Textile Industry Effluent Research Articles

La-supported SnO2–CaO composite catalysts for efficient malachite green degradation under UV–vis light

This study presents the development and optimization of La@SnO2–CaO composite catalysts for efficient photocatalytic degradation of malachite green dye in aqueous solutions under UV–vis light irradiation. The catalysts were prepared via conventional incipient-wetness impregnation and thoroughly characterized using advanced analytical techniques, including X-ray diffraction, Fourier transform infrared spectroscopy, UV–vis diffuse reflectance spectroscopy, N2 adsorption–desorption analysis, and scanning electron microscopy. To optimize photodegradation efficiency, the effects of three independent factors were systematically investigated using response surface methodology: Temperature, pH, and Sn/Ca molar ratio. Our results reveal optimal conditions for maximum dye degradation: pH 7, Sn/Ca molar ratio of 0.33, and a process time of 35 min, resulting in a maximum photodegradation efficiency of 98.80% for malachite green dye. Notably, visible light exhibited a more pronounced effect on dye degradation compared to UV light over time, with visible light achieving 25% greater dye removal after 60 min of illumination. Furthermore, the catalyst showed excellent recyclability, retaining 85% of its initial activity after five consecutive cycles. These findings contribute significantly to the development of sustainable methods for dye removal from wastewater and highlight the potential of La@SnO2–CaO composite catalysts in environmental remediation processes, particularly in treating textile industry effluents.

Benchmarking of key performance factors in textile industry effluent treatment processes for enhanced environmental remediation

This article presents a comprehensive benchmarking analysis of merit performance factors in the Effluent Treatment Plants (ETP) of the textile industry. The study aims to identify and evaluate key factors that contribute to the efficient operation and performance of ETPs. The performance of ETP was analyzed by valuable data gained from figures of PH, Dissolved oxygen, Dissolved solids, Suspended solids, Density, COD and BOD. The technical trends showed the deviations in the working conditions of Effluent Treatment Plant by variation in temperature. This variation is achieved by varying the settling time of wastewater in the sedimentation tank during the working process. The required dosing, plant efficiency and economic factors were taken into account. The Plant efficiency was determined to be 83.5% at normal conditions of water entering at temperature of 30°C and pressure of 1 atm along with addition of coagulants and flocculants in the wastewater. While the efficiency of the ETP plant was calculated about 88% using a Compact photometer at elevated conditions of temperature such as > 45°C, while at other temperatures the efficiency decreases significantly due to several reasons. The operating time of water treatment was decreased due to the variations in temperature of wastewater while other conditions kept constant like pressure, flow rates of water and chemicals (Polyacrylamide and Polymeric Ferric Sulfate). The usage of coagulants and flocculants at optimum conditions has been discussed in this study.

Immobilization of laccases on mechanically ground silk fibroin nanofibers for enhanced stability

Azo dyes in textile industry effluents pose significant health and environmental risks. Laccase is an enzyme capable of degrading azo dyes, offering an environmentally friendly solution for treating textile wastewater. However, laccases need to be immobilized on specific carriers to enable effective reuse in batch reactors and continuous operation in flow-through reactors. This study employed silk fibroin nanofibers (SFNFs) obtained by mechanically grinding degummed silkworm silk as sustainable carriers to immobilize laccases through carbodiimide-mediated crosslinking. The immobilized laccases (SFNF-laccases) exhibited improved pH tolerance in the range of pH 3.0–8.0 with a smaller reduction in activity compared to free laccases (SFNF-laccases: 32.9 %, free laccases: 50.4 %). The thermal stability of immobilized laccases was also improved, showing 19, 13, and 9 % higher activities than those of free laccases at 40, 50, and 60 °C, respectively. After 8 days of storage, the activity of SFNF-laccases was 79 % of their activity immediately after immobilization, whereas free laccases retained only 29 % of their initial activity. In addition, SFNF-laccases maintained 73 % of their original operational activity in a flow-through reactor after 8 days. These results demonstrate the great potential of mechanically ground SFNFs as carriers of laccase and the resulting SFNF-laccases in industrial wastewater treatment.

Robust regenerable metal-selenide-chitosan photocatalyst for the effective removal of Bromothymol Blue (BB) from wastewater

Water scarcity has been a crucial debate in recent years regarding the critical scenario of water pollution. The water body is continuously contaminated by organic effluents of textile industries, including pigmented dye pollutants. To tackle water bodies contamination, there is a need to develop an eco-friendly and efficient method for removing toxic dyes. Herein, ternary metal selenide nanocomposites of barium nickel selenide (NBSe-NPs) were synthesized by the solvothermal method supported by chitosan microsphere (NBSe-NPs-CM). Recovery of the catalyst was convenient by capping nanoparticles in the microsphere to maintain effective stability, biocompatibility, and well-designed surface coating. FTIR spectrum verified nanocomposite synthesis and chitosan microsphere (NBSe-CM) formation. SEM observations of nanocomposites and NBSe-CM indicated an average size of 13.78 nm and 253 μm, respectively. The presence of barium, nickel, and selenium elements in the NBS-NPs was verified by EDX analysis. The nanocomposites had a crystallite size of 15.73 nm. The photocatalyst exhibited a narrow bandgap of only 1.3 eV based on Tauc's plot. In addition, the synthesized microsphere demonstrated an efficient photocatalytic degradation (97 %) of Bromothymol Blue dye within 100 min under optimized operating conditions (pH of 6.0, dye concentration of 40 ppm, catalyst dosage of 0.25 g). The photocatalysis process followed the pseudo-first-order kinetics. The repeatability studies showed a slight decline in the catalyst's efficiency after four successive cycles. The DFT study shows that the NBSe-CM is energetically stable with more considerable negative binding energy, and the dye molecule interacts more strongly with the NBSe-CM surface. The findings highlight the exceptional characteristics of the newly designed ternary-metal-selenide-containing chitosan-microspheres for degrading dye contaminants from textile effluents.

Development of free flowing granular hybrid functionalized clay sorbent filters for chromium removal from waste water

Chromium (VI) contamination in water resources at industrial sites poses significant environmental and health risks. Conventional sorbents often suffer from limitations such as clogging, back pressure, poor kinetics, and challenges in coupling with flow systems and regeneration. This study focuses on developing, characterizing, and applying free-flowing granular (FFG) amidoxime-functionalized montmorillonite (Mt) clay sorbents (AO-Mt-H-C) to enhance chromium (VI) removal from contaminated waste water. Batch adsorption experiments demonstrated that AO-Mt-H-C outperformed montmorillonite clay modified with quaternary ammonium alone (Mt-H-C), achieving a Cr (VI) removal efficiency of 50.6 mg g−1 compared to 44.3 mg g−1, due to the synergistic interactions of quaternary ammonium and amidoxime functionalities. To address the limitations of conventional sorbents, such as clogging and poor kinetics, an FFG filter column was developed and tested, showing effective Cr (VI) removal across various water sources with minimal interference in drinking and groundwater. In industrial wastewater with higher matrix loads, over 99 % removal efficiency was achieved with a 25 % increase in sorbent dosage. Desorption and reusability assessments confirmed the AO-Mt-H-C's effectiveness across three cycles. Mathematical modelling using Thomas and Yoon–Nelson equations supported the design of customized treatment systems. Scalability was demonstrated by treating 1.6 m3 of textile industrial effluents (100 mg L−1 Cr (VI)) with quantitative removal efficiency (>99.5 %). This study illustrates that the hybrid functionalization and free-flowing granulation of clay sorbent materials significantly enhance Cr (VI) removal, providing valuable insights for advanced water pollution mitigation and environmental sustainability.

Insights on Microplastic Contamination from Municipal and Textile Industry Effluents and Their Removal Using a Cellulose-Based Approach.

The rampant use of plastics, with the potential to degrade into insidious microplastics (MPs), poses a significant threat by contaminating aquatic environments. In the present study, we delved into the analysis of effluents from textile industries, a recognized major source of MPs contamination. Data were further discussed and compared with a municipal wastewater treatment plant (WWTP) effluent. All effluent samples were collected at the final stage of treatment in their respective WWTP. Laser diffraction spectroscopy was used to evaluate MP dimensions, while optical and fluorescence microscopies were used for morphology analysis and the identification of predominant plastic types, respectively. Electrophoresis was employed to unravel the prevalence of negative surface charge on these plastic microparticles. The analysis revealed that polyethylene terephthalate (PET) and polyamide were the dominant compounds in textile effluents, with PET being predominant in municipal WWTP effluents. Surprisingly, despite the municipal WWTP exhibiting higher efficiency in MP removal (ca. 71% compared to ca. 55% in textile industries), it contributed more to overall pollution. A novel bio-based flocculant, a cationic cellulose derivative derived from wood wastes, was developed as a proof-of-concept for MP flocculation. The novel derivatives were found to efficiently flocculate PET MPs, thus allowing their facile removal from aqueous media, and reducing the threat of MP contamination from effluents discharged from WWTPs.

Kinetics of the decomposition of reactive black 5 on carbon nanostructured adsorbents

Textile industry effluents, containing vast quantities of toxic organic pollutants and synthetic dyes like Reactive Black 5 (RB5), pose a significant environmental threat. RB5 contamination can harm ecosystems and human health, necessitating effective treatment for water recycling and compliance with quality standards. Traditional methods like filtration often fall short in removing dye chemicals. This study examines the efficiency of nanocarbon-based adsorbents in removing RB5 from textile industry effluents. RB5 solutions at concentrations of 10 µM, 30 µM, 60 µM and 100 µM were investigated and characterized using scanning electron microscopy (SEM) and UV-Vis spectrophotometry. Activated carbon (AC) demonstrated the highest degree of RB5 decomposition, outperforming graphene nanoplatelets (GNPs) and graphene oxide (GO) and offering a promising solution for mitigating textile wastewater pollution. Kinetic studies revealed that RB5 adsorption follows a pseudo-second-order model for all adsorbents. The rate constants were determined using PSO kinetics and they were comparable with the rate constants of prior studies, indicating the applicability of the model to the study of the kinetics of similar dye adsorption and decomposition processes.

Investigating the efficacy of Palladium Doped Ceria for the Photodegradation of Azo Dyes

Ceria (CeO2) was prepared by microwave assisted precipitation method while sonothermal method was utilized for the synthesis of palladium doped ceria (Pd-CeO2) photocatalyst. HR-TEM analysis confirms the face centered cubic geometry (FCC) of CeO2. The particle size of Pd-CeO2 calculated from HR-TEM analysis (7.6±2.18 nm) is in close relation with XRD (8.25±0.25 nm). The SAED pattern of Pd-CeO2 shows the poly crystallinity where the d-spacing was 0.31 and 0.30 nm which corresponds to CeO2 and Pd crystal facets 111 and 100 respectively. The amount of dopant and existence of Pd, Ce and O was confirmed from EDX spectra and elemental mapping. BET surface area analysis of CeO2 (64.45 m2/g), Pd-CeO2 (60.20 m²/g) revealed that the decrease in the surface area of CeO2 due to Pd loading which is confirmed by pore volume (0.079 cm³/g) for CeO2 and pore volume for Pd-CeO2 (0.073 cm³/g). The photocatalytic activity of Pd-CeO2 was screened against a model azo dye Acid red-4 (AR-4). The fluctuation of the rate of photodegradation (PD) of AR-4 was observed under different reaction conditions. Therefore, the reaction parameters were optimized to achieve best catalytic activity up to PD; 98%. The kinetic study suggests that the PD of AR-4 follows 1st order kinetics with regression coefficient (R2=0.973) and rate constant (k=0.024/min). Recycling study revealed the prolong use of catalyst without significant loss of activity. DFT study and experiments revealed the synergism of Pd on the photo response of CeO2. Perhaps this synergistic effect due to metal support interaction, causes redistribution of charges and Fermi energy levels. The synthesized catalyst showed potential application for the treatment of textile industrial effluents.

Fabrication of nanocomposite membranes containing Ag/GO nanohybrid for phycocyanin concentration

In this research, silver/graphene oxide (Ag/GO) nanohybrid was first synthesized and used in production of polysulfone (PSF) ultrafiltration (UF) membranes via phase inversion method for concentrating phycocyanin (PC) and treating methylene blue (MB) dye effluent. Designing the experiment (DOE) using Box-Behnken method by Design Expert software helped to calculate the optimal values of the variables under study. The studied variables included PSF polymer concentration, polyvinyl pyrrolidone (PVP) pore-former concentration and Ag/GO nanohybrid content, which were investigated for their effects on pure water flux (PWF) and MB pigment rejection. According to the results of the DOE, the membrane containing 19.485 wt% PSF, 0.043 wt% PVP and 0.987 wt% Ag/GO was selected as the optimal membrane. Due to the high price of PC as drug, and the importance of removing MB pigment from the effluent of dyeing and textile industries, the membranes were first optimized with MB pigment and then the optimal membrane was used for concentrating PC. The results showed that PWF reaches from 40.05 L.m− 2.h− 1 (LMH) for the neat membrane to 156.73 LMH for the optimized membrane, which shows about 4 times improvement. Compared to the neat membrane, flux recovery ratio (FRR) of the optimized membrane increased by about 20% and its total fouling (Rt) decreased by about 10%. Also, the results showed that the optimized membrane can remove 81.6% of MB, as well as to reject 93.8% of PC.

MoS2@MIL-53 (Ni) nanocomposite for water splitting and water remediation through real time effluent treatment

A novel molybdenum disulfide@ materials institute of Lavoisier (MoS2@MIL-53 (Ni)) hetero-structure material has been designed to act as a hydrogen/oxygen generator and as a water remediation agent. Two-dimensional layered MoS2@MIL-53 (Ni) nanocomposites were prepared through the hydrothermal method. Flower and layered morphology were observed for MoS2, and MIL-53 (Ni), respectively in the field emission scanning electron microscopy (FESEM) images. The MoS2@MIL-53 (Ni) nanocomposite demonstrated a high dye degradation efficiency of ∼98 % and ∼96 % for Rhodamine B (RhB) and bodactive blue (BAB) within 80 minutes of time duration, respectively. In the case of untreated textile industrial effluent (TIE), the nanocomposite achieved an efficiency of around 86 % over a period of 9 hours. The ultraviolet-visible absorption spectra of RhB, BAB, and TIE displayed peaks at ∼565 nm, 665 nm, and 530 nm, respectively. Additionally, the nanocomposite exhibited excellent stability over five cycles when tested against RhB. During hydrogen evolution reaction (HER), MoS2@MIL-53 (Ni) nanocomposite showed a Tafel slope of 105 mV/decade and overpotential of −0.073 V vs. RHE. Similarly, oxygen evolution reaction (OER) studies exhibited a reduced over potential at 0.49 V vs. RHE @ 10 mA/cm2 and the Tafel slope was calculated to be 42 mV/decade. Further, the chronoamperometry analysis of MoS2@MIL-53 (Ni) confirmed that the sample exhibited relatively good stability with respect to both HER and OER analysis for 24 hours. This is indicative of MoS2@MIL-53 (Ni)’s structural stability and its strong electrocatalytic activity.

Facile synthesis, morphological, optical, catalytic and photocatalytic properties of Ag nanoparticles decorated Ce doped ZnO hybrid plasmonic nanorods

Designing plasmonic metal–semiconductor hybrid nanostructures for photodecomposition of industrial textile effluent has been considered as a great way to boost the catalytic and photocatalytic capability by promoting effective separation of photoexcited charge carriers. Herein, fabrication of Ag nanoparticles decorated Ce doped ZnO nanostructures were demonstrated via facile wet chemical method. The morphology and structure of the fabricated photocatalysts were analysed using FESEM, XRD and Raman spectroscopy whereas PL, TRPL and UV–vis absorption spectroscopy were employed to examine their optical behaviour. Catalytic response of the synthesized catalysts was studied for 4-NP to 4-AP reduction and the results are more favourable for Ag loaded Ce doped ZnO catalysts and achieved 96.4 % reduction of 4-NP in only 4 min. Photocatalytic measurements showed that higher Ag NP loading onto Ce doped ZnO nanostructures led to superior photodegradation ability over other photocatalysts for the degradation of synthetic dyes and levofloxacin antibiotic. The sunlight driven photodecolorization of harmful synthetic dyes and levofloxacin were studied and efficacy of 97.5, 97.1, 85.1, and 70.9 % were achieved for MG, MB, RhB and MO dyes, respectively in 12 min and 97.2 % efficiency for degradation of levofloxacin was achieved in 20 min of sunlight exposure. Furthermore, the key reactive species was identified and tentative photodegradation process was explained. This work provides an excellent plasmonic-semiconductor catalyst and photocatalyst with good photostability and practical applicability indicating its enormous potential for application in environmental remediation.

A practical approach to demonstrate the circular economy in remediation of textile dyes using nutraceutical industrial spent.

We used Nutraceutical Industrial Coriander Seed Spent (NICSS), a readily available, cheap, eco-friendly, and ready-to-use material, as an innovative adsorbent for the bioremediation of a bisazo Acid Red 119 (AR 119) dye, which is likely a mutagen from textile industrial effluents (TIE). A laboratory-scale experiment was tailored to demonstrate the framework of the circular economy (CE) in the remediation of textile dyes using Nutraceutical Industrial Spent to align with the principles of sustainability and valorization. An experimental q e value of 97.00 mg g-1 was obtained. For the practicality and effectiveness of the method, a two-level fractional factorial experimental design (FFED) was employed to determine variables that influence the adsorption capacity of NICSS. At optimal settings (pH of 1.4, adsorbent dosage of 6.000 g L-1, adsorbent particle size of 96 μm, initial dye concentration of 599 mg L-1, adsorption duration of 173 min, orbital shaking speed of 165 rpm, and temperature of 35 °C), the maximum adsorption efficiency achieved through statistical optimization was 614 mg g-1. Six factors influencing the adsorption process were examined experimentally and were considered important for commercialization. Three orders of magnitude were applied to the identified variables in scaling experiments. Adsorption-equilibrium data were analyzed using nine isotherm models. The best fit was discovered to be the Vieth-Sladek adsorption isotherm model. The suitable mechanism for the overall rate of the adsorption process was a pseudo-second-order reaction: mass-transfer mechanistic studies were predicted to predominate over the diffusion process. NICSS was characterized using SEM and FTIR spectroscopy. Utilizing plastic trash, the dye-adsorbed NICSS that was recovered as "sludge" was utilized as a reinforcing material to create composites. Dye-adsorbed NICSS thermoplastic and thermoset composites were studied and compared with NICSS composites in terms of their physicomechanical and chemical properties.

Photocatalytic nanohybrid UV-light-driven PVDF/GO-NiFe@SiO2 membrane coupled with bentonite adsorption and ozonation process for a sustainable textile wastewater treatment

The textile industries face significant environmental challenges due to the presence of complex pollutant dyes in its wastewater, making it one of the world's major sources of industrial water pollution. Numerous studies have been employed to overcome this problem, including physical, chemical, and biological treatments. However, most of those methods still suffered to achieve higher dye removal performance. This study provides new insight regarding textile wastewater treatment containing indigo red as the main colorant by carrying out a hybrid process combining bentonite adsorption, ozonation, and photocatalytic membrane filtration. For the membrane, we propose a modified polyvinylidene fluoride (PVDF) membrane incorporated with graphene oxide (GO) and nickel-iron doped silica (NiFe@SiO2) photocatalyst, which is named PVDF/GO-NiFe@SiO2 membrane. The membrane was employed under different sets of filtrations (dark and under ultraviolet irradiation) to treat natural dye wastewater from textile industry effluent. Further improvement was achieved when UV light irradiation was subjected to the process. This sequential adsorption-ozonation-membrane process under UV exposure exhibited improved dye removal from 55.11 % to 97.22 %. The results show that the proposed hybrid process successfully improved the membranes' antifouling behavior, thus boosting the membranes' performance and durability. From a broader perspective, our work promotes new insights for the integration of other physical, chemical, and biological treatment methods to improve the performance and durability of membrane-based processes, particularly for dye wastewater treatment.

Textile azo dye, Sudan Black B, inducing hepatotoxicity demonstrated in in vivo zebrafish larval model.

Environmental pollution, particularly from textile industry effluents, raises concerns globally. The aim of this study is to investigate the hepatotoxicity of Sudan Black B (SBB), a commonly used textile azo dye, on embryonic zebrafish. SBB exposure led to concentration-dependent mortality, reaching 100% at 0.8mM, accompanied by growth retardation and diverse malformations in zebrafish. Biochemical marker analysis indicated adaptive responses to SBB, including increased SOD, CAT, NO, and LDH, alongside decreased GSH levels. Liver morphology analysis unveiled significant alterations, impacting metabolism and detoxification. Also, glucose level was declined and lipid level elevated in SBB-exposed in vivo zebrafish. Inflammatory gene expressions (TNF-α, IL-10, and INOS) showcased a complex regulatory interplay, suggesting an organismal attempt to counteract pro-inflammatory states during SBB exposure. The increased apoptosis revealed a robust hepatic cellular response due to SBB, aligning with observed liver tissue damage and inflammatory events. This multidimensional study highlights the intricate web of responses due to SBB exposure, which is emphasizing the need for comprehensive understanding and targeted mitigation strategies. The findings bear the implications for both aquatic ecosystems and potentially parallels to human health, underscoring the imperative for sustained research in this critical domain.

Synthesis and Characterization of a New Ion Exchange Cellulose -1- Butane Sulphonic Acid (CBSA) Resin and its Application for Removal of Hazardous Metal Ion (Pb2+) from Industrial Waste Water by Batch Method

Objective: The purpose of this work is to develop and evaluate a new cellulose-1-butane sulphonic acid resin and use it for the elimination of hazardous metallic ions from textile industry effluent. Method: In the laboratory, a new cellulose-based resin containing 1- Butane sulphonic acid group has been synthesized. 1-Butane sulphonic acid group has been introduced into cellulose matrix through modified Porath’s method. Findings: Development of cellulose-1-butane sulphonic acid resin based on natural polysaccharides for the removal of lead ions, a dangerous metal, from industrial wastewater. Cellulose -1-Butane sulphonic acid resin's adsorbed metal ions were efficiently eluted using varying strengths of HCl solution. The resin could then be washed with pure, acidic distilled water to restore it to its H+ cationic exchanger state ten times. The hazardous metal ion Pb2+ can be specifically extracted from industrial waste water using the cellulose-1-Butane Sulphonic Acid (CBSA) resin. Novelty: Ion exchange capacity, pH titration, FTIR spectra, elemental analysis, and moisture levels were used to characterize the CBSA resin. At various pH levels, the distribution coefficient value (Kd) of lead metal ions has been methodically investigated using the batch method. Keywords: Effluent, Distribution Coefficient, Resin, Waste Water, Polysaccharide

Enhanced photodegradation of textile dye wastewater using silane/polymer doped ZnO nanocomposites and antibacterial activity

Accumulation of textile dye wastewater is major global issue that causes negative impact to the ecosystem. This study focuses on industrial textile dye effluent treatment by photodegradation, and degradation of Malachite green dye under sunlight, visible and UV light. ZnO demonstrated hexagonal wurtzite structure with average crystallite size 38 nm for ZnO/PEG, 21 nm for ZnO/PEG/VTES and 17 nm for ZnO/PEG/VTMS. Field Emission Scanning Electron Microscopy and Energy Dispersive Spectroscopy revealed nanometer sized particles and purity. Bandgap energy and particle size of ZnO/PEG/VTMS is 102 nm and 3.134 eV is lesser than ZnO/PEG (147 nm, 3.181 eV) and ZnO/PEG/VTES (109 nm, 3.151 eV). Photoluminescence analysis revealed reduced recombination rate of ZnO/PEG/VTMS. Antibacterial efficacy of ZnO/PEG/VTMS was tested against Staphylococcus aureus (35 mm) and Escherichia coli (29 mm). Photodegradation of textile dye wastewater by ZnO/PEG/VTMS under visible and UV light exposure revealed an effective way for textile dye effluent treatment, which maintained its efficiency even after five photodegradation cycles.

Correction: Anodic oxidation as promoting technology for treatment and reuse of industrial textile effluent using ruthenium-doped lead dioxide (PbO2) anode

Correction: Anodic oxidation as promoting technology for treatment and reuse of industrial textile effluent using ruthenium-doped lead dioxide (PbO2) anode

Oxalic Acid-Assisted Photo-Fenton Catalysis Using Magnetic Fe3O4 Nanoparticles for Complete Removal of Textile Dye

Textile industry effluents contain several hazardous substances, such as dye-containing effluents, which pose environmental and aesthetic challenges. Presently, the microbial-based remediation process is in use. This study investigated the application of ferrous–ferric oxide (Fe3O4) nanoparticles, a readily formulated nanoadsorbent, to remove scattered dye molecules from industrial effluents. The ferrous–ferric oxide nanoparticles were prepared using a chemical co-precipitation method. The nanoparticles had 26.93 emu g−1 magnetization, with sizes smaller than 20 nm, and possessed a highly purified cubic spinel crystallite structure. The catalytic activity of the iron oxide depended on the dose, photocatalytic enhancer, i.e., H2O2 level, pH of the reaction medium, and dye concentration. We optimized the Fenton-like reaction to work best using 1.0 g/L of ferrous–ferric oxide nanoparticles, 60 mM oxalic acid at pH 7.0, and 60 ppm of dye. Iron oxides act as photocatalysts, and oxalic acid generates electron–hole pairs. Consequently, higher amounts of super-radicals cause the rapid degradation of dye and pseudo-first-order reactions. Liquid chromatography–mass spectrometry (LC-MS) analysis revealed the ferrous–ferric oxide nanoparticles decolorized and destroyed Disperse Red 277 in 180 min under visible light. Hence, complete demineralization is observed using a photo-Fenton-like reaction within 3 h under visible light. These high-capacity, easy-to-separate next-generation adsorption systems are suggested to be suitable for industrial-scale use. Ferrous–ferric oxide nanoparticles with increased adsorption and magnetic properties could be utilized to clean environmental pollution.

Activated Carbon Prepared from Waste Coffee Grounds: Characterization and Adsorption Properties of Dyes.

Spent coffee grounds (SCGs) have great potential as a useful, value-added biological material. In this context, activated carbon (AC) was prepared from SCGs by an activation process using H3PO4 at 600 °C in the air and used as an adsorbent for the azo dye AO7, a model molecule for dye colorants found in textile industry effluents. X-ray diffraction, SEM and BET revealed that the AC was predominantly amorphous, consisting of a powder of 20-100 µm particles with mesopores averaging 5.5 nm in pore size. Adsorption kinetics followed a pseudo-second-order law, while the Langmuir model best fitted the experimental isotherm data (maximum capacity of 119.5 mg AO7 per AC g). The thermodynamic parameters revealed that adsorption was endothermic and spontaneous. All the characterizations indicated that adsorption occurred by physisorption via mainly π-π interactions. The best experimental removal efficiency optimized by means of a Box-Behnken design and response surface methodology was 98% for an initial AO7 concentration of 20 mg·L-1 at pH 7.5 with a dose of 0.285 g·L-1 of AC and a contact time of 40 min. These results clearly show that activated carbon prepared from SCGs can be a useful material for efficiently removing organic matter from aqueous solutions.

Treatment of textile industry effluents with up‐flow anaerobic sulfidogenic reactor

AbstractBACKGROUNDDyes present in textile wastewater can pose various environmental problems, including toxicity, carcinogenicity and mutagenicity, when released into receiving environments. Sulfidogenic bacteria play a crucial role in wastewater treatment by reducing sulfate and producing sulfide through the utilization of organic compounds in water. The resulting sulfide often transfers its electrons to another electron acceptor. This study focused on the treatment of real textile wastewater using an up‐flow sulfidogenic column bioreactor.RESULTSThe reactor was acclimated to sulfate‐reducing conditions when influent chemical oxygen demand and sulfate concentrations were 1742 and 2000 mg L−1, respectively. Subsequently, a gradual transition was made from sulfate‐reducing conditions to dye‐reducing conditions. Throughout the study, the hydraulic retention time was maintained at 1 day.CONCLUSIONThe influent dye concentration was 2722 Pt‐Co, and an impressive dye removal efficiency of approximately 90 ± 2% was achieved. This corresponds to a removal rate of 2450 Pt‐Co L−1 day−1. Although the sulfide concentration in the reactor decreased in the last period, investigating the extent to which this sulfide participates in the dye removal may expand the use of sulfidogenic reactors in the treatment of real textile industry wastewater. © 2024 The Author(s). Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).