Textile Wastewater Treatment Research Articles

Sequential anaerobic–intermittently aerated treatment of textile and domestic wastewater

Sequential anaerobic–intermittently aerated treatment of textile and domestic wastewater

Native microorganisms for sustainable dye biodegradation in wastewaters from jeans finishing.

The textile mill is one of the most water-consuming industries. Wastewater production is very high, and among the main generated pollutants are dyes. In particular, jeans finishing, which is performed all over the world, generates wastewater with indigo dye that has to be eliminated before discharge. This work studies the biological treatment of this type of wastewater using native microorganisms, i.e., without the need for external seed sludge to start-up the process. Two strategies for starting up the biological treatment using laboratory sequencing batch reactors have been compared: the addition of seed sludge from a biological reactor of a wastewater treatment plant and the non-addition of seed sludge, which means that native microorganisms (those in wastewater coming from the industry facilities) are responsible for COD and color degradation. Special attention is paid to biomass shift in both reactors, analyzing both bacterial and fungal populations. Results yielded more than 90% of COD and color removal after 25days in both reactors. MLSS increased in both reactors during the operation, reaching very similar values (around 1840mg/L). Rozellomycota was the predominant phylum in the reactors. Concerning bacteria, Planctomycetota abundance increased considerably in both reactors, which shows the important role of these bacteria in the treatment. It can be concluded that the lower bacterial diversity in the native population in comparison with the seeded sludge was shifting to a higher microbial diversity during the process, achieving a similar microbial population in reactors. It implies that it is not necessary to either work with isolated cultures or seeded sludge, which leads to a simpler and more sustainable solution for textile wastewater treatment in areas all over the world.

Separation properties and fouling resistance of polyethersulfone membrane modified by fungal chitosan.

This research explores the enhancement of polyethersulfone (PES) membranes through the incorporation of chitosan derived from the lignicolous fungus Ganoderma sp. Utilizing wet phase inversion and solution casting techniques, chitosan was successfully integrated into the PES matrix, as confirmed by Fourier Transform Infrared Spectroscopy (FT-IR), which indicated a high deacetylation degree of 75.7%. The incorporation of chitosan significantly increased the membrane hydrophilicity, as evidenced by a reduction in the water contact angle and a substantial improvement in pure water permeability, from 17.9L m-2 h-1 bar-1 to 27.3L m-2 h-1 bar-1. The membrane anti-fouling properties were also notably enhanced, with the Flux Recovery Ratio (FRR) increasing from approximately 60-80%. Moreover, the chitosan-modified PES/CS membrane, particularly at a 5% chitosan concentration, demonstrated exceptional efficacy in pollutant removal, achieving over 90% elimination of total suspended solids, cadmium (Cd), and lead (Pb), alongside a 79% reduction in color during the treatment of textile wastewater.

Establishing robust ZnO-sodium alginate nanocomposite for dye wastewater treatment: characterization, RSM methodology, and mechanism evaluation.

In today's world, water is a highly valued resource, and enhancing the quality of this natural endowment is a significant concern and a worldwide endeavor. This study sought to purify real wastewater and water tainted with methylene blue (MB) by immobilizing ZnO nanoparticles onto an alginate matrix using a straightforward approach and a three-dimensional structure. After analyzing the impact of , it was determined that 93.84% of MB was successfully removed (time = 120 min, dye concentration = 15 mg/L, catalyst amount = 2.5 g). The effects of inorganic ions and water types were investigated to simulate real wastewater conditions, and the catalyst performed satisfactorily. Alginate played a significant role in selectively removing dye, and the catalyst effectively removed 80.36% of MB and, in contrast, 20% of methyl orange (MO). The practical application of the catalyst was evaluated in textile wastewater treatment, and the catalyst showed satisfactory performance. An average 2.49% reduction in dye removal was observed after five stages of using the catalyst, demonstrating the beads' excellent stability. The composites were subjected to free radical trapping experiments to ascertain the active species. According to the results, and acted as the main reaction species in the degradation of MB. At the end, the synergistic mechanism of adsorption and degradation in MB removal was presented.

Weakly-negatively-charged loose nanofiltration membranes tailored by polyethyleneimine for dye/salt separation

Loose nanofiltration membranes with a weakly negatively charged surface were made from interfacial polymerization between natural hydrophilic polymer carboxylated chitosan (C-CS) and trimesoyl chloride (TMC) firstly and further depositing branched polyethyleneimine (PEI) on top of the surface to tailor the membrane structures and surface charge properties. This kind of membrane was exploited for dye/salt separation in textile wastewater treatment. The effects of contents and molecular weights of PEI on the morphologies, surface charge, hydrophilicity, pore size, and dye/salt separation performance of the membrane were comprehensively investigated. We found that the top layer of PEI with a moderate molecular weight is suitable to form a loose structure for dye/salt separation. The optimized membrane has a comparable high water permeability (44.4 L/m2.h.bar), a low salt rejections (2.6 % for Na2SO4, 7.7 % for NaCl, and 6.8 % for MgCl2), a relatively high dye rejection (96.9 % for Congo Red, 85.4 % for Methyl Blue, 51.1 % for Bromophenol Blue, and 48.3 % for Reactive Black 5), and an extremely high CR/Na2SO4 fractionation ratio (37.27). Moreover, the resultant membrane shows excellent anti-fouling performance after 5 cycles (50 h) of filtration. It maintains a high Congo Red rejection during a 10-day long-term run. This study shows an easy way to fabricate and adjust the properties of loose nanofiltration membranes that work well for dye/salt separation using common and low-cost polymers. It shows promising potential in the application of textile wastewater treatment and resource recovery.

Utilizing electrooxidation for textile effluent wastewater treatment and simultaneous electrocatalytic hydrogen production: Transforming waste into energy and promoting water reuse in a circular economy context

Textile effluent wastewater poses a serious environmental risk because of its high concentration of pollutants, which include organic compounds, heavy metals, and dyes. The present study investigates the technical and economic feasibility of hybrid water electrolysis performances. Specifically, real textile effluent wastewater was utilised to examine simultaneous abatement and electrochemical hydrogen production. The treated water can be recycled in the textile mill, offering the benefits of trash-to-treasure and cost savings through the circular economy. In addition to reducing the environmental impact of textile wastewater, the synergistic approach seeks to maximise its potential for producing hydrogen as clean energy. Here, the commercially available stainless sheet was used as the anode in the electrochemical setup system and the two-dimensional Ti3C2TX MXene was used as the catalyst embedded cathode. The optimal electrode-electrolyte parameter settings resulted in an 83 % decrease in COD level and a degradation efficiency of about 88 %. The potential for widespread adoption in the textile industry is highlighted by the discussion of the economic viability and environmental advantages of using wastewater from textile effluents for pollutant degradation and hydrogen production. Hence, the energy estimation was looked at and estimated in order to evaluate the process viability. For instance, the hybrid electrolysis process uses a very small amount of electricity (0.825 kWh m−3 order−1) and has an apparent operating current (30 mA/cm2). This work could serve as a guide for the methodical assessment and choice of hybrid water electrolysis using actual wastewater. The electrode's recyclability and reuse were proven for possible commercial applications. The stability of the Ti3C2TX electrode over a wide pH range was investigated in order to produce hydrogen on a big scale at a reasonable cost.

Catalytic ozone oxidation performance of Fe-Ce@γ-Al2O3 in reverse osmosis concentrate treatment

The reverse osmosis concentrate (ROC) produced in the process of textile wastewater treatment has a high salt content, posing a significant environmental threat. In this study, catalytic ozone oxidation was used to treat ROC, which initially had a chemical oxygen demand (COD) of 127.38 mg/L. The Fe-Ce@γ-Al2O3 catalysts had the best performance under the Fe/Ce doping ratio of 3:1, calcination temperature of 500 °C with calcination time of 4 h. SEM and XRD analyses confirmed the successful loading of Fe and Ce on γ-Al2O3. The catalytic ozone oxidation conditions were optimized by the response surface method (RSM). Under the optimal reaction conditions (catalyst dosage of 139.07 g/L, ozone ventilation rate of 1.65 L/min, and initial pH of 9.86), the actual COD removal rate reached 89.21 %. Three-dimensional fluorescence spectroscopy was used to analyze the degradation mechanism of dissolved organic matter (DOM) during the treatment of ROC. Three-dimensional fluorescence spectrum (3DEEM) results demonstrated the obvious degradation of DOM in ROC after the catalytic ozone oxidation treatment. The COD removal rate remained at approximately 80 % after 10 recycles, indicating that the Fe-Ce@γ-Al2O3 catalyst had good catalytic stability and reusability. In summary, the Fe-Ce@γ-Al2O3 catalysts demonstrate sustained practical effectiveness and high catalytic efficiency, making them suitable for the treatment of ROC.

Treating waste with waste: Treatment of textile wastewater using upcycled food waste as a pore-forming agent in the fabrication of ceramic membranes employing DOE/FFD design

This study investigates a novel method for food waste management by using it as a sustainable replacement for conventional pore-forming agents in ceramic membrane production. The membranes were analyzed using various techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and a universal testing machine. The morphologies of the membranes were observed using scan electron microscopy (SEM). The effects of particle size (45–125 μm), pore-forming agent (5–20 wt%), and sintering temperature (900–1150 °C) on the porosity and mechanical strength of the membranes were investigated using the Design of Experiments (DoE) and Response Surface Methodology (RSM). The optimized membrane was evaluated for its performance in filtering industrial textile wastewater. It achieved impressive results, with approximately 98.4 % removal of turbidity and 71.3 % removal of chemical oxygen demand. This research paves the way for optimizing ceramic membrane fabrication using upcycled food waste, promoting sustainability and offering potential solutions for both food waste management and industrial wastewater treatment challenges.

Biological decolorisation of the anionic Dye Acid Blue 9 by bacterial consortium: A sustainable and ecofriendly approach for the treatment of textile wastewater

Industrialization has led to the proliferation of dye waste, posing significant environmental challenges due to the structural complexity of dyes. Various industries discharge untreated toxic waste into water bodies, posing severe environmental hazards to humans as well as aquatic ecosystem. Synthetic dyes from textiles exacerbate this issue due to their toxicity, making the management of industrial wastewater a significant environmental challenge. This study offers a potential solution by investigating the degradation of hazardous Acid Blue-9 (AB9) dye using bacterial consortium containing Pseudomonas fluorescens and Bacillus subtilis. The experiments were conducted in minimal salt media with varying concentrations of different parameters (pH, temperature, initial dye concentration, size of inoculum, carbon and nitrogen sources) used for optimization process. Using the One-Factor-At-A-Time method, the consortium in the study was able to decolorize at a noteworthy rate of decolorisation about 85–87.2 %. This rate was notably increased to around 90.02 % with the implementation of Response Surface Methodology. Additionally, the decolorisation process was further confirmed by using UV-Visible Spectroscopy and Fourier Transform InfraRed Spectroscopy. Additionally, a phytotoxicity assessment test on crops of agricultural significance supports the potential of this bacterial consortium for the bioremediation of AB9 contaminated water. The dye samples treated with bacterial consortium showed significantly higher seed germination rates (∼82.9 %), along with increased shoot (∼9.13 cm) and root lengths(∼3.01 cm), compared to the untreated samples. This promising finding suggests the potential for reusing treated water in agriculture and industry, offering a sustainable solution to water pollution.

Comparative treatment of textile dye wastewater with chemical coagulants and bacterial exopolysaccharides

Traces of chemical coagulants, such as alum, commonly used in wastewater treatment, remain in the water effluent and also result in secondary sludge that is difficult to treat. On the other hand, Extracellular Polymeric Substances (EPS) are safer and can be used as alternative bio flocculants. A study was hence done to compare the effectiveness of the treatment of Reactive Black 5 (RB5) textile wastewater with chemical coagulants and bacterial EPS. The jar test method was used to treat the wastewater with Alum and Polyferrous Sulphate (PFS) at varied pH (2–10) and respective dose concentrations. EPS was produced by bacteria isolated from cotton gin trash soil collected from Kitui ginnery in Kenya. EPS treatment was done at 30 °C for 72 h. EPS-producing bacteria isolates were identified by molecular analysis. The chemically and EPS-treated wastewater was analyzed for color, Total Dissolved Solids (TDS), and Chemical Oxygen Demand (COD). Respective color and TDS removal capacity by PFS and alum were (86.1% and 42.18%) and (85.1% and 69%) at their optimal conditions of (pH 7 and 100 mg/L) and (pH 7 and 140 mg/L). Similarly, PFS and alum reduced COD by 27.25% and 26.65%. Respective dye removal by YEAK2 −5 and YEPD K2 −2 EPS was 69.1% and 85.7%. However, YEPD K2 −2 and YEAK2 −5 EPS caused a respective rise of TDS by 40.14% and 67.17%. The respective reduction of COD by YEPD K2 −2 and YEAK2 −5 EPS was 56.25% and 54.24%. The chemically and EPS-treated wastewater met the National Environment Management Authority (NEMA) limits. The YEPD K2 −2 and YEAK2 −5 isolates were both identified as Bacillus sp. GC–MS and FTIR analysis results indicated that the two EPS were heteropolysaccharides composed of different sugar derivatives and hydroxyl as the main functional group. The results for treatment of the dye wastewater by Alum, PFS, and EPS were therefore comparable. The bacterial EPS bio flocculants can therefore serve as effective and cleaner substitutes to the alum and PFS chemical coagulants.

The potential of alkaline tolerant microbial consortia for textile wastewater treatment under integrated anaerobic/aerobic conditions: Performance evaluation and microbial community analysis

Sequential anaerobic/aerobic (A/O) treatment conditions for textile wastewater (WW) are more effective than conventional biological treatment. Anaerobic treatment is essential because anaerobic microbes can first break down complex and recalcitrant compounds, which are difficult to degrade under aerobic conditions. The simpler, more degradable compounds are then further broken down by aerobic microbes. This study aimed to evaluate the performance of a sequential A/O treatment process using a pilot-scale reactor to treat real textile WW and to characterize reactor and inoculum microbial community structures. The reactors were inoculated with microbial consortia originating from a diverse alkaliphilic soda lake in the Ethiopian Rift Valley. The WW test parameters were used to evaluate the performance of the treatment process. At steady state, the removal efficiencies were 97 % for dye, 86 % for Chemical Oxygen Demand (COD), and 93 % for Total Kjeldahl Nitrogen (TKN). Amplicon sequencing revealed that Firmicutes, Proteobacteria, and Actinobacteria were the dominant phyla in all the samples. Uncategorized microorganisms, followed by Alkalibacterium, Bifidobacterium, and Clostridium were the most abundant taxon in all the samples. The microbial community detected during the treatment process was not abundant in the inoculum originating from Lake Chitu, suggesting that the communities likely originated from textile WW. The textile WW treated with the integrated A/O process effectively degraded dyes, and the inoculated microbes demonstrated resistance to the toxic chemical composition of the WW. The integrated treatment process, along with the alkaliphilic microbial consortia, has proven to be practical for treating textile WW, offering valuable insights for field-scale applications.

Physical, chemical and biological treatment of textile wastewater for removal of dyes and heavy metals

The water consumption by textile industries is millions of gallons per day. Discharge of untreated wastewater causes environmental, health, and aquatic life problems. This study aims to remove the dyes and heavy metals in textile wastewater by three different methods. In physical treatment, adsorption includes rice husk and sawdust and coagulation includes lime and alum, in chemical treatment AOPs and biological treatment Pistia stratiotes and Eichhornia crassipes macrophytes were utilized. Results showed that the maximum removal efficiency of azo dyes AY-17, AY-36, DY-4, DR-28, EBT, AB-1 was 35 %, 87 %, 89 %, 95 %, 94 %, 78 % and basic dyes MV-10B, BG-4, BB-9 was 80 %, 76 %, 94 % and reactive dyes RO-4, RO-16 and RB-5 was 89 %, 78 %, 95 % after physical treatment. The maximum removal efficiency of heavy metal Cu was detected 28.46 % with alum compared to other materials used in the physical treatment. The maximum removal efficiency of azo dyes AY-17, AY-36, DY-4, DR-28, EBT, AB-1 was 74 %, 91 %, 94 %, 88 %, 89 %, 92 % and basic dyes MV-10B, BG-4, BB-9 was 89 %, 87 %, 94 % and reactive dyes RO-4, RO-16 and RB-5 was 82 %, 68 %, 86 % after chemical treatment. H2O2/O3 and ozonation yielded a maximum removal efficiency of 31.35 % and 26.36 %, respectively, for Cu metal after chemical treatment. The maximum removal efficiency of azo dyes AY-17, AY-36, DY-4, DR-28, EBT, AB-1 was 62 %, 78 %, 80 %, 92 %, 89 %, 69 % and basic dyes MV-10B, BG-4, BB-9 was 90 %, 80 %, 80 % and reactive dyes RO-4, RO-16 and RB-5 was 90 %, 84 %, 62 % after biological treatment on dilutions. The maximum removal efficiency of Zn was 69.4 %, 53.5 %, and 61.7 % with Eichhornia crassipes, Pistia stratiotes, Pistia stratiotes + Eichhornia crassipes respectively. Overall, the biological treatment showed the best results for the removal of dyes and heavy metals so for this reason, this technique could be integrated into the industrial management plan for treating wastewater.

Electrochemical advanced oxidation of biotreated dyeing and finishing wastewater by boron doped diamond electrode

The combination of advanced oxidation processes (AOPs) and biological treatments is a promising technique for the treatment of textile wastewater. In this study, a boron-doped diamond (BDD) electrode was utilized for electrocatalytic oxidation to abate organic pollutants in biotreated dyeing and finishing wastewater (BDFW). Three operational parameters of BDD electrochemical oxidation of BDFW were evaluated. The results showed that increasing the applied current density, decreasing the planar electrode spacing, and lowering the pH value all enhanced the COD removal efficiency. After 300min, the COD removal efficiency exceeded 90% and the specific energy consumption (Esp) was 129 kWh/kg COD. BDD electrochemical oxidation removed most of macromolecular organic compounds from the wastewater. Based on the excellent performance of five consecutive runs, the BDD electrochemical oxidation proves to be a promising technique as an advanced treatment of biologically pretreated wastewaters in practical applications.

Enhanced textile wastewater remediation in Phragmites karka-based vertical flow constructed wetlands using Phragmites-derived biochar

Vertical flow-constructed wetlands (VFCWs) are treatment systems that can be used for the phytoremediation of highly polluted textile wastewater. Using plant-derived biochar to simultaneously improve the contaminant removal performance of CWs and sustainable utilization of harvested plant biomass is an interesting proposition. The present study explored the phytoremediation potential of Phragmites karka and verified the impact of using P. karka-derived biochar as a substrate in VFCWs for the treatment of textile wastewater. For this, three types of VFCWs were designed; (i) non-vegetated (VFCW), (ii) vegetated with P. karka (VFCW–P), and (iii) vegetated with P. karka and amended with P. karka-derived biochar (VFCW-BP) and semi-batch experiments were conducted. The investigation confirmed that wetlands using biochar as substrate were more efficient than other wetlands in pollutant load reduction. The maximum pollutant removal efficiencies were recorded for VFCW-BP vis-à-vis COD (83.61%), color (77.87%), chloride (73.22%), calcium (73.52%), sodium (67.18%), and potassium (75.72%) after five days. Furthermore, biochar addition enhanced the growth conditions for wetland plants by alleviating osmotic and oxidative stresses and hence helped them to perform better while removing pollutants. The maximum reduction of various pollutant parameters was reached within 72 h, after which remediation efficiency was slowed down. The study suggests that VFCW with biochar amendment is a useful strategy for textile wastewater treatment. Because the experimental design satisfies the needs for low-cost wastewater treatment, it may find widespread applications.

Artificial neural network guided optimization of limiting factors for enhancing photocatalytic treatment of textile wastewater using UV/TiO₂ and kinetic studies

Wastewater effluents discharged from textile industries are characterized by excessive chemical and biochemical oxygen demands with significant amounts of harmful synthetic dyes that spoil the healthy environment. The present investigation focused on process optimization to develop an effective strategy for degrading and decolorizing wastewater from textile industries through an advanced photocatalysis oxidation process. The synergistic effect of Titanium dioxide (TiO2) nanoparticles as a photocatalyst with ultraviolet irradiation was applied as a novel technique to detoxify wastewater effluents from textile industries. In addition, the process was modeled and optimized using response surface methodology (RSM) and artificial neural networks (ANN). The kinetics of the photocatalytic degradation of wastewater effluents from textile industries were analyzed. The optimal condition predicted by the RSM was similar to the experimental outcomes, further, the predicted values from the ANN model had confirmed the prediction. The most significant limiting parameters, such as catalyst dosage, pH, and irradiation time, were optimized systematically as TiO2 dosage of 429.31mg/l, pH of 8.89, and irradiation time of 5h, respectively. Under these optimal conditions, COD reduction and decolorization of 90 and 88%, respectively, were achieved.

Enhancing textile wastewater treatment for subsequent biological processes by integrating electrooxidation and electrocoagulation

ABSTRACT The presence of refractory contaminants in textile wastewater is one of the major concerns while handling them with the biological processes at common effluent treatment. Electro-oxidation (EO) as a standalone process is an insufficient treatment method for the abolition of inorganic contaminants (carbon and non-carbon). By incorporating electrocoagulation (EC) as an associated treatment method after EO, removal of such contaminants becomes easy, which not only makes the treated wastewater fit for biological remediation but also reduces load on biological units. The removal of non-carbonic impurities was assessed in terms of improvement in the chemical oxygen demand (COD) post EC. L25 orthogonal array of experiments was obtained using the Taguchi method. From the S/N ratio plot, the optimal process combination was obtained as, EO with current density = 25 mA/cm2, electrolysis time = 50 min followed by EC with current density = 18 mA/cm2, speed of rotation = 50 rpm and electrolysis time = 40 min. The enhancement in COD and total organic carbon removal efficiencies after EC were 65.11 and 63.57%, respectively, over EO. The biodegradability index also improved from an initial value of 0.098–0.737 post-hybrid treatment. Inorganic carbon reduced from a value of 36.37 mg/L after EO to 0.1 mg/L post EC.

Industrial activated sludge model identification using hyperparameter-tuned metaheuristics

This study focuses on the parameter estimation of an industrial activated sludge model using hyperparameter-tuned metaheuristic techniques. The data used in this study were collected on-site from a textile industry wastewater treatment plant. A Modified Activated Sludge Model (M-ASM) was the 'first-principle model’ selected and implemented with suitable assumptions. Advanced metaheuristic techniques, as Adaptive Tunicate Swarm Optimization (ATSO), Whale Optimization Algorithm (WOA), Rao-3 Optimization (Rao-3) and Driving Training Based Optimization (DTBO) were implemented. The hyperparameter tuning was performed with Bayesian Optimization (BO). Optimized metaheuristic algorithms were implemented for model-parameter identification. The Bayesian optimized Rao-3(BO-Rao-3) algorithm provided the best validation results, with a Mean Absolute Percentage Error (MAPE) value of 7.0141 and Normalized Root Mean Square Error (NRMSE) value of 0.2629. It also had the least execution time. BO-Rao-3 is 0.93% to 4.7% better than the other implemented hyperparameter-tuned metaheuristic techniques.

Dual approach in textile wastewater treatment: optimisation and comparison of fluidised-bed and conventional Fenton processes

ABSTRACT This study optimises secondary textile dyeing wastewater removal using fluidised-bed Fenton (FBR-Fenton) and standard Fenton processes for chemical oxygen demand (COD) and colour removal efficiency. The Box–Behnken response surface approach optimised pH, iron ion concentration, and hydrogen peroxide concentration. At pH 3.3, [Fe2+] = 2.6 mm, [H2O2] = 6.4 mm in the fluidised bed reactor with 67 g/L quartz sand, with a 50% bed expansion after 40 min, the FBR-Fenton process removed 75.8% COD and 98.0% colour. The standard Fenton method was tuned to pH 3.2, [Fe2+] = 3.1 mm, [H2O2] = 6.6 mm, and COD and colour removal effectiveness of 69.7% and 97.5%, respectively. FBR-Fenton enhanced COD and total iron removal efficiency, reduced chemicals, and reduced sludge by 28.0% compared to conventional Fenton. This study also showed quartz sand reusability in FBR-Fenton treatment cycles. Experimental results matched response surface model predictions, proving regression equation correctness.

Pollutants Analysis and Life Cycle Assessment of a Photovoltaic Powered Textile Electro-Fenton Wastewater Treatment System.

Textile wastewater poses a substantial environmental challenge due to the persistence of organic dyes. This study introduces a novel approach using photovoltaic (PV) powered electro-Fenton (EF) technology for effective treatment of textile wastewater. Acid orange 7 (AO7), methylene blue (MB), and malachite green (MG) were selected as representative organic dyes to validate the method under varying experimental conditions. Analysis of variance (ANOVA) highlighted the significant influence of pollutant type, pH levels, and current density on the degradation efficiency of the system, with optimal conditions observed at pH = 3 and high current density. To underscore the environmental benefits, a comprehensive life cycle assessment (LCA) was conducted. The PV-powered EF system, when implemented in a textile mill, exhibited an energy payback time (EPBT) of 9.53 years, a greenhouse gas payback time (GPBT) of 4.45 years, and a life cycle cost (LCC) of 1.9 × 105 RMB. Comparative analysis with conventional Fenton and EF processes revealed substantial energy savings, with carbon emissions reduced by 95% and 78%, and energy consumption reduced by 87% and 52%, respectively.

Advanced chitosan-based composites for sustainable removal of Congo red from textile wastewater

The non-biodegradable Congo red (CR) dye which is widely used in textile industries has poses carcinogenic risks due to its complex reactions that may generate benzidine. Effective treatment of industrial effluent containing CR dye is imperative. This study assessed chitosan (Cs) and chitosan/fly ash (Cs/Fa) composites for biosorbing CR dye from synthetic textile wastewater. Fly ash varied in the range of (1:0.25–1:1) with chitosan to assess adsorption performance. Characterization techniques included FTIR, SEM, EDX, BET, and zeta potential analyses. Response surface methodology guided the determination of optimal variables. The study examined Cs and Cs/Fa dosage (A), time (B), and initial dye concentration (C) effects on CR removal. Incorporating fly ash substantially cut adsorption costs by 50% while enhancing dye removal up to 85% at pH 6. Improved acidic stability of chitosan (Cs/Fa 1:0.75) was notable. Chitosan (Cs) exhibited a high Congo red removal efficiency of 98% while the chitosan/fly ash (Cs/Fa) composites showed a substantial removal efficiency of 94%. Optimal conditions were 2 g L−1 of adsorbents, initial CR concentration of 40 mg L−1 for 120 min. Freundlich isotherm model best described adsorption behavior. Pseudo-second-order kinetics correlated significantly (R2 = 0.999). This study showed the potential of Cs and Cs/Fa bio-composites for effective textile wastewater treatment.