Dye Wastewater Research Articles

Electrocoagulation treatment for Remazol Brilliant Blue R (Reactive Blue 19) removal of textile dye simulated wastewater using iron-aluminum electrodes

Abstract The presence of non-biodegradable dyes, such as Remazol Brilliant Blue R (Reactive Blue 19), in wastewater poses a significant environmental challenge. This study investigates the application of electrocoagulation using iron-aluminum (Fe-Al) electrodes to efficiently remove Reactive Blue 19 dye from simulated textile dye wastewater. It considers various parameters such as electrode material, current, stirring speed, as well as the influence of sodium chloride acting as a supporting electrolyte to enhance conductivity. Additionally, it evaluates the economic feasibility through electrode consumption analysis. The experimental setup involved a designed reactor with aluminum and iron electrodes arranged at bipolar parallel connection, along with a 30-minute electrocoagulation process conducted at ambient temperature and subsequent filtration of the treated wastewater for UV-VIS analysis. The optimal parameter combination obtained consists of Fe-Al electrode material, a 3 A current, and a 200-rpm stirring speed, achieving 96.87% dye removal. Furthermore, extending the operating time to 60 minutes improved the removal by 99.15%. Under these optimal conditions, the energy consumption measured was 36 kWh/m3. The high dye removal rate obtained shows the effectiveness of this electrocoagulation process in treating Reactive Blue 19 simulated wastewater. A t-test, employed as a hypothesis testing technique with a significance level of 0.05, confirmed the optimal levels of the factors and interactions within the treatment process. A remarkable coefficient of determination of 0.9794 in the dye removal sensitivity analysis signifies a strong goodness of fit, indicating that these three (3) parameters collectively explain how they affect the outcome while accounting for dye removal efficiency variation. These results showed that electrocoagulation is a promising technology for treatment of Reactive Blue 19 dye wastewater.

Electrochemical degradation of small molecule dyes by TiO2-decorated polyacrylonitrile nanofiber membranes with superior properties

To optimize the uniform dispersion of nanoparticles and enhance their catalytic degradation effect on small molecule dyes in textile wastewater, titanium dioxide (TiO2) was deposited on polyacrylonitrile (PAN) fiber membranes using magnetron sputtering technology, and TiO2/PAN nanofiber membrane (NFM) with low content and high catalytic efficiency was successfully prepared. Through membrane separation coupling electrocatalysis, the composite membranes exhibited outstanding performance in removing Congo red (CR), Sunset yellow (SY), Methyl orange (MO), and Methylene blue (MB) dyes, with removal rates of 99.5%, 98.8%, 98.5%, and 87.2% respectively. Even after continuous catalysis for 10 h, the composite membranes maintained a high dye removal rate, demonstrating their remarkable stability and water treatment capabilities. Furthermore, TiO2/PAN NFMs displayed high pure water permeance, dye permeance, and mechanical strength. Specifically, M20 (magnetron sputtering time of 20 min) showed water permeance and dye (SY) permeance values of 1944 L·m−2·h−1·bar−1 and 816 L·m−2·h−1·bar−1, respectively, and indicate superior mechanical and electrochemical properties. During the electrocatalytic process, TiO2/PAN NFMs generated reactive oxygen species (ROS) on the surface, imparting a self-cleaning property that extended the service life of the membranes and offered an effective solution for textile wastewater treatment.

Efficiently removing four cationic dyes from aqueous solution by magnetite@polypyrrole@2-acrylamido-2-methyl-1-propanesulfonic acid microspheres

Water pollution caused by various cationic dyes is becoming more and more serious. A combination of magnetic materials, conductive polymers, and some strong adsorption groups is expected to solve this challenge. Herein, magnetite (Fe3O4)@polypyrrole@2-acrylamido-2-methyl-1-propanesulfonic acid (Fe3O4@PPy@AMPS) is fabricated as adsorbent for removing methylene blue (MB), rhodamine B (RhB), malachite green (MG), and crystalline violet (CV) from aqueous solution. The investigation of the factors including adsorbent type, adsorbent concentration, time, and temperature demonstrates that Fe3O4@PPy@AMPS has superior properties to adsorb the four cationic dyes. The maximum adsorption capacity of these dyes is separately 183.486, 215.054, 144.718 and 194.175 mg/g. Notably, although it goes through five cycles, the composite maintains a remarkable dye removal efficiency exceeding 95 %. Kinetic analysis reveals that the adsorption process conforms more closely to the pseudo-second-order kinetic model. The adsorption isotherm conforms to the Langmuir model, signifying monolayer adsorption of the dyes. Thermodynamic parameters also indicate that the adsorption process is endothermic and spontaneous. Furthermore, density functional theory (DFT) simulations affirm the molecular interactions between Fe3O4@PPy@AMPS and four dyes, elucidating the adsorption mechanism. The high efficiency and recyclable nature of the Fe3O4@PPy@AMPS composite underscores its significance in addressing dye wastewater pollution remediation.

PH-tuneable simultaneous and selective dye wastewater remediation with digestate-derived biochar: Adsorption behaviour, mechanistic insights and potential application

The use of biochar for organic pollutants adsorption has emerged as a key component in wastewater remediation research. In this study, biochar prepared from digestate was subjected to nitric acid functionalization to enhance its adsorption capacity for organic dye mixtures of methylene blue and methyl red in synthetic wastewater. Based on experimental evidence, modified biochar BC750-NM, with a micro-mesoporous structure and a specific surface area of ∼454.15 m2/g had the best adsorption performance at optimum conditions. This adsorbent exhibited both selective and simultaneous dye adsorption upon pH control, mainly attributable to a multi-interaction process in the medium. Notably, the adsorption of both methylene blue and methyl red approached 90% under acidic pH, while methylene blue was preferentially adsorbed over methyl red at alkaline pH to attain an excellent adsorption rate of 100% for methylene blue. Our approach not only yields a valuable resource for mitigating water pollution but also offers a sustainable solution for digestate management, showcasing the potential for innovative techniques to produce synergistic environmental solutions.

Development of a flow reactor incorporating polydopamine-poly(ε-caprolactone) with gold particles

Addressing the significant challenge of dye wastewater pollution, this study introduces a novel solution employing a flow catalytic reactor loaded with gold (Au) particles. The reactor utilizes a porous monolithic material with a Poly(ε-caprolactone) (PCL) matrix as the carrier for Au particles, with polydopamine employed to immobilize the Au onto the surface of the PCL monolith. To assess the catalytic efficiency of the reactor, a model catalytic degradation experiment involving the reaction between methyl orange (MO) and sodium borohydride was conducted. The catalytic reaction was facilitated by a peristaltic pump. The reactor setup involved fixing the monolith within a heat shrinkable tube, and the peristaltic pump ensured the flow catalytic reaction. The protective effect of liquid nitrogen was utilized to confirm that the porous structure of the PCL monolith, with its low melting point, remained intact after being fixed in the heat shrink tube. Catalytic results revealed remarkable efficacy, with the decomposition efficiency of MO reaching 98.54%. This flow reactor enables continuous operation, making it more practical for real-world applications compared to traditional batch methods. Furthermore, even after 5 cycles, the sample maintained a catalytic efficiency exceeding 90%, demonstrating the excellent reusability of the reactor.

Bio-derived carbon-based materials with high photothermal conversion and microstructure transport channels for efficient solar evaporation and water treatment

Solar-driven desalination technology can effectively solve the problem of global water shortage. However, the complexity and cost of the preparation process have hindered the further development of solar-driven water evaporation devices. In this paper, a promising and economical solar evaporator was designed based on carbonized reed poles. The vertically aligned carbon structure and carbonized surface folds can increase the light-absorbing area for efficient photothermal conversion. Reed poles are rich in water transport channels, where the uniform distribution of polyacrylamide accelerates the water transport and shortens the evaporation pathway. As a result, the water evaporation rate is as high as 2.42 kg−2 h−1 under the radiant illumination of one sun. In addition, the evaporator device is effective for seawater desalination and dye wastewater treatment. Therefore, this environmental-friendly and economical solar evaporation system is an effective way to achieve water purification.

Photocatalytic performance of water-soluble nucleobase-functionalized molybdenum disulfide nanocomposite against methyl blue dye

This report indicates the applicability of an ecofriendly and low cost modified MoS2 nanocomposite as photocatalytic degradation of organic dye from wastewater. The synthesized MoS2 nanocomposite, specifically the Cy-80 % and E-MoS2, demonstrated a high photodegradation efficiency of methyl blue dye in wastewater under UV light irradiation. The incorporation of a nucleobase-containing polymer within the MoS2 structure led to enhanced photocatalytic performance by creating separate wide surface areas and abundant active sites for efficient electron-hole pair separation. The obtained nanocomposite showed superior degradation efficiency compared to aqueous phase exfoliated MoS2 alone (75.6 %), with a photodegradation efficiency of up to 98.7 % within 60 min of UV light irradiation. Furthermore, the Cy-PPG modified MoS2 nanocomposite exhibited significant degradation efficiency over multiple cycles, making it a promising material for the degradation of dye-containing wastewater using visible irradiation sources.

Construction of mechanically robust and recyclable catalytic hydrogel based on hydroxypropyl cellulose-supported by montmorillonite/ionic liquid with different anions for pollutants(4-NP, MB, CR, Rhb) degradation

Dye wastewater poses a serious threat to the environment and human health, necessitating sustainable degradation methods. In this study, Na-based Montmorillonite (MMT) was exfoliated using different ionic liquids ([C16MIM][Cl], [C16MIM][BF4], [C16MIM][PF6]), and silver nanoparticles (Ag NPs) were green-synthesized using hydroxypropyl cellulose (HPC). The HPC significantly enhanced the dispersion of MMT in the hydrogel. By introducing lauryl methacrylate (LMA), a hydrophobic associative network was constructed in PAM/LMA/HPC/MMT@ILs&Ag NPs hydrogel. This hydrogel demonstrated outstanding mechanical properties, with a stress of 833.21 kPa, strain of 3300 %, and toughness of 14.36 MJ/m3. It also exhibited excellent catalytic activity, with a rate constant of 0.83 min−1 for 4-nitrophenol degradation at 28 °C. The effects of temperature and catalyst concentration on the catalytic reaction were systematically investigated. This study presents a simple green synthesis approach for Ag NPs using HPC, achieving superior mechanical performance and stable MMT dispersion in aqueous solutions.

Structure design and performance optimization of PVDF-CTFE nanofibrous composite nanofiltration membrane modified by C–Cl active site grafting

The substrate membrane plays a crucial role in determining the performance of composite nanofiltration membranes prepared by interfacial polymerization (IP). In this study, persistent hydrophilic modification of polyvinylidene fluoride-co-chlorotrifluoroethylene (PVDF-CTFE) was achieved by incorporating N-methylglucamine (N-MG) without altering the membrane's morphology or pore size. Moreover, thin-film nanofibrous composite (TFNC) nanofiltration membranes were prepared using the surfactant assembly regulated interfacial polymerization (SARIP) method with the modified PVDF-CTFE@N-MG nanofibrous membrane as the substrate. The effect of N-MG addition on the substrate membrane's hydrophilicity and the structure and performance of the polyamide (PA) separation layer was investigated. The results showed that the addition of N-MG significantly improved the hydrophilicity of the PVDF-CTFE nanofibrous membrane. The TFNC-5 membrane, prepared with the modified PVDF-CTFE@N-MG nanofibrous membrane as the substrate, exhibited permeability exceeding 13.5 L m−2 h−1·bar−1 for various dye solutions at 3 bar pressure, with rejection rates above 98 %. It also demonstrated excellent selective separation performance (separation factor for NaCl/Orange G reaching 97.38) and long-term operational stability. This work provides a method for the preparation of low-pressure, high-flux nanofiltration membranes, which is applicable to seawater desalination and dye wastewater treatment.

Extraction of luminescent compounds from wastewater by ionic liquids for fabricating fluorescence/afterglow anti-counterfeiting materials

Dyes in industrial wastewater are often toxic, polluting the environment, and harmful to animals and humans. The conventional methods of removing the dyes from wastewater are physical adsorption, precipitation, biodegradation, and photodegradation. Here we report the use of ionic liquids (ILs) to extract dyes from wastewater for the fabrication of fluorescence/afterglow materials. This method not only reduces the dye concentration by two to three orders of magnitude, but also obtains luminescent materials for anti-counterfeiting application. Diverse dyes such as rhodamine, acridones, difluoroboron compounds, and polycyclic aromatic hydrocarbons (PAHs) have been tested as model dyes in wastewater. In the case of rhodamine and some PAHs, fluorescence materials that exhibit diverse colors can be obtained after extraction by ILs. For difluoroboron compounds, room-temperature phosphorescence (RTP) materials have been achieved after extraction. Interestingly, in the case of acridones, the emergence of RTP/TADF dual afterglow emission has been evidenced in ILs, where TADF represents thermally activated delayed fluorescence. By the combination of these luminescent materials, lifetime-coded and multicolor-coded anti-counterfeiting functions have been demonstrated.

An eco-safety g-C3N4/Nb2O5/Ag ternary nanocomposite for photocatalytic degradation of pharmaceutical wastes and dyes in wastewater and zebrafish embryonic assessment

In this work, we developed a ternary g-C3N4/Nb2O5/Ag photocatalyst through a simple hydrothermal process with ultrasonic-assisted assembly for the photocatalytic degradation of Norfloxacin (NRF) and Methylene Blue (MB) in wastewater. The bandgap of the prepared nanocomposite was tuned to 2.81 eV, which is favorable for visible light photocatalytic reaction. The photocatalytic process involved the generation of reactive species such as hydroxyl radicals (·OH), photo-generated holes (h+), and superoxide radical (·O2−), with the reactivity following the order: ·OH > h+ > ·O2−. With the comprehensive characterizations, the g-C3N4/Nb2O5/Ag nanocomposite exhibited optimal degradation efficiency, achieving 83 % for NRF and 92 % for MB (pH 9) under visible light irradiation within 70 and 80 min, respectively. The intermediate products formed during the photocatalytic degradation were identified with gas chromatography-mass spectrometry (GCMS–). In addition, the biocompatibility and photocatalytic efficacy of g-C3N4/Nb2O5/Ag were examined through zebrafish embryo development studies in the degraded wastewater. The results indicated that treated wastewater did not adversely affect the zebrafish growth. This comprehensive study not only demonstrates the effectiveness of the ternary g-C3N4/Nb2O5/Ag photocatalysts in degrading complex organic pollutants under visible light but also underscores their potential environmental safety as evaluated through biological assays.

Enhancing the Concentration Capability of Nonsupported Electrically Driven Liquid-Phase Microextraction through Programmable Flow Using an All-In-One 3D-Printed Optosensor: A Proof of Concept.

A versatile millifluidic 3D-printed inverted Y-shaped unit (3D-YSU) was prototyped to ameliorate the concentration capability of nonsupported microelectromembrane extraction (μ-EME), exploiting optosensing detection for real-time monitoring of the enriched acceptor phase (AP). Continuous forward-flow and stop-and-go flow modes of the donor phase (DP) were implemented via an automatic programmable-flow system to disrupt the electrical double layer generated at the DP/organic phase (OP) interface while replenishing the potentially depleted layers of analyte in DP. To further improve the enrichment factor (EF), the organic holding section of the OP/AP channel was bifurcated to increase the interfacial contact area between the DP and the OP. Exploiting the synergistic assets of (i) the continuous forward-flow of DP (1050 μL), (ii) the unique 3D-printed cone-shaped pentagon cross-sectional geometry of the OP/AP channel, (iii) the bifurcation of the OP that creates an inverted Y-shape configuration, and (iv) the in situ optosensing of the AP, a ca. 24 EF was obtained for a 20 min extraction using methylene blue (MB) as a model analyte. The 3D-YSU was leveraged for the unsupervised μ-EME and the determination of MB in textile dye and urban wastewater samples, with relative recoveries ≥88%. This is the first work toward analyte preconcentration in μ-EME with in situ optosensing of the resulting extracts using 3D-printed millifluidic platforms.

A Supramolecular Polymer Network Based on Chitosan and Porphyrin and Its Application as an Adsorbent for Selective Removal of Dyes from Water

AbstractEnvironmentally friendly, high adsorption efficiency, and recyclable adsorbents meet the actual needs of organic dye wastewater treatment. Driven by noncovalent interactions between chitosan (CS) and 5,10,15,20‐tetra(4‐hydroxyphenyl) porphyrin sodium (THPPNa) under acidic conditions, a supramolecular polymer network is constructed. The supramolecular polymer network is applied as an excellent adsorbent for the removal of organic dyes from water with high efficiency. In addition, the supramolecular adsorbent shows excellent selectivity for the removal of organic anionic dyes from the mixtures of organic anionic and cationic dyes in water. Furthermore, the removal efficiency of anionic dyes of the network adsorbent keeps over 95% even after five adsorption–desorption cycles, indicating its reusability. This supramolecular polymer network shows its great potential as a low‐cost, effective, and selective adsorbent for removing organic dyes from water.

ZIF‐8 Composites for the Removal of Wastewater Pollutants

AbstractThe presence of dyes in wastewater poses a significant environmental challenge due to their permanence toxicity and potential to harm ecosystems. Because of their high porosity and adjustable characteristics, metal‐organic frameworks (MOFs) have become attractive materials for effective dye removal. Among various MOFs, zeolitic imidazolate frameworks (ZIFs) have garnered significant attention, especially ZIF‐8, for its excellent stability, significant porosity, adjustable pore size and remarkable adsorption capacity. This review article provides a comprehensive overview of recent advances in the implementation of ZIF‐8 and its composites for the removal of pollutants from wastewater. The various synthesis methods, structural characteristics and dye adsorption performance of ZIF‐8 and its composites are discussed. Furthermore, impact of the different factors such as pH, temperature, dye concentration, contact time etc. were also highlighted. Moreover, the detailed adsorption mechanism was also discussed. Finally, the current challenges and future perspectives in the production of materials based on ZIF‐8 for the removal of dyes were also presented.

Synthesis of Ag2O/CaMoO4 S-type heterojunction with enhanced sonocatalytic performance to remove crystal violet in dye wastewater

Herein, an S-type of Ag2O/CaMoO4 heterojunction was prepared by combining CaMoO4 with Ag2O and characterized. The sonocatalytic performance of the Ag2O/CaMoO4 composite was evaluated by analyzing the degradation of basic dye crystal violet (CV). The results showed that the Ag2O/CaMoO4 composite had the best sonocatalytic performance when the molar ratio of Ag2O to CaMoO4 in the Ag2O/CaMoO4 composite was 10 %. When the ultrasonic time was 120 min, the ultrasonic power was 200 W, the addition amount of 10 % Ag2O/CaMoO4 composite was 1.00 g/L and the initial concentration of CV solution was 5 mg/L, the removal rate of CV could reach 97.36 ± 1.46(%). In addition, 10 % Ag2O/CaMoO4 composite showed excellent sonocatalytic degradation performance to cationic dyes Rhodamine B (RhB) and methylene blue (MB), anionic dye Orange II (AO II) and azo dye Congo red (CR), indicating that the catalyst had a wide range of application. The study on the mechanism of sonocatalysis showed that the construction of S-type Ag2O/CaMoO4 heterojunction effectively separated the electron-hole (e−-h+) pairs in the sonocatalysis process, significantly improved the sonocatalytic performance of CaMoO4, and effectively degraded CV, and the degradation of CV was caused by the active components such as h+, superoxide anion radical (O2–) and hydroxyl radical (OH). Furthermore, the 10% Ag2O/CaMoO4 composite showed excellent repeatability and stability. In addition, the sonocatalytic degradation products of CV were detected and the possible degradation pathways of CV were summarized. These results suggested that the Ag2O/CaMoO4 composite was an extremely appropriate sonocatalyst for sonocatalytic degradation of organic pollutants and would provide a valuable research basis for the development of efficient sonocatalysts.

Utilization of Fly Ash Palm Oil Mill Waste as an Adsorbent of Methylene Blue in a Fixed Bed Column System by Using Response Surface Methodology

Palm kernel shell combustion waste in boiler units called fly ash (FA) is a low-cost alternative material as an adsorbent. FA contains high levels of silica (SiO2) and aluminium oxide (Al2O3). The content of both compounds is an important component as an adsorbent. FA was used to absorb methylene blue (MB) continuously from synthetic dye wastewater. The study was conducted by continuous system process optimization using Response Surface Methodology (RSM) Box-Behnken design. MB was flowed on a set of fixed-bed adsorption columns with independent variables in this study are X1 (bed height; 8, 12, 16 cm), X2 (contact time; 90, 120, 150 min) and X3 (flow rate; 2, 4, 6L/min). The dependent variables were Y1 (removal efficiency) and Y2 (adsorption capacity) with matrix design by Box-Behnken. Optimisation of MB removal in this study was obtained at X1 = 16 cm, X2 = 150 min and X3 = 2 L/min with removal efficiency of 98.45% and adsorption capacity of 0.115 mg/g. FA pores according to SEM analysis were obtained at 1-2 µm. Likewise, the results of EDX analysis showed that there were N and Cl atoms in FA after the adsorption process. This shows that FA is able to adsorb MB.

Synthesis of Ag-HKUST-1 composites and adsorption performance of neutral red dye

HKSUT-1 is often used as an adsorbent because of its excellent adsorption properties. In this study, Ag+ was impregnated into the HKSUT-1 precursor solution using the impregnation method, with sodium borohydride (NaBH4) serving as the reducing agent. This was done to examine the removal efficiency of NR dye. The Ag-HKSUT-1 composites were prepared by varying the additions of AgNO3 and NaBH4. The morphology and structure of the Ag-HKSUT-1 composites were characterized by TG, FT-IR, BET and TEM. The adsorption performance of AH1 for neutral red dye in wastewater was investigated. The adsorption process was described by the Langmuir model and the pseudo-second-order kinetic model. The adsorption capacity of AH1 for NR dye at 298 K was calculated to be 64.59 mg/g, indicating that Ag-HKUST-1 effectively adsorbed NR dye. The adsorption process is driven by a chemisorption mechanism, where intermolecular forces between Ag-HKUST-1 and NR, electrostatic interactions, and π-π conjugation between benzene rings play key roles. The results enhance our understanding of the surface interactions between Ag-HKUST-1 and NR dyes and broaden the application of HKUST-1 as an adsorbent for pollutant removal in water.

Self-cleaning of metal-organic framework membranes achieved by photocatalytic ZIFs for dye and antibiotic separation

The progress of membrane-based applications is hindered by widespread membrane fouling, which leads to a significant decrease in separation effectiveness and lifespan, even though membrane separations have shown great potential in the treatment of dye wastewater. The metal-organic framework MOFs (ZIF-8) display strong thermal and chemical stability and an exceptional capacity to degrade organic molecules under visible light, making them extremely promising for the development of self-cleaning membranes. In this investigation, a ZIF-8/L-DOPA/PVDF mixed matrix membrane with excellent self-cleaning properties was constructed using the in-situ growth technique. The characterization results confirmed the formation of a continuous ZIF-8 coating layer, considerably increasing the surface roughness of the composite membrane from 22.9 nm to 76.3 nm compared to L-DOPA/PVDF substrates. The ZIF-8 layer deposited on the L-DOPA/PVDF membrane surface reduced the contact angle from 75.71° to 40.94°. The highest-performing ZIF-8/L-DOPA/PVDF membranes show a higher water permeability of 159.63 (L·m−2 h−1 bar−1) and superior dye rejection rates (Congo red: 97.3 %, Methylene Blue: 98.32 %, Methyl Blue: 98.62 %), along with enhanced removal of antibiotics (e.g., Tetracycline: 95.3 % and Ciprofloxacin: 93.34 %), and long-term nanofiltration stability. Furthermore, the treated membrane recovers almost all of its initial separation efficacy after exposure to visible light due to the successful removal of attached dyes from the membrane surface through photocatalysis. This work presents the potential to fabricate membranes with advantageous photocatalytic properties and effectively treat dye wastewater using self-cleaning membranes.

Advanced treatment and reuse of dye wastewater using thermo-irreversible on/off switch starch with disruption of dissolution/precipitation dynamic equilibrium

The development of irreversible on/off switching materials is a potential strategy for unidirectional capture and encapsulation of pollutants, preventing the pollutant leakage problem resulting from the reversible dissolution of flocculants. Herein, a thermo-irreversible on/off switch starch (TISS) is prepared through modifying starch by etherification grafting glycidyl phenyl ether and 2,4-bis(dimethylamino)-6-chloro-[1,3,5]-triazine. It breaks the dissolution/precipitation dynamic equilibrium across heating–cooling cycles by thermal-induced irreversible coil-to-globule self-assembly of polymer chains, resulting in a 50-fold decrease in polymer solubility. Particularly, TISS shows a superior double-locking effect on pollutants and flocculants through its unique irreversible conformation memory capability, leading to a high-quality reuse water. 99.9 % of reactive brilliant red dye and 97.9 % of TISS remain fixed within sludge flocs even after prolonged immersion in cold water at 24 °C for 60 days. Furthermore, direct recycling and reuse of dye-bath energy can be realized through the isothermal flocculation and dyeing method, showing a 75 % decrease in energy consumption after three cycles compared to traditional dyeing techniques. This work presents a novel approach to constructing an irreversible pollutant delivery system using thermo-irreversible on/off switch starch, addressing the problems of high energy dissipation and water quality fluctuations during wastewater treatment.

Study of the Preparation and Performance of TiO2-Based Magnetic Regenerative Adsorbent.

Against the backdrop of "carbon neutrality", the green treatment of dye wastewater is particularly important. Currently, the adsorption method shows strong application prospects. Therefore, selecting efficient and recyclable adsorbents is of significant importance. TiO2 is an excellent adsorbent, but its difficult recovery often leads to secondary pollution. γ-Fe2O3-modified coal-series kaolin exhibits both excellent adsorption properties and rapid separation through magnetic separation technology. By utilizing the synergistic effects of both, TiO2/-γFe2O3 coal-series kaolin, magnetic adsorbent regeneration materials were prepared using coprecipitation method and characterized. The influencing factors of this functional material on the adsorption of Congo red dye and its regeneration performance are discussed. The experimental results indicated that the specific surface area, pore volume and Ms value of this functional material are 127.5 m2/g, 0.38 cm3/g, and 13.4 emu/g, respectively. It exhibits excellent adsorption characteristics towards Congo red, with an adsorption rate reaching 96.8% within 10 min, conforming to the pseudo-second-order kinetic model, and demonstrating Langmuir IV-type monolayer adsorption. After the adsorption of Congo red, magnetic separation shows superior efficiency. Furthermore, treatment of the adsorbed composite with EDTA allows for recycling, with adsorption rates still above 91% after three cycles, indicating an excellent regeneration capability.