pollutants increased. The degradation of 4-NP, MB, and RhB followed pseudo-first-order kinetics, with RhB degrading dosage 20 and 44 times higher than 4-NP and MB, respectively. H2 and H· contributed to the organic degradation. nZVI directly participated in the formation H2 and H·. PAN@Fe0 possessed good recyclability and moderate cost. The degradation process adhered to the classical surface reaction controlled Langmuir-Hinshelwood (L-H) model. The integration of synergistic production capacity and pollutant degradation aligns well with the principles of green chemistry and sustainable development. This study demonstrates a novel approach to no precursor loss catalysts preparation, efficient production clean H2, advanced treatment of dye-containing wastewater, carbon neutral operation of sewage treatment plant.

Possible Remediation Approaches for Wastewater Containing Dyes; A Review

Abstract One of the most serious environmental problems is water scarcity and water pollution is a worldwide issue that can have an impact on people, plants, animals, and trees. Reusing wastewater makes sense in light of the limited availability of freshwater sources to conserve and expand the pool of available water sources. Numerous things can contaminate water supplies. Although the fundamental concepts are usually the same, the process of water restoration may vary from one location to another based on the source of contamination. Dyes are a versatile group of organic compounds found in many industries ranging from textiles, papermaking, leather tanning, and food processing. However, untreated or partially treated dye-containing wastewater in the environment can have a significant impact on human health and ecosystems. Dyes can color water bodies, making them aesthetically displeasing and inhibiting the penetration of sunlight. This may cause water plants and algae to produce less. While certain dyes are carcinogenic or mutagenic to humans, others are poisonous to aquatic life.

Modeling sustainable photocatalytic degradation of acidic dyes using Jordanian nano-Kaolin–TiO2 and solar energy: Synergetic mechanistic insights

The abstract highlights the global issue of environmental contamination caused by organic compounds and the exploration of various methods for its resolution. One such approach involves the utilization of titanium dioxide (TiO2) as a photocatalyst in conjunction with natural adsorption materials like kaolin. The study employed a modeling-based approach to investigate the sustainable photocatalytic degradation of acidic dyes using a Jordanian nano-kaolin–TiO2 composite material and solar energy. Mechanistic insights were gained through the identification of the dominant reactive oxygen species (ROS) involved in the degradation process, as well as the synergetic effect between adsorption and photocatalysis. The Jordanian nano-kaolin–TiO2 composite was synthesized using the sol-gel method and characterized. The nanocomposite photocatalyst exhibited particle sizes ranging from 27 to 41 nm, with the TiO2 nanoparticles well-dispersed within the kaolin matrix. The efficacy of this nanocomposite in removing Congo-red dye was investigated under various conditions, including pH, initial dye concentration, and photocatalyst amount. The optimal conditions for dye removal were found to be at pH 5, with an initial dye concentration of 20 ppm, and using 0.1 g of photocatalyst, resulting in a 95 % removal efficiency. The mechanistic insights gained from this study indicate that the hydroxyl radicals (•OH) generated during the photocatalytic process play a dominant role in the degradation of the acidic dye. Furthermore, the synergetic effect between the adsorption of the dye molecules onto the photocatalyst surface and the subsequent photocatalytic degradation by the ROS was found to enhance the overall removal efficiency. These findings contribute to the fundamental understanding of the photodegradation mechanisms and guide the development of more efficient photocatalytic systems for the treatment of acidic dye-containing wastewater. The use of solar power during the purification procedure also leads to cost reduction and strengthens sustainability efforts.