Textile Dye Research Articles

Evaluation of blue textile dye decolorization by immobilized polyphenol oxidase using pumice stone under optimum conditions

Industrial dyes are major pollutants in wastewater and river water with an initial visible concentration of 1 mg/L. Recent studies have shown the possibility of using polyphenol oxidase in catalytic biological treatment due to its ability to oxidize a large number of dyes and pollutants in wastewater and the flexibility to work in wide ranges of temperature, pH and salinity. It is easy availability as well as the low economic cost resulting from its use in biological treatments, this enzyme polyphenol oxidase was used. The findings in this study showed that the extraction of polyphenol oxidase (PPO) from potato peel was homogenized with potassium phosphate buffer (0.1 M, pH 7) at a ratio of 1:10 (weight: volume) for two min. The result of enzyme purification by ion exchange chromatography showed that the yield of this step was 64 % and the specific activity was 6541.67 U/mg. The polyphenol oxidase was immobilized covalently on the functionalized pumice stone (25.2 U/gm) compared with other methods. The characterization results demonstrated that the optimum pH for immobilized and free enzyme activity was 6.0 while the pH range of free and immobilized polyphenol oxidase stability was from 4.5 -7.0 and 3.5 - 8.5 respectively. The better temperature for free and immobilized polyphenol oxidase activity was 25 ºC, whereas the free and immobilized polyphenol oxidase was stable at 15-35 and 15-50 °C respectively. The outcomes showed that the decolorization efficiency of blue textile dye employing immobilized polyphenol oxidase reached 99.85 % after 24 hr. for 100 mg/L concentration while for other concentrations 200, 300, 400, 500 and 1000 mg/L the decolorization efficiencies were 85.96, 76.15, 72.54, 66.94 and 63.5 % respectively. Based on the results, the immobilized polyphenol oxidase on pumice stone is highly efficient in removing textile dyes at large concentrations and in different environmental conditions.

EXPLOITING ECO-FRIENDLY NATURAL DYES FROM PLANT SOURCES: EXTRACTION AND DIVERSE APPLICATIONS

Natural pigments extracted from plant sources offer eco-friendly and sustainable alternatives to synthetic colorants. In this study, pigment samples were obtained through aqueous extraction from beetroot (S1), red cabbage (S2), and turmeric (S3). Their physicochemical properties and potential applications were thoroughly evaluated. The research problem addressed in this study is the need to overcome the limitations of natural dyes, such a slower color fastness, reduced reproducibility, and limited color range, in order to promote their wider adoption in various industries as sustainable alternatives to synthetic colorants. The pigment extracts were assessed for their suitability in textile dyeing, paper pH indicators, food coloring, ink production, and natural stamp pad formulations. Cotton and wool fabrics were dyed by adding traditional mordants, and the pigment-treated textiles exhibited distinctive color changes and varying levels of color fastness. The pigment samples demonstrated the ability to act as effective acid-base indicators, displaying characteristic color transitions in response to varying pH levels. When used as natural food colorants, the extracts imparted attractive hues to rice and cream without altering their flavor profiles. The feasibility of incorporating these plant-derived pigments in ink manufacturing and stamp pad production was also explored. Beetroot pigment exhibited superior color retention and fastness properties, while red cabbage and turmeric extracts displayed effectiveness in selected applications. The findings of this comprehensive study highlight the viability of these plant sources as natural substitutes for synthetic colorants in diverse fields. The observed performance characteristics and the eco-friendly nature of the pigments underscore their potential to serve as sustainable alternatives in various industries.

A Novel Sensing Method to Detect Malachite Green Contaminant on Silicon Substrate Using Nonlinear Optics.

We propose a nonlinear-optics-based nanosensor to detect malachite green (MG) contaminants on semiconductor interfaces such as silicon (Si). Applying the simplified bond hyperpolarizability model (SBHM), we simplified the second-harmonic generation (SHG) analysis of an MG-Si(111) surface and were able to validate our model by reproducing experimental rotational anisotropy (RA) SHG experiments. For the first time, density functional theory (DFT) calculations using ultrasoft pseudopotentials were implemented to obtain the molecular configuration and bond vector orientation required by the SBHM to investigate and predict the second-harmonic generation contribution for an MG-Si 001 surface. We show that the SBHM model significantly reduces the number of independent components in the nonlinear tensor of the MG-Si(111) interface, opening up the possibility for real-time and non-destructive contaminant detection at the nanoscale. In addition, we derive an explicit formula for the SHG far field, demonstrating its applicability for various input polarization angles. Finally, an RASHG signal can be enhanced through a simulated photonic crystal cavity up to 4000 times for more sensitivity of detection. Our work can stimulate more exploration using nonlinear optical methods to detect and analyze surface-bound contaminants, which is beneficial for environmental monitoring, especially for mitigating pollution from textile dyes, and underscores the role of nonlinear optics in real-time ambient-condition applications.

Research Progress of Printing and Dyeing Wastewater Treatment

In the textile industry, printing and dyeing technology, as an essential technical basis, produces a lot of printing and dyeing wastewater (PDW) that jeopardizes the ecological environment and human health. PDW generally has the characteristics of large discharge, high chromaticity, strong toxicity, strong alkalinity, complex componentization, poor biodegradability, large fluctuations in water quality and quality, and high content of organic pollutants, belonging to the type of industrial wastewater that is difficult to manage. In this paper, the current research progress of PDW treatment technology from the aspects of physical technology, chemical technology, and biological technology are reviewed. In addition, measures to reduce the damage caused by printing and dyeing wastewater from three perspectives: treatment principle, processes, advantages, and disadvantages are discussed, which provides a reference point for the treatment of printing and dyeing wastewater. It is worth noting that the article reviews the ABS system, which is gaining attention as an emerging technology under biological technology. The purpose of this paper is to provide a reference basis for the selection and application of technology, and then promote the innovation and development of printing and dyeing wastewater treatment technology.

Preparation and Characterization of Acid and Base Modified Fish Scales of Labeo Rohita and Their Application as an Adsorbent

The study is carried out to investigate the removal efficiency of the textile dye Congo Red (CR) on fish scales (FS) of Labeo rohita. Huge fish scales are dumped as waste from the fish markets and are not converted into valuable products. That is why a fish scale of widespread fish in Bangladesh Labeo rohita has been selected as an adsorbent in removing Congo red from an aqueous solution. In the present study, the effect of different parameters such as adsorption dosage, contact time, concentration of dye, and pH on the removal of CR were investigated. The maximum dye removal efficiency (88.53 %) was observed for 3g/100 mL of adsorbent at an initial concentration of 1×10-4 M and pH 8.80 after 60 minutes. Modification of the surface of the fish scales was carried out by using HCl and KOH. The surface of the adsorbents was characterized by FTIR spectroscopy. After 60 minutes of contact time, the percentage of adsorption for the acid and base-modified FS was 54.81% and 90.51% respectively. The higher intense FTIR spectra of the base-modified FS denoted the better efficiency of the adsorbent at the basic medium. The adsorption kinetics of CR on FS is studied by following the pseudo-first-order and pseudo-second-order kinetic model. Experimental results showed that fish scales of Labeo rohita have satisfying color removal efficiency and might be a better alternative to other adsorbents to detoxify industrial wastewater. A mechanism of adsorption of CR on FS has been proposed.

Synthesis of metal(II) acetate complexes with a heterocyclic azo dye ligand: Characterization, geometrical molecular structures, antioxidant, biological activities, DNA binding and molecular docking studies

A series of Cu(II), Co(II), Ni(II), Mn(II), and UO2(II) complexes have been prepared from the ligand 4-(2’,4’-dihydroxybenzaldehyde phenylazo)antipyrine (H2L). FT-IR spectra demonstrated that the ligand under investigation behaves as a bi-and tridentate centre ligand through the phenolic oxygen of aldehydic, azo nitrogen atoms and carbonyl oxygen of antipyrine and forms a stable five- and six-membered chelating ring. From the X-ray crystallographic analysis (XRD) patterns of the ligand and complexes showed the polycrystalline phases are indicated by the multiple diffraction peaks in the 1igand and its complex (5). The HOMO‒LUMO energy gaps (∆E) were used to create theoretical models for the structure and confirmation barriers in molecular systems for the ligand (H2L) and metal complexes. It was found that the Cu(II), Co(II), Ni(II), and Mn(II) complexes have lower values for HOMO‒LUMO energy gaps (∆E), indicating that they are more stable than the 1igand. The biological activities of ligand (H2L) and its metal complexes showed that ligand was stronger antimicrobial and antioxidant agent than its metal complexes. 50 µg/ml H2L caused inhibition zones ranged from 13 to 20 mm against the tested bacteria and 13 to 16 against fungi. In addition, the present study tested metal (II) acetate complexes with a heterocyclic azodye ligand for their application in the textile industry as antimicrobial dyed fabrics. All obtained results confirmed the possibility of using the prepared compounds in different industrial applications. The 1igand (H2L) and its metal complexes showed moderate to strong antimicrobial activities in agar well diffusion, MIC, and antioxidant tests. Ligand and its metal complexes revealed inhibition zones against all tested microbes ranged between 6 to 24 mm. The MIC values of ligand and its metal complexes were recorded at 20 to 30 μg/ml and 30 to 145 μg/ml, respectively. 50 µg/ml of 1igand and its metal complexes was enough to complete inhibit Gram negative E. coli moreover they could inhibit the multidrug resistant bacteria K. pneumoniae and Pseudomonas sp. By molecular docking study, it was found that the complex (1) showed the highest and better binding affinity (-8.38874 and -7.74442 kcal/mol) than other 1igand (H2L) and complexes (2–5) for the breast cancer (3HB5) protein central activity and the colon cancer (2HQ6) protein central activity.

Anaerobic Digestion for Textile Waste Treatment and Valorization

AbstractTextile waste is becoming among the most polluting waste in the world, discarded mostly in landfills. Valorizing textile waste via anaerobic digestion (AD) helps conserve resources, reduce environmental impact, and foster a circular economy. Although several reviews have discussed textile waste AD, there is a lack of detailed understanding of the challenges encountered during textile waste AD. Therefore, the goal of this review is to focus on challenges encountered and possible solutions for those challenges for biogas and fertilizer conversion via AD. Potential strategies include chemical, biological, and thermal pretreatments that significantly increase the digestion process. Co‐digestion of natural textile waste, cotton, and wool with carbon and nitrogen‐rich substrates improves AD efficiency by twofold. Moreover, separating polyester from polycotton and textile dye removal via solvent and advanced oxidation processes significantly increases methane yield compared with untreated textile waste. This review can aid in analyzing suitable methods to optimize the biogas production of textile waste via AD.

Amorphous carbon nanotubes as a potent remover of textile dyes: methylene blue and malachite green

Amorphous carbon nanotubes as a potent remover of textile dyes: methylene blue and malachite green

Leveraging multi-output modelling for CIELAB using colour difference formula towards sustainable textile dyeing

Textile dyeing requires optimizing combinations of ingredients and process parameters to achieve target colour properties. Modelling the complex relationships between these factors and the resulting colour is challenging. In this case, a physics-informed approach for multi-output regression to model CIELAB colour values from dyeing ingredient and process inputs is proposed. Leveraging attention mechanisms and multi-task learning, the model outperforms baseline methods at predicting multiple colour outputs jointly. Specifically, the Transformer model’s attention mechanism captures the complex interactions between dyeing ingredients and process parameters, while the multi-task learning framework exploits the intrinsic correlations among the L*, a*, and b* dimensions of the CIELAB colour space. In addition, the incorporation of physical knowledge through a physics-informed loss function integrates the CMC colour difference formula. This loss function, along with the attention mechanisms, enables the model to learn the nuanced relationships between the dyeing process variables and the final colour output, thereby improving the overall prediction accuracy. This reduces trial-and-error costs and resource waste, contributing to environmental sustainability by minimizing water and energy consumption and chemical emissions.

Occurrence and Ecological Risk Assessment of Highly Toxic Halogenated Byproducts during Chlorination Decolorization of Textile Printing and Dyeing Wastewater.

Textile printing and dyeing wastewater is a substantial source of highly toxic halogenated pollutants because of the chlorination decolorization. However, information on the occurrence and fate of the highly toxic halogenated byproducts, which are produced by chlorination decolorization of the textile printing and dyeing wastewater, is very limited. In this study, the occurrence of six categories of halogenated byproducts (haloacetic acids (HAAs), haloacetonitriles (HANs), N-nitrosamines (NAs), trihalomethanes, halogenated ketones, and halonitromethanes) was investigated along the full-scale treatment processes of textile printing and dyeing wastewater treatment plants. Furthermore, the ecological risk of the halogenated byproducts was evaluated. The results showed that the total concentration of halogenated byproducts increased significantly after chlorination. Large amounts of HAAs (average 122.1 μg/L), HANs (average 80.9 μg/L), THMs (average 48.3 μg/L), and NAs (average 2314.3 ng/L) were found in the chlorinated textile wastewater, and the results showed that the generations of HANs and NAs were positively correlated with the BIX and β/α index, indicating that the HANs and NAs might form from the microbial metabolites. In addition, HAAs and HANs exhibited high ecological risk quotients (>1), suggesting their high potential ecological risk. The results also demonstrated that most halogenated byproducts could be effectively removed by reverse osmosis treatment processes except NAs, with a lower removal rate of 18%. This study is believed to provide an important theoretical basis for controlling and reducing the ecological risks of halogenated byproducts in textile printing and dyeing wastewater effluents.

Sustainable and cost-effective metastable white cast iron powder for the degradation of textile dyes

The textile industry is one of the main consumers of dyes. The treatment of wastewater containing dyes is a major challenge worldwide for a sustainable and environmental friendly goods production. Therefore, it is necessary to develop an effective method for removing the dyes from wastewater. In this study, an economical and efficient white cast iron powder was reported to degrade reactive red 195A azo dye in an aqueous solution. The white cast iron powder was obtained by ball-milling a rapidly solidified cast iron ribbon, exhibiting unique metastable properties and a large surface area. These metastable phases are particularly effective in providing electrons for the dye degradation of NN double bonds, thereby improving the catalytic process, and enhancing the overall bond degradation efficiency. The influence of different parameters such as temperature, dye concentration, and reusability of metallic iron powder on the degradation efficiency was investigated. The experimental analysis revealed rapid and efficient dye degradation that was achieved within 15 min using 0.1 g of white cast iron powder. The study also demonstrated the effectiveness of the degradation rate improved significantly with an increase in temperature. Even after seven recycling experiments, the Fe82C15Si3 powders maintained high degradation efficiency toward the reactive red 195A solutions. This research will contribute to developing a new, highly efficient, and low-cost method for treating organic dye wastewater.

Influence of Different Cow Manure Application Rates on the Growth, Yield and Indigo Blue Color of Indigofera suffruticosa Mill

Background: Indigo is a key ingredient in the natural dyeing of fabrics. However, the conventional use of chemical fertilizers in indigo cultivation has led to an increase in production costs and soil degradation. Low-fertility soils further compromise the growth and yield of indigo plants. To address these challenges, employing manure is recognized as a sustainable approach for indigo cultivation. The use of manure enhances soil nutrient levels, improves soil structure and mitigates production costs. In this study, our objectives were to compare different rates of cow manure in relation to indigo growth, yield and the effect of cow manure rate on the value of indigo blue color. Methods: The experiments were carried out at the Plant Science Field from June to October 2022. Employing a randomized complete block design (RCBD), the study featured four treatments with four replications each. The treatments included: Treatment 1: no fertilizer (control); Treatment 2: cow manure at a rate of 3,125 kg/ha; Treatment 3: cow manure at a rate of 6,250 kg/ha; and Treatment 4: cow manure at a rate of 9,375 kg/ha. Data collection included plant height, canopy width, number of branches, plant weight, indigo blue weight and indigo blue color value. The CIE color system (Commission International de l’Éclairage) determined the color value. Result: The application of cow manure at a rate of 9,375 kg/ha resulted in the highest plant height and canopy width, with the corresponding number of branches of 150.73 cm, 46.45 cm and 31.73 cm, respectively. As compared to the other treatments, these values were statistically different. The color that was associated with the indigo finished product was dark blue and the yield; plant weight and indigo blue weight were recorded as 15,663.44 kg/ha and 2,540.44 kg/ha, respectively. The color value of indigo blue showed that the L* values of 24.94, a* -9.32, b* -2.44 and C* 9.63 were not significant but h* 194.66 was statistically significant.

Green synthesis of zero‐valent copper nanoparticles for removal of D‐yellow 119 textile dye from aqueous medium

AbstractZero‐valent copper nanoparticles (CuNPs) were beneficially green synthesized via Ficus Benjamina leaves. Applying scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT‐IR), Ficus Benjamina nano zero‐valent copper (FB‐nZVCu), an innovative adsorbent, was examined. The obtained zero‐valent CuNPs have a size range of 16–18 nm. The removal of D‐yellow 119 dye from textile wastewater was tested using this novel adsorbent. Many operating parameters were examined and tested to control the adsorbent's maximum removal efficiency. These variables included dye concentration, stirring rate, time, pH, and adsorbent dosage. Different adsorption mechanisms have been tested, and the Langmuir isotherm (qmax = 21.83 mg g−1) and (R2 = 0.9993) represent adequate for the adsorption process. The FB‐nZVCu green adsorbent is a promising material for eliminating D‐yellow 119 from simulated and real samples, according to the data obtained and the fruitful analysis. The impact of different operating factors was examined using IBM SPSS Statistics software. They were shown to be responsible for approximately 94% of the factors influencing the removal process.

Seidlitzia rosmarinus as a multipurpose environmentally friendly alkali in simultaneous dyeing and nanofinishing of polyester fabric: ZnO-NPs synthesis, carrier-free dyeing, and reduction clearing

A multipurpose product could be produced by synthesizing metal oxides and dyeing the fabric. However, to achieve better, cleaner results while consuming less energy, it is ideal to shorten the time and reduce costs by simultaneously creating nanoparticles and dyeing. This work facilitates carrier-free dyeing of polyester fabric and the synthesis of ZnO-NPs using Kelyab as a green alkali. The remarkable results demonstrated reduced bending length, i.e., a softer handle, higher air permeability, and tensile strength, longer resistance in alkaline conditions, and comparable color strength and fastness. Moreover, the after-treatment, the last treatment step on the finished or dyed fabric, pertains to the reduction clearing. It is essential for dyed PET fabric, given its significance in colorimetric characteristics and other fastness attributes, particularly washing. Thus, it is necessary to develop innovative techniques to achieve these objectives without using harmful chemicals. Kelyab, as an environmentally safe reducing agent, produced comparable results to those of the conventional method, especially in color strength. In addition, air plasma was applied as a surface activation and green pre-treatment, resulting in the highest color and tensile strength. The prepared samples were examined using FT-IR, XRD, and FESEM, among other tests. Using fewer chemicals (50% lower) in the reduction clearing, saving time and energy for preparing reduction solution, and lowering the requirement for waste-water treatment in the simultaneous nanosynthesis and dyeing are the novelties of the introduced processing that can replace conventional method in dyeing, post-dyeing, and nanofinishing treatments.

Decolorization of industrial dye wastewater using an underwater non-thermal plasma system

The textile dyeing industry, in its developmental phase, significantly contributes to the discharge of large quantities of organic chemicals into rivers and oceans. Existing water purification technologies have not been effective in mitigating the associated risks. This study presents the development of a novel dielectric barrier discharge (DBD) plasma system aimed at decolorizing industrial dye wastewater through the generation of reactive oxygen species, ultraviolet light, ozone, and hydrogen peroxide. A new electrode configuration has been devised, exhibiting a 1.3-fold increase in energy consumption efficiency compared to conventional DBD plasma systems, facilitated by simultaneous cooling and discharging mechanisms. The proposed system showcases an 80 % reduction in chromaticity and achieves impressive removal performances, with 97 J/L within 1 min for methylene blue and 5527 J/L within 30 min for the treatment of industrial dye wastewater. This innovative DBD system promises to advance industrial wastewater treatment methodologies, potentially safeguarding aquatic ecosystems.

The Application of Wood Biowaste Chemically Modified by Bi2O3 as a Sorbent Material for Wastewater Treatment

Textile dyes discharged into aquatic systems can have significant environmental impacts, causing water pollution and toxicity to aquatic life, and constituting a human health risk. To manage these effects, the sorption ability of wood biowaste chemically modified by Bi2O3 for textile dye removal was investigated. Sorbent characterization was performed using scanning electron microscopy, and elemental analysis by energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), the Brunauer–Emmett–Teller (BET) method for the specific surface area, and Fourier transform infrared spectroscopy–attenuated total reflectance (FTIR-ATR). The optimization of the sorption process was carried out, and optimal parameters, such as contact time, pH, the dose of sorbent, the concentration of dye, and temperature, were defined. Also, desorption studies were conducted. Kinetics and isotherms studies were carried out, and the data fits to a pseudo-second order model (r2 ≥ 0.99) and Langmuir model (r2 ≥ 0.99), indicating that the process occurs in the monolayer form and the dye sorption depends on the active sites of the sorbent surface. The maximal sorption capacity of the sorbent was 434.75 mg/g.

Examining plasma-generated ozone and nitric oxide's role in synthetic textile dye water remediation and ecotoxicological analysis

Synthetic dyes produced by the textile dyeing industry and released into wastewater contribute significantly to water pollution. This study explores the efficacy and versatility of a novel multi-electrode dielectric barrier discharge (MEDBD) plasma system that mainly generates ozone (O3 generator) and nitric oxide (NO generator) selectively to degrade various synthetic textile dyes, namely Methylene Blue (MB), Congo Red (CR), Methyl Orange (MO), Crystal Violet (CV), and Evans Blue (EB). Plasma achieved selective enrichment of O3 and NO by utilizing optimized plasma generation duty cycles of 15% and 100%, respectively. The proposed O3 generator plasma involves plasma-generated aqua electron impact, excited species, and reactive oxygen species notably O3, which degrades synthetic textile dyes into simple forms such as CO2, H2O, and N2. This approach achieved over 95% degradation of the above synthetic textile dyes when employing the O3 enriched plasma with 2.44 ± 0.21 W of power. Ecotoxicological evaluation, including microbial, human cell, and phytotoxicity evaluations of the O3 generator plasma for MB and CR dye-contaminated water, underscored the potential of this plasma system for environmentally friendly dye degradation. Overall, this study promotes MEDBD plasma, particularly the O3 generator, as a sustainable and efficient solution for treating synthetic dye-contaminated water across industries.

The Photocatalytic Activity of TiO2 Nanotube Doped Zn for Methylene Blue Degradation

TiO2 nanotube (TiO2-NT) is one of the promising materials for photocatalytic water remediation. TiO2-NT doped Zn (Zn/TiO2-NT) is synthesized from P25 Degussa via one step hydrothermal method. From XRD and UV-DRS analysis, it showed that Zn as a doping material led to decrease band gap energy and decrease the crystallite size. The best results obtained was Zn/TiO2-NT with a crystallite size of 7.14 nm, and band gap energy value of 3.18 eV. Photocatalytic activity of Zn/TiO2-NT was also tested for photocatalytic activity of textile dye (methylene blue) degradation. During the photocatalytic activity for methylene blue degradation, the Zn/TiO2-NT shows higher activity compared to non-doped sample. The non-doped sample shows degradation activity of 87.72%, meanwhile the Zn/TiO2-NT shows degradation activity of 95.88%.

Functionalization of silk with actinomycins from Streptomyces anulatus BV365 for biomedical applications.

Silk, traditionally acclaimed as the "queen of fiber," has been widely used thanks to its brilliant performance such as gentleness, smoothness and comfortableness. Owing to its mechanical characteristics and biocompatibility silk has a definitive role in biomedical applications, both as fibroin and fabric. In this work, the simultaneous dyeing and functionalization of silk fabric with pigments from Streptomyces anulatus BV365 were investigated. This strain produced high amounts of orange extracellular pigments on mannitol-soy flour agar, identified as actinomycin D, C2 and C3. The application of purified actinomycins in the dyeing of multifiber fabric was assessed. Actinomycins exhibited a high affinity towards protein fibers (silk and wool), but washing durability was maintained only with silk. Acidic condition (pH5) and high temperature (65°C) facilitated the silk dyeing. The morphologies and chemical components of the treated silk fabrics were analyzed using scanning electron microscopy and Fourier transform infrared spectroscopy. The results showed the pigments bind to the silk through interaction with the carbonyl group in silk fibroin rendering the functionalized, yet surface that does not cause skin irritation. The treated silk exhibited a remarkable antibacterial effect, while the biocompatibility test performed with 3D-reconstructed human epidermis model indicated safe biological properties, paving the way for future application of this material in medicine.

Biosynthesis of mechanically recyclable 3D-Cu2O@megacatalyst for Fenton-like catalysis of tetracycline and the mechanistic insights

Treating sewage waters contaminated with persistent organic pollutants (POPs) presents a pressing environmental concern, mandating, affordable, implementable and sustainable remediations. Supported catalysts, wherein metal nanoparticles are grafted onto inert supports to endow porosity, reactant access, performance and catalyst re-use are emerging as sustainable catalytic platforms. Herein, size-controllable, mechanically recyclable 3D-Cu2O@megacatalyst of ∼81 ± 5 cm2, ∼37 ± 3 cm2 and ∼1 ± 0.6 cm2 were biofabricated by exploiting the innate metal binding feature of pristine eggshells. The as-fabricated Cu2O@megacatalyst was utilized for the Fenton-like treatment of POPs, with exceptional activities against diverse molecules: antibiotic (tetracycline (TC)), textile dye (methylene blue) and pharmaceutical precursor (4-nitrophenol) with the degradation efficiencies of 95.6 %, 96.8 % and 93.4 %, respectively. Optimization studies revealed that our megacatalyst can function consistently in the presence of various oxidising agents, free radical scavengers, wide pH, temperatures and inorganic and organic contaminants. The catalyst demonstrated stability and catalytic efficiency in different real-time water matrices: ultrapure water-95.6 %, tap water-84 %, lake water-86 %, and river water-91 %. Furthermore, plausible reaction mechanism and decomposition pathways for TC degradation were assessed using GC-MS, while evaluating the toxicity using ECOSAR and oxygen uptake assay, which revealed less toxic reaction intermediates and end products. Overall, our results provide new insight into the sustainable development of a generalized highly stable, scalable, ultra-efficient and mechanically recyclable Fenton-like supported catalyst for the detoxification of POPs in sewage waters.