Real Textile Wastewater Research Articles

Evaluation of Integrated Anaerobic/Aerobic Conditions for Treating Dye-Rich Synthetic and Real Textile Wastewater Using a Soda Lake Derived Alkaliphilic Microbial Consortia

Textile industry wastewater (WW) has intense color, high chemical oxygen demand (COD), pH, and salinity, making it challenging for conventional treatment. Soda lakes, with high alkalinity and salinity, host diverse microbes capable of textile dye degradation. This study evaluated anaerobic/aerobic reactors using alkaliphilic microbial consortia from Lake Chitu, an Ethiopian soda lake, for treating synthetic and real textile WW. The experimental setup consisted of a first-stage anaerobic reactor followed by a second-stage aerobic reactor, operating continuously with a predetermined flow rate and hydraulic residence time. After evaluating synthetic WW, real textile WW was collected in two batches (rounds I and II). The treatment setup removed 99% of the dye color for synthetic WW, 98% for round I, and 96% for round II. COD removal was 87% for synthetic WW, 86% for round I, and 93.37% for round II. TKN removal reached 90% for synthetic WW, 91% for round I, and 96% for round II at a steady state. Residual COD and TKN values met the final effluent discharge standards. GC–MS and IR analyses revealed that dyes were broken down into intermediate organic compounds under anaerobic conditions and further degraded into smaller molecules under aerobic conditions. This integrated reactor approach effectively removes dyes and enhances COD and TKN removal. The study’s novelty lies in evaluating both synthetic and real textile WW using integrated reactors under alkaline conditions in a continuous process, inoculating alkaliphilic consortia, without pre-enrichment or external nutrient addition to real WW. The study provides insights into the effectiveness of alkaliphilic microbial consortia derived from soda lakes for treating textile WW using integrated reactor conditions. Reactor microbiome characterization is needed to further explore microbial diversity and community structure.

The potential of integrating solar-powered membrane distillation with a humidification-dehumidification system to recover potable water from textile wastewater

Textile production is energy- and water-intensive, and membrane distillation (MD) has shown potential for reclaiming potable water from textile wastewater. However, in the current state, the energy and water recovery potential of MD is lower compared to other conventional distillation technologies. To address these issues, this study proposes and assesses a novel solar-powered hybrid Sweeping Gas MD (SGMD) unit integrated with a humidification dehumidification (HDH) system. Real textile wastewater from bleaching and dyeing processes is treated in the hybrid SGMD-HDH system to recover freshwater. An optical-thermal sub-model for the parabolic trough collector and the heat and mass transfer model for the dehumidifier are developed and validated using experimental measurements. The results reveal that the hybrid SGMD-HDH can exhibit nearly 20% higher water flux and 50% higher gain output ratio (GOR) compared to the standalone MD system. The highest water production and average GOR for bleaching wastewater feed solution reached 11.72 kg/day and 0.64, respectively. The higher concentration of chemical contaminants in dyeing wastewater decreased water flux and GOR by up to 14% and 10%, respectively, compared to bleaching wastewater. Elemental analysis showed increased carbon concentrations on the polytetrafluoroethylene membrane surface arising from organic fouling.

Photo Fenton-like oxidation of real textile wastewater: Operating conditions, kinetic modelling and cost analysis

The reusability of the pretreated textile wastewater was improved by using bismuth ferrite/activated carbon hybrid photocatalysts in photo-Fenton-like oxidation process. BiFeO3/WAC (WAC: walnut shell based activated carbon) and BiFeO3/CAC (CAC: Commercial activated carbon) catalysts were synthesized and used for the photocatalytic oxidation of in-situ pretreated textile wastewater. The influences of the mixing speed, oxidant dosage, light source, catalyst loading, and temperature were studied. The highest TOC removal efficiencies were evaluated as 56.3% and 76.2% in the presence of BiFeO3/WAC and BiFeO3/CAC, respectively. A kinetic study was performed to derive the kinetic models expressing the TOC removal as a basis for the semi-pilot and industrial scale studies. The kinetic data fit to a two-step second order reaction rate model in the presence of both of the catalysts. The activation energies of the first and the second steps were calculated as 36.0 and 16.0 kJ/mol, respectively, on BiFeO3/WAC catalyst while 43.4 and 13.3 kJ/mol of activation energies were calculated on BiFeO3/CAC.

Controlling of irreversible fouling and mechanism in a hybrid ceramic membrane bioreactor (CMBR)-reverse osmosis (RO) process for textile wastewater reclamation

In this study, the fouling propensity of a hybrid ceramic membrane bioreactor (CMBR)-reverse osmosis (RO) process was investigated over a prolonged period using real textile wastewater effluent. Additionally, the effectiveness of in-situ ozonation for fouling mitigation was investigated. The results revealed that the CMBR-RO system achieved approximately 99.8 % removal of chemical oxygen demand and 97.4 % removal of total nitrogen. Despite this, soluble extracellular polymeric substances, particularly biopolymers and humics-like substances, remained in the system, resulting in irreversible fouling on the ultrafiltration (UF) membrane. The implementation of in-situ ozonation notably reduced ceramic membrane fouling by enhancing the filterability of larger macromolecules and eliminating inorganic/organic foulants from the membrane surface. Multiple modified fouling indexes were also utilized to evaluate the fouling potential of the RO feed water through size fractionation. It is worth noting that ozonation could pose a potential risk for subsequent RO membrane fouling due to the formation of low molecular weight neutrals, acids, and calcium- or silica- related inorganic-organic complexes. Overall, the integrated CMBR-RO system with in-situ ozonation exhibited excellent performance in producing clean water, achieving nearly 100 % removal of 20 Aromatic Amines. These findings underscore the viability of the CMBR-RO system as a practical and sustainable choice for the reclamation of textile wastewater.

Electrochemical treatment of textile wastewater using electrodes from pyrolyzed rice husk

Rice husk char (RHC) electrodes were used for the first time in electrochemical treatment of textile wastewater. SEM analysis revealed RHC's porous structure, while TGA showed it decomposes in four stages and is stable up to 189 °C. BET analysis indicated a high surface area of 734 m2/g and a microporous structure with 11.7 Å pore diameter and 0.213 mL/g pore volume. RHC electrodes pyrolyzed at 700 °C for 2 h and placed 15 cm apart worked best in a 2 L batch reactor with methylene blue (MB) as the model pollutant and 6 g/L NaCl as the electrolyte. The process followed first-order kinetics, with fastest reaction at 100 mg/L initial MB. Reduced TOC and changed FTIR spectra confirmed MB breakdown. The batch system removed 85.8 % of dye from real textile wastewater in 150 min. In continuous flow, lower rates achieved higher efficiencies, up to 90 % at 0.45 L/h after 210 min. Although RHC electrodes had lower conductivity and strength than metal, they represent a sustainable, cost-effective alternative for electrochemical wastewater treatment.

Removal of a model reactive azo dye from aqueous solution by a bioadsorbent in batch and fixed-bed column modes: Application of the developed technology to a textile wastewater

Sugarcane bagasse (SB) was used to produce a new bioadsorbent (STEA), drawing on circular economy concepts. STEA was synthesized using a two-step one-pot reaction, employing epichlorohydrin and triethylamine in the presence of N,N-dimethylformamide, without the use of a petroleum-based catalyst. The structure and surface of STEA were characterized by elemental C, H, N, and Cl analysis, X-ray diffraction, infrared spectroscopy, 13C solid-state nuclear magnetic resonance spectroscopy, thermogravimetric analysis, specific surface area and pore size distribution determination, and point of zero charge measurement. Batch adsorption and desorption tests were performed with the model dye Remazol Golden Yellow (RGY) RNL, a reactive anionic azo dye widely used in textile industry, to evaluate the potential reuse and application of STEA in a fixed-bed column for wastewater treatment. For batch adsorption, the best dose and agitation speed were 0.2 g L−1 and 50 rpm, respectively. STEA effectively removed RGY over a wide range of pH (2.00–10.00). The equilibrium time, maximum adsorption capacity (Qmax), and desorption efficiency (Edes) were 720 min, 369 mg g−1 (0.71 mmol g−1), and 49.5 %, respectively. The fixed-bed column fed with a spiked aqueous RGY solution could be operated for 415 min, with Qmax of 422 mg g−1 (0.81 mmol g−1) and Edes of 58.9 %. Batch and continuous experiments using real textile industry wastewater containing reactive azo dyes showed high color removal efficiency by STEA, with no interference of other compounds present in wastewater on adsorption of the reactive azo dyes (overshooting effect). The technology was validated in a relevant environment and achieved technology readiness level 5, showing potential to be upscaled. Therefore, STEA proved to be an efficient bio-based technology for application in tertiary treatment of real textile plant wastewater to remove reactive anionic azo dyes.

Fast and effective hydroquinone adsorption by poly (2-dimethylaminoethyl methacrylate)/zinc oxide nanocomposite hydrogel in textile wastewater treatment

ABSTRACT Hydroquinone, a widely used phenolic compound, poses significant health and environmental risk and must be removed from wastewater. In this study, a novel adsorbent was developed for the removal of hydroquinone from aqueous solutions through the in-situ polymerisation of 2-(dimethylamino)ethyl methacrylate (DMAEMA) in the presence of zinc oxide nanoparticles (ZnO NPs). The kinetics of equilibrium swelling in deionised water (DI) and the effect of pH on the swelling behaviour were investigated. The structure of the nanocomposite hydrogel was analysed using FTIR, XRD, FESEM, EDX, TEM, and BET analysis. Various factors affecting the adsorption process, such as solution pH (2–12), initial concentration (25–200 mg/L), adsorbent dosage (4.0–80 mg/100 mL), NaCl concentration (0.1–1.0 mol/L), and temperature, were also investigated. The adsorption capacity of hydroquinone and the removal efficiency of PDMAEMA@ZnO reached 455 mg/g and 91%, respectively, at pH 11 within 15 minutes. Furthermore, PDMAEMA@ZnO showed a high removal efficiency of 99.47% in tests with real wastewater. Reusability studies showed that the adsorbent retained its ability to remove hydroquinone after four regeneration cycles. The adsorption data were well described by the pseudo-second order and Langmuir models. The thermodynamic parameters indicated that the adsorption process is spontaneous and endothermic. Therefore, the adsorbent, has considerable industrial potential as it quickly and efficiently adsorbs phenolic impurities such as hydroquinone from real textile wastewater.

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).

Rapid pretreatment strategy to control nanofiltration membrane fouling in recycling of real textile wastewater: Comparison and mechanisms

The recycling of textile wastewater by membrane technology often necessitates intricate pretreatment steps to prevent severe membrane fouling, which lead to prolonged process-flow and elevated operation expenses. This research focuses on a two-step coagulation (TS-Co) pretreatment-nanofiltration process for treating real textile wastewater and examines its mechanism for controlling membrane fouling. The findings indicated that the removal of organic pollutants from real textile wastewater could be enhanced through first coagulation under acidic conditions, and the secondary coagulation under neutral conditions further removed the residual organics and the metal coagulants released at first stage. This synergistic effect led to chemical oxygen demand (COD) and turbidity removal efficiencies of 56.31 % and 99.29 %, respectively, which were superior to those of ultrafiltration (UF) and conventional coagulation (C-Co) pretreatment. The foulant composition and correlation analysis confirmed that protein, humic acid, and polysaccharides were the primary pollutants causing the fouling of nanofiltration membrane. Interestingly, the removal efficiency of polysaccharides using TS-Co (63.72 %) was lower than that obtained using UF (95.57 %), while the TS-Co exhibited higher removal efficiencies for humic acid and protein (97.43 % vs. 49.90 %, and 96.99 % vs. 81.07 %, respectively), indicating its excellent performance to controlling membrane fouling. Additionally, the proposed short process-flow offers cost advantages over conventional long process-flow and shows promising application prospects.

Evaluation of batch and fed-batch rotating drum biological contactor using immobilized Trametes hirsuta EDN082 for non-sterile real textile wastewater treatment

White rot fungi, in both free and immobilized forms, excel in degrading dyes through adsorption and enzyme degradation. However, existing studies often focus on synthetic wastewater within sterile lab conditions. This study extends the application of Trametes hirsuta EDN082 immobilized in light-expanded clay aggregates (myco-LECAs) packed in a rotating drum biological contactor (RDBC) for treating real textile wastewater under non-sterile conditions to simulate industrial treatment scenarios. Experiments included batch and fed-batch RDBC to assess the impact of additional glucose and stepwise dilution on quality indicators like pH, chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), color, and solids. In fed-batch RDBC with 0.5 % additional glucose, myco-LECAs achieved a maximum of 94 % COD removal (day 15), 99 % NH4+-N reduction (day 33), and 39 % decolorization without additional glucose. In comparison, myco-LECAs in batch RDBC highlighted 89 % NH4+-N reduction in 9 days without pH adjustment or additional nutrients. The pH maintained between 6−9, with no toxicity in Artemia salina, and 97−100 % removal of E. coli. Compared to Indonesian textile wastewater discharge limits, the technology achieved effective ammonia removal below 8 mg/L. This suggests that immobilized T. hirsuta EDN082 in LECAs presents a viable, non-sterile treatment for real textile wastewater.

WITHDRAWN: High crystallinity nano-biochar synthesized from lotus leaf wastes for uptake of dye molecules from synthetic and real wastewater

This article investigates the potential of lotus leaves-derived nano-biochar in eliminating methyl violet (MV) dye from synthetic and real textile wastewater. The surface of nano-biochar was characterized by TEM, BET, FTIR, XRD, DLS, and FESEM analyses. The BET surface area of nano-biochar was 456.3 m2.g-1, demonstrating an excellent specific surface area. The highest biosorption efficiency and maximum biosorption capacity of MV were 96.3% and 526.3mg/g, respectively, which were obtained at pH 10, equilibrium time of 200min, adsorbent concentration of 0.5g/L, MV ion concentration of 150 ppm, and temperature of 50oC. Also, the mechanism of the biosorpiton process shows that the process is endothermic. Based on R2 and RSME error values, the biosorpion process followed the pseudo-first-order and Langmuir models, indicating that monolayer biosorption of MV molecules on the biochar surface is dominant. Besides, nano-biochar was successfully reused in three steps with high efficiency. The impact of interference ions such as methylene blue, methyl orange, crystal violet, and brilliant blue on MV sorption was investigated and the outcomes revealed that nano-biochar has a remarkable ability to simultaneously eliminate these dye molecules. Additionally, nano-biochar could eliminate COD, BOD5, turbidity, TDS, and EC from a real textile wastewater with high efficiency. Overall, biochar nano-powder, owing to its high reusability, high sorption capacity, easy synthesis, and low-cost, can be considered an ideal option for industrial application.

Magnetic coagulant derived from Cassia fistula seed for real textile wastewater treatment: A pilot-scale study

Cassia fistula (C. fistula) seed-derived coagulants have demonstrated substantial potential for treating dye-based wastewater. Such coagulants exhibit notable coagulating-flocculating activity and are environmentally friendly. However, recovering these natural coagulants from aqueous media poses challenges. In this study, we introduce a novel plant-derived magnetic coagulant that is a combination of C. fistula seed gum with magnetic spinel ferrite. This research includes a pilot-scale study to simulate full-scale textile wastewater treatment using this composite. Material characterisations revealed that spherical CoFe2O4 particles could be effectively coated with the active coagulant, C. fistula gum. The saturation magnetisation of the composite, measured at 54.11 emu/g, facilitates its convenient separation from aqueous solutions using an external magnetic field. Bench-scale studies showed that initial pH and coagulant dosage substantially affect the removal efficiency of colour and chemical oxygen demand (COD). In the pilot-scale study, the C. fistula–CoFe2O4 composite demonstrated promising coagulant properties. It achieved a colour removal percentage of 94.0 % with a volume of 30 L and a coagulant dosage of 12.3 g L− 1. Using this coagulation–flocculation process as a primary treatment step, possibly followed by biological or membrane methods, can help meet Vietnamese environmental standards.

Synthesis of novel bentonite/pectin-grafted-poly(crotonic acid-co-acrylic acid) hydrogel nanocomposite for adsorptive removal of safranin O dye from aqueous solution

ABSTRACT This novel work is devoted to the synthesis of the bentonite/pectin-grafted-poly(crotonic acid-co-acrylic acid (AA-co-CA) hydrogel nanocomposite by free-radical copolymerisation method for exploring its potential towards safranin O dye removal. The prepared nanocomposite was characterised by different techniques revealing the presence of numerous functionalities, porous nature and greater swelling % at basic pH. The pHpzc of the nanocomposite was determined to be 4. Maximum of 97.09% of safranin O dye removal take place under optimised conditions, that is, 0.03 g of bentonite dose (bentonite to net hydrogel weight ratio (1.295%), with pH of 7, nanocomposite dose of 5 g/l for 120 min. The dye concentration was 500 mg/l at the temperature of 25°C. Effect of ionic strength confirmed the greatest decrease in adsorption capacity in the presence of divalent cations. The highest R2 and the lowest error margins of the Freundlich isotherm and pseudo-second-order kinetic models make these models well fitted to the experimental data. Further, the spontaneous and exothermic nature of the process was confirmed by the negative values of ΔG and ΔH, respectively. The enhanced adsorption of safranin O dye by the prepared nanocomposite was informed by several mechanisms, including electrostatic, pore filling and H-bonding. A comparison of the adsorption capacity of the prepared nanocomposite with various other adsorbents was also studied. Stability of the prepared adsorbent was revealed from its recovery upto five cycles in different desorption media. Finally, the treatment of the adsorbent with real textile wastewater showed its removal efficiency as 95.8% highlighting its promising nature for treating large industrial wastewater.

Methylene blue (MB) removal from aqueous solution by alum; catalytic ozonation process

Textile wastewater is among the most polluted types of industrial waste. Wastewater treatment in the textile industry is notoriously difficult because of the use of complex chemicals and dyes in the textile production steps, and conventional methods are not enough to treat these. Textile wastewater, known for its high pollution levels, poses challenges for treatment due to complex chemicals and dyes. A comparative study was conducted on simple ozonation and catalytic ozonation (CO) using alum to degrade methylene blue (MB). The authors analyzed various factors like time, pH, catalyst loading and ozone dosages during the study. Results showed that catalytic activity in ozonation depends on pH and ozone flow. The maximum MB elimination was achieved at pH 6.6 and 200 V ozone flow. Scanning electron microscopy (SEM) was used to characterize the surface morphology of the catalyst, Fourier transform infrared spectroscopy (FTIR) was used to identify the important functional groups, and energy dispersive X-ray spectroscopy (EDS) was used to characterize the catalyst's elemental composition. Compared to simple ozonation, CO showed higher removal in the initial phase. Real textile wastewater analysis confirmed the effectiveness of alum catalysts in achieving significant removal of MB (87%) through this novel cost-efficient process.Graphical

Comparing efficacy of anodic and cathodic chambers in a low-cost algae-assisted microbial fuel cell for textile wastewater remediation

Remediation of industrial textile effluent using both the anodic and cathodic chambers of an algae-assisted microbial fuel cell (AMFC) is demonstrated and evaluated in this study. A low-cost AMFC is developed using clayware as the anode compartment housed inside a plastic bucket which acts as the cathode chamber. A comparative analysis of textile wastewater (TWW) treatment in both chambers is presented. Four treatment configurations were considered, namely T1 (only cathode supplied with TWW), T2 (both cathode and anode supplied with TWW), T3 (only anode supplied with TWW) and the control AMFC (no TWW was added in any compartment). It was observed that the bacterial populations in the anodic compartment were more adapted towards TWW than the microalgae in the cathodic chamber. The color removal efficiency by the anode and cathode chamber was respectively 89.55% and 40.53%. The COD removal was 94% and 48% from the anodic and cathodic chambers respectively. The T3 AMFC with effluent being supplied only to the anode chamber exhibited the highest power and current density of 2.1 W/m3 and 8 A/m3. The proposed system was able to degrade dyes from real textile wastewater and simultaneously generate bioelectricity and algal biomass.

A Study of the Feasibility of Pinus patula Biochar: The Regeneration of the Indigo Carmine-Loaded Biochar and its Efficiency for Real Textile Wastewater Treatment

The feasibility of an adsorbent material like biochar (BC) depends on its regeneration capacity and its ability to achieve high removal efficiencies on real wastewater (WW) effluents. In this study, the regeneration capacity of the Pinus patula BC previously used in the removal of Indigo Carmine from water was evaluated. The regeneration technique that resulted in the highest desorption efficiency was a thermo-chemical method that consisted of heating the spent BC in a stove at 160 °C for 45 min followed by regeneration with ethanol (C2H6O) at a concentration of 75% for 6 h. Through this regeneration method, it was found that Pinus patula BC could be used in seven consecutive adsorption–desorption cycles. The feasibility of this BC was also assessed by evaluating the adsorbent’s efficiency in real textile WW. Under optimal operational conditions (solution pH = 3, BC dose = 13.5 g/L, and BC particle size = 300–450 µm), the highest removal efficiencies in terms of colour and dissolved organic carbon (DOC) were 81.3 and 76.8%, respectively, for 120 min of treatment. The results obtained in the regeneration studies and the treatment of real textile WW suggested that the use of Pinus patula BC could be suitable to be scaled to an industrial level, contributing to sustainable development and the circular bioeconomy by using a waste to solve the dye pollution problem of another waste.

Efficacy and mechanism of enhanced Sb(V) removal from textile wastewater using ferric flocs in aerobic biological treatment

Antimony contamination from textile industries has been a global environmental concern and the existing treatment technologies could not reduce Sb(V) to meet the discharge standards. To overcome this shortcoming, ferric flocs were introduced to expedite the biological process for enhanced Sb(V) removal in wastewater treatment plant (WWTP). For this purpose, a series of laboratorial-scale sequential batch reactor activated sludge processes (SBRs) were applied for Sb(V) removal with varied reactor conditions and the transformation of Fe and Sb in SBR system was investigated. Results showed a significant improvement in Sb(V) removal and the 20 mg L−1 d−1 iron ions dosage and iron loss rate was found to be only 15.2%. The influent Sb(V) concentration ranging 153–612 μg L−1 was reduced to below 50 μg L−1, and the maximum Sb(V) removal rate of the enhanced system reached about 94.3%. Furthermore, it exhibited high stability of Sb(V) removal in the face of antimonate load, Fe strike and matrix change of wastewater. Sludge total Sb determination and capacity calculation revealed decreasing in Sb adsorption capacity and desorption without fresh Fe dosage. While sludge morphology analysis demonstrated the aging and crystallization of iron hydroxides. These results verify the distinct effects of fresh iron addition and iron aging on Sb(V) removal. High-throughput gene pyrosequencing results showed that the iron addition changed microbial mechanisms and effect Fe oxidized bacterial quantity, indicating Sb(V) immobilization achieved by microbial synergistic iron oxidation. The present study successfully established a simple and efficient method for Sb(V) removal during biological treatment, and the modification of biological process by iron supplement could provide insights for real textile wastewater treatment.

LDH–Ferrite–Biochar–Polymeric Composites for Enhanced Adsorption–Desorption of Acid Blue 41 and Real Textile Wastewater Purification: A Batch and Column Study

LDH–Ferrite–Biochar–Polymeric Composites for Enhanced Adsorption–Desorption of Acid Blue 41 and Real Textile Wastewater Purification: A Batch and Column Study

Enhancing water recovery through integrated graphene oxide-modified forward osmosis and membrane distillation for real textile wastewater treatment

The textile industry is a highly water-intensive sector, emphasizing the increasing importance of reclaiming clean water from textile wastewater and advancing water recovery towards zero liquid discharge. This study proposes and assesses an integrated forward osmosis and membrane distillation (FO-MD) process for treating real textile wastewater, aiming for enhanced water recovery and ensure robustness towards zero liquid discharge. Firstly, a newly developed graphene oxide (GO)-enhanced FO membrane (GFO) was fabricated by adding GO into the polyamide layer during the interfacial polymerization process. Furthermore, the real textile wastewater treatment performance of the FO-MD process based on the GFO membrane was compared to that of a commercial FO membrane (CFO). The results indicated the GFO-based FO-MD process outperformed due to enhanced antifouling properties and stable water flux. Remarkably, the GFO membrane-based FO-MD system achieved over 80% water recovery and nearly 100% rejections for COD, Na+, K+, Cl-, and S2- during continuous 24-hour filtration. The findings highlighted FO-MD as a viable solution, surpassing the individual FO and MD processes by overcoming the limitations of FO draw solution dilution and MD membrane wetting challenges. Moreover, a preliminary techno-economic study for a 200 m3 day−1 textile wastewater estimated water production costs of $6.48 m−3 and $5.73 m−3 for CFO-MD and GFO-MD systems. The analysis highlighted maintaining the water flux above 10 L m−2 h−1 is crucial for economic viability. This work demonstrates the potential of the FO-MD system as a sustainable solution to address the textile wastewater treatment challenges, providing insights for FO-MD system design and optimization.

Effective degradation of synthetic micropollutants and real textile wastewater via a visible light-activated persulfate system using novel spinach leaf-derived biochar

A novel biochar (BC), derived from spinach leaves, was utilized as an activator for persulfate (PS) in the degradation of methylene blue (MB) dye under visible light conditions. Thorough analyses were conducted to characterize the physical and chemical properties of the biochar. The (BC + light)/PS system exhibited superior MB degradation efficiency at 83.36%, surpassing the performance of (BC + light)/hydrogen peroxide and (BC + light)/peroxymonosulfate systems. The optimal conditions were ascertained through the implementation of response surface methodology. Moreover, the (BC + light)/PS system demonstrated notable degradation ratios of 90.82%, 81.88%, and 84.82% for bromothymol blue dye, paracetamol, and chlorpyrifos, respectively, under optimal conditions. The predominant reactive species responsible for MB degradation were identified as sulfate radicals. Notably, the proposed system consistently achieved high removal efficiencies of 99.02%, 96.97%, 94.94%, 92%, and 90.35% for MB in five consecutive runs. The applicability of the suggested system was further validated through its effectiveness in treating real textile wastewater, exhibiting a substantial MB removal efficiency of 98.31% and dissolved organic carbon mineralization of 87.49%.