Search Results (272)

In response to the increasing demand for environmentally friendly and cost-effective adsorbents in wastewater treatment, this study reports the green synthesis, characterization, and application of a magnetic epichlorohydrin Rosa canina (m-ECH-RC) nanocomposite for removing Safranin O (SO), a commonly used cationic dye in textile effluents. The synthesized material was characterized using Brunauer–Emmett–Teller (BET), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and zeta potential analyses to reveal its surface morphology, pore structure, functional groups, crystallinity, and colloidal stability. Adsorption performance was systematically tested under various conditions, including pH, adsorbent dose, contact time, ionic strength, and initial dye concentration. Kinetic analyses revealed that the adsorption process of Safranin O dye mainly obeys pseudo-second-order kinetics, but intraparticle and film diffusion also contribute to the process. As a result of the Isotherm analysis, it was found that the adsorption process conformed to the Langmuir model. Testing on real textile wastewater samples demonstrated a removal efficiency of 75.09% under optimized conditions. Reusability experiments further revealed that the material maintained high adsorption–desorption performance for up to five cycles, emphasizing its potential for practical use. These findings suggest that m-ECH-RC is a viable and sustainable adsorbent for treating dye-laden industrial effluents. Full article

Fungal laccases are promising oxidative enzymes for bioremediation applications, particularly in the degradation of synthetic dyes present in industrial effluents. Here, we evaluated the inhibitory effects of sodium chloride (NaCl) and sodium sulfate (Na₂SO₄) on the activity of Trametes versicolor laccase and its ability to decolorize Congo Red (CR), Malachite Green (MG), and Remazol Brilliant Blue R (RBBR). Enzyme assays revealed concentration-dependent inhibition, with IC₅₀ values of 0.22 ± 0.04 M for NaCl and 1.00 ± 0.09 M for Na₂SO₄, indicating stronger inhibition by chloride. Kinetic modeling showed mixed-type inhibition for both salts. Despite this effect, the enzyme maintained significant activity: after 12 h, decolorization efficiencies reached 95 ± 4.0% for MG, 88 ± 3.0% for RBBR, and 75 ± 3.0% for CR, even in the presence of 0.5 M salts. When applied to a mixture of the three dyes, decolorization decreased only slightly in saline medium (94.04 ± 4.0% to 83.43 ± 5.1%). FTIR spectra revealed minor structural changes, but toxicity assays confirmed marked detoxification, with radicle length in lettuce seeds increasing from 20–38 mm (untreated dyes) to 41–48 mm after enzymatic treatment. Fungal growth assays corroborated reduced toxicity of treated dyes. These findings demonstrate that T. versicolor laccase retains functional robustness under ionic stress, supporting its potential application in saline textile wastewater remediation. Full article

Membranes were assessed on a bench scale for their performance in methylene blue dye separation. The sawdust, along with Brazilian clay and kaolin, were mixed and compacted by uniaxial pressing and sintered at 650 °C. The membranes were characterized by several techniques, including X-ray diffraction, scanning electron microscopy, porosity, mechanical strength, water uptake, and membrane hydrodynamic permeability. The results demonstrated that the incorporation of sawdust not only altered the pore morphology but also significantly improved water permeation and dye removal efficiency. The ceramic membrane had an average pore diameter of 0.346–0.622 µm and porosities ranging from 40.85 to 42.96%. The membranes were applied to the microfiltration of synthetic effluent containing methylene blue (MB) and, additionally, subjected to investigation of their adsorptive capacity. All membrane variants showed high hydrophilicity (contact angles < 60°) and achieved MB rejection efficiencies higher than 96%, demonstrating their efficiency in treating dye-contaminated effluents. Batch adsorption using ceramic membranes (M0–M3) removed 34.0–41.2% of methylene blue. Adsorption behavior fitted both Langmuir and Freundlich models, indicating mixed mono- and multilayer mechanisms. FTIR confirmed electrostatic interactions, hydrogen bonding, and possible π–π interactions in dye retention. Full article

The aim of this study was to evaluate the treatment efficiency and applicability of using textile-based mats as roof biofilters on urban buildings for purifying preliminary treated wastewater (PTW) collected from a three-chamber septic tank. Therefore, a pilot plant with a 15° pitched wooden roof and two tracks for laying two mats made of different materials—polypropylene (PP), designated as Mat 1, and polyethylene terephthalate (PET), designated as Mat 2—was constructed at ground level under outdoor conditions. The plant was operated in parallel for a period of 455 days. Significant differences (p < 0.05) were observed in the results of the mass removal efficiencies between the two mats, with Mat 1 achieving mean removals of five-day biochemical oxygen demand (BOD₅), chemical oxygen demand (COD), ammonium-nitrogen (NH₄-N), and total nitrogen (TN) of 85%, 73%, 75%, and 38%, respectively, and Mat 2 achieving comparatively higher removals of 97%, 84%, 90%, and 57%, respectively. The mean concentrations of BOD₅ and COD at the outflow of both mats met the minimum water quality requirements for discharge and successfully met the minimum water quality class B for agricultural reuse. However, the comparatively low mean E. coli removal efficiencies of 2.0 and 2.4 log-units in Mat 1 and Mat 2, respectively, demonstrate the need for an effluent disinfection system. Highly efficient mass removal efficiencies were observed in the presence of dense vegetation on the mats, which may lead to a potential improvement in the urban climate through high daily evapotranspiration. Overall, this study demonstrates the potential for using lightweight, textile-based mats on rooftops to efficiently treat PTW from urban buildings, offering a promising decentralized wastewater management approach for climate-resilient cities. Full article

This study investigates the adsorption behavior of 4-methylbenzylidene camphor (4-MBC), a persistent ultraviolet filter, onto microplastic fibers (MPFs) released from domestic textiles, under environmentally relevant conditions. Two types of MPFs were used: MPF A, a heterogeneous blend of synthetic and natural fibers, and MPF B, a uniform polyester source. Adsorption experiments were conducted in municipal wastewater, Danube River surface water, and laundry effluent. Kinetic data best fit the pseudo-second-order model (R² > 0.95), and the Elovich model indicated chemisorption involving heterogeneous binding sites. MPF A exhibited superior adsorption capacities (qₑ = 85.4–90.1 µg/g) compared to MPF B (58.8–66.8 µg/g). Langmuir isotherms yielded maximum adsorption capacities of 204.9 µg/g for MPF A and 116.7 µg/g for MPF B (R² = 0.929–0.977), while D–R isotherm energies (12.0–21.7 kJ/mol) confirmed specific interactions, such as π–π stacking and hydrogen bonding. Adsorption efficiency was highest in municipal wastewater (total organic carbon—TOC = 13.12 mg/L, electrical conductivity—EC = 1152 µS/cm), followed by laundry and surface waters. These findings emphasize the critical role of polymer composition and matrix complexity in pollutant transport, suggesting MPFs are effective transporters of hydrophobic micropollutants in aquatic systems. Full article

Persistent reactive azo dyes released from textile finishing are a serious threat to water systems, but effective methods using sunlight to break them down are still limited. Everzol Yellow 3RS (EY-3RS) is particularly recalcitrant: past studies have relied almost exclusively on physical adsorption onto natural or modified clays and zeolites, and no photocatalytic pathway employing engineered nanomaterials has been documented to date. This study reports the synthesis, characterization, and performance of a visible-active ternary nanocomposite, Cu₄O₃/ZrO₂/TiO₂, prepared hydrothermally alongside its binary (Cu₄O₃/ZrO₂) and rutile TiO₂ counterparts. XRD, FT-IR, SEM-EDX, UV-Vis, and PL analyses confirm a heterostructured architecture with a narrowed optical bandgap of 2.91 eV, efficient charge separation, and a mesoporous nanosphere-in-matrix morphology. Photocatalytic tests conducted under midsummer sunlight reveal that the ternary catalyst removes 91.41% of 40 ppm EY-3RS within 100 min, markedly surpassing the binary catalyst (86.65%) and TiO₂ (81.48%). Activity trends persist across a wide range of operational variables, including dye concentrations (20–100 ppm), catalyst dosages (10–40 mg), pH levels (3–11), and irradiation times (up to 100 min). The material retains ≈ 93% of its initial efficiency after four consecutive cycles, evidencing good reusability. This work introduces the first nanophotocatalytic strategy for EY-3RS degradation and underscores the promise of multi-oxide heterojunctions for solar-driven remediation of colored effluents. Full article

Ozonation and ozone-based advanced oxidation processes, including ozone/hydrogen peroxide and ozone/ultraviolet irradiation, have been extensively studied for their efficacy in treating wastewater across various industries. While sectors such as pulp and paper, textile, food and beverage, microelectronics, and municipal wastewater have successfully implemented ozone at full scale, others have yet to fully embrace these technologies’ effectiveness. This review article examines recent publications from the past two decades, exploring novel applications of ozone-based technologies in treating wastewater from diverse sectors, including food and beverage, agriculture, aquaculture, textile, pulp and paper, oil and gas, medical and pharmaceutical manufacturing, pesticides, cosmetics, cigarettes, latex, cork manufacturing, semiconductors, and electroplating industries. The review underscores ozone’s broad applicability in degrading recalcitrant synthetic and natural organics, thereby reducing toxicity and enhancing biodegradability in industrial effluents. Additionally, ozone-based treatments prove highly effective in disinfecting pathogenic microorganisms present in these effluents. Continued research and application of these ozonation and ozone-based advanced oxidation processes hold promise for addressing environmental challenges and advancing sustainable wastewater management practices globally. Full article

Industrial wastewater management remains a critical barrier to achieving Sustainable Development Goal 6 (SDG 6) in many developing countries, where regulatory frameworks exist but affordable and scalable treatment solutions are lacking. In Pakistan, the textile sector is a leading polluter, with untreated effluents routinely discharged into rivers and agricultural lands despite stringent National Environmental Quality Standards (NEQS). This study presents a pilot-scale case from Faisalabad’s Khurrianwala industrial zone, where a decentralized, nature-based bioreactor was piloted to bridge the gap between policy and practice. The system integrates four treatment stages—anaerobic digestion (AD), floating treatment wetland (FTW), constructed wetland (CW), and sand filtration (SF)—and was further intensified via nutrient amendment, aeration, and bioaugmentation with three locally isolated bacterial strains (Acinetobacter junii NT-15, Pseudomonas indoloxydans NT-38, and Rhodococcus sp. NT-39). The fully intensified configuration achieved substantial reductions in total dissolved solids (TDS) (46%), total suspended solids (TSS) (51%), chemical oxygen demand (COD) (91%), biochemical oxygen demand (BOD) (94%), nutrients, nitrogen (N), and phosphorus (P) (86%), sulfate (26%), and chloride (41%). It also removed 95% iron (Fe), 87% cadmium (Cd), 57% lead (Pb), and 50% copper (Cu) from the effluent. The bacterial inoculants persist in the system and colonize the plant roots, contributing to stable bioremediation. The treated effluent met the national environmental quality standards (NEQS) discharge limits, confirming the system’s regulatory and ecological viability. This case study demonstrates how nature-based systems, when scientifically intensified, can deliver high-performance wastewater treatment in industrial zones with limited infrastructure—offering a replicable model for sustainable, SDG-aligned pollution control in the Global South. Full article

This study presents the development of a textile-based cascade filter for the removal of microplastics from an industrial laundry effluent. The cascade microfilter consists of three stages of 3D textile sandwich composite filter media, which have successively finer pores and are aimed at filtering microplastic particles down to 1.5 µm. Polypropylene fabrics with pore sizes of 100, 50 and 20 µm and 3D warp-knitted fabrics with high porosity (96%) were used. Filtration tests were carried out with polyethylene model microplastic particles at a concentration of 167 mg/L. To regenerate the filter and restore its filtration performance, backwashing with filtered water and compressed air was applied. Field trials at an industrial laundry facility and a municipal wastewater treatment plant confirmed high removal efficiencies. The 3D textile sandwich structure promotes filter cake formation, allowing extended backwash intervals and the effective recovery of filtration capacity between 89.7% and 98.5%. The innovative use of 3D textile composites enables a high level of microplastic removal while extending the filter media lifetime. This makes a significant contribution to the reduction in microplastic emissions in the aquatic environment. The system is scalable, space and cost efficient and adaptable to various industrial applications and is thus a promising solution for advanced wastewater treatment. Full article

Textile dyeing wastewater is one of the most challenging industrial effluents to treat due to its high concentrations of persistent organic compounds and nitrogenous substances. Conventional treatment methods often fall short in achieving both sufficient removal efficiency and environmental safety. In this study, we aimed to remove the total nitrogen (T-N) and total organic carbon (TOC) of dyeing wastewater from an industrial complex in D City, Korea, by applying bipolar and packed bipolar electrolysis using aluminum (Al) electrodes and activated carbon (AC). The system was operated for 60 min under varying conditions of applied voltage (5–15 V), electrolyte type and concentration (non-addition, NaCl 5 mM, NaCl 10 mM, Na₂SO₄ 5 mM, Na₂SO₄ 10 mM), and AC packing amount (non-addition or 100 g/L). The highest T-N and TOC removal efficiencies were observed at 15 V, reaching 69.53% and 63.68%, respectively. Electrolyte addition significantly improved initial treatment performance, with NaCl 10 mM showing the best results. However, Al leaching also increased, from 549.83 mg/L (non-addition) to 623.06 mg/L (NaCl 10 mM). When AC was used without electrolysis (control experiment), the T-N and TOC removal efficiencies were limited to 30.24% and 29.86%, respectively. In contrast, AC packing combined with 15 V electrolysis under non-addition achieved 86.04% T-N and 77.98% TOC removal, while also reducing Al leaching by 40.12%. These results suggested that electrochemical treatment with AC packing under non-addition conditions offers the best balance between high treatment efficiency and low environmental impact. These findings demonstrate that the synergistic use of packed activated carbon and electrochemical treatment under additive-free conditions can overcome the limitations of conventional methods. This study contributes to the development of more sustainable and effective technologies for treating high-strength industrial wastewater. Full article

To overcome the low efficiency, high cost and less environmentally friendly limitations in existing textile wastewater disposal technology, an innovative approach of cation exchange membrane electrolysis coupled with magnesium salt precipitation (CEM-MSP) was implemented. This method simultaneously achieved the high-efficiency adsorption decolorization of dyes and the recovery of lye. The results indicated that cation exchange membrane electrolysis with MgSO₄ added to the anode chamber (CEM-EA) exhibited excellent decolorization performance on DB86 dye and achieved low residual Mg²⁺ concentration. Furthermore, the adsorption mechanism of Mg(OH)₂ on DB86 was systematically investigated. The adsorption process fitted with the first-order kinetic, where the adsorption of DB86 by Mg(OH)₂ was dominated by electrostatic attraction. Detailed comparison of the four systems demonstrated that CEM-EA was superior to the single magnesium addition method (85.24%) or the stand-alone membrane electrolysis method (10.36%), with 99% decolorization efficiency. In comparison to the cation exchange membrane electrolysis with MgSO₄ added to the cathode chamber (CEM-EC), the CEM-EA could diminish the Mg²⁺ concentration in the effluent to facilitate the lye recovery while guaranteeing the decolorization efficiency. In addition, the DB86 adsorption behavior during the formation of Mg(OH)₂ in the cathode chamber was investigated. The Mg(OH)₂ particles were relatively dense copper-blue agglomerates with a thin lamellar layer on the surface. Notably, only slight mass contamination was observed on the cation exchange membrane (CEM) surface after multiple cycles. Minor CEM contamination illustrated the stable treatment efficiency of the CEM-EA after several cycles. This study constructed a novel approach integrating membrane electrolysis with magnesium salt precipitation, delivering valuable technical solutions for textile wastewater disposal. Full article

This study intended to examine and assess the performance of raw and treated Eriobotrya Japonica seed waste for the adsorption-based removal of methylene blue dye from an aqueous solution. The effects of several factors, including pH, adsorbent dose, and initial concentration, on the elimination of this dye were examined. To optimize the removal process, a Box-Behnken design (BBD) based on response surface methodology (RSM) was employed to evaluate the influence of key variables, adsorbent dose, initial dye concentration, and pH, along with their interactions. The findings demonstrated that the statistical analysis reveals a high significance of the dye for raw and treated Eriobotrya Japonica seed waste, with extremely weak probability values (p < 0.0001). The optimal conditions achieved were the adsorbent dose = 21.21 mg, initial dye concentration = 7.54 mg/L, and pH = 10.92 for the raw waste and adsorbent dosage = 21.75 mg, initial dye concentration = 7.5 mg/L, and pH = 11.7 for the extracted waste. These conditions result in a dye removal efficiency of 99.48% and 99.88% for raw and treated Eriobotrya Japonica seed waste, respectively. The methylene blue adsorption kinetics on the adsorbent can be precisely represented by an effective pseudo-second-order equation. The Freundlich model showed a significantly better fit to the experimental results compared to the Langmuir model. Full article

The environmental impacts of industrial processes have increased the demand for sustainable alternatives in wastewater treatment. Conventional chemical coagulants, though widely used, can generate toxic residues and pose environmental and health risks. Biocoagulants, derived from natural and renewable sources, offer a biodegradable and eco-friendly alternative. This review explores their potential to replace synthetic coagulants by analyzing their origins, mechanisms of action, and applications. A total of 15 studies published between 2020 and 2025 were analyzed, all focused on industrial wastewater. These studies demonstrated that biocoagulants can achieve similar, or the superior, removal of turbidity (>67%), solids (>83%), and heavy metals in effluents from food, textile, metallurgical, and paper industries. While raw materials are often inexpensive, processing costs may increase production expenses. However, life cycle assessments suggest long-term advantages due to reduced sludge and environmental impact. A textile industry case study showed a 25% sludge reduction and improved biodegradability using a plant-based biocoagulant compared to aluminum sulfate. Transforming this waste into inputs for wastewater treatment not only reduces negative impacts from disposal but also promotes integrated environmental management aligned with circular economy and cleaner production principles. The review concludes that biocoagulants constitute a viable and sustainable alternative for industrial wastewater treatment. Full article

This study examines the use of a1 mm-diameter tubular microreactor submerged in a temperature-controlled water bath to activate potassium persulfate (KPS) via thermal, Fe²⁺-catalyzed, and combined thermo-catalytic processes for degrading the persistent textile dye Safranin O (SO). The efficiency of these methods was evaluated under varying conditions, including KPS, dye, and Fe^2⁺ flow rates, solution pH, reactor length, and water matrix quality (deionized water, tap water, seawater, and secondary effluent from a wastewater treatment plant (SEWWTP)) across bath temperatures of 30–80 °C. Total organic carbon (TOC) analysis validated the results. Maximum dye conversion (up to 89%) occurred at 70 °C, with no improvement beyond this temperature, mainly due to radical-radical recombination. Longer reactors (2–6 m) enhanced conversion, though this effect diminished at higher temperatures due to efficient thermal activation. Increasing dye flow rates reduced removal efficiency, particularly above 50 °C, highlighting kinetic and mass transfer limitations. Persulfate flow rate increases improved conversion, but a plateau emerged at 80 °C. At lower temperatures (30–40 °C), Fe²⁺ addition significantly boosted SO conversion in deionized water. Between 40 and 50 °C, conversion rose from 30.27% (0 mM Fe²⁺) to 85.91% (0.2 mM Fe²⁺) at 50 °C. At higher temperatures (60–80 °C), conversion peaked at 70 °C for lower Fe²⁺ concentrations (100% for 0.01–0.05 mM Fe²⁺), but higher Fe²⁺ levels (0.1–0.2 mM) caused a decline above 60 °C, dropping to 68.44% for 0.2 mM Fe²⁺ at 80 °C. Deionized, tap, and mineral water showed similar performance, while river water, secondary effluent, and seawater inhibited SO conversion at lower temperatures (30–60 °C). At 70–80 °C, all matrices achieved efficiencies comparable to deionized water for both thermal and thermo-catalytic activation. The thermo-catalytic system achieved >50% TOC reduction, indicating significant organic matter mineralization. The results were comprehensively analyzed in relation to thermal and kinetic factors influencing the performance of continuous-flow reactors. Full article

The periodate/hydrogen peroxide (PI/H₂O₂) system is a recently developed advanced oxidation process (AOP) characterized by its rapid reaction kinetics, making it highly suitable for continuous-flow applications compared to conventional batch systems. Despite its potential, no prior studies have investigated its performance under flowing conditions. This work presents the first application of the PI/H₂O₂ process in a tubular microreactor, a promising technology for enhancing mass transfer and process efficiency. The degradation of textile dyes (specifically Basic Yellow 28 (BY28)) was systematically evaluated under various operating conditions, including reactant concentrations, flow rates, reactor length, and temperature. The results demonstrated that higher H₂O₂ flow rates, increased PI dosages, and moderate dye concentrations (25 µM) significantly improved degradation efficiency, achieving complete mineralization at 2 mM PI and H₂O₂ flow rates of 80–120 µL/s. Conversely, elevated temperatures negatively impacted the process performance. The influence of organic and inorganic constituents was also examined, revealing that surfactants (SDS, Triton X-100, Tween 20, and Tween 80) and organic compounds (sucrose and glucose) acted as strong hydroxyl radical scavengers, substantially inhibiting dye oxidation—particularly at higher concentrations, where nearly complete suppression was observed. Furthermore, the impact of water quality was assessed using different real matrices, including tap water, seawater, river water, and secondary effluents from a municipal wastewater treatment plant (SEWWTP). While tap water exhibited minimal inhibition, river water and SEWWTP significantly reduced process efficiency due to their high organic content competing with reactive oxygen species (ROS). Despite its high salt content, seawater remained a viable medium for dye degradation, suggesting that further optimization could enhance process performance in saline environments. Overall, this study highlights the feasibility of the PI/H₂O₂ process in continuous-flow microreactors and underscores the importance of considering competing organic and inorganic constituents in real wastewater applications. The findings provide valuable insights for optimizing AOPs in industrial and municipal wastewater treatment systems. Full article