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This article focuses on comparing the characteristics of cotton fabric dyed with Diospyros mollis extract (DME) solution and that of cotton fabric dyed with the reactive dye. The parameters of the cotton fabric after dyeing with both types of dyes were assessed, including color strength (K/S), structural morphology, infrared spectrum, antibacterial properties, UV resistance, color fastness to washing, rubbing, light, moisture absorption, breathability, and wastewater indices. The obtained results show that the K/S value of cotton fabric dyed with DME solution is slightly lower than that of cotton fabric dyed with the reactive dye, 18.52 and 19.36, respectively. The cotton fabric dyed with the reactive dye does not exhibit antibacterial activity against Escherichia coli and Staphylococcus aureus, whereas the antibacterial effectiveness against these bacteria for cotton fabric dyed with DME solution is 99.99 %. The UV protection capability of cotton fabric dyed with DME solution is superior to cotton fabric dyed with the reactive dye. The BOD/COD ratio of wastewater from the dyeing process with DME is higher than that of the reactive dye, with values of 0.70 and 0.32, respectively. The findings of this study indicate the superior ability of using DME solution as compared to the reactive dye, which is promising as a natural dye for fabric in medical applications. [ABSTRACT FROM AUTHOR]

The presence of pollutants in water sources, particularly dyes coming by way of the textile industry, represents a major challenge with far-reaching environmental consequences, including increased scarcity. This phenomenon endangers the health of living organisms and the natural system. Numerous biosorbents have been utilized for the removal of dyes from the textile industry. The aim of this study was to optimize discarded Zygophyllum gaetulum stems as constituting an untreated natural biosorbent for the efficient removal of C.I. Direct Black 80, an azo textile dye, from an aqueous solution, thus offering an ecological and low-cost alternative while recovering the waste for reuse. The biosorbent was subjected to a series of characterization analyses: scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET) method, X-ray diffraction (XRD), and infrared spectroscopy (IR) were employed to characterize the biosorbent. Additionally, the moisture and ash content of the plant stem were also examined. The absorption phenomenon was studied for several different parameters including the effect of the absorption time (0 to 360 min), the sorbent mass (3 to 40 g/L), the pH of the solution (3 to 11), the dye concentration (5 to 300 mg/L), and the pH of the zero-charge point (2–12). Thermodynamic studies and desorption studies were also carried out. The results showed that an increase in plant mass from 3 to 40 g/L resulted in a notable enhancement in dye adsorption rates, with an observed rise from 63.96% to 97.08%. The pH at the zero-charge point (pHpzc) was determined to be 7.12. The percentage of dye removal was found to be highest for pH values ≤ 7, with a subsequent decline in removal efficiency as the pH increased. Following an initial increase in the amount of adsorbed dye, equilibrium was reached within 2 h of contact. The kinetic parameters of adsorption were investigated using the pseudo-first-order, pseudo-second-order and Elovich models. The results indicated that the pseudo-first-order kinetic model was the most appropriate for the plant adsorbent. The isotherm parameters were determined using the Langmuir, Frendlich, Temkin, and Dubinin–Radushkevich models. The experimental data were more satisfactory and better fitted using the Langmuir model for the adsorption of dye on the plant. This study demonstrated that Zygophyllum gaetulum stems could be employed as an effective adsorbent for the removal of our organic dye from an aqueous solution. [ABSTRACT FROM AUTHOR]

Cu0.25Zn0.75Fe2O4 MNPs were synthesised by the sol-gel method and their characterisation was investigated by FTIR, XRD, DRS, BET, VSM, FESEM, EDX/Map, and TEM. The XRD pattern confirmed that the prepared nanoparticles are in the cubic phase. The synthesised nanocatalyst was used as a photocatalyst under visible light and at room temperature to remove reactive blue 222 dye as a pollutant. The optimum condition for the degradation reaction was obtained as catalyst amount of 40 mg, time 45 min and RB 222 concentration of 20 mg/L. Due to the magnetic properties of Cu0.25Zn0.75Fe2O4 MNPs, its separation from the solution and its reuse was investigated, which showed very little change in the quality of the catalyst after six uses. The unique features of the catalyst are its environmental friendliness due to its green synthesis, low cost, magnetic properties, high stability and reuse for many times. [ABSTRACT FROM AUTHOR]

Abstract This paper explores the photocatalytic degradation of Reactive Orange 16 (RO16) dye in textile wastewater employing a novel CuO@A-TiO2/Ro-TiO2 nanocomposite. The nanocomposite was synthesized via a hydrothermal technique, resulting in a monoclinic phase of leaf-shaped CuO loaded on a hexagonal wurtzite structure of rod-shaped ZnO, as confirmed by FE-SEM and XRD analyses. Optical experiments revealed band gap energies of 1.99 eV for CuO, 2.19 eV for ZnO, and 3.34 eV for the CuO@A-TiO2/Ro-TiO2 nanocomposite. Photocatalytic degradation experiments showcased complete elimination of a 100 mg/L RO16 solution (150 mL) after 120 min of UV light illumination and 100 min of sunlight illumination, emphasizing the nanocomposite's efficiency under both light sources. The study further delves into the application of the CuO@A-TiO2/Ro-TiO2 nanocomposite for the degradation of actual textile wastewater samples under sunlight irradiation. The results underscore the nanocomposite's remarkable efficacy in treating RO16 in textile wastewater, positioning it as a promising candidate for sustainable and efficient wastewater treatment applications. This research contributes valuable insights into the development of advanced photocatalytic materials for textile dye degradation in wastewater treatment.

The release of the dye Disperse Blue 35 (DB35) into water has serious environmental and health consequences, due to its toxicity and resistance to degradation. This paper investigates the effectiveness of cloud point extraction (CPE) to remove this industrial dye from aqueous solution by Lutensol AO7 and Triton X-114, two environmentally friendly nonionic surfactants. First, the partial phase diagrams of the water–surfactant binary systems are constructed. Then, the effects of pollutants, sodium sulfate and cetyltrimethylammonium bromide on the cloud point temperature (Tc) are determined. The experimental results are expressed by four responses: Extraction efficiency (E), residual concentrations of solute and surfactant in the dilute phase (Xs,w and Xt,w, respectively) and the volume fraction of coacervate (Фc). An empirical smoothing method was applied. For each parameter, the results obtained were modeled using the response surface methodology (RSM) and represented on three-dimensional diagrams. The results show that the efficiency of dye extraction with Lutensol AO7 and Triton X-114 at a concentration of 6 wt% is about 95 % and 82 %, respectively. The influence of salt and ionic surfactant on the effectiveness of CPE for the removal of DB 35 dye was determined. The regeneration of surfactant was only achieved by pH adjustment. [ABSTRACT FROM AUTHOR]

The textile dying industry is one of the most important industrial sectors in Bangladesh. The discharged untreated effluent from different industries adds to the environment a wide variety of harmful chemicals, which cause severe damage to the water. The present study aimed to characterize the discharged effluent surrounding the areas of cottage textile dyeing industries. The effluent samples were collected from different locations of the four upazilas (administrative regions) in Sirajganj district in three seasons, namely the pre-monsoon, monsoon, and post-monsoon, covering two years. The study considered the major physicochemical and chemical parameters, including biological oxygen demand (BOD), chemical oxygen demand (COD), heavy metals, and anions. The analysis results showed that most of the physicochemical parameters, including EC, pH, TDS, TSS, turbidity, BOD, COD, organic matter (OM), total hardness (TH), the cationic and anionic parameters, and trace metals, including Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Cd, and Pb, in effluent samples exceeded the Department of Environment, Bangladesh (DoE-BD) standard, 2008. The most toxic heavy metals, such as Cr, Mn, Cd, and Pb, were found to be higher than the standard permissible limit in all of the collected samples, indicating heavy metal pollution in the area. The analysis results of the Fourier-transform infrared spectroscopy (FTIR) showed that the effluent samples contained toxic functional groups, like azo, cyano, etc., indicating higher levels of pollution due to the discharge of untreated textile dyeing effluent. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Extensive use of dyes by the textile industries poses a serious threat to the aquatic flora and fauna. Low‐cost bio‐sorbent derived from marine red, Gracilaria verrucosa (RAC), and green macroalgae, Enteromorpha intestinalis (GAC) have been used for effective removal of unsafe Malachite Green (MG) dye. Batch study was conducted to determine the different bio‐sorption parameters such as biochar dosage, pH, initial concentration of MG, and contact time including MG bio‐sorption capacities. The physicochemical characterization results show the presence of lower crystallite sizes, and active functional groups such as carbonyl, hydroxyl, carboxyl, sulfate and amine with the mesoporous morphology of the algal biochar. The FT‐IR, XRD and SEM analyses were also performed to characterize the structural investigation of adsorbents. The kinetics of adsorption such as pseudo‐first‐order and pseudo‐second‐order were analyzed and pseudo‐second‐order confirms about the nature of process to be chemisorption. The bio‐sorption test for 20 mg/L of initial MG at an equilibrium time of 90 min by RAC showed maximum removal efficiency of about 97.49% at pH 8 whereas GAC showed a removal efficiency of 93.37% at pH10. Thus, marine macroalgae RAC and GAC can be a substitute for the commercially available adsorbents for degradation of dyes from textile effluents. [ABSTRACT FROM AUTHOR]

Due to increasing problems of freshwater availability and wastewater treatment and management, there is a dire need to control water pollution. A major portion of wastewater is produced through dye contamination from textile industries. In this study, efforts were made to evaluate the renewable, environment-friendly, and biomass-based adsorbent for the effective removal of dyes from aqueous solution. Pine sawdust biomass samples were subjected to adsorption under different parametric studies to optimize the adsorption process efficiency. The maximum adsorption efficiency was observed around 50-60 % under different working conditions. This study demonstrates that the non-linear versions of the PSO and IPD kinetic models were better than the linear forms from the perspective of the dye adsorption mechanism. Comparably, the nonlinear fitting of the Freundlich model yielded lower χ² values and higher R² values than the linear fitting. Positive Gibbs free energy values imply that the adsorption is non-spontaneous and thermodynamically unfavorable at the investigated temperatures. The thermodynamic study shows that the adsorption of BBY onto the PSD adsorbent is an exothermic process. [ABSTRACT FROM AUTHOR]

Dye is a substance that imparts colour onto textiles, fabrics, paper, leather, etc. and is not altered by washing, heating, and light. Dyes were extracted from plants, animals, and minerals until synthetic dyes came to the market, as synthetic dyes were more stable, readily available, and inexpensive. Despite being extremely important to the economy, they have been among the most significant global polluters. Textile dye industries have become the chief source of water pollution, with their effluents increasing the turbidity of water and reducing photosynthesis and dissolved oxygen levels. This leads to significant damage to aquatic biodiversity, threatening the survival of many species. Synthetic dyes have carcinogenic, mutagenic, and genotoxic effects on animals and human beings, posing a severe health risk. The degradation of dyes is essential for ensuring the sustainability of the environment for future generations. The traditional physicochemical means of dye treatment are not convenient because of the high solubility in water, cost of method utilisation and other disadvantages related to these techniques. To overcome the disadvantages of physicochemical treatment, biological methods or bioremediation can be used as an alternative. The objective of this review article is to study the mechanisms involved in the degradation of textile dyes by bacteria to obtain sustainable, economically and ecologically sound solutions for dye treatment. This paper will explain the various types of natural and synthetic dyes utilised in the textile industry, their chemistry, and how they affect water and soil ecosystems. The treatment of textile dye by various physicochemical methods and their advantages and disadvantages are also discussed. In bioremediation, the microorganisms utilize organic pollutants as a source of food or energy. Bioremediation uses biosorption and enzymatic activity for dye degradation, which does not disturb natural processes and is thus sustainable. The microorganisms secrete crucial extracellular and intracellular enzymes that carry out decolourisation and degradation through a series of events, which include hydrolysis, acidogenesis, and methanogenesis. We will discuss how aerobic and anaerobic microorganisms degrade these textile dyes through the process of biodegradation and bioaugmentation and how this technology provides a clean and eco-friendly method for removing textile dyes. [ABSTRACT FROM AUTHOR]

Non-woven jute (NWJ) produced from carpet industry waste was oxidized by H2O2 or alkali-treated by NaOH and compared with water-washed samples. Changes in the structure of the NWJ, tracked by X-ray diffraction (XRD), showed that both chemical treatments disrupt hydrogen bond networks between cellulose Iβ chains of the NWJ fibers. Thereafter, nano-carbon nitride (nCN) was impregnated, using a layer-by-layer technique, onto water-washed jute samples (nCN-Jw), NaOH-treated samples (nCN-Ja) and-H2O2 treated samples (nCN-Jo). Analysis of the Fourier transform infrared spectroscopy (FTIR) spectra of the impregnated samples revealed that nCN anchors to the water-washed NWJ surface through hemicellulose and secondary hydroxyl groups of the cellulose. In the case of chemically treated samples, nCN is preferentially bonded to the hydroxymethyl groups of cellulose. The stability and reusability of prepared nCN-jute (nCN-J) samples were assessed by tracking the photocatalytic degradation of Acid Orange 7 (AO7) dye under simulated solar light irradiation. Results from up to ten consecutive photocatalytic cycles demonstrated varying degrees of effectiveness across different samples. nCN-Jo and nCN-Ja samples exhibited declining effectiveness over cycles, attributed to bond instability between nCN and jute. In contrast, the nCN-Jw sample consistently maintained high degradation rates over ten cycles, with a dye removal percentage constantly above 90%. [ABSTRACT FROM AUTHOR]

This paper explores the photocatalytic degradation of Reactive Orange 16 (RO16) dye in textile wastewater employing a novel CuO@A-TiO2/Ro-TiO2 nanocomposite. The nanocomposite was synthesized via a hydrothermal technique, resulting in a monoclinic phase of leaf-shaped CuO loaded on a hexagonal wurtzite structure of rod-shaped ZnO, as confirmed by FE-SEM and XRD analyses. Optical experiments revealed band gap energies of 1.99 eV for CuO, 2.19 eV for ZnO, and 3.34 eV for the CuO@A-TiO2/Ro-TiO2 nanocomposite. Photocatalytic degradation experiments showcased complete elimination of a 100 mg/L RO16 solution (150 mL) after 120 min of UV light illumination and 100 min of sunlight illumination, emphasizing the nanocomposite's efficiency under both light sources. The study further delves into the application of the CuO@A-TiO2/Ro-TiO2 nanocomposite for the degradation of actual textile wastewater samples under sunlight irradiation. The results underscore the nanocomposite's remarkable efficacy in treating RO16 in textile wastewater, positioning it as a promising candidate for sustainable and efficient wastewater treatment applications. This research contributes valuable insights into the development of advanced photocatalytic materials for textile dye degradation in wastewater treatment. [ABSTRACT FROM AUTHOR]

This paper explores the photocatalytic degradation of Reactive Orange 16 (RO16) dye in textile wastewater employing a novel CuO@A-TiO2/Ro-TiO2 nanocomposite. The nanocomposite was synthesized via a hydrothermal technique, resulting in a monoclinic phase of leaf-shaped CuO loaded on a hexagonal wurtzite structure of rod-shaped ZnO, as confirmed by FE-SEM and XRD analyses. Optical experiments revealed band gap energies of 1.99 eV for CuO, 2.19 eV for ZnO, and 3.34 eV for the CuO@A-TiO2/Ro-TiO2 nanocomposite. Photocatalytic degradation experiments showcased complete elimination of a 100 mg/L RO16 solution (150 mL) after 120 min of UV light illumination and 100 min of sunlight illumination, emphasizing the nanocomposite's efficiency under both light sources. The study further delves into the application of the CuO@A-TiO2/Ro-TiO2 nanocomposite for the degradation of actual textile wastewater samples under sunlight irradiation. The results underscore the nanocomposite's remarkable efficacy in treating RO16 in textile wastewater, positioning it as a promising candidate for sustainable and efficient wastewater treatment applications. This research contributes valuable insights into the development of advanced photocatalytic materials for textile dye degradation in wastewater treatment. [ABSTRACT FROM AUTHOR]

Among the metal oxide nanoparticles, zinc oxide (ZnO) has recently been cited as the new material of the future due to its unique properties and wide application areas. In this study, we offer a simple technique for the production of extremely stable ZnO nanoparticles (CA-ZnO NPs) using the aqueous and ethyl alcohol (1/1, v/v) extract of Cupressus arizonica (CA, Blue cypress) leaves and cones and zinc acetate (Zn-Ac) salt. The structure of the produced CA-ZnO NPs was elucidated and nanoparticles were used as a photocatalyst for the removal of textile dyestuffs. The particle sizes of CA-ZnO NPs calcined at different temperatures (60°C, 150°C, and 400°C) increased from 20 nm to 50 nm. Produced CA-ZnO NPs were used to investigate photocatalytic degradation of Basic Yellow (BY28), Basic Violet 39 (BV39), Methylene blue (MB), Brilliant Blue (BB3) and Basic Red 46 (BR46) in aqueous solution under UV-light and daylight irradiation. After stirring dye solutions containing CA-ZnO NP for one hour in darkness and 7 hours under UV-light, decolorization rates varied from 53% to 100%. Decolorization of the dyestuff molecules follows the pseudo first-order kinetics. Produced CA-ZnO NPs showed antibacterial efficiency against Escherichia coli and Staphylococcus aureus. CA-ZnO NPs formed zones ranging from 10 mm to 11 mm against gram+ and gram-bacteria. Green production of ZnO NPs utilizing Cupressus arizonica plant extract can replace chemical methods, and the resulting CA-ZnO NPs can be used in industries like water purification. This eco-friendly biogenic synthesis method is a new, inexpensive and useful technique suitable for large scale. [ABSTRACT FROM AUTHOR]

Abstract This article focuses on comparing the characteristics of cotton fabric dyed with Diospyros mollis extract (DME) solution and that of cotton fabric dyed with the reactive dye. The parameters of the cotton fabric after dyeing with both types of dyes were assessed, including color strength (K/S), structural morphology, infrared spectrum, antibacterial properties, UV resistance, color fastness to washing, rubbing, light, moisture absorption, breathability, and wastewater indices. The obtained results show that the K/S value of cotton fabric dyed with DME solution is slightly lower than that of cotton fabric dyed with the reactive dye, 18.52 and 19.36, respectively. The cotton fabric dyed with the reactive dye does not exhibit antibacterial activity against Escherichia coli and Staphylococcus aureus, whereas the antibacterial effectiveness against these bacteria for cotton fabric dyed with DME solution is 99.99 %. The UV protection capability of cotton fabric dyed with DME solution is superior to cotton fabric dyed with the reactive dye. The BOD/COD ratio of wastewater from the dyeing process with DME is higher than that of the reactive dye, with values of 0.70 and 0.32, respectively. The findings of this study indicate the superior ability of using DME solution as compared to the reactive dye, which is promising as a natural dye for fabric in medical applications.

The awareness of the concept of the "Circular Economy" is motivating scientists to convert drinking water treatment plant by-products, which are based on aluminum waste, into a valorized material for wastewater treatment. Alum sludge from a local waterworks plant in Egypt was collected and dewatered using chitosan-coated magnetic nanoparticles. The role of the conditioned sludge in wastewater treatment was then examined. Chitosan (Ch) augmented with magnetite nanoparticles (MNs), labeled as ChMNs, was prepared by means of a simple co-precipitation route with mixing ratios of 1:1, 2:1, and 3:1 of chitosan and magnetite nanoparticles to form the ChMN catalyst. The ChMNs were shown to beneficially enhance alum sludge conditioning and dewaterability. The conditioned and dried aluminum-based sludge (AS) loaded with ChMNs was then used as a source of Fenton's catalyst for Synozol Red-KHL textile dyeing wastewater. The characteristics of the AS-ChMN sample were investigated using Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The photocatalytic activity of the AS-ChMN composite was assessed by examining its diffuse reflectance spectra (DRS). Response surface methodological analysis was applied to optimize the operational parameters in order to reduce the use of chemicals and improve dye oxidation to form a complete (99%) dye oxidation strategy. The experiments demonstrated that the optimal operating parameters included doses of 1.5 g/L and 420 mg/L for AS-ChMNs and hydrogen peroxide, respectively, as a source of Fenton's reaction at a working pH of 3.5. Kinetic and thermodynamic analyses for potential full-scale applications were conducted, showing the reaction to be exothermic and spontaneous in nature and following second-order reaction kinetics. Hence, the novelty of this work lies in the introduction of conditioned and dewatered alum sludge waste as a photocatalyst for textile dye effluent oxidation, which could be considered a "win–win" strategy. [ABSTRACT FROM AUTHOR]

Azo dyes, widely used in the textile industry, contribute to effluents with significant organic content. Therefore, the aim of this work was to synthesize cobalt ferrite (CoFe2O4) using the combustion method and assess its efficacy in degrading the azo dye Direct Red 80 (DR80). TEM showed a spherical structure with an average size of 33 ± 12 nm. Selected area electron diffraction and XRD confirmed the presence of characteristic crystalline planes specific to CoFe2O4. The amount of Co and Fe metals were determined by ICP-OES, indicating an n(Fe)/n(Co) ratio of 2.02. FTIR exhibited distinct bands corresponding to Co–O (455 cm−1) and Fe–O (523 cm−1) bonds. Raman spectroscopy detected peaks associated with octahedral and tetrahedral sites. For the first time, the material was applied to degrade DR80 in an aqueous system, with the addition of persulfate. Consistently, within 60 min, these trials achieved nearly 100% removal of DR80, even after the material had undergone five cycles of reuse. The pseudo-second-order model was found to be the most fitting model for the experimental data (k2 = 0.07007 L mg−1 min−1). The results strongly suggest that degradation primarily occurred via superoxide radicals and singlet oxygen. Furthermore, the presence of UV light considerably accelerated the degradation process (k2 = 1.54093 L mg−1 min−1). The material was applied in a synthetic effluent containing various ions, and its performance consistently approached 100% in the photo-Fenton system. Finally, two degradation byproducts were identified through HPLC–MS/MS analysis. [ABSTRACT FROM AUTHOR]

The presence of pollutants in water sources, particularly dyes coming by way of the textile industry, represents a major challenge with far-reaching environmental consequences, including increased scarcity. This phenomenon endangers the health of living organisms and the natural system. Numerous biosorbents have been utilized for the removal of dyes from the textile industry. The aim of this study was to optimize discarded Zygophyllum gaetulum stems as constituting an untreated natural biosorbent for the efficient removal of C.I. Direct Black 80, an azo textile dye, from an aqueous solution, thus offering an ecological and low-cost alternative while recovering the waste for reuse. The biosorbent was subjected to a series of characterization analyses: scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET) method, X-ray diffraction (XRD), and infrared spectroscopy (IR) were employed to characterize the biosorbent. Additionally, the moisture and ash content of the plant stem were also examined. The absorption phenomenon was studied for several different parameters including the effect of the absorption time (0 to 360 min), the sorbent mass (3 to 40 g/L), the pH of the solution (3 to 11), the dye concentration (5 to 300 mg/L), and the pH of the zero-charge point (2–12). Thermodynamic studies and desorption studies were also carried out. The results showed that an increase in plant mass from 3 to 40 g/L resulted in a notable enhancement in dye adsorption rates, with an observed rise from 63.96% to 97.08%. The pH at the zero-charge point (pHpzc) was determined to be 7.12. The percentage of dye removal was found to be highest for pH values ≤ 7, with a subsequent decline in removal efficiency as the pH increased. Following an initial increase in the amount of adsorbed dye, equilibrium was reached within 2 h of contact. The kinetic parameters of adsorption were investigated using the pseudo-first-order, pseudo-second-order and Elovich models. The results indicated that the pseudo-first-order kinetic model was the most appropriate for the plant adsorbent. The isotherm parameters were determined using the Langmuir, Frendlich, Temkin, and Dubinin–Radushkevich models. The experimental data were more satisfactory and better fitted using the Langmuir model for the adsorption of dye on the plant. This study demonstrated that Zygophyllum gaetulum stems could be employed as an effective adsorbent for the removal of our organic dye from an aqueous solution.

Indigo carmine has a variety of uses in foods, textiles, medicine, pharmaceuticals, and cosmetics. There are studies reporting the toxic potential of indigo carmine on human health and the environment. In this study, we investigated the cytogenotoxic effects of indigo carmine using apical root cells of Allium cepa. Allium cepa bulbs were subjected to four treatments with indigo carmine (0.0032, 0.0064, 0.0125, and 0.2 mg/mL) and to ultrapure water as a control. After 5 days, root growth, root length, mitotic index, mitotic inhibition, chromosomal anomalies, and cell morphology were analyzed. According to our results, a decrease in root length and mitotic index was observed at all concentrations of indigo carmine. Additionally, several types of chromosomal abnormalities were observed, such as disturbed metaphase, sticky chain metaphase, anaphase bridge, and laggard chromosomes. Moreover, histological observation indicated that indigo carmine induces alterations in various components of root tip tissue, such as deformation and alteration of the cell wall, progressive condensation of chromatin, shrinkage of the nuclei, and an increase in the number of irregularly shaped nuclei and nuclear fragments. Our results indicate that the tested concentrations of indigo carmine may have toxic effects and raise concerns about its intensive use in many fields. [ABSTRACT FROM AUTHOR]

It has been demonstrated that bismuth oxyhalides [BiOX (X = Cl, Br, and I)] nano‐crystals can efficiently behave as photocatalysts both under visible light and UV light. Different types of dyes, phenols, etc. can be degraded by bismuth oxyhalides materials efficiently, for the purification of wastewater. The raw materials used in the synthesis of bismuth oxyiodide (BiOI) are pure Bi2O3, halide salt, and capping agent (poly‐vinyl‐pyrrolidone). A variety of characterization techniques are used to characterize the as‐synthesized samples, including X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV–Vis diffuse reflection spectroscopy (UV–Vis DRS), photoluminescence (PL), Mott–Schottky, field emission scanning electron microscopy (FESEM), energy dispersive X‐ray spectroscopy (EDX), and high resolution transmission electron microscopic (HRTEM), etc. A potential application in environmental remediation is achieved through 95.25% degradation of organic Rhodamine B (RhB) dye within 100 min using the synthesized materials under visible light irradiation. [ABSTRACT FROM AUTHOR]

The contamination of wastewater with textile dyes has emerged as a pressing environmental concern due to its persistent nature and harmful effects on ecosystems. Conventional dye treatment methods have proven inadequate in effectively breaking down complex dye molecules. However, a promising alternative for textile dye degradation lies in the utilization of white rot fungi, renowned for their remarkable lignin‐degrading capabilities. This review provides a comprehensive analysis of the potential of white rot fungi in degrading textile dyes, with a particular focus on their ligninolytic enzymes, specifically examining the roles of lignin peroxidase (LiP), manganese peroxidase (MnP), and laccase in the degradation of lignin and their applications in textile dye degradation. The primary objective of this paper is to elucidate the enzymatic mechanisms involved in dye degradation, with a spotlight on recent research advancements in this field. Additionally, the review explores factors influencing enzyme production, including culture conditions and genetic engineering approaches. The challenges associated with implementing white rot fungi and their ligninolytic enzymes in textile dye degradation processes are also thoroughly examined. Textile dye contamination poses a significant environmental threat due to its resistance to conventional treatment methods. White rot fungi, known for their ligninolytic capabilities, offer an innovative approach to address this issue. The review delves into the intricate mechanisms through which white rot fungi and their enzymes, including LiP, MnP, and laccase, break down complex dye molecules. These enzymes play a pivotal role in lignin degradation, a process that can be adapted for textile dye removal. The review also emphasizes recent developments in this field, shedding light on the latest findings and innovations. It discusses how culture conditions and genetic engineering techniques can influence the production of these crucial enzymes, potentially enhancing their efficiency in textile dye degradation. This highlights the potential for tailored enzyme production to address specific dye contaminants effectively. The paper also confronts the challenges associated with integrating white rot fungi and their ligninolytic enzymes into practical textile dye degradation processes. These challenges encompass issues like scalability, cost‐effectiveness, and regulatory hurdles. By acknowledging these obstacles, the review aims to pave the way for practical and sustainable applications of white rot fungi in wastewater treatment. In conclusion, this comprehensive review offers valuable insights into how white rot fungi and their ligninolytic enzymes can provide a sustainable solution to the urgent problem of textile dye‐contaminated wastewater. It underscores the enzymatic mechanisms at play, recent research breakthroughs, and the potential of genetic engineering to optimize enzyme production. By addressing the challenges of implementation, this review contributes to the ongoing efforts to mitigate the environmental impact of textile dye pollution. Practitioner Points: Ligninolytic enzymes from white rot fungi, like LiP, MnP, and laccase, are crucial for degrading textile dyes. Different dyes and enzymatic mechanisms is vital for effective wastewater treatment.Combine white rot fungi‐based strategies with mediator systems, co‐culturing, or sequential treatment approaches to enhance overall degradation efficiency.Emphasize the broader environmental impact of textile dye pollution and position white rot fungi as a promising avenue for contributing to mitigation efforts. This aligns with the overarching goal of sustainable wastewater treatment practices and environmental conservation.Consider scalability, cost‐effectiveness, and regulatory compliance to pave the way for sustainable applications that can effectively mitigate the environmental impact of textile dye pollution. [ABSTRACT FROM AUTHOR]

This work concerns the coacervate extraction of industrial dye, namely Acid Green 9 (AG-9) from aqueous solution by nonionic surfactant Lutensol AO7 and TX-114 (readily biodegradable). Binary water/surfactant and pseudo-binary phase diagrams were plotted. The extraction results as a function of wt% of the surfactant and temperature are expressed by: percentage of solute extracted, E%, residual concentrations of solute and surfactant in the dilute phase (Xs,w and Xt,w respectively) and volume fraction of coacervate at equilibrium (Фc). For each parameter, whose values are determined by a design of experiments, these results are subjected to empirical smoothing in three dimensionsusing response surface methodology (RSM). The aim of this study is to find out the best compromise between E % and Фc. Under optimal conditions, the extraction extent of AG-9 reaches 98 % and 96 % using TX-114 and Lutensol AO7, respectively. The effect of Na2SO4 and CTAB addition is also studied. Finally, the possibility of recycling the surfactant is proved. [ABSTRACT FROM AUTHOR]

Water contaminant and pathogenic microorganism elimination using nanotechnology is a fantastic potential. NaBH4 was used to create copper nanoparticles, and the effectiveness of the dye removal was assessed. Utilising scanning electron microscopy (SEM), DLS, UV-visible spectroscopy, and energy dispersive analysis by X-rays, the synthesised nanoparticles were characterised. This study examined the elimination of COD and BOD utilising (CuNPs) at various (20-100 ppm) levels. Both the chemical oxygen demand (COD) and the biological oxygen demand (BOD) were shown to be effectively removed by CuNPs. Additionally, the synthesised copper nanoparticles are highly effective at removing synthetic dyes like methyl orange (89%), methylene blue (95%), and malachite green (97%). [ABSTRACT FROM AUTHOR]

Dyes, such as indigo carmine, have become indispensable to modern life, being widely used in the food, textile, pharmaceutical, medicine, and cosmetic industry. Although indigo carmine is considered toxic and has many adverse effects, it is found in many foods, and the maximum permitted level is 500 mg/kg. Indigo carmine is one of the most used dyes in the textile industry, especially for dyeing denim, and it is also used in medicine due to its impressive applicability in diagnostic methods and surgical procedures, such as in gynecological and urological surgeries and microsurgery. It is reported that indigo carmine is toxic for humans and can cause various pathologies, such as hypertension, hypotension, skin irritations, or gastrointestinal disorders. In this review, we discuss the structure and properties of indigo carmine; its use in various industries and medicine; the adverse effects of its ingestion, injection, or skin contact; the effects on environmental pollution; and its toxicity testing. For this review, 147 studies were considered relevant. Most of the cited articles were those about environmental pollution with indigo carmine (51), uses of indigo carmine in medicine (45), and indigo carmine as a food additive (17).

AbstractThe Bi2VO2Se nanocomposite was successfully synthesized by hydrothermal method. The physical and chemical properties of photocatalyst sample were characterized by XRD, SEM, FTIR, UV–Vis spectroscopy. The nanocomposite showed the band-gap (Eg) 2.38 eV. To evaluate the photocatalytic efficiency of a synthesized composite, Congo red (CR) and Methylene blue (MB) dyes were used as organic pollutants. The Bi2VO2Se photocatalyst was found to degrade CR dye with degradation efficiency of 92.7% in 50 min, while MB dye degraded only 38% in 50 min when exposed to direct sunlight. Due to its optimal optical stability and consistency, the Bi2VO2Se photocatalyst might be promoted as a cost-effective photocatalyst for practical uses. The results indicated that suitable optical absorption, better efficiency separation, and decreased electron-hole interaction due to the nanocomposite effect are all factors that contribute to enhanced photocatalytic activity. [ABSTRACT FROM AUTHOR]

Humic substances are naturally occurring materials composed of complex biogenic mixtures of substituted aromatic and aliphatic hydrocarbon core materials derived from the degradation and decomposition of dead plant and animal matter. They are ubiquitous in both terrestrial and aquatic systems constituting biotic pools and are characterized by unique properties; they are amphiphilic redox compounds with exceptional chelating features. Humic substances play a crucial role in both agriculture and the environment as carbon sequestrators, soil improvers, plant health promoters, as well as stabilizers of soil aggregates and regulators of organic/inorganic nutrients bioavailability. This review article attempts to summarize current knowledge about the molecular nature and characterization techniques employed for the study of humic substances worldwide as the chemistry of their components differs markedly and depends on natural processes, several abiotic and biotic factors, the origin of the organic matter, and their complexation with inorganic, e.g., metal-ion, compounds. This work is equally concerned with the association of humic substances with dyes, a notorious pollutant, responsible for various environmental issues generally arising from the discharge of untreated effluents into soils and water bodies. Azo dyes, in particular, negatively affect soil microbial communities, as well as plant germination and growth. The aim is to feature the potential contribution of humic substances as novel materials for environment-friendly and sustainable processes. [ABSTRACT FROM AUTHOR]

Indeed, the textile dye industry has a significant impact on the global economy, as it is an integral part of the textile and fashion industries. However, this advancement has become a great concern with industrial waste, a good part of these dyes have toxic characteristics to the environment and living beings. The objective of this work is the use of local corn starch as an adsorbent, for the removal of acid violet (AV19), a dye that is highly toxic and carcinogenic in real water samples. The material was characterized by scanning electron microscopy (SEM) and infrared (IR). The optimized parameters were concentration, time, and pH, in which the best results will be obtained at 60 min and pH 7. The experiment was compared to the Langmuir, Freundlich, and Temkin models. The concentration of dye was 4 mg L−1 had the highest removal which was 84.46 %. The prim rate constant is k′ = 0.8592 therefore the adsorption system studied obeys the pseudo-second-order kinetic model. In the next step, we will apply the top-performing starch to environmental samples containing the investigated dye. An analytical curve was constructed in the 2–14 ppm range at a maximum wavelength of 590 nm. The detection limit was 0.541 mg/L, and the percentage recovery was obtained in the range of 95–99.8 % for real water samples. [ABSTRACT FROM AUTHOR]

Background: The development of an environment-friendly nanomaterial with promising antimicrobial and antioxidant properties is highly desirable. The decolorization potentiality of toxic dyes using nanoparticles is a progressively serious worldwide issue. Methods: The successful biosynthesis of zinc nanoparticles based on phosphates (ZnP-nps) was performed using the extracellular secretions of Aspergillus fumigatus. The antibacterial activity of the biosynthetic ZnP-nps was investigated against Gram-negative bacteria and Gram-positive bacteria using the agar diffusion assay method. The antioxidant property for the biosynthetic nanomaterial was evaluated by DPPH and H2O2 radical scavenging assay. Results: Remarkable antibacterial and antiradical scavenging activities of ZnP-nps were observed in a dose-dependent manner. The minimum inhibitory concentration (MIC) for Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli was 25 µg/ml, however, the MIC for Bacillus subtilis was 12.5 µg/ml. The maximum adsorptive performance of nanomaterial was respectively achieved at initial dye concentration of 200 mg/L and 150 mg/L using methylene blue (MB) and methyl orange (MO), where sorbent dosages were 0.5 g for MB and 0.75 g for MB; pH was 8.0 for MB and 4.0 for MO; temperature was 30 °C; contact time was 120 min. The experimental data was better obeyed with Langmuir's isotherm and pseudo-second-order kinetic model (R2 > 0.999). The maximum adsorption capacity (qmax) of MB and MO dyes on nanomaterial were 178.25 mg/g and 50.10 mg/g, respectively. The regenerated nanomaterial, respectively, persist > 90% and 60% for MB and MO after 6 successive cycles. The adsorption capacity of the prepared zinc phosphate nanosheets crystal toward MB and MO, in the present study, was comparable/superior with other previously engineered adsorbents. Conclusions: Based on the above results, the biosynthesized ZnP-nanosheets are promising nanomaterial for their application in sustainable dye decolorization processes and they can be employed in controlling different pathogenic bacteria with a potential application as antiradical scavenging agent. Up to our knowledge, this is probably the first study conducted on the green synthesis of ZnP-nanosheets by filamentous fungus and its significant in sustainable dye decolorization. [ABSTRACT FROM AUTHOR]

Background: Synthetic dyes are one of the main pollutants in the textile industry and bioremediation is considered as an environmentally friendly method to degrade them. Soil microbial consortia (MCs) are reported having the potential of decolorizing most of textile dyes. This study aimed at evaluating dye-degrading ability of MCs developed from fungi and bacteria. Methods and results: Fungi and bacteria were isolated from the soil samples obtained from textile waste dumping site at Horana industrial zone, Sri Lanka and were screened for crystal violet (CV) and congo red (CR) dyes to develop MCs. Decolorization assay was performed for MCs along with individual isolates under variable pH levels. Metabolized products were characterized to confirm the biodegradation. A. tamari (F5) and P. putida (B3) significantly (P < 0.05) decolorized both dyes. All the MCs showed higher decolorization percentages over the individual microorganisms. Neutral pH (pH 7) was the optimum pH for the decolorization of both dyes by individual isolates and the percentages were significantly changed under the acidic and basic pH levels. However, decolorization ability by all MCs was not significantly changed with pH. Consortium with A. tamari - P. putida significantly (P < 0.05) decolourized both dyes under optimum pH 7. Conclusion: All MCs showed better pH tolerance in degrading CV and CR. Thus, it can be concluded that the selected MC with A. tamari - P. putida can degrade CV and CR textile dyes efficiently into non-toxic compounds against plants under neutral pH. [ABSTRACT FROM AUTHOR]

The inadequate treatment of industrial wastewater with organic contaminants is a worldwide problem, requiring the development of alternative wastewater treatment methods. This study focused on the degradation and mineralization processes of two dyes, Rhodamine B and Direct Orange 39, in water using atmospheric plasma. Aqueous solutions of the dyes were treated at an initial concentration of 1.0 mM in a volume of 250 mL using iron filings (Fe2+) as a catalyst. Their absorption spectra in the ultraviolet-visible range, total organic carbon, and chemical oxygen demand were monitored. Furthermore, their physicochemical properties such as pH, electrical conductivity, and nitrate and nitrite concentrations were determined. The results showed a process efficiency greater than 90% for both dyes owing to atmospheric plasma exposure. [ABSTRACT FROM AUTHOR]

For the first time, cobalt ferrite spinel (CoFe2O4) was used as a catalyst in the Fenton process for Remazol Red RR dye degradation in water. CoFe2O4 was synthesized via gel combustion using tris(hydroxymethyl)aminomethane as an alternative fuel in one step with a ratio of Ψ = 0.8. Its structural, surface optics, magnetic properties, and the optimal conditions of the Fenton reagents for dye degradation were evaluated. The saturation magnetization and remanence (Ms and Mr, respectively) for the as-prepared powder were 65.7 emu/g and 30.4 emu/g, respectively, and the coercivity (Hc) was 1243 Oe, indicating its ferromagnetic nature and suitability as a magnetic catalyst. Red Remazol RR dye degradation tests were performed using the Fenton process to evaluate the influence of the catalyst dosage and H2O2 concentration. The tests were performed in a batch reactor in the dark with constant agitation for 24 h. The best result was obtained using 1 g/L of catalyst with a dye degradation of 80.6%. The optimal concentration of H2O2 (1.0 M) resulted in 96.5% dye degradation. Nanoparticle recyclability testing indicated that the material could be satisfactorily reused as a catalyst for at least three cycles. The potential use of the CoFe2O4 synthesized in this study as a catalyst for dye degradation by the Fenton process was demonstrated. [ABSTRACT FROM AUTHOR]

This work was conducted to evaluate the adsorption performance of coffee spent modified Fe-Al-Zr composite. The Al2O3/Fe3O4/ZrO2 ternary oxide system was efficiently synthesized from the respective salt precursors by a two-step co-precipitation method under nitrogen atmosphere in basic condition. XRD, SEM-EDX, FTIR and ICP-OES were used to characterize the features of the adsorbents. The pH point of zero charge of the selected adsorbent was also determined. Batch adsorption experiment was conducted under different conditions such as contact time, initial concentration of dye, pH, sorbent dosage and agitation speed. The Langmuir and Freundlich, isotherms were tested to examine the adsorption behavior. The equilibrium data was well fitted to Langmuir isotherm model. The maximum adsorption capacity (qo) was 8.4 mg/g for acidic brown 75 dyes. The kinetic data correlated (R2 = 0.999) well with the pseudo second order kinetic model. To evaluate the practical applicability of the coffee spent supported nanocomposite adsorbent to real samples, effluent was collected from Batu Leather Industry. The result demonstrated 95.7% (10 mg/L) removal efficiency of the dye by the as-obtained composite indicating its potential application for environmental application. [ABSTRACT FROM AUTHOR]

Textile dye effluents have been reported for many deleterious effects; therefore, it is essential to remove before releasing into waterbodies. A two-step agro-waste-based technology for the remediation of a textile dye Lanasyn olive was developed in this study. The first step involved the chemical modification of agro-waste sugarcane bagasse (SCB) with a natural acid (alginic acid). The modified SCB was used for the column bed preparation and adsorptive removal of the dye. In the second step, SCB used for dye removal was decolorized through a fungus Pleurotus sp. to produce a dye-free SCB with a potential for application as manure. To evaluate the efficacy of the column device, parameters like removal percentage, and adsorption capacity were determined. There was 90% removal of dye in aqueous dye solution and 83% removal in dye spiked textile industry effluent. To comprehend the column properties, three non-equilibrium models—Thomas, Yoon-Nelson, and Adams-Bohart—were used. Among the models applied, Adams-Bohart fitted well with the obtained data. Dye bioremediation efficiency by Pleurotus sp. was assessed by studying the deviation in absorption maxima, dye decolorization on the agar plate, Fourier-transform infrared spectroscopy (FTIR). The fungus-treated SCB showed no signs of residual toxicity towards alga Chlorella vulgaris. The carbon, hydrogen, nitrogen, sulfur (CHNS) profile examination of spent SCB revealed significantly improved nitrogen content after the treatment (from 0.35% to 0.69%). The prototype of the column, chemical valorization of SCB, and degradation of dye-adsorbed SCB through Pleurotus sp. provides a green solution for the safe disposal of textile dye through a novel agro waste-based treatment process.

The awareness of the concept of the “Circular Economy” is motivating scientists to convert drinking water treatment plant by-products, which are based on aluminum waste, into a valorized material for wastewater treatment. Alum sludge from a local waterworks plant in Egypt was collected and dewatered using chitosan-coated magnetic nanoparticles. The role of the conditioned sludge in wastewater treatment was then examined. Chitosan (Ch) augmented with magnetite nanoparticles (MNs), labeled as ChMNs, was prepared by means of a simple co-precipitation route with mixing ratios of 1:1, 2:1, and 3:1 of chitosan and magnetite nanoparticles to form the ChMN catalyst. The ChMNs were shown to beneficially enhance alum sludge conditioning and dewaterability. The conditioned and dried aluminum-based sludge (AS) loaded with ChMNs was then used as a source of Fenton’s catalyst for Synozol Red-KHL textile dyeing wastewater. The characteristics of the AS-ChMN sample were investigated using Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The photocatalytic activity of the AS-ChMN composite was assessed by examining its diffuse reflectance spectra (DRS). Response surface methodological analysis was applied to optimize the operational parameters in order to reduce the use of chemicals and improve dye oxidation to form a complete (99%) dye oxidation strategy. The experiments demonstrated that the optimal operating parameters included doses of 1.5 g/L and 420 mg/L for AS-ChMNs and hydrogen peroxide, respectively, as a source of Fenton’s reaction at a working pH of 3.5. Kinetic and thermodynamic analyses for potential full-scale applications were conducted, showing the reaction to be exothermic and spontaneous in nature and following second-order reaction kinetics. Hence, the novelty of this work lies in the introduction of conditioned and dewatered alum sludge waste as a photocatalyst for textile dye effluent oxidation, which could be considered a “win–win” strategy.

Dyes, such as indigo carmine, have become indispensable to modern life, being widely used in the food, textile, pharmaceutical, medicine, and cosmetic industry. Although indigo carmine is considered toxic and has many adverse effects, it is found in many foods, and the maximum permitted level is 500 mg/kg. Indigo carmine is one of the most used dyes in the textile industry, especially for dyeing denim, and it is also used in medicine due to its impressive applicability in diagnostic methods and surgical procedures, such as in gynecological and urological surgeries and microsurgery. It is reported that indigo carmine is toxic for humans and can cause various pathologies, such as hypertension, hypotension, skin irritations, or gastrointestinal disorders. In this review, we discuss the structure and properties of indigo carmine; its use in various industries and medicine; the adverse effects of its ingestion, injection, or skin contact; the effects on environmental pollution; and its toxicity testing. For this review, 147 studies were considered relevant. Most of the cited articles were those about environmental pollution with indigo carmine (51), uses of indigo carmine in medicine (45), and indigo carmine as a food additive (17). [ABSTRACT FROM AUTHOR]

Textile wastewater containing dyes poses significant risks to the environment. Advanced oxidation processes (AOPs) effectively eliminate dyes by converting them into harmless substances. However, AOPs have drawbacks such as sludge formation, metal toxicity, and high cost. As an alternative to AOPs, calcium peroxide (CaO2) offers an eco-friendly and potent oxidant for dye removal. Unlike certain AOPs that generate sludge, CaO2 can be directly employed without resulting in sludge formation. This study examines the use of CaO2 for oxidizing Reactive Black 5 (RB5) in textile wastewater without any activator. Various independent factors—pH, CaO2 dosage, temperature, and certain anions—were investigated for their influence on the oxidation process. The effects of these factors on dye oxidation were analyzed using the Multiple Linear Regression Method (MLR). CaO2 dosage was determined to be the most influential parameter for RB5 oxidation, while the optimal pH for oxidation with CaO2 was found to be 10. The study determined that 0.5 g of CaO2 achieved approximately 99% efficiency in oxidizing 100 mg/L of RB5. Additionally, the study revealed that the oxidation process is endothermic, with an activation energy (Ea) and standard enthalpy (ΔH°) for RB5 oxidation by CaO2 determined as 31.135 kJ mol−1 and 110.4 kJ mol−1, respectively. The presence of anions decreased RB5 oxidation, with decreasing effectiveness observed in the order of PO43−, SO42−, HCO3−, Cl−, CO32−, and NO3−. Overall, this research highlights CaO2 as an effective, easy-to-use, eco-friendly, and cost-efficient method for removing RB5 from textile wastewater. [ABSTRACT FROM AUTHOR]

Contamination of water through microplastics/polyethylene (PE) and textile waste effluents has become a global environmental threat that needs to be addressed sooner. This research aimed to assess a green approach to treat toxic dye effluents and PE using beneficial microbes. The bacterial strains were isolated from a habitat of waste effluent, collected from a Textile Dyeing Industry, Karachi Pakistan. Besides screening for laccase secretion, the isolates with an ability to degrade PE and transform toxic dye effluents into a reusable metabolite were identified by 16S rDNA sequencing as B. tequilensis M1 (Accession# MZ357709), B. subtilis M7 (Accession# MZ357959), Bacillus sp. (in: Bacteria) M8 (Accession# MZ360013), P. megaterium S8 (Accession# MZ422441) and Bacillus sp. (in: Bacteria) S5 (Accession# MZ382863). Average maximum bioremediation of 87% of reactive black and 97.6% of reactive blue dye were sufficiently taken place by B. tequilensis M1. The treated dye metabolites were comparatively effective and useful for irrigating radish plants, revealing bioremediation efficiency leading to potential use of biologically treated dye effluents. The reusability of treated toxic dye effluents was determined by phytotoxicity and seed germination analysis, along with water purity analysis experiments. [ABSTRACT FROM AUTHOR]

The development of technologies for the removal of dye from aqueous solution is most desirable if the end product is relatively green (i.e., environmentally friendly). Photodegradation (as one of such technology) and photolysis (without the catalyst) was applied to investigate the role of sol-gel synthesized calcium oxide nanoparticle (using the oyster shell as the precursor). The results obtained gave substantial evidence that calcium oxide nanoparticles catalyzed the degradation of the methylene blue dye up to a maximum percentage of 98 % removal. Degradation efficiency displayed a strong dependency on time, initial dye concentration, catalyst load, pH, and ionic strength. Chi-square and sum of square error analysis indicated that the photodegradation kinetics fitted the Langmuir-Hinshelwood, first order, and pseudo first-order models best. The half-life of the dye was significantly reduced from hours to minutes due to photocatalysis. Quantum chemical calculations indicated that the degradation proceeded through adsorption, deformation/degradation, and desorption through the chloride end of the molecule linked to the calcium active center of the catalyst. Results from Fukui functions and molecular descriptors analysis confirmed the mechanism of photocatalysis. [ABSTRACT FROM AUTHOR]