A review on the sustainability of textile industries wastewater with and without treatment methodologies

Green algae Ulva lactuca-derived biochar-sulfur improves the adsorption of methylene blue from water

The present investigation explores the efficacy of green algae Ulva lactuca biochar-sulfur (GABS) modified with H2SO4 and NaHCO3 in adsorbing methylene blue (MB) dye from aqueous solutions. The impact of solution pH, contact duration, GABS dosage, and initial MB dye concentration on the adsorption process are all methodically investigated in this work. To obtain a thorough understanding of the adsorption dynamics, the study makes use of several kinetic models, including pseudo-first order and pseudo-second order models, in addition to isotherm models like Langmuir, Freundlich, Tempkin, and Dubinin-Radushkevich. The findings of the study reveal that the adsorption capacity at equilibrium (qe) reaches 303.78 mg/g for a GABS dose of 0.5 g/L and an initial MB dye concentration of 200 mg/L. Notably, the Langmuir isotherm model consistently fits the experimental data across different GABS doses, suggesting homogeneous adsorption onto a monolayer surface. The potential of GABS as an efficient adsorbent for the extraction of MB dye from aqueous solutions is highlighted by this discovery. The study's use of kinetic and isotherm models provides a robust framework for understanding the intricacies of MB adsorption onto GABS. By elucidating the impact of various variables on the adsorption process, the research contributes valuable insights that can inform the design of efficient wastewater treatment solutions. The comprehensive analysis presented in this study serves as a solid foundation for further research and development in the field of adsorption-based water treatment technologies.

Plasmonic photocatalytic nanocomposite of in-situ synthesized MnO2 nanoparticles on cellulosic fabric with structural color

The textile industry produces 20 % of the industrial water pollution containing toxic substances mostly dyes. Reducing material consumption and developing more efficient and scalable textile waste-water treatment methods such as photocatalytic degradation is essential. In this work, manganese dioxide nanoparticles (MnO2 NPs) were synthesized on the cotton fabric via a facile in-situ process. The preparation process was optimized for the highest photocatalytic activity under sunlight and color change originating from the plasmonic structural color of the nanoparticles. This promotes the photocatalytic activity by delocalization of the hot electrons while demonstrating the best washing and light fastness by using the least chemicals, and energy in a short time. In this way, the fabric was colored without any dye and possessed robust photocatalytic activity. Further, no dye-containing waste-water is made, and also accomplished to degrade dyes in a few hours under sunlight which is substantial for sustainable development. The treated fabrics indicated favorable mechanical properties, enhanced thermal stability, and perfect biocompatibility.

Efficient integration of electrocoagulation treatment with the spray-pyrolyzed activated carbon coating on stainless steel electrodes for textile effluent-bath reuse with ease

In this study, the electrocoagulation (EC) treatment was used to minimize and separate pollutants from textile industrial wastewater (TIWW), including high color, chemical oxygen demand (COD), total organic carbon (TOC), and total dissolved solids (TDS). To enhance the EC treatment efficiency, a novel strategy has been followed in the study that involves thin-film coating on 316 stainless steel (SS) electrodes with banana peel-derived activated carbon (BPAC) by dip coating, spin coating, or spray coating. Among the different types of coating, thickness and contact angle measurements have elucidated that the spray coating of BPAC on SS electrode is the best tool with minimum thickness and contact angle. In this study, a bare SS electrode was used as the anode and a thin-film spray-coated BPAC on the SS electrode was used as the cathode. Moreover, optimization plays a key role in EC treatment process, where operating conditions such as a current density of 10 mA/cm2 , contact time of 15 min, and a pH of 7 were fixed. As a result, the findings indicate comparatively high color removal of 98%, COD removal of 91%, TOC removal of 89.6%, and TDS removal of 68% are achieved with ease. Accordingly, in comparison with plain SS electrodes or dip- or spin-coated BPAC on SS electrodes, spray-coated BPAC on SS electrodes in EC treatment outperforms in removing high color, TOC, COD, and TDS. Overall, the study highlights the potential of EC treatment integrated with adsorption procedures for TIWW treatment. Particularly, the use of thin-film spray-coated BPAC on SS electrodes in the EC treatment process led to an effective and sustainable tool for treating and reuse of TIWW. It is due to its low operation and maintenance cost and studied in a short interval of time. Finally, the ultimate goal was firmly achieved in pilot-scale studies by the safe discharge into the environment or reuse of treated textile wastewater. Thus, it is a promising alternative with an environmentally friendly footprint that could be easily implemented in any textile industry premises. PRACTITIONER POINTS: Heavy metals, oils, facts, suspended solids, and other pollutants can be removed from industrial effluent by using electrocoagulation. The process is both cost-effective and energy-efficient, and it is easily integrated with other water treatment technologies. According to the findings of this study, minimum current density should be applied to BPAC-SS-coated electrodes by DC power supplies to treat textile industry effluents at low operating costs. When compared with a plain SS electrode, the spray-coated BPAC on SS electrode provides better performance in effluent treatment.

Preparation and characterization of a novel cobalt-substitution cadmium aluminate spinel for the photodegradation of azo dye pollutants

Modern-year organic contaminants have been highly observed in ecosystems since they are not removed entirely and remain dangerous. Semiconductor binary oxide photocatalysts have been well accredited as capable technology for ecological contaminants degradation in the existence of visible irradiation. In this research, novel Co ions doped CdAl₂O₄ materials were fabricated by a facile co-precipitation approach. The fabricated pure and Co-doped CdAl₂O₄ exhibited the typical peaks of CdAl₂O₄ with the E_g of 3.66, 3.24, 2.57, and 2.41 eV respectively. The HR-TEM microstructures revealed that the Co (0.075 M) doped CdAl₂O₄ has rod-like morphology, and some places are spherical with particle sizes reaching 21 nm. The PL peaks of the Co (0.075 M)-CdAl₂O₄ are much lesser than that of the other dopant and pure CdAl₂O₄, representing much more effectual separation of generated e^- and h⁺ at the interface which in fact outcomes in superior expected photodegradation behaviours. The Co (0.075 M)-CdAl₂O₄ catalyst demonstrated the highest performances of 92 and 94% toward the degradation of both dyes, respectively, owing to the lowest e^- and h⁺ recombination rate. The Co (0.075 M) doped CdAl₂O₄ photocatalyst revealed outstanding reusability and stability under visible irradiation, retaining the performance of about 83 and 86% after the fifth consecutive run of BB and BG elimination. A probable photodegradation mechanism of Co (0.075 M) doped CdAl₂O₄ was suggested since the photoexcited h⁺, OH^- and O₂^- species contributed to the removal process, and that was affirmed by the scavenging test and ESR analysis. This research offers new ways to improve the photodegradation performance of the Co-doped CdAl₂O₄ catalyst that will be employed in pharmaceutical applications and wastewater treatment.

EfectroH2O: Development and evaluation of a novel treatment technology for high-brine industrial wastewater

Textile production is one of the main sources of freshwater consumption by industries worldwide. In addition, according to the world bank, 20 % of the wastewater generated globally is caused by textile wet-processing. Textile wet-processing includes the processes in textile production where garments are dyed or given the final functions like water-repellency. Several thousand chemicals were used in this process, some of which are highly toxic. Discharging untreated or insufficiently treated wastewater in water bodies results in high pollution levels, severely impacting the environment and human health. Especially in textile-producing countries like India, environmental pollution and water consumption from textile wet-processing have severe impacts. Next to the high volume of chemicals used in textile production, the high salt concentration in textile wastewater also poses a challenge and is critical for freshwater systems. Moreover, textile wastewater is one of the most difficult to treat wastewater. Currently, used treatment technologies do not meet the requirements to treat textile wastewater. Therefore, the further development of efficient treatment technologies for textile wastewater is critically important. Hence, in the interdisciplinary project, effect-based monitoring demonstrates the efficiency of electrically-driven water treatment processes to remove salts and micropollutants from process water (EfectroH₂O), a low-energy Zero Liquid Discharge (ZLD) textile wastewater treatment technology is being developed consisting of a combination of capacitive deionization (CDI) and advanced oxidation processes (AOP). In addition to treatment technology development, methods for evaluating the efficiency of treatment technologies also need to be improved. Currently, mainly physicochemical parameters such as pH, biochemical oxygen demand (BOD) and chemical oxygen demand (COD) are tested worldwide to check water quality. However, these methods are insufficient to make a statement about the toxic potential of such complex mixtures as textile wastewater. Therefore, also next to chemical analyses, effect-based methods (EBM) are used to verify the treated wastewater.

New energy approaches to the use of waste biosorbents of microalgae Chlorella kessleri (Chlorellaceae, Chlorellales)

The use of microalgae Chlorella kessleri VKPM A1-11 ARM (RF, NPO Algobiotechnology) for environmental and energy purposes is considered. The results of our study of the use of C. kessleri microalgae biomass as a biosorbent to purify model wastewater from Cu2+ ions under static conditions are presented. Biosorption is a promising technology for the treatment of industrial effluents containing various heavy metal compounds, but the issues of economic benefits of using biosorbents, their environmental safety and the cost of disposal of used sorbents are subject to much discussion. The paper proposes to dispose the used biosorbent formed after wastewater treatment from copper as an additional fuel. The copper concentration in the filtrate was determined by colorimetric analysis with sodium diethyldithiocarbamate. The cleaning efficiency and sorption capacity of the dry mass of C. kessleri were obtained by calculation. The maximum sorption capacity for Cu2+ ions was 4.2 mg/g. The purification efficiency reached 87% at the initial concentration of Cu2+ ions being 97 mg/l. Tests to estimate the specific heat of combustion of C. kessleri biomass and used biosorbents based thereon were carried out by the calorimetric method using a bomb calorimeter. The specific heats of combustion were 22,125 kJ/kg and 21,674 kJ/kg, respectively. A comparison of these values with traditional energy carriers is given. A technological scheme has been developed for a waste-free cycle of using C. kessleri to treat wastewater from industrial enterprises with the production of several valuable resources as end products, such as purified water, energy resources, fertilizers, and recycled metals. The obtained results of our study can be applied in technologies for post-treatment of wastewater from various industrial enterprises using biological non-waste resources.

Photocatalytic and Antimicrobial Activities of Biosynthesized Silver Nanoparticles Using Cytobacillus firmus

The toxicity of the ecosystem has increased recently as a result of the increased industrial wastewater loaded with organic contaminants, including methylene blue (MB), which exerts serious damage to the environment. Thus, the present work aims to green the synthesis of silver nanoparticles (Ag-NPs) and to evaluate their degradability of notorious MB dye, as well as their antimicrobial activities. Ag-NPs were synthesized by Cytobacillus firmus extract fully characterized by UV-vis, TEM, DLS, XRD, and FTIR. Ag-NPs showed good antibacterial and antifungal activities against Escherichia coli ATCC 25922, Enterococcus feacalis ATCC 29212, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923, and Candida albicans ATCC 90028. Moreover, Ag-NPs exhibited a high biodegradability level (98%) of MB dye after 8 h of co-incubation in the presence of sunlight. Additionally, the phytotoxicity of treated MB dye-contaminated water sample showed good germination of Vicia faba as compared with non-treated MB dye-contaminated solution. In conclusion, the herein biosynthesized Ag-NPs demonstrated its feasibility of the purification of contaminated water from microbes and methylene blue dye and the probability of reusing purified water for agricultural purposes.

Biodegradation of Azo Dye Methyl Red by Pseudomonas aeruginosa: Optimization of Process Conditions

Water pollution due to textile dyes is a serious threat to every life form. Bacteria can degrade and detoxify toxic dyes present in textile effluents and wastewater. The present study aimed to evaluate the degradation potential of eleven bacterial strains for azo dye methyl red. The optimum degradation efficiency was obtained using P. aeruginosa. It was found from initial screening results that P. aeruginosa is the most potent strain with 81.49% degradation activity and hence it was subsequently used in other degradation experiments. To optimize the degradation conditions, a number of experiments were conducted where only one variable was varied at a time and where maximum degradation was observed at 20 ppm dye concentration, 1666.67 mg/L glucose concentration, 666.66 mg/L sodium chloride concentration, pH 9, temperature 40 °C, 1000 mg/L urea concentration, 3 days incubation period, and 66.66 mg/L hydroquinone (redox mediator). The interactive effect of pH, incubation time, temperature, and dye concentration in a second-order quadratic optimization of process conditions was found to further enhance the biodegradation efficiency of P. aeruginosa by 88.37%. The metabolites of the aliquot mixture of the optimized conditions were analyzed using Fourier transform infrared (FTIR), GC-MS, proton, and carbon 13 Nuclear Magnetic Resonance (NMR) spectroscopic techniques. FTIR results confirmed the reduction of the azo bond of methyl red. The Gas Chromatography-Mass Spectrometry (GC-MS) results revealed that the degraded dye contains benzoic acid and o-xylene as the predominant constituents. Even benzoic acid was isolated from the silica gel column and identified by ¹H and ¹³C NMR spectroscopy. These results indicated that P. aeruginosa can be utilized as an efficient strain for the detoxification and remediation of industrial wastewater containing methyl red and other azo dyes.

Adsorptive removal of methylene blue dye from aqueous streams using photocatalytic CuBTC/ZnO chitosan composites

In this study, a CuBTC/ZnO chitosan composite was synthesized for the adsorptive removal of methylene blue dye from aqueous streams. Characterization techniques, namely, scanning electron microscopy, Brunauer-Emmett-Teller, Fourier transform infrared, X-ray diffraction, and thermogravimetric techniques, were used to characterize CuBTC, ZnO, and CuBTC/ZnO chitosan composites. The scanning electron microscopy images revealed the rough and porous structures of the CuBTC/ZnO chitosan composite. The composites were tested for the adsorption capacity and removal efficiency towards the methylene blue dye by varying adsorbent dosage, adsorbate concentration, pH, and contact time. The pseudo-second-order and Langmuir models were the best fit for the adsorption of methylene blue on CuBTC/ZnO chitosan composite beads, indicating that the adsorption was monolayer and chemical in nature. The equilibrium dose of the composites was 1.6 g L^-1, and the contact time was 90 min with a removal efficiency of 98.75%. The maximum adsorption capacity was 50.07 mg g^-1. Regeneration of the composites was performed to check the reusability of the synthesized CuBTC/ZnO chitosan composite beads. The active oxygenated species generated by the photocatalytic action of ZnO on the contaminated water was responsible for the degradation of methylene blue. The reported composite beads can be used for up to 5 cycles to remove methylene blue.

Degradation of Azo Dyes with Different Functional Groups in Simulated Wastewater by Electrocoagulation

Increasing attention has been paid to the widespread contamination of azo dyes in water bodies globally. These chemicals can present high toxicity, possibly causing severe irritation of the respiratory tract and even carcinogenic effects. The present study focuses on the periodically reverse electrocoagulation (PREC) treatment of two typical azo dyes with different functional groups, involving methyl orange (MO) and alizarin yellow (AY), using Fe-Fe electrodes. Based upon the comparative analysis of three main parameters, including current intensity, pH, and electrolyte, the optimal color removal rates for MO and AY could be achieved at a rate of up to 98.7% and 98.6%, respectively, when the current intensity is set to 0.6 A, the pH is set at 6.0, and the electrolyte is selected as NaCl. An accurate predicted method of response surface methodology (RSM) was established to optimize the PREC process involving the three parameters above. The reaction time was the main influence for both azo dyes, while the condition of PREC treatment for AY simulated wastewater was time-saving and energy conserving. According to the further UV–Vis spectrophotometry analysis throughout the procedure of the PREC process, the removal efficiency for AY was better than that of MO, potentially because hydroxyl groups might donate electrons to iron flocs or electrolyze out hydroxyl free radicals. The present study revealed that the functional groups might pose a vital influence on the removal efficiencies of the PREC treatment for those two azo dyes.

A Novel N-Doped Nanoporous Bio-Graphene Synthesized from Pistacia lentiscus Gum and Its Nanocomposite with WO3 Nanoparticles: Visible-Light-Driven Photocatalytic Activity

This paper reports the synthesis of a new nitrogen-doped porous bio-graphene (NPBG) with a specific biomorphic structure, using Pistacia lentiscus as a natural carbon source containing nitrogen that also acts as a bio-template. The obtained NPBG demonstrated the unique feature of doped nitrogen with a 3D nanoporous structure. Next, a WO₃/N-doped porous bio-graphene nanocomposite (WO₃/NPBG-NC) was synthesized, and the products were characterized using XPS, SEM, TEM, FT-IR, EDX, XRD, and Raman analyses. The presence of nitrogen doped in the structure of the bio-graphene (BG) was confirmed to be pyridinic-N and pyrrolic-N with N1 peaks at 398.3 eV and 400.5 eV, respectively. The photocatalytic degradation of the anionic azo dyes and drugs was investigated, and the results indicated that the obtained NPBG with a high surface area (151.98 m²/g), unique electronic properties, and modified surface improved the adsorption and photocatalytic properties in combination with WO₃ nanoparticles (WO₃-NPs) as an effective visible-light-driven photocatalyst. The synthesized WO₃/NPBG-NC with a surface area of 226.92 m²/g displayed lower bandgap and higher electron transfer compared with blank WO₃-NPs, leading to an increase in the photocatalytic performance through the enhancement of the separation of charge and a reduction in the recombination rate. At the optimum conditions of 0.015 g of the nanocomposite, a contact time of 15 min, and 100 mg/L of dyes, the removal percentages were 100%, 99.8%, and 98% for methyl red (MR), Congo red (CR), and methyl orange (MO), respectively. In the case of the drugs, 99% and 87% of tetracycline and acetaminophen, respectively, at a concentration of 10 mg/L, were removed after 20 min.

Magnetic and electric field accelerate Phytoextraction of copper Lemna minor duckweed

In accordance with the opinion of the World Health Organization and the World Water Council the development of effective technologies for the treatment of wastewater from heavy metals for their discharge into water bodies or reuse is an urgent task nowadays. Phytoremediation biotechnologies is the most environmentally friendly and cheapest way of the treatment of wastewater, suitable for sustainable development principals. The main disadvantage of the phytoremediation is the slow speed of the process. A method for accelerating the process of phytoremediation by the combined effect of magnetic and weak electric fields is proposed. The purpose of this study is to determine the values of the parameters of the magnetic and weak electric fields that are most suitable for extracting cuprum ions from wastewater using the higher aqua plants (Lemna minor). A corresponding technological process based on the results of the study is proposed. The results have shown that the removal of copper cations from sulfate solutions effectively occurs in the initial period of time (1–5 hours) under the influence of a magnetic field with an intensity of H = 2 kA/m. Under the combined influence of an electrical current with density j = 240 μA/cm² and a magnetic field (H = 2 kA/m) the highest rate of copper extraction by duckweed leaves is achieved. Under these conditions, the greatest growth and development of plant leaves occurs. The paper presents the results of determining of the parameters of the electrochemical release from the eluate of the spent phytomass of duckweed. It has been determined that the release of metal occurs at E = 0.32 V. An original scheme for wastewater treatment from copper with subsequent separation of copper from the spent phytomass of duckweed is proposed. In general, the presented results are a scientific justification of wastewater treatment technologies and a contribution to resolving the crisis in the field of fresh water supply. An important contribution in the circular economy is a technology recommendation proposed for recovering copper from duckweed after wastewater treatment.

Efficient removal of ammoniacal nitrogen from textile printing wastewater by electro-oxidation considering the effects of NaCl and NaOCl addition

In this study, an electro-oxidation (EO) process using graphite electrodes as electrode pairs was used for the removal of chemical oxygen demand (COD), ammoniacal nitrogen (NH₄⁺-N), and color from real textile printing wastewater. The effects of solution pH, sodium chloride (NaCl) dosage, sodium hypochlorite (NaOCl), which is the oldest and still most important chlorine-based bleach, dosage, and oxidation time were investigated on the removal efficiencies. Operating conditions for the EO reactor were applied to current density 1 mA/cm², distance between the electrodes: 2 cm, 150 min operation time, and stirring speed of 500 rpm. At optimum conditions: pH 9.5, applied current density 1 mA/cm², NaCl dosage of 8 g/L, NaOCl dosage of 44.4 mg/L and 150 min electro-oxidation time, the obtained removal efficiencies were 86.5% and 91.1% for chemical oxygen demand (COD) and ammoniacal nitrogen, respectively. Efficiency was increased to 91.1% for ammoniacal nitrogen from 21.7% after applying EO combined with NaOCl addition compared to individual NaOCl addition.

Content of Carotenoids, Violaxanthin and Neoxanthin in Leaves of Triticum aestivum Exposed to Persistent Environmental Pollutants

Persistent pollutants such as pharmaceuticals, pesticides, musk fragrances, and dyes are frequently detected in different environmental compartments and negatively impact the environment and humans. Understanding the impacts of diffuse environmental pollutants on plants is still limited, especially at realistic environmental concentrations of contaminants. We studied the effects of key representatives of two major classes of environmental pollutants (nine different antibiotics and six different textile dyes) on the leaf carotenoid (violaxanthin and neoxanthin) content in wheat (Triticum aestivum L.) using different pollutant concentrations and application times. The wheat plants were watered with solutions of selected environmental pollutants in two different concentrations of 0.5 mg L⁻¹ and 1.5 mg L⁻¹ for one week (0.5 L) and two weeks (1 L). Both categories of pollutants selected for this study negatively influenced the content of violaxanthin and neoxanthin, whereas the textile dyes represented more severe stress to the wheat plants. The results demonstrate that chronic exposure to common diffusively spread environmental contaminants constitutes significant stress to the plants.

Investigation into the Adsorption of Methylene Blue and Methyl Orange by UiO-66-NO2 Nanoparticles

In this work, the adsorptive removal of methylene blue and methyl orange by UiO-66-NO₂ nanoparticles was studied. The influence of pH on the adsorption capacity was assessed. The kinetics of the adsorption process were investigated and compared with pseudo-first-order, pseudo-second-order, Elovich, and intraparticle models. The kinetics of the adsorption fits moderately with the pseudo-first-order, but perfectly fits with pseudo-second-order models, and has a very good fit with the Elovich and intraparticle models. The adsorption isotherms were measured and compared with the Langmuir and Freundlich models. The adsorption capacity of methyl orange (MO) on UiO-66-NO₂ nanoparticles (142.9 mg/g) was over three times higher than that of methylene blue (MB) on the nanoparticles (41.7 mg/g). The discrepancy between these capacities was attributed to the presence of the -NO₂ functional group, which caused a strong negative mesomeric effect in the metal-organic framework structure.

Photocatalytic and biocidal activities of ZnTiO2 oxynitride heterojunction with MOF-5 and g-C3N4: A case study for textile wastewater treatment under direct sunlight

The work aimed to synthesize three heterojunction photocatalysts (E_g = 2.65-2.78 eV) via in-situ encapsulation of 5% zinc doped titanium oxynitride (Zn_0.05TiO_xN_y) catalyst into MOF-5 and bulk (BCN)/sulfur-doped (SCN) g-C₃N₄ supports using a microwave method. The prepared photocatalysts were characterized and utilized to purify textile industrial wastewater from the organic dye (e.g., methylene blue, MB) and microbial (e.g., E. coli, S. aureus, and C. albicans) contaminants under dark, visible, and solar lights. The output data confirmed the higher activity of Zn_0.05TiO_xN_y@SCN and Zn_0.05TiO_xN_y@MOF-5 for photo-induced microbial growth inactivation (> 90%) under visible light, with photo-biocidal efficiency of 0.91-1.69 mCFU/Einstein. Such a phenomenon is ascribed to the synergism between the high antimicrobial capacity of supports and photoactivity of Zn_0.05TiO_xN_y. Also, Zn_0.05TiO_xN_y@SCN exhibited far superiority to mineralize MB dye (K_photo of 2.73 × 10^-2 min^-1) under direct sunlight due to its high photonic (ζ% of 4.4-8.3%)/quantum (QE of 0.56-0.54%) efficiencies for the generation of hydroxyl and superoxide (^-•O₂/•OH) oxidative species. As a practical case study, all heterojunction photocatalysts also demonstrated high-performance stability (5 cycles) for real textile wastewater treatment under sunlight (efficiency = 76.1-84.6%).

Facile one step green synthesis of iron nanoparticles using grape leaves extract: textile dye decolorization and wastewater treatment

The existing knowledge on the reactivity of green iron particles on textile dye and wastewater decolorization is very limited. In this study, the potential of green iron particles synthesized using grape leaves extract on reactive dye (reactive red 195, reactive yellow 145, reactive blue 4 and reactive black 5) decolorization were investigated. 95-98% of decolorization was achieved for all reactive dyes at 1.4-2.0 g/L of green iron. Maximum decolorization was attained at lower dye concentration and showed very little impact on decolorization when pH was increased from 3 to 11. The pseudo-first-order fit confirms the reaction between iron particles and dye molecules with rate constant 0.317-0.422 and it is followed by adsorption, data fit with pseudo-second-order model. Hence, not only adsorption but also the reduction process is involved in the reactive dye decolorization. Benzene, phenyl sodium, 2-chloro-1,3,5-triazine, naphthalene, sodium benzene sulfonate, benzene 1,2 di amine, anthracene-9,10 dione, aniline, phenol, benzene sulfonic acid were the major intermediates detected in dye decolorization and the respective reaction pathway is proposed. Green iron from grape leaves extract demonstrated better performance and it is recognized as the promising cost-effective material for textile wastewater treatment.

Natural or synthetic - how global trends in textile usage threaten freshwater environments

As the global demand for textiles increases, so to do the potential environmental impacts that stem from their production, use and disposal. Freshwater ecosystems are particularly at risk: rivers often act as the primary recipients of waste generated during the production of textiles and are subject to pollutants released during the broader lifecycle of a textile product. Here, we investigate how global technological and societal processes shape the way we produce, use and dispose of textiles, and what this means for the environmental quality and ecological health of freshwaters. We examine two predominant 'natural' and synthetic textiles (wool and Polyethylene terephthalate (PET), respectively), and find that risks to freshwater ecosystems vary throughout the lifecycle of these textiles; and across geographies, in-line with regulatory and economic landscapes. Woollen textiles pose most risk during the Production Phase, while PET textiles pose most risk during the Use and Disposal Phases. Our findings show that: (i) both 'natural' and synthetic textiles present substantial challenges for freshwater environments; and (ii) bespoke solutions are needed in areas of the world where the global division of labour and less stringent environmental regulations have concentrated textile production; but also in regions where high textile consumption combines with unsustainable disposal behaviours. Effective mitigation may combine technological advances with societal changes in market mechanisms, regulations, textile use and disposal.

Combination of catalytic ozonation by regenerated granular activated carbon (rGAC) and biological activated carbon in the advanced treatment of textile wastewater for reclamation

Wastewater reclamation in the textile industry has attracted considerable attention. In this study, catalytic ozonation by regenerated granular activated carbon (rGAC) and its combination with biological activated carbon (BAC) was investigated for the reclamation of a real bio-treated dyeing and finishing wastewater (BDFW). Catalytic ozonation by rGAC (O₃/rGAC) was 1.6-2.0 times more efficient than ozonation alone for pollutants degradation. Although iron oxide loaded rGAC (rGAC-Fe) improved the performance of catalytic ozonation by 14%-25%, but was labile (<2 days) compared to stable rGAC (>20 days). Catalytic ozonation improved the generation of ^•OH, contributing 1.1-1.7 times faster of chromophores decomposition and 0.24-0.55 times more increase of biodegradability than ozonation. However, catalytic ozonation increased the acute toxicity of BDFW by two times. The combination of O₃/rGAC and BAC can synergistically reduce COD, chromophores, and color in BDFW during 45-day's continuous operation, the improvements than O₃/rGAC being 21.0%, 18.8%, and 13.6%, respectively. Moreover, although O₃/rGAC of BDFW increased the toxicity from 98.3 to 146.5 μg-HgCl₂/L, post BAC significantly reduced the toxicity to 13.1 μg-HgCl₂/L. Engineering practice of water reclamation by O₃/rGAC-BAC was approved to be feasible based on both the water quality of treated water and the operation cost.

Human health risks due to exposure to inorganic and organic chemicals from textiles: A review

It is well known that a number of substances used in the textile industry can mean not only environmental, but also health problems. The scientific literature regarding potential adverse health effects of chemical substances in that industry is mainly related with human exposure during textile production. However, information about exposure of consumers is much more limited. Although most research on the health effects of chemicals in textiles concern allergic skin reactions, contact allergy is not the only potential human health problem. In this paper, we have reviewed the current scientific information regarding human exposure to chemicals through skin-contact clothes. The review has been focused mainly on those chemicals whose probabilities of being detected in clothes were rather higher. Thus, we have revised the presence of flame retardants, trace elements, aromatic amines, quinoline, bisphenols, benzothiazoles/benzotriazoles, phthalates, formaldehyde, and also metal nanoparticles. Human dermal exposure to potentially toxic chemicals through skin-contact textiles/clothes shows a non-negligible presence in some textiles, which might lead to potential systemic risks. Under specific circumstances of exposure, the presence of some chemicals might mean non-assumable cancer risks for the consumers.