Textile Wastewater Treatment Research Articles

Environmental and Economic Evaluation of the Sequential Combination of Coagulation–Flocculation with Different Electro-Fenton-Based Configurations for the Treatment of Raw Textile Wastewater

This study reports, for the first time, on the assessment of a multistage sequential system composed of coagulation–flocculation with different electro-Fenton-based configurations, followed by neutralization (N), for the treatment of raw textile wastewater heavily contaminated with acid black 194 dye and other pollutants. Electrochemical peroxidation (ECP-N), electro-Fenton (EF-N) and peroxi-coagulation (PC-N) were tested at laboratory scale and compared in terms of their efficiency for the removal of organic matter and color, current efficiency and energetic parameter, operating cost and environmental sustainability using life cycle analysis conducted in large-scale virtual reactors. The three electro-Fenton-based systems complied with current environmental standards (color removal > 87%, COD < 400 mg/L, among others) requiring different electrolysis times: ECP-N (52 min) < PC-N (120 min) < EF-N (160 min); energy consumptions: ECP-N (2.27 kWh/m3) < PC-N (4.28 kWh/m3) < EF-N (33.2 kWh/m3); operational costs: ECP-N (2.63 USD/m3) < EF-N (6.65 USD/m3) < PC-N (6.98 USD/m3); among others. Electricity (for ECP-N and EF-N) and reagents (for ECP-N and PC-N) were found as main environmental hotspots. ECP-N presented the lowest carbon footprint of 10.3 kg CO2-Eq/FU (<PC-N (26.3 kg CO2-Eq/FU) < EF-N (38.0 kg CO2-Eq/FU), had lower incidence in all the impact categories analyzed (ReCiPe-2016 at midpoint level) and can be considered technically, economically and environmentally sustainable for large-scale applications.

Ozone nanobubble technology as a novel AOPs for pollutants degradation under high salinity conditions

Conventional water treatment systems frequently exhibit diminished efficiency at high salinity - a significant issue especially for real industrial effluents - mostly due to the creation of intricate structures between pollutants and salts. One of the primary obstacles associated with high salinity conditions is the generation of by-products that pose additional hurdles for treatment. In this work, we have investigated the novel advanced oxidation process a so-called ozone nanobubble technology for degradation of the pollutants at high salinity conditions. The mass transfer is often the rate-limiting step in gas-liquid process and the poor rate of mass transfer diminishes the overall efficacy. One of the primary disadvantages associated with ozone is its restricted solubility and instability when dissolved in an aqueous solution. These characteristics impose limitations on its potential applications and need the use of specialized systems to facilitate gas-liquid interaction. In this work, we have also suggested enhancing the ozonation process through the utilization of ozone nanobubbles. The findings of our experiment and subsequent analysis indicate that the presence of nanobubbles enhances the process of ozonation through three key mechanisms: (i) an increased mass transfer coefficient, (ii) a higher rate of reactive oxygen species (ROS) generation attributed to the charged interface, and (iii) the nanobubble interface serving as an active surface for chemical reactions. The predicted mass transfer coefficients were found to range from 3 to 3.5 min−1, a value that is notably greater than that seen for microbubbles. The study showcased the degradation of methylene blue dye through the utilization of ozone nanobubbles, which exhibited a much higher rate of dye degradation compared to ozone microbubbles. The confirmation of the radical degradation mechanism was achieved by the utilization of electron spin resonance (ESR) measurements. The developed process has high potential for application in industrial scale textile wastewater treatment.

Combined electrocoagulation/flotation technique and membrane desalination for textile wastewater reuse

A novel integrated system that combined electrocoagulation/flotation (ECF) technique with membrane desalination was used for textile wastewater treatment to reduce the environmental pollution of textile wastewater. Two scenarios were examined: the first is ECF followed by membrane desalination; the second is the application of membrane desalination for treatment of raw wastewater. Iron electrodes were used in batch-wise tests to examine the effects of electrolysis time and current intensity on percentage removals. The SiO2/PA(TFC) membrane was used to treat raw wastewater and ECF effluents. As the current intensity increased from 50 mA to 600 mA, the color elimination was improved from 94 % to 99 % and the COD elimination improved from 59.1 % to 81.5 %. The findings demonstrate the efficacy of ECF in removing color and COD, although the treated wastewater sample's TDS increased from 4200 mg/L to 19,400 mg/L (raw textile wastewater sample). The SiO2/PA(TFC) membrane displays the salt rejection and water flux reduction of the raw wastewater samples 95 %, and 22 (L/m2.h). Corresponding results for ECF treated wastewater were 94, 93, 91 % and 13, 11.5, and 10 (L/m2.h), respectively. The SiO2/PA(TFC) membrane displays the reduction of COD from 760 mg O2/L (raw) and 310 mg O2/L (ECF effluent) to zero%. Also, it proves the capabilities of SiO2/PA(TFC) membrane for the removal of TDS, COD and color. This integrated system can provide sustainable source for fresh water supply used for landscape, irrigation, industry and various purposes.

Sustainable Textile Wastewater Treatment Using Biodegradable Chitosan for High-Efficiency Dye Removal

Sustainable Textile Wastewater Treatment Using Biodegradable Chitosan for High-Efficiency Dye Removal

Preparation of Graphene Oxide (GO) incorporated-Polyvinylidene Fluoride (PVDF) Nanofiltration Membrane with Alkaline Post-Treatment for Textile Wastewater Treatment

The purpose of this research is to study the potential of polyvinylidene fluoride (PVDF) polymer incorporated with graphene oxide (GO), following with the alkaline etching post-treatment process for dye waste water treatment. Its anti-oxidation properties of PVDF, have led to its choice as a host polymer due to its high thermal stability, great organic selectivity, and excellent chemical and mechanical resistance. In addition, the post-treatment with a NaOH solutions of varied concentration ranging from 0 M to 0.2 M for 30 minutes was conducted in alter the morphology of the fabricated membrane with the aim to increase the perm-selectivity of the membranes. Besides, the fabricated membranes were further characterized in terms of the chemical and physical properties using Fourier-Transform Infrared Spectroscopy (FTIR), Contact Angle (CA), Ultraviolet Visible spectroscopy (UV-Vis), Atomic Microscopy (AFM) and Scanning Electron Microscopy (SEM). The experimental results showed that the post-treatment has decreased the membrane flux of dye wastewater. Based on the obtained result, as the concentration of NaOH solution increased, the permeability increased. While the overall dye rejection of the membrane remained of above 90 %.

Enhancing the permeability and selectivity of graphene oxide membrane through polyhedral oligomeric silsesquioxane intercalation for textile wastewater treatment

Graphene oxide-based loose nanofiltration membranes have shown significant potential in nanofiltration processes due to their unique 2D mass transfer nanochannels. However, they still suffer from poor structural stability and overly compact laminar stacking. To address these issues, a novel AP-POSS was intercalated into GO-based membrane to construct a tuned interlayer structure and mass transfer characteristics. The aromatic ring structure of aminophenyl groups on AP-POSS act as hydrophobic side walls of the mass transfer channels between adjacent GO nanosheets, reducing the interaction between water molecules and channel structure. With an optimal amount of AP-POSS as an intercalator, the permeation flux of the prepared POSS-GO membrane could be improved by 30 wt% while maintaining nearly complete rejection of Congo Red (CR). Moreover, the prepared membrane exhibited enhanced structural stability, long-term stability, and a separation factor above 91.0 for CR/NaCl in binary solutions. Our study highlights the excellent performance of the POSS-GO membrane and demonstrates its potential application in dye/salt wastewater treatment.

Adroit effect of copper nanoparticles and copper nanozyme and their effective decolorization of azo dyes

Copper nanoparticles (CuNPs) have garnered considerable attention owed to their straightforward and cost-effective synthesis techniques, making them suitable for various applications across several fields. This paper describes a straightforward method for synthesizing CuNPs using the aqueous chemical reduction approach. A unique copper nanozyme (CNZ) is also prepared to degrade dyes. The nanoparticles were analyzed using various techniques to examine their morphological structure, optical properties, functional groups, and crystallite size via SEM, UV–visible spectrophotometry, FTIR, XRD, and zeta potential with particle size analyzer. SEM analysis showed that the CuNPs have a cubical form, with particle size fluctuating from 250 to 300 nm. The CNZ has a flower-like structure with a typical 100 to 150 nm size. The zeta potential of CuNPs is measured to be + 23.4 mV, indicating a high level of stability for the nanoparticles. The XRD evaluation showed that the CuNPs displayed a prominent peak at an angle of 36.64°, indicating a crystallite size of 26.97 nm. The CNZ displayed a peak at 31.18 nm, corresponding to a crystallite size of 44.84 nm. The capacity of CuNPs and CNZ to degrade a combination of dyes (Methyl orange, Methyl red, Congo red, Tropaeolin-O, and Tartrazine) was investigated. The innovative approach utilizing CNZ and CuNPs resulted in a degradation percentage of 84.61 % for mixed colors. Experimental findings have demonstrated that the combined effect of CuNPs and CNZ is remarkably effective in catalytically degrading azo dyes, making it a highly efficient method for treating effluents from the textile sector and wastewater treatment.

Investigating the efficiency of electrocoagulation using similar/dissimilar electrodes for the detoxification of Coralene Rubine dye: a cost effective approach.

Efficient treatment of textile dyeing wastewater can be achieved through electrocoagulation (EC) with minimal sludge production; however, the selection of the appropriate electrode is essential in lowering overall costs. Also, the reuse of the treated aqueous azo dye solution from this process has not been explored in detail. With these objectives, this study aims to treat synthetic azo dye solutions and achieve high colour removal efficiency (CRE%) using similar (Ti-Ti) and dissimilar (Ti-Cu) metal electrodes through EC with an attempt to reduce the cost. The aqueous Coralene Rubine GFL azo dye was used to examine the efficiency and cost of the EC process. X-Ray Photoelectron Spectroscopy was used to study the EC mechanism, while High Performance Liquid Chromatography was used to analyse the degradation of the dye and the formation of intermediate compounds. The concentration of metal ions in the treated dye solution was quantified using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), with Ti-Ti treated solution having 14.20mg/L concentration of Ti and Ti-Cu treated solution having 0.078mg/L of Ti and 0.001mg/L of Cu, respectively. Colour removal efficiency of 99.49% was obtained for both electrode sets, with a lower operating time and voltage for dissimilar metal combination. Ecotoxicity studies showed negligible toxicity of Ti-Cu treated dye samples compared to untreated solutions. Survival rate, protein estimation, and catalase activity was used to validate the treatment method's efficacy. The study found that the dissimilar electrode material exhibited reduced toxicity due to the presence of heavy metals below the permissible limit.

Salt-responsive polyamide thin-film nanocomposite membrane based on zwitterionic polymeric nanoparticles for high-efficient dye desalination

To simultaneously improve the water permeability, selectivity, and antifouling properties of polyamide nanofiltration (NF) membranes in textile wastewater treatment, we fabricated a salt-responsive thin-film nanocomposite (TFN) membrane with the incorporation of zwitterionic polymeric nanoparticles (ZNPs) into polyamide selective layer. Herein, the ZNPs were synthesized via an inverse miniemulsion polymerization with zwitterionic monomer, amino monomer, and cross-linker reagent. The salt-responsive property of ZNPs rendered their resultant membranes TFN-ZNPs with adjustable microstructure and separation performance via varying the sodium chloride (NaCl) concentration in water. The water permeance of TFN-ZNPs was enhanced to be 1.7 times that of its pure water permeance with the 10 g L−1 NaCl solution, and the salt-responsive behavior was reversible. Moreover, this salt-responsive property endowed the membrane with outstanding separation performance for the salt/dye or dye/dye mixtures. The selectivity of TFN-ZNPs to NaCl/congo red and methyl orange/neutral blue was enhanced to ∼104 and ∼127, respectively. The TFN-ZNPs with salt-responsive property also exhibited an improved antifouling performance, i.e., the flux recovery ratio was enhanced from 85.6 % to 96.5 % by washing with NaCl solution instead of deionized water. Thus, this work provided a paradigm shift in the fabrication of salt-responsive TFN membranes for the highly efficient separation of organic molecules and inorganic salts and wastewater treatment.

High antifouling graphene membranes with Fe2O3 nanoparticles in-situ intercalation for selective dye/salt separation

Effective organic dyes selective separation from high salinity textile wastewater consisting of inorganic salts and organic dyes is of great significant for the textile wastewater treatment. Graphene oxide (GO) have been used widely to form ultrathin high-permeance membrane for molecular and ionic sieving. However, swelling and membrane fouling of GO membrane hampered its practical applications. In this work, high stability and antifouling reduced graphene oxide (rGO) membranes were prepared, and Fe2O3 nanoparticles was used as intercalation to turn the membrane interlayer spacing. The rGO/2Fe2O3 nanocomposite blended membrane exhibited high permeance of 24.90 L m−2 h−1 bar−1, excellent organic dyes rejection (98.15 % and 98.69 % for methylene blue and Evans blue, respectively) and low salt retention (6.26 % for NaCl). Meanwhile, this membrane demonstrated a superior selective dye/salt separation factor up to 232 with a high rejection of 99.59 % to Evans blue and a lower salt rejection of 5.03 % to NaCl. Furthermore, nanofiltration experiments towards Evans blue/NaCl mixed solution indicated that the membrane also exhibited excellent antifouling performance with flux recovery rate of >86 % after six fouling/backwash cycles. Therefore, our work may provide a promising idea for the development of two-dimensional nanofiltration membranes for efficient high salinity textile wastewater treatment.

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.

Comparative life cycle assessment of sequential chemical and electrochemical processes for the treatment of industrial textile wastewater

AbstractFenton-based processes, chemical and electrochemical, have attracted the interest of industrial and academic researchers for wastewater treatment. However, the deficiency of rigorous comparison between different methods, including assessment of their impact on the environment, has hindered their large-scale application. This study reports for the first time on the sustainability of raw textile wastewater treatment through two sequential processes, Coagulation-Flocculation-Fenton-Neutralization (CF-F-N) and Coagulation-Flocculation-Electro-Fenton-Neutralization (CF-EF-N), based on Life Cycle Assessment (LCA) approach. The CF-F-N and CF-EF-N were optimized at laboratory scale and compared through LCA, using the IPCC-2013 and ReCiPe-2016 midpoint and endpoint methods. The highest CO2 emissions relied on the wastewater primary treatment by CF. This due to the high amount of hazardous sludge generated and the technology necessary for its disposal (i.e., 16.89 kg CO2-Eq/FU for underground deposit in security cells or 47.52 kg CO2-Eq/FU for incineration) as well as the consumption of reagents required for the treatment (alum, 7.72 kg CO2-Eq/FU; and slaked lime, 5.56 kg CO2-Eq/FU). Regarding the sequential processes, the EF-N presented lower carbon footprint (CFP) than the F-N (14.74 kg CO2-Eq/FU vs. 20.74 kg CO2-Eq/FU). Electricity (87.02% of the total CFP) and reagents (88.63% of the total CFP) denoted the main environmental hotspot during the EF-N and F-N, respectively. The EF-N, compared to the F-N, had an inferior incidence in 14 of the 18 impact categories analyzed using the ReCiPe-2016 method at the midpoint level. This is the result of low consumption of reagents and auxiliary chemicals. The electricity was also found as main environmental hotspot of the EF-N. The ReCiPe-2016 method at the endpoint level showed that the EF-N resulted in lower environmental load in all impact categories. The economic performance (11.91 USD/m3 for CF-EF-N vs. 13.66 USD/m3 for CF-F-N) and LCA demonstrated the competitiveness of the electrochemical sequential process compared to the chemical one. The CF-EF-N can be considered more environmentally sustainable technology.

Treatment of azo dye-containing wastewater in a combined UASB-EMBR system: Performance evaluation and membrane fouling study

This work investigated the treatment of azo dye-containing wastewater in an upflow anaerobic sludge blanket (UASB) reactor combined with an electro-membrane bioreactor (EMBR). Current densities of 20 A m−2 and electric current exposure mode of 6′ON/30′OFF were applied to compare the performance of the EMBR to a conventional membrane bioreactor (MBR). The results showed that dye (Drimaren Red CL-7B) removal occurred predominantly in the UASB reactor, which accounted for 57% of the total dye removal achieved by the combined system. When the MBR was assisted by electrocoagulation, the overall azo dye removal efficiency increased from 60.5 to 67.1%. Electrocoagulation batch tests revealed that higher decolorization rates could be obtained with a current density of 50 A m−2. Over the entire experimental period, the combined UASB-EMBR system exhibited excellent performance in terms of chemical oxygen demand (COD) and NH4+-N removal, with average efficiencies above 97%, while PO43--P was only consistently removed when the electrocoagulation was used. Likewise, a consistent reduction in the absorption spectrum of aromatic amines was observed when the MBR was electrochemically assisted. In addition to improving the pollutants removal, the use of electrocoagulation reduced the membrane fouling rate by 68% (0.25–0.08 kPa d−1), while requiring additional energy consumption and operational costs of 1.12 kWh m−3 and 0.32 USD m−3, respectively. Based on the results, it can be concluded that the combined UASB-EMBR system emerges as a promising technological approach for textile wastewater treatment.

Treatment of textile wastewater in a single‐step moving bed‐membrane bioreactor: Comparison with conventional membrane bioreactor in terms of performance and membrane fouling

AbstractMembrane bioreactor (MBR) is a promising technology for the treatment of municipal and industrial wastewater, including highly contaminated textile wastewater. However, membrane fouling remains a critical challenge due to reduced flux. This study investigates the efficacy of a moving bed MBR (MB‐MBR) technology for textile wastewater treatment, focusing on chemical oxygen demand (COD) removal, and its impact on mitigating membrane fouling. In a 50‐day study, a conventional MBR (R1) was compared with an MB‐MBR (R2) augmented with free‐floating biocarriers (accounting for 20% of the reactor volume). Both systems used flat sheet ceramic membrane modules. The results indicate that the MB‐MBR achieved superior performance, with COD and colour removal of 89% and 81%, respectively, compared with 87% and 73% in the conventional MBR. Importantly, the introduction of biocarriers eliminated the need for offline physical membrane cleaning in the MB‐MBR. The free‐floating biocarriers lowered transmembrane pressure, reduced capillary suction time and reduced fouling through their scouring action.

Algal-biochar and Chlorella vulgaris microalgae: a sustainable approach for textile wastewater treatment and biodiesel production

Microalgae technology is a viable solution for environmental conservation (carbon capture and wastewater treatment) and energy production. However, the nutrient cost, slow-kinetics, and low biosorption capacity of microalgae hindered its application. To overcome them, algal-biochar (BC) can be integrated with microalgae to treat textile wastewater (TWW) due to its low cost, its ability to rapidly adsorb pollutants, and its ability to serve as a nutrient source for microalgal-growth to capture CO2 and biodiesel production. Chlorella vulgaris (CV) and algal-BC were combined in this work to assess microalgal growth, carbon capture, TWW bioremediation, and biodiesel production. Results showed the highest optical density (3.70 ± 0.07 OD680), biomass productivity (42.31 ± 0.50 mg L−1 d−1), and dry weight biomass production (255.11 ± 6.01 mg L−1) in an integrated system of CV-BC-TWW by capturing atmospheric CO2 (77.57 ± 2.52 mg L−1 d−1). More than 99% bioremediation (removal of MB-pollutant, COD, nitrates, and phosphates) of TWW was achieved in CV-BC-TWW system due to biosorption and biodegradation processes. The addition of algal-BC and CV microalgae to TWW not only enhanced the algal growth but also increased the bioremediation of TWW and biodiesel content. The highest fatty acid methylesters (biodiesel) were also produced, up to 76.79 ± 2.01 mg g−1 from CV-BC-TWW cultivated-biomass. Biodiesel’s oxidative stability and low-temperature characteristics are enhanced by the presence of palmitoleic (C16:1) and linolenic (C18:3) acids. Hence, this study revealed that the integration of algal-biochar, as a biosorbent and source of nutrients, with living-microalgae offers an efficient, economical, and sustainable approach for microalgae growth, CO2 fixation, TWW treatment, and biodiesel production.Graphical

Assessment of Natural Bentonite Efficacy for Dye Removal in Textile Wastewater Treatment : Implication for Mitigating River Citarum Pollution

Textile industries contribute significantly to the economy but release harmful pollutants into the environment, especially rivers. The effluent from the textile industry contained toxic dyes that can harm the river ecosystem. Several studies have been conducted to reduce toxic dyes in a river system using bentonite as an adsorbent to reduce river pollution effectively. However, the effectiveness of bentonite still needs to be tested again using textile liquid waste that has not gone through any waste processing at all. Citarum is one of the main rivers on Java Island, which suffers from textile effluent, especially azo dyes which are toxic, mutagenic and carcinogenic which can harm the aquatic ecosystem. Therefore, this study aims to implement natural bentonite as an adsorbent to remove dyes from textile wastewater. We performed a laboratory test to adsorption on bentonite and textile wastewater considering the variation of adsorbent weight of 10 g and 20 g in 100 mL of textile wastewater stirred in an Erlenmeyer flask at room temperature for 0-300 minutes. The initial concentration of textile wastewater used was 10%, 30%, and 50%. We found that the maximum dye removal efficiency was 91.25% with 10% initial concentration treatment, 20 g adsorbent weight, and 60 minutes contact time. Longer contact time will increase the removal efficiency and adsorption capacity, while higher adsorbent dosage will decrease the concentration of dyes in wastewater. Efficient textile wastewater treatment has improved water quality, effectively meeting river water quality standards and environmental regulations.

Research on color treatment of industrial textile wastewater using synthesized inorganic bentonite composite as an adsorbent

Vietnamese bentonite with poor quality had been purified before being modified with iron salts to create inorganic bentonite composite (Ben-C). This process increased the specific surface area to 221.83 m2g−1. The test showed that the reactive dye was rapidly adsorbed in about 1 h by the Ben-C and the adsorption efficiency reached its maximum value at a Ben-C content of 3 g/L. Ben-C had been used as an adsorbent for 6 types of textile industrial wastewater. Companies used different kinds of dyes and additives, so the color adsorption time of each wastewater was also different, ranging from 0.25 to 2 h. Adsorption efficiency tended to increase with adsorbent content, but the increased level depended on the type of wastewater. Wastewater color treatment was more effective when the adsorption process was carried out at a low temperature, 20–25 °C. The FTIR spectrum of wastewater also evaluated the effectiveness of wastewater color removal.

Electrochemical degradation of small molecule dyes by TiO2-decorated polyacrylonitrile nanofiber membranes with superior properties

To optimize the uniform dispersion of nanoparticles and enhance their catalytic degradation effect on small molecule dyes in textile wastewater, titanium dioxide (TiO2) was deposited on polyacrylonitrile (PAN) fiber membranes using magnetron sputtering technology, and TiO2/PAN nanofiber membrane (NFM) with low content and high catalytic efficiency was successfully prepared. Through membrane separation coupling electrocatalysis, the composite membranes exhibited outstanding performance in removing Congo red (CR), Sunset yellow (SY), Methyl orange (MO), and Methylene blue (MB) dyes, with removal rates of 99.5%, 98.8%, 98.5%, and 87.2% respectively. Even after continuous catalysis for 10 h, the composite membranes maintained a high dye removal rate, demonstrating their remarkable stability and water treatment capabilities. Furthermore, TiO2/PAN NFMs displayed high pure water permeance, dye permeance, and mechanical strength. Specifically, M20 (magnetron sputtering time of 20 min) showed water permeance and dye (SY) permeance values of 1944 L·m−2·h−1·bar−1 and 816 L·m−2·h−1·bar−1, respectively, and indicate superior mechanical and electrochemical properties. During the electrocatalytic process, TiO2/PAN NFMs generated reactive oxygen species (ROS) on the surface, imparting a self-cleaning property that extended the service life of the membranes and offered an effective solution for textile wastewater treatment.

Constructing novel GO microcomposite membranes with β-CD based microporous nanosheets for efficient dye/salt separation

Graphene oxide (GO) membrane is considered as one of the preferred choice for textile wastewater treatment thanks to its unique 2D interlayer channel features. However, GO laminar stacking is inclined to water-induced structure instability, and the narrow interlayer spacing limit mass transport efficiency, hampering its effectiveness in water treatment applications. Herein, a layer-by-layer stacked microcomposite membrane based on GO and highly microporous β-cyclodextrin based nanosheets (β-CDNS) served as intercalator was developed. The distinctive layered structure was further stabilized by covalent cross-linking with glutaraldehyde (GA). The microporous β-CDNS offered additional nanochannels that facilitated the rapid penetration of water molecules, while the abundant -OH groups provided sites for chemical cross-linking, enhancing membrane stability. The optimal GO/β-CDNS1 membrane exhibited a superior water permeance of up to 83.5 LMH/bar, with >99 % rejection for dyes such as Congo red (CR), methyl blue (MB), and chrome black T (CBT), 95.5 % for acid fuchsin (AF). Meanwhile, the GO/β-CDNS1 membrane demonstrated ultra-low (<5 %) retention for inorganic salts (MgSO4, MgCl2 and NaCl), with a separation factor as high as 194 for MB/NaCl mixtures. Therefore, employing functional interlayer nano-additives to well regulate the GO interlayer structure offers a promising guideline for developing high-performance GO-based membranes.

Demonstration scale chemical–physical treatment and agricultural reuse of highly saline textile wastewater

AbstractThis study aimed to develop an energy‐efficient process for treating highly saline textile wastewater (TWW) in a 10 m3/day pilot plant and evaluate forage sorghum irrigation with treated wastewater in terms of crop production and soil and irrigation device performance. The TWW treatment pilot plant, consisting of a coagulation/flocculation unit followed by a sand filter and an anion exchange resin column, produced treated effluent that complied with the permissible limits specified in the ISO 16075‐2:2020 standard for Category C irrigation water. The corresponding average energy consumption was 1.77 kWh/m3. Reusing treated TWW for forage sorghum irrigation over a 13‐week cycle yielded crop performances comparable with freshwater irrigation, with no negative impact on the irrigation system. Although soil profiles were similar between treated TWW and freshwater irrigation, both soils featured an increase in electrical conductivity, which may reversibly or irreversibly affect soil quality and damage salt‐sensitive crops. These findings demonstrate the effective treatment and reuse of saline TWW for irrigating salt‐tolerant crops, offering significant implications for industrial wastewater management and cropping patterns in arid and semi‐arid regions.