Dye Effluent Research Articles

Green synthesis of Co3O4 nanoparticles using spent coffee: Application in catalytic and photocatalytic dye degradation

Clean water is vital for societal progress, however, the pollution caused by dyes presents a significant global challenge. Dye-contaminated industrial effluent overwhelms wastewater treatment facilities, causing harm to water bodies and ecosystems. This study demonstrates the synthesis of Co3O4 nanoparticles using spent coffee extract as a bioreducing agent and its application in dye degradation. The structural and optical properties of nanostructures were confirmed using X-ray diffraction (XRD), Transmission Electron Microscopy (TEM), and UV–vis spectroscopy. The Co3O4-activated peroxymonosulfate (PMS) system exhibited exceptional catalytic efficiency by attaining a degradation rate of 89.27 % for Tartrazine dye within a 30-minute timeframe, even in the absence of illumination. When exposed to simulated visible light, the degradation kinetic rate increased by 37.60 %, highlighting the excellent photocatalytic activity of Co3O4 nanoparticles. Furthermore, leveraging natural sunlight led to a notable Tartrazine degradation rate of 97.11 %, signifying a substantial 45.41 % enhancement in reaction efficiency when contrasted with the conventional Co3O4/PMS system. Lastly, the Co3O4 nanoparticles illustrated remarkable degradation of synthetic industrial dye effluents (Tartrazine, Methyl Orange, and Remazol Brilliant Red), reaching up to 92.77 % removal, indicating its potential for use in real-world scenarios.

Synthesis of different types of nano-hydroxyapatites for efficient photocatalytic degradation of textile dye (Congo red): a crystallographic characterization.

The textile industry, a vital economic force in developing nations, faces significant challenges including the release of undesired dye effluents, posing potential health and environmental risks which need to be minimized with the aid of sustainable materials. This study focuses on the photocatalytic potential of hydroxyapatite together with different dopants like titanium-di-oxide (TiO2) and zinc oxide (ZnO). Here, we synthesized hydroxyapatite (HAp) using different calcium sources (calcium hydroxide, calcium carbonate) and phosphorous sources (phosphoric acid, diammonium hydrogen phosphate) precursors through a wet chemical precipitation technique. Pure and doped HAp were characterized via different technologies, which consist of X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), as well as UV-vis spectroscopy. The effectiveness of the synthesized photocatalyst was evaluated by its interactivity with synthetic azo dyes (Congo red). The photodegradation of Ca(OH)2_HAp, CaCO3_HAp, ZnO-doped HAp as well as TiO2-doped HAp, were obtained as 89%, 91%, 86%, and 91%, respectively. Furthermore, at neutral pH, TiO2-doped HAp shows the highest degradation (86%), whereas ZnO-doped HAp possesses the lowest degradation (73%). Additionally, various XRD models (Monshi-Scherrer's, Williamson-Hall, and Halder-Wagner methods) were employed to study crystallite dimension.

Water pollution remediation: Synthesis and characterization of poly(o‐methylaniline)/ZnO/rGO composite for photocatalytic degradation of dyes

AbstractWater pollution is growing at an alarming rate, particularly due to the colored wastewater released by the various industries into aquifers and fresh water sources, and in some extreme cases, they have reached the water table. Faisalabad, a city in Pakistan where there is an industrial cluster of textiles dyeing and manufacturers, water table has become undrinkable. The presence of hazardous dyes and chemicals imposes serious health issues on humans, animals, and plants. The treatment of such toxic dye effluents is crucial and could be done by efficient degradation methods such as photocatalysis. The current study presents synthesis of poly(o‐methylaniline)/zinc oxide/reduced graphene oxide nanocomposite (POMA/ZnO/rGO NC) using a chemical oxidative polymerization process and explores its properties as a photocatalyst by demonstrating degradation of three dyes. The composite was characterized using X‐ray diffraction (XRD), Fourier‐transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), photoluminescence emission spectroscopy (PL), Brunauer Emmett–Teller analysis (BET), and UV–visible spectroscopy (UV–visible). Further, the photocatalytic activity of POMA/ZnO/rGO NC was evaluated and compared by degrading the direct yellow 12 (DY 12), congo red (CR), and malachite green (MG) dyes in aqueous media under UV irradiation. The results indicated that after 110 min, POMA/ZnO/rGO composite degraded the dyes by 92% (DY 12), 86.1% (CR), and 82.1% (MG), respectively. Moreover, kinetic studies of the photocatalyst were also performed along with reusability test, total organic carbon, chemical oxygen demand, and degradation mechanism.

Green ternary composite of graphitic carbon nitride/TiO2/ polyorthoanisidine for the enhanced photocatalytic treatment of Direct Red 28 for industrial water treatment solutions.

Industrial dye effluent causes significant risks to the environment. The present study was focused on photocatalytic degradation of the dye Direct Red 28 using a ternary composite of graphitic carbon nitride, TiO2, and polyorthoanisidine (g-C3N4/TiO2/POA), prepared by in-situ oxidative polymerization o-anisidine. The synthesized composite g-C3N4/TiO2/POA properties were characterized using different analytical techniques. X-ray diffraction (XRD) results revealed the prominent pattern of TiO2 and g-C3N4 in the composite peak at 2θ° while Fourier transform infrared (FTIR) results provided the confirmation peaks for g-C3N4/TiO2/POA and POA at 1,110cm-1 and 1,084cm-1 for C-O-C ether. Scanning electron microscopy (SEM) demonstrated an increase in the average size of the composite up to 428nm. The energy-dispersive X-ray spectroscopy (EDX) spectrum provided the weight percentages of the C, O, and Ti in the composite were 8.5%, 45.69%, and 45.81%, respectively. The photocatalytic degradation of Direct Red 28 dye under UV irradiation using a composite showed that 86% Direct Red 28 dye was degraded by a 30mg/L dose of g-C3N4/TiO2/POA in 240min at pH 2. After four consecutive cycles, the utilized composite showed 79% degradation of Direct Red 28, demonstrating the stability and effectiveness of the g-C3N4/TiO2/POA photocatalyst. The high reusability and efficiency of the g-C3N4/TiO2/POA composite are due to increased light absorption range and reduced e-/h+ recombination rate in the presence of g-C3N4 and POA.

Photocatalytic and Antimicrobial Properties of ZnO and Mg-Doped ZnO Nanoparticles Synthesized Using Lupinus albus Leaf Extract.

Dye effluents discharged from various industries contribute to environmental contamination, making their treatment highly necessary. Infectious diseases also pose a threat to public health worldwide. Nanomaterials have promising features and are potential candidates for overcoming the problems of drug resistance in microbes and environmental pollution. Therefore, this study aimed to synthesize zinc oxide (ZnO) and magnesium-doped zinc oxide (Mg-doped ZnO) nanoparticles (NPs) using the plant extract of Lupinus albus for applications in photocatalysis and antimicrobial activity. A sample of Lupinus albus leaves was collected from Motta, in the eastern Gojjam zone of Ethiopia. The leaves were air-dried and then ground into a powder. The powdered plant material was extracted using distilled water. The ZnO and Mg-doped ZnO NPs were synthesized using 0.1 M Zn(NO3)2·6H2O, 7.5% 0.1 M Mg(NO3)2.6H2O, and 10 mL of the leaf extract. The nanoparticles (NPs) were characterized using UV-vis, FT-IR, XRD, and SEM. The average crystallite sizes of ZnO and Mg-doped ZnO NPs were determined using the Debye-Scherrer formula and were found to be 28.1 and 34.4 nm, respectively. The antimicrobial activity of the synthesized NPs was evaluated against four bacterial strains (Escherichia coli, Bacillus cereus, Salmonella typhi, and Staphylococcus aureus) and one fungal strain (Candida albicans) by using the agar disk diffusion method. The Mg-doped ZnO NPs exhibited significant antimicrobial activity, with a maximum zone of inhibition measuring 24 and 22 mm against Escherichia coli and Salmonella typhi, respectively. The photocatalytic activity of ZnO and Mg-doped ZnO NPs was investigated by studying the degradation of methylene blue (MB) dye under sunlight irradiation for 120 min. The results showed that Mg-doped ZnO NPs exhibited higher photocatalytic activity (99.6%) than ZnO NPs (94.1%). In conclusion, the synthesized NPs could serve as viable alternatives for antimicrobial drugs and photocatalysts to mitigate the pollution of the environment caused by organic dyes.

An all-in-one aPAN/MXene@Ag–Ag2S nanofibrous aerogel for efficient oil/water separation, solar interfacial evaporation and photocatalytic degradation of high-concentration dyes

An ‘all-in-one’ aPAN/MXene@Ag–Ag2S aerogel with combined oil/water separation, solar interfacial evaporation, and photodegradation capacities was developed for efficiently purifying high-concentration dyeing effluents under natural sunlight.

Mangosteen pericarp extract mediated synthesis of Ag/TiO2 nanocomposite and its application on organic pollutant degradation by adsorption-photocatalytic activity

Herein, Ag/TiO2 nanocomposite was synthesized via a green chemistry approach, which is an eco-friendly, simple, and cost-effective method involving mangosteen pericarp extract as a reducing agent. The as-prepared nanocomposites were characterized using X-ray powder diffraction (XRD), Fourier transformation infrared spectroscopy (FT-IR), UV-Vis spectrophotometer, Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDS), Transmission electron microscopy (TEM), Zeta potential measurement, and nitrogen (N2) adsorption-desorption analysis. The performance of Ag/TiO2 nanocomposite was examined by degradation of methylene blue (MB) dye as a model of organic pollutant. The dye degradation using the Ag/TiO2 nanocomposite containing 45 mM of Ag revealed the high MB degradation, which is 85.77 % after 30 min under dark condition. Furthermore, complete degradation of 96.76 % was achieved after 2 h under visible light irradiation. In contrast, bare TiO2 only achieved 41.45 % after 30 min dark and 2 h visible light irradiation. This increase in degradation efficiency can be attributed to the adsorption process and the enhanced light absorption resulting from the localized surface plasmon resonance (LSPR) effect of Ag. Therefore, the green-synthesized Ag/TiO2 nanocomposite has great potential as an integrated adsorbent photocatalyst materials for remediating organic pollutants in dye effluents.

Phytotoxic and electrochemical properties of mixed Cu-Ni cobaltite nanoflowers: Environmental and energy storage applications

Herein, the flower-like mixed Cu-Ni cobaltite spinels Cu1−xNixCo2O4 (x = 0, 0.05, 0.15, and 0.25) were successfully synthesized via simple hydrothermal approach followed by annealing process. Copper cobaltite flowers were characterized using XPS, XRD, FT-IR, SEM, TEM, EDAX, BET, and UV–Vis analysis. The photodegradation efficiency (PDE) of the cobaltite photocatalysts was determined by the degradation of rhodamine 6 G (Rh6G), methylene green (MG), and mixed dye effluents (Rh6G+MG, 1:1 v/v) upon visible-light radiation. The PDE of the CNC 3 catalyst was found to be 90%, 83%, and 86% for degradation of Rh6G, MG, and mixed dye effluents, respectively, and it retained 87% of photocatalytic efficiency even after four cycles. The phytotoxic analysis of control, untreated, and treated Rh6G dye solutions was examined in Phaseolus vulgaris for real-time applications. The electrochemical characteristic was investigated by CV, GCD, and EIS. The CNC 3 electrode showed excellent electrochemical performance (315 Fg−1 at 0.5 Ag−1), and the capacity reached 93% of its initial capacitance after 3000 cycles. The b values of oxidative and reductive currents were determined to be 0.67 and 0.68, respectively. The capacitance contribution was 56% at 10 mVs−1, indicating a mixture of surface capacitive and diffusion controlled behavior in charge/discharge processes. The two-electrode symmetric cell was fabricated using CNC 3 as the positive and negative electrodes for real-life applications. CNC 3 cell delivered a significant energy density (13.47 Wh/kg) and a power density (251.01 W/kg) at 0.5 Ag−1.

Treatment of textile effluent by using Burflower tree (Neolamarckia cadamba) leaf powder: Batch biosorption study

The textile industry is one of the leading causes of major environmental problems worldwide. The textile dye effluents hold diverse kinds of dyes along with other contaminants. Various environmental legislations have been formulated and obligate the textile industries to treat the effluents prior to discharge into water bodies. The present study aimed to evaluate the efficacy of removing two dyes, Congo red and Methylene blue, present in raw textile effluent by employing the powdered leaves of the Burflower (Neolamarckia cadamba) tree as adsorbent. The experiment was performed in a laboratory scale. The surface characterization of the adsorbent was carried out using Brunauer-Emmett-Teller (BET) surface area analysis, CHN elemental analyzer, FTIR and SEM-EDX analyses. The effluent was characterised before and after the biosorption process to check the efficiency of the process on the various parameters of the effluent. The values of the examined parameters were found to be decreased after the adsorption process. The removal percentages of the two dyes (Congo red = 76.35% and Methylene blue = 85.8%) using the adsorbent were also estimated by batch experiment studies. The findings of this study infer that the adsorbent as mentioned above, can be used to treat dye effluents.

Microbial communities drive flux of acid orange 7 and crystal violet dyes in water-sediment system

Unchecked dye effluent discharge poses escalating environmental and economic concerns, especially in developing nations. While dyes are well-recognized water pollutants, the mechanisms of their environmental spread are least understood. Therefore, the present study examines the partitioning of Acid Orange 7 (AO7) and Crystal Violet (CV) dyes using water-sediment microcosms and reports that native microbes significantly affect AO7 decolorization and transfer. Both dyes transition from infused to pristine matrices, reaching equilibrium in a fortnight. While microbes influence CV partitioning, their role in decolorization is minimal, emphasizing their varied impact on the environmental fate of dyes. Metagenomic analyses reveal contrasting microbial composition between control and AO7-infused samples. Control water samples displayed a dominance of Proteobacteria (62%), Firmicutes (24%), and Bacteroidetes (9%). However, AO7 exposure led to Proteobacteria reducing to 57% and Bacteroidetes to 3%, with Firmicutes increasing to 34%. Sediment samples, primarily comprising Firmicutes (47%) and Proteobacteria (39%), shifted post-AO7 exposure: Proteobacteria increased to 53%, and Firmicutes dropped to 38%. At the genus level, water samples dominated by Niveispirillum (34%) declined after AO7 exposure, while Bacillus and Pseudomonas increased. Notably, Serratia and Sphingomonas, known for azo dye degradation, rose post-exposure, hinting at their role in AO7 decolorization. Conversely, sediment samples showed a decrease in the growth of Bacillus and an increase in that of Pseudomonas and Serratia. These findings emphasize the significant role of microbial communities in determining the environmental fate of dyes, providing insights on its environmental implications and management.

Isolation and Characterization of Dye Decolorizing Bacteria from The Textile Dye Effluents

The most significant challenge confronted by the textile industries is the discharge of dye effluents which contains toxic chemicals posing a considerable threat to environmental pollution. Biological method of treating effluents using bacteria is one of the renewed and accepted method in effluent treatment. The present study aims to isolate and characterise the dye decolorizing bacteria from the effluent samples of a dye industry from Chinnalapatti, Tamilnadu. The dye effluents were collected from the effluent plant of a leading dye industry and the Physiochemical parameters were analysed. The samples were plated in a Nutrient Agar and bacterial isolation were performed according to the standard microbiological procedures. The bacterial isolates identified by biochemical identification were tested for its efficiency to decolorize Methyl red and crystal violet dyes. Among the three isolates S1showed 98% decolorizing efficiency in reducing Methyl red dye and 92% efficiency in decolorizing crystal violet dye. Sample S2 showed 85% activity in decolorizing methyl red dye and 86% activity in decolorising Crystal violet dye. S3 showed a low decolorizing activity compared to S1 and S2. Both of these phenotypically identified isolates are subjected to molecular identification by 16s gene amplification and gene sequencing. The obtained FASTA sequence were analysed for the phylogenetic relationship and submitted to NCBI. The potential isolate that has the capacity to decolorise the dyes were identified as Bacillus Tropicus and Pseudomonas mosselli. This study proves that these bacterial strains can be used as a potential bioremediation agent in decolorizing the dye effluents.

Fabrication of coconut shell activated carbon filter system for removal of colour and pollutants in textile dye effluent

The present study evaluates the Decolorization and pollutant removal efficiency of chemically impregnated coconut shell-activated carbon using textile dye effluent in the filtration system. The coconut shell zinc chloride activated carbon (CSZAC) was used as a filtering media in wastewater treatment due to its wider pore space with better surface area (590.80 m2 g−1) and higher adsorption capacity. The SEM micrograph revealed that the activated carbon had networks of parallel running pores with internal microstructure and more active sites. The designed activated carbon filter system has dimensions of 90 x 60 x 30 cm; the sections included are the holding tank (50 liters capacity), filtration tank and storage tank with the optimized flow rate of 5 x 10−4 m3 min−1. The Color, pH, EC, TDS, TSS, BOD and COD of textile dyeing wastewater were significantly reduced, after the treatment through the CSZAC filtration system. The initial color concentration of textile dye effluent was 7021 HU and after treatment, the color was fully reduced and became colorless. CSZAC treatment reduced the BOD from 600 mg L−1 to 89.7 mg L−1 (80.6 per cent) and COD from 2500 mg L−1 to 205 mg L−1 (90.5 per cent). Therefore, CSZAC can be used as an effective adsorbent material to remove different dye compounds and pollutants from textile wastewater.

Treatability Study on Textile Wastewater using Water Hyacinth Bioadsorbent

Textile dye effluent consists of dye colour and other harmful organics has been a major problem to the Environment due to Industrial development. The most effective adsorption in textile dye wastewater is attained by using commercially activated carbon. The creation of adsorbent, which may be utilized as an alternative, inexpensive method of treating the dye produced during the textile manufacturing process, can benefit greatly from agricultural wastes. In this study, the characterization of the textile dye waste water sample was done and the adsorptive capacity of Water hyacinth biochar in the COD,TDS, TSS removal of textile dye wastewater was studied. Water hyacinth biochar is used as the adsorbent in investigations using batch adsorption. COD values were determined through back titration before adsorption process and after the adsorption process to ascertain whether water hyacinth biochar is helpful at lowering COD of wastewater from textile dyes. Adsorbent dose, contact time, and agitation speed were some of the adsorption parameters that were varied during the adsorption investigation. The reduction of COD, TSS and TDS due to adsorption was found to effective. Hence, the study demonstrated a successful application of Water hyacinth biochar as a promising long-lasting adsorbent for cleaning out impurities from effluent from textile dyeing.

Treatment of waste using waste-derived materials and free energy: A practical concept of circular-economy

Controlling industrial effluent and treating it with improvised technologies continues to be a dominant research topic in the scientific community. In this study, the concepts of circular-economy and control-of-waste-by-waste were applied to the synthesis of a photocatalyst composite composed entirely of waste resources, namely waste rust (Fe2O3) and seashells (CaO). The ratio of these two waste materials was optimized to yield a composition 10% Fe2O3/90% CaO (10-FC) that was effective in decolorizing 85% of methylene blue in 60 min, with a formal quantum efficiency of 0.27% in direct sunlight. The heterogeneous photocatalyst was characterized by UV–Vis/NIR, SEM and XRD and is proposed to follow Langmuir-Hinshelwood kinetics and Z-scheme mechanism of charge transfer. Here, waste products were integrated and utilized to create a resource that is recommended for the treatment of dye effluent using a renewable energy source. This research aims to identify elements present in waste dumps and create a valuable resource from them to promote sustainable practices.

Biodegradation Assay of Heavy Metals and Dyes Decolorization in Textile Industrial Effluent using Laccase Isolated from Pleurotus ostreatus

This study focused on the isolation of laccase enzyme from the fungus Pleurotus ostreatus and its application in the biodegradation of various pollutants present in textile industrial effluent, including chemicals, ions, salts, heavy metals, brittle metals, total suspended solids, total dissolved solids, chemical oxygen demand, biological oxygen demand, minerals, total hardness, total alkalinity, turbidity, electrical conductivity, and dyes. Textile industrial effluent poses a significant threat to the environment, contaminating water bodies and posing risks to human, animal, and plant life. This study employed an economical and ecofriendly biological approach for wastewater treatment, distinguishing it from traditional physical and chemical methods. The optimum temperature of laccase is found to be 30 degree Celsius and pH is 3. Enzyme activity of laccase is 7.25 U/ml. This fugal laccase decolorizes textile Industrial dye effluent containing various dyes, such as Turquoise VG, Black B, Yellow R, Methyl red, Trypan blue, and Acid Orange 7. Laccase depicts maximum decolorization efficacy on Black B dye. Similarly, Laccase from P.ostreatus shows higher decolorization efficacy when compared to other fungal laccase. Additionally, the study assessed the biodegradation of various wastewater quality parameters, including physical and chemical parameters like toxic heavy metals and ions. This research of isolation, characterization, and utilizing laccase from P. ostreatus for the bioremediation of textile industrial effluent wastewater containing dyes, toxic chemicals, ions and metals is effective, economical and ecofriendly.

New Methyl Methacrylate Derived Adsorbents - Synthesis, Characterization and Adsorptive Removal of Toxic Organic Compounds.

This study aimed to synthesize polymeric adsorbents by suspension polymerization using methyl methacrylate (MMA) with different crosslinking monomers. Divinylbenzene (DVB) and aliphatic monomers: ethylene glycol dimethacrylate (EGDMA) or N,N'-methylenebisacrylamide (NN) containing additional amide groups were used. The possibility of using the prepared copolymers (MMA-NN, MMA-EGDMA, MMA-DVB) as adsorbents for the removal of toxic compounds such as dyes (C.I. Acid Red 18 (AR18), C.I. Acid Green 16 (AG16), C.I. Acid Violet 1 (AV1), C.I. Basic Yellow 2 (BY2), C.I. Basic Blue 3 (BB3) and C.I. Basic Red 46 (BR46)) and phenol (PhOH) from dye baths and effluents was evaluated. Preferential adsorption of basic-type dyes compared to acid-type dyes or phenol was observed by the polymers. Adsorbent based on MMA-EGDMA exhibited the highest capacity for investigated dyes and phenol. The pseudo-second order kinetic model as well as the intraparticle diffusion model can find application in predicting sorption kinetics. Based on the equilibrium sorption data fitted to the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich model, uptake of BB3, AV1 and PhOH is rather physisorption than chemisorption. The regeneration yield of MMA-EGDMA does not exceed 60 % using 1 M HCl, 1 M NaCl, and 1 M NaOH in 50 %v/v methanol.

Facile synthesis of ZnO/CeO2/CeFeO3 photocatalysts sensitive to visible light with tandem n-n heterojunctions and improved performance towards tetracycline and dye effluent removals

Nowadays, ZnO-based photocatalysts are very effective in wastewater treatment. Herein, CeO2 and CeFeO3 nanoparticles were anchored on ZnO through a coprecipitation-calcination procedure. The fabricated materials were studied by TEM, EDX, SEM, XRD, HRTEM, XPS, PL, UV–vis DRS, BET, BJH, FTIR, and EIS analyses. The optimized ZnO/CeO2/CeFeO3 nanocomposite showed significant performance for the degradation of tetracycline hydrochloride, amoxicillin, Congo red, and Fuchsine with rate constants of 313 × 10−4, 104 × 10−4, 204 × 10−4, and 163 × 10−4 min−1, which was 24.1, 1.44, 20.4, and 2.03 times higher than ZnO, respectively. Moreover, the reduction of Cr(VI) to Cr(III) (189 × 10−4 min−1) over the ZnO/CeO2/CeFeO3 photocatalyst was almost 2.12 times faster than the ZnO photocatalyst (88.7 × 10−4 min−1). Besides, the photocatalyst presented remarkable stability after four cycles in the photodegradation of tetracycline hydrochloride contaminant. The purified solution over the photocatalyst was also tested in terms of biocompatibility. The optical, electrochemical, and textural analyses attributed the enhanced activity to the effective production and separation of charge carriers, facile transfer of electron/hole pairs, and promoted textural characteristics. The enhanced charge segregation was ascribed to the developing tandem n-n heterojunctions among ZnO, CeO2, and CeFeO3.

Development of an antimicrobial inorganic polymer based on fly ash and metakaolin incorporated by nano-TiO2 for reactive dye removal

Advanced and eco-friendly construction materials are being developed to reduce pollution and improve wastewater treatment efficiency. One such material is a photocatalytic nanocomposite that uses industrial wastes and natural substances to eliminate pollution. A recent study explored using an inorganic polymer composite (FM) made from a mixture of 70% fly ash and 30% metakaolin, with sodium hydroxide and sodium silicate as an alkali activator. The study evaluated the mechanical and hydration characteristics of the FM composite after 28 days in 100% humidity at room temperature. The study also examined the effect of adding 2.5 wt.% of Nano-TiO2 to FM composite and how it affects its properties. Results indicate that adding Nano-TiO2 to FM composite enhances its mechanical, antibacterial, and photocatalytic capabilities. Specifically, FM-TiO2 composite showed 90% removal of reactive blue 19 dye effluent in sunlight after 90 min, making it an excellent choice for sustainable wastewater treatment. This study presents a cost-effective, eco-friendly solution to wastewater treatment, with added antimicrobial properties from Nano-TiO2.

Toxicity of Beauty Salon Effluents Contaminated with Hair Dye on Aquatic Organisms.

Cosmetic residues have been found in water resources, especially trace elements of precursors, couplers, and pigments of hair dyes, which are indiscriminately disposed of in the sewage system. These contaminants are persistent, bioactive, and bioaccumulative, and may pose risks to living beings. Thus, the present study assessed the ecotoxicity of two types of effluents generated in beauty salons after the hair dyeing process. The toxicity of effluent derived from capillary washing with water, shampoo, and conditioner (complete effluent-CE) and effluent not associated with these products (dye effluent-DE) was evaluated by tests carried out with the aquatic organisms Artemia salina, Daphnia similis, and Danio rerio. The bioindicators were exposed to pure samples and different dilutions of both effluents. The results showed toxicity in D. similis (CE50 of 3.43% and 0.54% for CE and DE, respectively); A. salina (LC50 8.327% and 3.874% for CE and DE, respectively); and D. rerio (LC50 of 4.25-4.59% and 7.33-8.18% for CE and DE, respectively). Given these results, we can infer that hair dyes, even at low concentrations, have a high toxic potential for aquatic biota, as they induced deleterious effects in all tested bioindicators.

Fabrication of visible-light induced fluorine doped bismuth oxide (Bi2O3-xFx) photocatalyst in degrading textile dyes from wastewater

Discharge of unused and untreated dye effluents into the environment by the textile industries is a major issue. In this wastewater, the methylene blue (MB) and methyl orange (MO) remain in a dissolved state along with various pollutants at different levels. To remove these dyes, visible light (λ ​≥ ​420 ​nm) active F (fluorine) doped bismuth oxide (Bi2O3-xFx) photocatalyst was synthesized through facile sol-gel method utilizing bismuth oxide (Bi2O3) and hydrofluoric acid (HF). Bi2O3-xFx demonstrated enhanced photocatalytic activity to decompose methylene blue (MB) and methyl orange (MO) under visible light. The F content in Bi2O3-xFx composite was optimized to 0.94 atom % with respect to organics decomposition. The study showed that enhanced photocatalytic activity of Bi2O3-xFx was ascribed due to participation of photo-induced electron (e¯)-hole (h+) in photocatalysis. The existence of hole (h+) and the generated °OH radical was experimentally confirmed in aqueous medium. The formation mechanism of these reactive species was explained on the basis of relative energy band position of Bi2O3-xFx and a detail photocatalytic decomposition reaction mechanism was proposed.